Rex

A Human male clone of the acclaimed bounty hunter Jango Fett, Rex was born as a clone trooper with the designation CT-7567 around the year 32 BBY on the planet Kamino for service in the Grand Army of the Republic. Granted advanced growth by the Kaminoan cloners, he was part of one of the first batches of clone troopers, and his early life largely incorporated Kaminoan flash training. As was the case with other clones who became officers, the Kaminoans spotted his natural leadership abilities early on, and over the next decade, he was put through additional command training and intensive programmed learning to develop his skills. By 22 BBY, he had begun training as a squad leader.

That same year, CT-7567 served on the planet Geonosis in the opening battle of the Clone Wars, fighting on the side of the Galactic Republic against the native Geonosians and the Droid Army of the Confederacy of Independent Systems. He survived the First Battle of Geonosis and continued his Grand Army service in the resultant intergalactic conflict, swearing to defend all Republic citizens from harm as part of his oath of loyalty to the Republic state. He served with Jedi Generals on multiple occasions and learned to respect their abilities; in turn, Jedi officers came to rely on him. Thanks to his aggression on the battlefield, he earned a reputation as one of the Republic Military's best and toughest clone troopers. Such was his prowess and performance that he was withdrawn from his unit and was among the 100 clone officers recalled to Kamino to undergo specialized command training.

Under the hardened eye of Advanced Recon Commando Alpha, CT-7567 and his fellow soldiers endured grueling exercises to develop independent thought, improvisation, and individuality. The ARC program led CT-7567 to befriend another officer, Marshal Commander CC-2224. After Alpha rewarded their individualism by granting them proper names, CT-7567 and CC-2224 became known as Rex and Cody, respectively, with the former keeping the origins of his nickname to himself. Rex often found himself working with Cody, particularly in a number of dangerous campaigns. One example was the Battle of Tibrin, in which they tried and failed alongside several Jedi to oust a Separatist military presence from Tibrin. Although the battle was a crushing Republic defeat, Rex and Cody managed to survive.

Within several weeks of the First Battle of Geonosis, Rex, having become well respected by clones and Jedi officers alike, was given the rank of clone trooper captain. In addition, the Mandalorian veterans who trained clone officers on Kamino bestowed on him the battle honor of Mandalorian Jaig eyes, and he had the adornments emblazoned on his clone trooper armor's helmet. In the same year, a new elite unit was formed within the Grand Army: the 501st Legion, whose members' training surpassed even that of the lethal Advanced Recon Commandos. Rex was given command of the core group of the 501st Legion, with which he was tasked with patrolling the galaxy's lawless Outer Rim Territories. As part of his designated 501st detachment, Rex received his own troop detail—Torrent Company, which became based out of the GAR clone barracks on the Republic capital world of Coruscant. He and his men were placed under the overall command of Jedi General Anakin Skywalker, who accepted his officer's commission after being appointed as a Jedi Knight four weeks into the war.

As Skywalker's second-in-command, Rex learned much from his commanding officer, developing a certain friendship with him. He operated with Skywalker on the front lines, with the two frequently turning unconventional tactics into Republic victories. As Skywalker later recalled, Rex, as a rookie trooper, was initially eager to follow every order to the letter but became less wound tight with the passage of time. The 501st Legion garnered fame and veteran status under their leadership, and Supreme Chancellor Palpatine took notice of how Rex and his men adopted Skywalker's unorthodox strategies with repeated success. Under Palpatine's direction, the 501st grew into an amalgamation of clone units whose members underwent secret training and were moved across the galaxy's battlefields as the war effort required. Besides his friendship with Cody, Rex formed a working relationship with Denal, a fellow 501st member, and befriended Advanced Recon Force Sergeant Boomer. He also became acquainted with Cody's own Jedi General, Obi-Wan Kenobi. On one assignment, Rex and his battalion teamed up with a squad of elite Advanced Recon Commandos to attack a battle droid army that had captured a strategic city.

At some point during his service, while equipped with a JT-12 jetpack, Rex was along a pathway and encountered an A-DSD advanced dwarf spider droid, which he fired upon from the air. Shortly after the Battle of Skye, Rex and Cody were sent to the planet to collect the remains of the genetic terrorist Zeta Magnus, who was seemingly killed by Jedi Commander Halagad Ventor. However, the being slain by Ventor was merely a clone of the real Magnus. Rex and Cody escorted the two vast halves of the fallen terrorist on separate grav-stretchers, while other clone troopers loaded the remains of Magnus' lab-instruments and cloning tanks into a Republic gunship. During the battle, Obi-Wan Kenobi, Anakin Skywalker, and Ventor were betrayed by clone commandos of Tark Squad, who turned out to be Thyrsian mercenaries working for Magnus. Upon learning that, Rex remarked that Mandalorian-trained soldiers were more trustworthy than those trained by Thyrsians. He also advised Skywalker to start wearing a helmet upon noticing a fresh scar on his face.

Seven weeks into the war, Rex and Cody were dispatched with a Republic battle group under the command of Skywalker and Kenobi to liberate the planet Christophsis, which had fallen to the Confederacy and its Retail Caucus conglomerate. En route to Christophsis aboard a Venator-class Star Destroyer, Rex witnessed a holographic broadcast alongside Skywalker, Kenobi, and Cody in which General Whorm Loathsom, the leader of the enemy invasion, pressured the Christophsian populace into submitting to Separatist rule. After reaching the Christoph system, the Republic forces defeated Confederate Admiral Trench's naval blockade and established a base on the surface.

Skywalker and Kenobi then took a clone contingent led by Rex and Cody into the capital, Chaleydonia, more commonly known as Crystal City. Once there, the Jedi and clones prepared an ambush to offset the Confederacy's advantage in troop strength. They moved into a business complex with two north- and south-facing towers, from which they intended to intercept a Separatist droid battalion set to pass through the major plaza below. Rex and Skywalker stationed their men in the north tower's forty-sixth level, while that of the south tower housed the detail led by Kenobi, Cody, and Clone Sergeant Slick.

As the Separatist battalion commanded by the T-series tactical droid TJ-55 marched through the business complex's plaza, the troop column unexpectedly split in half. The Republic's strategy was thus compromised when numerous B1-Series battle droid squads ambushed Kenobi's men in the south tower. After signaling clone trooper pilot Hawk for an evacuation, Skywalker, Rex, and their men used their DC-15A blaster rifles' ascension cables to rappel over to the south tower. They avoided laser fire from the droid infantry below and arrived to reinforce Kenobi and Cody, who were holding out against overwhelming numbers. Once Kenobi temporarily impeded the droids' advance by Force-pushing a blaster cannon at them, the combined clone detachment took a turbolift to the roof for their evacuation. TJ-55 pursued them to the roof with more droid troops, and Rex, Cody, and the clones provided cover fire for Skywalker and Kenobi to cut through the droids. Hawk's LAAT/i gunship soon arrived, and Rex and his comrades escaped with TJ-55's cranial unit, which trooper Gus had pilfered.

Back at the base that night, Rex and Cody analyzed TJ-55's cranial unit in the command center under a robolobotomy, but they only confirmed that the Confederacy had been aware of their plan before the unit stopped processing. Upon being apprised of their clone officers' findings, Skywalker suggested that a security breach was the cause for the Separatists' acquisition of their strategy, but Kenobi went so far as to suspect that there was a spy among their men. Skywalker and Kenobi decided to investigate behind enemy lines, ordering Rex and Cody to keep their mission confidential and remain behind to apprehend the potential traitor.

Shortly after the Jedi departed, Cody was alarmed to find a Hush-98 comlink deliberately left activated on a nearby table with the troops' other equipment, indicating that someone had remotely eavesdropped on their conversation with the Jedi. Rex then noticed a figure in the hallway too far away to be identified: Sergeant Slick, who had become a spy for the Dark Acolyte Asajj Ventress and the Confederacy out of a grudge against the Jedi. Slick immediately broke into a run and ignored Rex's commands to halt, forcing Rex and Cody to pursue him through the base. Despite losing their target, the two officers were able to follow his path through the complex's hallways to the clones' mess hall, where they realized that the traitor was one of their own brethren.

Returning to the command center, Rex and Cody attempted to contact Skywalker and Kenobi but found that communications were being blocked, potentially by the spy in their camp. Rex resolved to use Skywalker's astromech droid, R2-D2, to check the station's outgoing transmission logs from the past few days. Musing through R2-D2's findings with a datapad, Rex traced an odd spike in wavelength interference to a computer terminal located in the barracks of Slick's platoon. Inferring that one of Slick's men was the spy, Rex and Cody decided to individually interrogate the platoon's members despite protest from Slick.

Though troopers Jester, Punch, Sketch, and Gus all passed interrogation with credible alibis, trooper Chopper was forced to reveal that he had broken war protocols by stealing battle droid fingers from the battlefield and stringing them into a necklace. While attempting to derail Chopper's trustworthiness, Slick inadvertently revealed his knowledge of the Jedi's mission—information he could only have obtained via the open comlink that Cody had found in the command center. When put on the spot, Slick attacked Cody and Chopper and promptly fled from the barracks, leaving his platoon charges, as well as Rex and Cody, shocked with the revelation of the sergeant's true allegiances.

Rex and Cody immediately gave chase to the exposed Slick, tracing a signal from his utility belt to the gunship landing platform. Instead of Slick, they found his utility belt attached to a primed thermal detonator, and they scrambled for cover just before the explosive triggered a series of others. The resulting explosion decimated the landing platform and the weapons supply depot, as well as the base's power generators. Upon learning from Gus and Chopper that Slick had been spotted running into the command center, Rex headed with Cody to apprehend the saboteur, leaving Slick's platoon and the other troops to seal the perimeter. In the command center, Rex and Cody noticed that Slick was hiding in the above ventilation shaft and engaged in a ploy to bait him out of his hiding place. While Cody secretly removed the ammunition from his DC-15S and left the weapon on the holotable console, Rex appeared to leave for the south exit to restart the base's power generators. Once the blast doors had closed behind him, he reentered the room and assisted Cody in confronting Slick, who had forsook his cover to steal Cody's empty blaster. Although held at blasterpoint, Slick refused to surrender, grabbing Rex's DC-15S and bowling him over.

In the ensuing brawl, Cody and Slick disarmed each other and engaged in unarmed combat. When Rex joined in, he received a blow to the head, and Slick knocked him to the floor and used the "groin popper" maneuver to dislocate his leg. Nevertheless, Cody swiftly knocked out Slick, and the enemy agent was detained and locked in handcuffs. When Skywalker and Kenobi returned, Rex and Cody presented them with Slick, who, no longer comatose, attempted to justify his actions with his hatred for the Jedi. Slick's accusations elicited rebuttals from his clone officers, who countered that his exploits had endangered the lives of the clone brothers he claimed to love. Once Slick had been ushered away to lockup, Rex and Cody reported the sabotage of the weapons depot to Skywalker and Kenobi, who replied that they had discovered the full strength of the on-world Separatist invasion force, numbering close to a thousand units.

Whorm Loathsom soon launched his first assault on the Republic forces, which became based out of Crystal City. After several days of battle, the Jedi and clones were able to beat back the Separatists, forcing them into retreat for the time being. Rex took advantage of the lapse in fighting to shave his hair and review casualty reports on his datapad near the Republic's temporary forward aid station. He conferred and joked there with the medic on duty, Clone Sergeant Coric, as well as trooper Ged, who was being treated for a shoulder injury. The moment the Confederate forces initiated another attack, Rex grabbed his rifle and joined Skywalker and Kenobi in the streets. While Cody assisted Kenobi in marshaling a defense of their base, Rex took a clone platoon to accompany Skywalker along a route parallel to the city's main street.

As the clones made their way behind enemy lines, Rex recalled how the antebellum Crystal City had been glittering with beauty just days prior until the fighting crippled the city. He followed Skywalker and the rest of their men, including Coric and a patched-up Ged, to an energy sphere tower, where they divided their troops. While most of the platoon was tasked with targeting the street-level droids, Rex and Skywalker took several troopers to the roof to surprise a trio of advancing octuptarra magna tri-droids from above. Rex and his men used JT-12 jetpacks to reach the street below, while Skywalker landed on one of the tri-droids himself.

Rex and his comrades' combined efforts brought down the three droids, and they turned their attention to the droid infantry's exposed rear flank, pressing on without haste. Once Loathsom and his droid army had been driven into another retreat, a Republic Nu-class attack shuttle landed in Crystal City's Central Plaza. Although Kenobi believed that his new Padawan learner was on board, he and Skywalker found that instead of delivering some expected reinforcements, the shuttle had brought the young Padawan Ahsoka Tano, who had been apprenticed not to Kenobi, but to Skywalker. Rex was introduced to Tano at the base's observation post and was surprised to meet the new Padawan, as Skywalker had previously sworn never to take a Padawan. Rex could not help but chuckle when Tano nicknamed her new Master "Skyguy," but Skywalker, annoyed with her hubris and arrogant behavior, told his captain to give her an "acquaint of the position" while taking her on his inspection rounds of Central Plaza's lookout points. Rex complied and ushered Tano away to confer with her privately.

Harnessing various elements of his training, Rex helped Tano to better understand her role as a commander in the Grand Army, and they were able to reach an understanding of each other—although Tano was still eager to prove that she was ready to be Skywalker's apprentice, she learned to be more appropriate and respectful to her superiors. While near the Republic's setup of AV-7 Antivehicle Cannons, Tano noticed that the Confederacy was deploying a deflector shield, a development that alarmed Rex, who knew that such a shield would render the Republic's artillery useless. Both of them joined Skywalker and Kenobi at the comm station to devise a tactic to repel the imminent Separatist counterattack.

The group decided that Skywalker would take his Padawan behind enemy lines to eliminate the shield generator, while Rex and Kenobi would engage the droids to stall for time. After Skywalker and Tano departed, Rex and Kenobi attempted to use the heavy cannons against the enemy's expanding shield but only confirmed that they were indeed useless. Using an unencrypted comlink channel to appear more convincing to the Separatists, Rex ordered the clone forces to fall back before switching back to a secure channel. Via eavesdropping on Confederate voice traffic, he learned that Loathsom had ordered his infantry to target the heavy cannons, which had impeded his troops earlier in the battle but were now ineffectual and vulnerable.

As soon as the deflector shield passed over them, Kenobi led a forward charge on Loathsom's front lines, while Rex and his men lured the droids into the buildings along the main street. When the droids fired a missile at the comm post that Rex was using as cover, the explosion winded him and knocked him to the ground. After being forced to pull back his men, he met with Kenobi at the command center. Although Rex proposed that they use the heavy cannons in spite of the shield, which would cause fatal overpressure and result in severe collateral damage, Kenobi instead ordered him to mobilize a defense of the cannons while the Jedi Master delayed the droids. Despite his reluctance to leave Kenobi to fend for himself, Rex obeyed orders and retreated while Kenobi confronted the oncoming droids. As the shield approached the heavy cannons, Rex, Coric, and their men countered the advancing droids' fire from some rubble near the main street. Rex soon learned that Kenobi had surrendered to Loathsom, but he deduced that the Jedi General was simply stalling and rallied his men to hold the line.

As Rex and his men withstood the onslaught from the droids' overwhelming numbers, Skywalker and Tano eliminated the shield generator. Rex was aiming at a Kerkoiden tank commander when he caught a glimpse of the receding shield, and he killed the enemy officer out of sheer relief at the sight. He quickly ordered the heavy cannons to commence firing on the exposed Separatists and their Armored Assault Tanks, to great effect. With Republic Admiral Wullf Yularen and Jedi Grand Master Yoda arriving with reinforcements to complete the process of securing Christophsis, Rex allowed himself to breathe and personally feel the deaths of his men, acknowledging the pain that came with losing them. Although LAAT/i gunships flew in and began to bombard the nearby droid lines, he braved the incoming fire to help Coric search through the debris for two surviving troopers whom they had located via their helmets' heads-up displays. Rex later took a gunship to pick up Skywalker and Tano from the shield generator site, then returned with them to the command base in Crystal City. During the flight back, he congratulated Skywalker and Tano on their successful mission—making a point to commend the young Tano, who was slowly earning his respect.

Following the victory on Christophsis, Skywalker and Tano were assigned to rescue Rotta, the son of the Hutt crime lord Jabba Desilijic Tiure, from enemy kidnappers. Their orders came as part of the Republic's overall effort to convince Jabba to grant the Grand Army access to hyperspace lanes running through Hutt-controlled space. Rex and Torrent Company accompanied the two Jedi to the planet Teth—where Republic Advanced Recon Force trooper scouts had tracked the Huttlet—in an Acclamator-class transport. Because the clifftop monastery where Rotta was being held was a half-mile off the ground and was being guarded by a detachment of battle droids, Skywalker elected to launch a vertical assault up the cliff face to reach the monastery. LAAT/i gunships ferried Torrent Company to the surface, and LAAT carriers brought a pair of AT-TE walkers along as extra support. When the monastery's droid defenders opened fire on the approaching craft, Clone Lieutenant Hawk—the pilot of the gunship carrying Skywalker, Tano, Rex, and their men—closed the gunship's blast shields to deflect the incoming fire. The gunships landed in the forest below the cliff, and the AT-TEs returned fire at the droids, providing cover for the Jedi and clones to take refuge in an overhang.

Rex soon sighted an object falling from the cliff, and what he initially believed was an explosive device turned out to be a fallen battle droid. Following Skywalker and Tano's lead, the men of Torrent Company employed their blasters' ascension cables to scale the cliff, with Rex using his rappel line to ascend it. As a vertical crossfire commenced, the droid cannonades felled one of the AT-TE walkers, severing its grip on the cliff. Rex watched in horror as the AT-TE plummeted to the ground, taking all of the troops beneath along with it. When B1 battle droids on Single Trooper Aerial Platforms flew in to attack the clones in mid-climb, Rex trained his blasterfire at the airborne droids before Skywalker eliminated them. Torrent Company reached the monastery and destroyed the remainder of the droid infantry, albeit at the loss of half of its men. Upon arrival at the summit, Rex called in a gunship to casevac their fifteen wounded troopers, assigning several men to look after them in the meantime. He and Skywalker deduced from the heavy droid presence that the Separatists were the Huttlet's captors.

Leaving most of the men outside in the event of another assault, Rex took Sergeant Coric and troopers Lunn, Vaize, and Ayar to help Skywalker and Tano scour the monastery for the missing Huttlet. Entering the dimly lit castle, Rex and his men activated their helmet's headlights for better vision. Inside, the protocol droid 4A-7, claiming to be the monastery's caretaker, greeted and thanked them for liberating him from the battle droids. Learning from the protocol droid that the Separatists had kept their prisoners on the detention level, Skywalker and Tano proceeded there to rescue the Huttlet while Rex and his men stayed behind to guard the entrance. Though unable to confirm his suspicions, Rex correctly suspected that 4A-7 was not what he appeared to be—the droid was aiding the Dark Acolyte Asajj Ventress as part of a Separatist plot to frame the Republic and the Jedi Order for Rotta's kidnapping. Rex returned to the monastery courtyard and finished securing the castle with his troops. As midday approached, he learned from Skywalker that Rotta had been found and sent Coric to help transport the Huttlet with a backpack. Upon their return, Skywalker and Tano prepared to leave Teth with Rotta aboard a gunship that Rex had on standby for them. However, Tano's discovery that the Huttlet was ill halted their preparations for an evacuation and forced them to consider another solution.

While Skywalker and Tano were delivering a status report to Kenobi through R2-D2's holoprojector link, a pair of Confederate C-9979 landing craft approached the monastery and deployed Vulture droid starfighters and ground troops. With battle droids invading the courtyard, Rex and Skywalker mobilized Torrent Company to defend their position while Tano returned inside with Rotta. After briefly conferring with Skywalker on the weak chances of getting Tano and Rotta safely off-planet, Rex dispatched Sergeants Coric and Hez and their squads to provide covering fire for the rest of the company. Their remaining AT-TE walker was shot down, and Torrent Company began to take heavy losses. Rex joined his men in retreating into the monastery, and with everyone else inside, Skywalker ordered his captain to shut the entrance door. He initially refused, as Skywalker would be locked outside with the droids, but when his general tersely repeated the order, he complied and fired a blaster round at the controls. Skywalker used the Force to propel himself through the closing gap and into the entrance chamber, sealing all of them inside. With three-quarters of their men dead, several wounded, and only three medic-trained troopers remaining, Tano convinced her Master that it was best to find medical attention for the sick Rotta. Skywalker and his Padawan left with R2-D2 to escape from the castle while Rex remained with Torrent Company to hold their position.

Rex and his men braced themselves as the Separatist battalion—under the command of Asajj Ventress—disabled the door's lock mechanism, allowing B1, B2, and DSD1 dwarf spider droids to flood into the stronghold in overwhelming numbers. Rex watched as his men fell to enemy fire one by one before being knocked to the ground himself. Feigning death, he secretly contacted his surviving comrades through their private comm frequency and learned that only five of his men, including Coric, remained. As Ventress entered the antechamber and gave orders to an OOM command battle droid, Rex destroyed the droid with one of his DC-17 hand blasters and then targeted the Dark Acolyte. However, Ventress immediately drew her double-bladed lightsabers and deflected his laser shots. She telekinetically disarmed him of his blaster pistol and Force-choked him, demanding that he reveal Skywalker's whereabouts. Having been trained in mental resistance, Rex kept repeating his name, rank, trooper designation, and battle group to avoid succumbing to her influence. She finally gave up her interrogation and, after dropping the defiant Rex to the floor, performed a mind trick, ordering him to contact Skywalker and ask for his general's location.

Rex resisted Ventress's influence and commed Skywalker of his own accord, using a false voice and addressing him as "Anakin" instead of his usual "General Skywalker" to allude to Ventress's presence. Unaware of his exploit, Ventress threw him aside and departed to personally confront Skywalker, tasking her battle droids with guarding the survivors of Torrent Company. Though he suspected that his ribs had been broken, Rex mimicked unconsciousness to avoid attracting the droids' attention. He repeatedly checked in with his men over their private frequency, keeping them prepared to mount a last stand. Skywalker soon made contact via comlink, and because Rex had forgotten to divert the signal to his helmet, the battle droids overheard the device. As the enemy units converged on him, he destroyed several of the droids closest to him and stole an E-5 blaster rifle from one of them. Moving as one, the other 501st survivors—Coric, Nax, Zeer, Del, and Attie—sprang to their feet and also attacked their captors, pilfering blasters for themselves. Using the fallen AT-TE as cover, they engaged the droids in a crossfire. Rex took a painkiller from his utility belt medpac before reporting their situation to Skywalker. Eventually, Zeer planted explosives in an eviscerated super battle droid and detonated the unit once it had been sent back into the Confederate lines. The trap droid destroyed many of its comrades, but only a few minutes elapsed before the droids regrouped to resume their attack.

Rex and his comrades were able to bring down an advancing Vulture droid starfighter, using it as cover to combat the droids at a closer proximity. Nevertheless, the clone troopers were seriously outnumbered, and the battle droids demanded their surrender. At that moment, Obi-Wan Kenobi arrived at Teth with Commander Cody, the 212th Attack Battalion, and an armada under the command of Wullf Yularen. Leading an aerial assault on the droids, Kenobi jumped out of his Delta-7B starfighter to assist Rex and the other Torrent Company survivors while LAAT/i gunships deployed Cody and his men. Learning from Rex that Skywalker was most likely still in the stronghold, Kenobi left to find his fellow Jedi General. Eventually, Skywalker—having found and commandeered the Twilight, an old spice freighter, with Tano and Rotta—contacted Rex, reluctantly telling him that they would be unable to give support since returning Rotta to his father on Tatooine was still their priority. Rex understood his general's dilemma and replied that he and his men would be able to hold out thanks to Kenobi's aid. Under covering fire from his men, Rex charged at an advancing dwarf spider droid and planted a primed thermal detonator on it, jumping away in time to avoid the explosion that engulfed it.

As Rex and his men cut through the battle droids, Kenobi returned from a duel with Ventress. Rex voiced his doubt that Skywalker and Tano would be able to reach Tatooine in their dilapidated freighter, but Kenobi was confident that Skywalker's expertise at a starship's controls would prove adequate. After the Republic finally emerged victorious on Teth, Rex conferred with Cody amidst the settling dust, venting his frustration with the poorly handled operation. Although Rex was still devastated with the loss of Torrent Company, his friend stated that their efforts had not been in vain, as Skywalker and Tano had reached Tatooine with Rotta. The two clone officers accompanied Masters Yoda and Kenobi to Jabba's Palace on Tatooine to retrieve Skywalker and Tano, who had returned Rotta to his father and established a treaty with the Hutts for Grand Army access through Hutt Space. Upon meeting with Rex, Skywalker and Tano wanted to hear all the details of the battle's end, of the men who had won and paid the ultimate price for the victory. Despite his distress, Rex agreed to recount it to them. Though Torrent Company was replenished with new troops, the defeat of the original unit stayed with Rex for a long time.

As warfare continued to devastate the galaxy, the Confederate Navy, outnumbering the Republic Navy fourfold, put the Republic's war effort at a supreme disadvantage. With the likelihood of being prematurely defeated in the war, the Jedi High Council decided to impair Separatist starship production by targeting the InterGalactic Banking Clan's Confederate-allied Gwori shipyards. Because the shipyards' exact location on Gwori's planetary surface had yet to be determined, the task of pinpointing it fell to Rex, Skywalker, and Kenobi. To penetrate Gwori's defenses—namely, a droid-operated blockade and a radiation beam that eradicated all life forms bound for the planet—Skywalker chalked out a plan for a small strike force to be temporarily frozen in carbonite. R2-D2, whose presence would not cause much suspicion to the blockade's droid security, would then pilot the team to Gwori. After locating the shipyards, they would relay the coordinates to Generals Plo Koon and Saesee Tiin, who would eliminate the facility with a Republic squadron. Initiating preparations on Coruscant, Rex gathered a clone squad at carbonite freezing plant CT-642, where Skywalker assured his captain that they would not be frozen long enough for hibernation sickness to take effect. Rex and his men, along with Skywalker and Kenobi, were encased in carbonite with the addition of Tano, who had been ordered not to participate in the mission but nonetheless manipulated Admiral Yularen to grant her clearance.

Rex and the strike team proceeded to Gwori aboard the freighter VX-391, with R2-D2 at the controls. When the blockade's battle droids discovered that the ship was unregistered, R2-D2 was forced to release the task force and jettison from the vessel just before the battle droids shot down the freighter. The astromech droid freed Tano from her carbonite slab, and she in turn released Rex and the others. Once they had found the enemy facility, Skywalker and Kenobi sent Rex, Tano, R2-D2, and two other clone troopers to contact Koon and Tiin from a nearby communication tower. After the group broke into the station, Tano transmitted the shipyards' coordinates to Koon, Tiin, and Yularen, who were waiting in the Moskk system. Before Rex and his comrades could arrange to be evacuated from Gwori, the transmission was cut off when the shipyards' supervisor, Overseer Juhm, contacted the station and discovered the presence of the Republic strike team. Rex, Tano, and their men managed to flee with R2-D2 just before Juhm remotely destroyed the station, and Tano relayed the developments to Skywalker and Kenobi. While their superiors infiltrated the shipyards, Rex, Tano, and their team went to find cover on Gwori's plains, where a squad of jetpack-equipped B2-RP battle droids attacked them.

After escaping from the droids, Rex and his comrades took refuge in a cave that they soon found was the current residence of a large lizard-like creature, which killed one of the clones before Tano could eliminate it. As time passed, the extended lack of communication from Skywalker and Kenobi led Tano to conclude that their commanders were in trouble. She decided that it was time to "alter" Skywalker's orders of staying concealed, and though Rex voiced some doubt, he left the cave with Tano and the other trooper. However, Juhm was waiting for them just outside with a squad of B2 super battle droids and killed their clone companion on sight. Presented with the choice of capitulating or being immediately gunned down, Rex and Tano decided to comply with Juhm's demands and were taken away, leaving R2-D2 back in the cave. As night fell, Juhm had Rex and Tano attached to electrically charged frames alongside Skywalker and Kenobi, who had been captured at the shipyards. Before departing, Juhm left a trio of IG-100 MagnaGuards to guard them from a horde of local spiders, his intent being to let them survive as a reminder to the shipyards' slaves of his absolute superiority. Although the four were tortured and electrocuted in turn, Rex grudgingly expressed his gratitude for the MagnaGuards' protection from the spiders.

In an attempt to free themselves, Skywalker, Tano, and Kenobi used the Force to destroy the MagnaGuards, and R2-D2 arrived and cut them and Rex from their frames before the spiders could attack. The team proceeded to the shipyards and convinced Juhm's slaves, who numbered over a thousand, to emancipate themselves from their servitude. At dawn the next day, Rex, Skywalker, Tano, and Kenobi stole one of the shipyards' near-completed Munificent-class star frigates and escaped aboard it with the ex-slaves, just as Koon and Tiin arrived with their team of bombers. Koon and Tiin led the BTL-B Y-wing starfighters of Hunter Squadron on their strike on the Banking Clan facility, dropping their munitions on the site. Skywalker, meanwhile, used their frigate's tractor beam to retrieve trooper Toomer, who had been left behind at the drop zone when his carbonite slab's controls malfunctioned, and headed for the Separatist blockade. However, the battle droids overseeing the blockade detected the multitude of life forms aboard the stolen frigate, and at Juhm's behest, they activated the radiation beam. Before the beam could vaporize Rex and the other passengers, Koon and Tiin intervened, disabling the scan gate that was projecting the beam. The two Jedi Masters hitched a ride on the vessel, as their hyperdrive booster rings had been destroyed, and they left the Gwori system for Coruscant, where Juhm's ex-slaves found employment with the Republic. Once Toomer had been freed from his carbonite, Rex reassured the disappointed trooper that there would be more fighting to come.

Rex was stationed with Skywalker, Tano, and Admiral Yularen aboard Skywalker's flagship, the Venator-class Star Destroyer Resolute, when it was deployed to the Bith system during the emerging threat of a new Separatist superweapon. After the enemy weapon executed a devastating assault on Plo Koon's forces in the nearby Abregado system, the Resolute was reassigned to protect the Republic's supply convoys alongside Kenobi; his flagship, the Negotiator; and the rest of their fleet. Skywalker thereafter divided his armada to increase their defensive perimeter and departed with Tano to scout ahead for enemy activity. Rex was present on the Resolutes bridge with Yularen when Kenobi contacted them to check on their progress as well as Skywalker's whereabouts. Yularen reported that the convoys were on schedule and also informed Kenobi of Skywalker's orders. Skywalker and Tano soon discovered that the Separatist superweapon was the Malevolence, a powerful Subjugator-class heavy cruiser that was equipped with an ion pulse cannon. Rex later reviewed the file on the Abregado incident, hoping that it would give him an edge in future battles against the Separatists. The Resolute was again reassigned, this time to join a Republic naval strike on the Malevolence near the Kaliida Nebula. The ensuing Battle of the Kaliida Nebula saw the battleship eradicated, its threat to the Republic ended.

Rex and Commander Cody were next assigned to inspect several small but integral Republic bases and listening posts. Their first inspection site was a tracking station in the Pastil system. Upon arrival on Pastil aboard Rex's Nu-class attack shuttle, the Obex, Rex began assessing the outpost with Cody and commented on the station's extreme cleanliness. Trooper Stripe informed them that an MSE-series droid nicknamed "Rodent" maintained the base, mentioning that the droid had a glitch and spent hours cleaning the outpost. Recognizing the droid's characteristics as those of a spy droid, Rex called out a Code Aurek alert and ordered the facility's troopers to track down Rodent. The rookie clones were unaware of Rex's suspicions and initially thought he was crazy, but when Rex found the droid and blasted its body, the droid's wheels activated of their own accord and fled, a feature uncommon in regular MSE droids. The troopers eliminated three of the wheels, and when the fourth made for a grate, Stripe destroyed it with a thermal detonator; the resulting explosion caused a significant amount of damage to the hallway. Amused with Stripe's solution, Rex told the troops to clean up the mess before leaving the station with Cody.

After Cody reported their successful inspection to Skywalker and Kenobi, who were aboard the Resolute, he and Rex proceeded to Rishi Station, an outpost in the Outer Rim's Rishi system. They were unaware that Confederate BX-series droid commandos had just overrun the base. When Cody contacted Rishi Station for landing authorization, a droid commando posing as a clone trooper answered the transmission. Hearing the trooper's droid-like responses, Rex sensed that something was amiss but continued with Cody to the moon where the outpost was located, with Cody placing him in charge of the inspection. Upon landing at the station, Rex noted the absence of an on-duty deck officer, remarking that such an error was sloppy. A droid commando disguised in clone armor came out to greet Rex and Cody. When Rex caught sight of a droid attack flare launched from close by, he promptly shot the "trooper" who had greeted them in the head. At first, Cody was shocked with his brazen behavior, but Rex removed his victim's helmet to unmask the disabled droid.

More droid commandos appeared and ambushed Rex and Cody, who exchanged fire with them while using some of the surrounding crates as cover. The droids tossed a series of thermal detonators at the Obex, forcing the two officers to jump off the landing platform. They fired their blaster cables at the underside of the platform and rappelled to the ground below; the droids, meanwhile, presumed that the explosion had claimed their lives. With the Obex destroyed, Rex and Cody mused over being stranded on the Rishi moon, recalling their similar situation on Tibrin. They came across the three survivors of the droid assault—Hevy, Fives, and Echo, who had also launched the warning flare—and Rex ordered them to take off their helmets to verify that they were clones. After the three did so, a predatory Rishi eel emerged from a nearby crevice; Rex impressed the three rookie troopers by expertly killing the eel with a single blaster shot to its eye. Once they introduced themselves, Rex and Cody learned from Echo that their sergeant had died in the initial attack. Dubbing Echo, Hevy, and Fives "shinies," a derogatory term for their as-yet-unspoiled armor, Rex placed a handprint of blood from the eel's carcass on Echo's armor to commemorate his valor.

When Hevy expressed the rookies' shared desire to recover their outpost regardless of their inexperience, Rex stated that there was hope for them yet. The five troopers climbed up the canyon wall to Rishi Station, with Rex and Cody offering the carbines of their DC-15S blasters to the rookie troopers. Rex devised a plan to gain access to the enemy-held base, posing as Commando Unit 26 in clone armor and mechanically walking toward the blast doors' surveillance systems. He conferred with Droid Units 07, 08, and 09, who were guarding the entrance from inside. He maintained his cover by pretending to adjust his "vocabulator" and using an inert droid head as visual verification of his identity. Although Cody doubted the tactic would work, the droids admitted Rex entry, and he and the others gunned down the guards with celerity. Taking point despite Hevy's request for the lead position, Rex led the assault on the droids in the command center. He gunned down several of the droid commandos manning the central computer before the droid commando captain targeted him from atop a perch on a higher level. Rex blasted the droid's blaster out of his hand, which only caused his opponent to draw a vibroblade, but he quickly snapped the droid's neck with his gloved hands.

Though Rex and the others triumphed over the droid commandos, their victory was short-lived. The group of five discovered that a Separatist fleet—led by General Grievous—was passing over the moon, and they deduced that the droids had hot-wired the station's all-clear signal to prevent the Republic from learning of the impending invasion. To investigate the lack of response from the droid commandos, Grievous dispatched a C-9979 troopship, which landed at the base and deployed droid infantry reinforcements. As Cody noted their slim chances of success, Rex decided that they had to destroy Rishi Station: Despite the plan's lack of convention, the subsequent cessation of the all-clear signal would alert the Republic to the invasion. Echo contributed to Rex's plan, offering that they could repurpose the station's supply of liquid Tibanna gas as explosives to raze the facility. Before setting the operation into motion, Rex and Cody spoke with Echo, Fives, and Hevy to prepare them for the forthcoming battle. Rex stated that the Confederacy's main target could only be Kamino and cited its personal importance to the clones, rallying the rookie troopers with the knowledge that they were fighting for all of their brethren back home on Kamino.

While Cody, Hevy, and Fives confronted the battle droids at the entrance, Rex and Echo ushered several PLNK-series power droids, or "plunk droids," containing the liquid Tibanna into the command center. As they wired the three plunk droids together, Rex encountered problems with the detonator's remote handset. Hevy offered to stay and repair the remote, allowing Rex, Cody, Echo, and Fives to escape outside via a maintenance pipe. Rex assumed that Hevy had summarily fixed the remote and was right behind them, but when he told Hevy to detonate the explosives, he discovered that the trooper had not yet joined them. He contacted Hevy and ordered him to vacate the base, but Hevy stated that he would have to manually activate the charges due to the remote's defectiveness, ignoring Rex's protests. Although Rex and the others backtracked to help their comrade, Hevy sacrificed himself to destroy the base and warn the Republic of the Separatist invasion. The termination of the all-clear signal elicited an immediate reaction from the Republic fleet, which arrived and drove Grievous's invasion force out of the system. LAAT/i gunships collected Rex, Cody, Fives, and Echo from the moon and brought them aboard the Resolute. In the Star Destroyer's hangar, Skywalker and Kenobi commended Echo and Fives for their valor, awarding them medals, and also honored Hevy's sacrifice. Rex, impressed by the efforts of the former "shinies," inducted Fives and Echo into the 501st Legion.

Rex and Skywalker soon returned to Coruscant, where Rex manned a blaster training range to maintain his troops' marksmanship skills. Just over a week after their return, word reached the Jedi High Council that General Grievous was targeting the planet Bothawui, home to the key Republic-affiliated Bothan Spynet. Skywalker was subsequently given command of his own battle group to defend the strategic world from the Confederacy. Kenobi, who was out of action due to being injured in a recent terrorist bombing, had Rex and the 501st Legion put on standby, knowing that Skywalker would want them for his strike force. After receiving his orders, Rex got his men settled on the Resolute, which was being prepared for Skywalker's fleet along with two other Venator-class Star Destroyers, the Pioneer and Dauntless. He enjoyed a brief reunion with Skywalker and Tano, who were pleased that he had been assigned to their task force. Once all was ready, they set off for the Both system, with Grievous and an armada of four Munificent-class star frigates pursuing them there. Although they beat Grievous to Bothawui, Rex, Skywalker, and Tano learned from Kenobi that Grievous had not abandoned his pursuit of them.

As Kenobi told them, Grievous was still on course to the Both system, having merely stopped to take on two additional frigates, which he had used to overwhelm Republic forces on the planet Falleen. Despite being outnumbered two-to-one in vessels, Skywalker was intent on protecting Bothawui and was unwilling to let it fall to the Confederacy. He deployed a detachment of AT-TE walkers under Rex's command to the asteroid belt surrounding the gas giant Bothawui Prime, from where they would be able to outflank Grievous once his fleet passed through the asteroids. After Grievous's frigates arrived in the system, proceeded through the asteroid belt—as well as the AT-TEs hidden there—and opened fire on the Republic Star Destroyers, Rex and his men turned the tide of the battle by attacking the frigates, targeting their aft sections. The ambush was all the more successful because the unsuspecting Grievous had diverted all of his frigates' power to their forward shields instead of their rear ones. The Resolute, Pioneer, and Dauntless annihilated the trapped Separatist armada but not before Grievous could flee from his command ship. Skywalker's Delta-7B starfighter took on damage while pursuing Grievous's personal starfighter, Soulless One, and veered off-course toward the asteroid belt.

Rex led a search-and-rescue mission into the asteroid belt; he managed to save Skywalker from his crippled starfighter but could not retrieve R2-D2, who had served as the Jedi General's astromech co-pilot. Rex and Tano met with Skywalker in the Resolutes medbay once he had regained consciousness and brought him up to date with the battle's success, albeit with the loss of R2-D2. After conducting an unsuccessful search for his astromech droid, Skywalker was forced to declare R2-D2 missing in action. Believing that the Resolute, Dauntless, and Pioneer could use modifications, Skywalker took his fleet back to the Allanteen Six shipyards, where they had been manufactured. Eventually, Kenobi contacted Skywalker and Tano and tasked them with finding a new Confederate listening post that was intercepting Grand Army transmissions. Departing from the shipyards on his new assignment, Skywalker elected to personally reconnoiter space suspected of Confederate activity while the rest of his forces concentrated on a more central path. Upon being informed of Skywalker's reconnaissance plan, Rex questioned whether he was sure about scouting ahead alone, but Skywalker was certain that more than one fighter would attract too much enemy attention.

Skywalker brought along the replacement astromech droid R3-S6 and departed from the Resolute in his retrieved Delta-7B starfighter, unaware that R3-S6 was a spy working for Grievous. Not long after Skywalker left, Tano received a signal from the homing beacon of her Master's interceptor—his covert position had been compromised. Rex quickly gathered a squad of troopers to accompany Tano aboard the Twilight, and they arrived to reinforce Skywalker, whom Grievous was cornering with two Munificent-class frigates and a squadron of Vulture droids. Because enemy fire had ruptured his hyperspace docking ring, Skywalker piloted his starfighter into the Twilights cargo bay to retreat aboard the freighter. With Rex and his men providing covering fire as gunners, Tano maneuvered the Twilight right between the adjacent wings of the enemy frigates. As soon as they were clear, Rex engaged the Twilights hyperdrive, executing a successful escape. A short while later, R2-D2, whom the scavenger Gha Nachkt had captured, was able to get a message through to the Twilight. Rex tracked the transmission's origin to Ruusan 2, a moon of the planet Ruusan, where they proceeded to investigate the source.

Within the upper atmosphere of Ruusan 2, Rex and his comrades found Skytop Station, the Separatist listening post that they were after, and they concluded from R2-D2's message that the astromech droid was aboard the station. Despite orders from Kenobi to focus on sabotaging the enemy outpost, Skywalker resolved to mount a dual operation to destroy the base and save R2-D2. Once the Twilight entered the gassy atmosphere of the moon, Skywalker, Tano, Rex, and four other troopers used the Force and JT-12 jetpacks, respectively, to safely land on the station many meters below. Rex carried R3-S6 to the station at Tano's behest, a job he was not enthusiastic about undertaking because of the astromech's substantial weight. Upon landing with the heavy R3-S6 in his arms, he insisted that he would never lug around an astromech droid again. Rex entered the station with the squad and joined another trooper in shooting down two B1 battle droid guards in their path. At a nearby computer terminal, R3-S6 accessed the building schematics of the battlesphere, which Rex used to brief their team on the location of the station's reactors. If its reactors were destroyed, Skytop Station's repulsorlift generators would be compromised, which would consequently plummet the battlesphere to Ruusan 2's surface.

While Skywalker left to rescue R2-D2 on his own, Rex, Tano, and their men went to plant explosives at the reactor room thirty levels below, where they found that an alarm had triggered the door's ray shield. R3-S6 plugged into a terminal and tried to bypass the shield, but as time went on, Rex became doubtful of R3-S6's abilities and questioned them. Though Tano admonished him, telling him to be patient, R3-S6 was actually stalling to give a battle droid patrol time to ambush the Republic team. The astromech droid's efforts succeeded when a squad of B1 battle droids reached their location and attacked them. While Tano deflected laser shots with her lightsaber, Rex and his men used the hallway's supports as cover and opened fire on the battle droids. Meanwhile, R3-S6 activated the reactor room's secondary door, sealing off the Jedi and clones from the reactors. When B2 super battle droids arrived from the other direction, effectively outgunning the clone troopers and trapping them in a crossfire, Tano had Rex utilize electromagnetic pulse grenades—nicknamed "droid poppers"—against their adversaries. A grenade tossed in both directions deactivated all of the droids, though the ensuing respite in fighting did not last long. Immediately thereafter, Grievous arrived and confronted the team, batting Tano aside and attacking Rex and the clone troopers. They targeted their blasterfire at Grievous but were knocked aside, and all of the troopers save for Rex and Denal were killed.

As Grievous prepared to kill the unconscious Rex, Tano intervened mid-strike to block the cyborg general's blow with her own lightsaber. She continued to distract Grievous by drawing him into a storage room; Rex and Denal learned of her exploits after regaining consciousness. Although Rex protested to Tano's course of action over a comlink transmission, he complied with her orders to complete their mission. He and Denal broke into the reactor room and planted the explosives, then departed for the landing bay to rendezvous with Skywalker and the Twilight. The Jedi General was alarmed to learn that Tano had engaged Grievous in single combat and insisted that they take him to assist her. As Rex and Denal headed for the hangar's exit with Skywalker and the Twilights clone trooper pilot, R3-S6 sealed the blast doors and the rest of the exits. The astromech droid also activated several Vulture droids hanging from recharge racks on the roof to prevent the Jedi and clones from escaping, revealing his loyalties to Grievous and the Separatists. Surrounded by Vulture droids on one side and super battle droids on the other, Rex, Skywalker, and the troopers ran for cover behind several nearby crates while returning the droids' blasterfire.

During the ensuing firefight, Skywalker ordered Rex to activate the explosives at the reactors even though they were still in the station. Rex complied and detonated the charges, beginning Skytop Station's gravity-pulled descent into the atmosphere of Ruusan 2. Presently, Tano—having escaped from Grievous—reached the hangar via a ventilation shaft and joined the fight, eliminating two of the Vulture droids. When Rex noticed several fuel cells close by, Skywalker called on the Force to hurtle one of them at the droids, and Rex placed a well-aimed shot on the cell. The resulting explosion obliterated all of the battle droids. Once R2-D2 opened the hangar door via an external terminal, the Jedi and clones escaped from the doomed Skytop Station aboard the Twilight, and Skywalker completed their successful operation by finally retrieving his astromech droid.

While Rex, Skywalker, Tano, and Kenobi were serving aboard the flagship of the Republic Navy, Tano intercepted a Rebel SOS signal from Tatooine. Determined to prove herself, she secretly took a shuttle to investigate the transmission's source. Rex, Skywalker, and Kenobi soon discovered her absence and also learned that the signal had been fake—Tano had fallen into a Separatist trap. The two Jedi Generals quickly took the Twilight to Tatooine, where they rescued Tano from a battle droid detachment.

At least six months into the war, Rex agreed to relieve Skywalker of his Padawan for a few days by taking her along on a three-day shakedown cruise aboard Republic Navy Captain Gilad Pellaeon's newly refitted assault ship, Leveler, in the Dantus sector. After Pellaeon, an old acquaintance of his, permitted him to take part in Levelers testing session, Rex departed to join the cruise with Tano, Sergeant Coric, and six clone troopers new to Torrent Company—Ross, Boro, Joc, Hil, Vere, and Ince, who had completed their training several days prior. En route to Leveler aboard a shuttle, Tano questioned if her Master had taken a respite from training just for a break from her, but Rex abstained from directly answering to avoid speculating about Skywalker. He was more concerned about his new troops: He was considering using the inconsiderate tally sensor to tell the six apart because they had so far failed to display unique personalities. After Rex and his men arrived aboard Leveler, Pellaeon greeted them and allowed them to move into their barracks. At Tano's request, Rex took her to examine Levelers experimental concussion missiles, and Pellaeon joined them at one of the missile bays.

Rex and Pellaeon were cut off from a discussion about Levelers new weapons by an alert that a flotilla of Confederate ships had exited hyperspace in the nearby Fath sector. While Rex and Pellaeon monitored the Separatist activity, Tano sensed a disturbance in the Force that, at Rex's advice, Pellaeon took seriously. Despite the possibility that the enemy activity would not result in anything, Rex took precautions and went to round up his men in case they were needed. After Rex returned to Torrent Company's barracks and relayed the situation, Joc's inquiries into Pellaeon's private life sparked a debate between Tano and the rookie clones about the Jedi Code's ban on emotional attachment. Rex ended the argument by putting his men on standby, while Tano departed to check out the ops room at his suggestion. Once she had left, Rex reproved his men for putting her on the spot but was also pleased that they were settling in and expressing themselves. In an effort to keep them occupied, he took his men to the hangar deck to perform some deck circuits and familiarize themselves with the Fath system, where Leveler was headed to keep a closer eye on the active Separatist armada.

Rex contacted Skywalker to inform him of their diversion to the Fath system, and Skywalker responded by setting off to rendezvous with Leveler despite his captain's admission that his involvement was unnecessary. After taking a moment to shave his hair from a blue-dyed haircut—in support of the Sullustan Bylluran Athletic bolo-ball team—Rex joined Tano and Pellaeon on the bridge just as the warship became host to the Altisian Jedi sect. Jedi Master Djinn Altis, who spoke for the group, asked for permission to dock his freighter, Wookiee Gunner, on the grounds of receiving a distress signal from a Republic agent on the nearby planet JanFathal. Republic Intelligence confirmed Altis's story and reported that the agent had been captured during a Separatist-allied rebel uprising. Pellaeon approved the rendezvous with Altis, and Rex promised his men for the hostage extraction that they would soon be performing. However, matters were complicated when the captive operative was identified as Hallena Devis, a close acquaintance of Pellaeon. While Rex and his men were examining JanFathal's capital of Athar—where Devis was being held—via a holochart in Levelers meeting room, Altis and fellow Jedi Callista Masana and Geith Eris convened with them, Pellaeon, and Tano to formulate a plan to rescue Devis.

As Pellaeon briefed the impromptu team on the objective at hand, Rex objected when Pellaeon implied that he intended to participate in the mission; the clone captain cited that in the absence of embarked troops, the responsibility fell to him and his men. He noted that all they could hope for was a successful rescue operation and not a full-scale ouster of the Separatists from JanFathal. Eris and Masana voiced their desire to reconnoiter Athar on their own, as they did not approve of clone trooper production on account of their beliefs, but Rex and his men insisted that it was their job. With a plan in place, the team headed down to Levelers hangar bay, where a replenishment shuttle was prepared for them to take to JanFathal. Rex refused Pellaeon's suggestion to use civilian clothing, stating that he preferred armor advantages to stealth, and also assured the distressed Pellaeon that they would rescue Devis. Once the sensor technician Benb finished outfitting the shuttle, Rex and his men boarded the craft alongside Tano, Altis, Masana, and Eris. As Sergeant Coric flew them to Athar, Rex attempted to mediate a heated conversation between Tano and the Altisian Jedi, whose controversial beliefs conflicted with the orthodox Jedi principles upon which she had been raised. He also checked in with his rookie troopers over their private circuit and took pity on the new inductees, as they had not been prepared to be confronted with Jedi of such incongruous beliefs and behavior.

After bypassing a Separatist landing craft, Coric landed the team's shuttle in the south district of Athar. Rex immediately disembarked with the others and headed for a nearby building, where Altis and Ross worked with a recording remote to observe the surrounding enemy deployments in the city. Rex, Tano, and Masana then moved in to reconnoiter the vicinity of the building where the Separatist-backed rebels were holding Devis. Rex formed a plan for a standard hostage extraction, electing to first secure the building's exit and then deploy teams to infiltrate the structure via the roof and front entrance. After the rest of the team joined them, Rex sent Altis with Joc, Ince, and Ross to cover the exit and led the others to enter the building via the roof. Once Altis had distracted Devis's captors—the young insurgents Merish Hath, Shil Kaval, and Varti—Rex and his men used explosives to open a hole in the roof and joined the Jedi in confronting the rebels. Though Varti, holding his blaster to Devis, tried to bargain with him, Rex surprised everyone by laconically shooting down Varti, subsequently freeing Devis. He used a vibroblade from his gauntlet to sever Devis's handcuffs and ushered her toward the exit, ignoring her attempts to retrieve her comlink from the badly wounded Kaval.

After Devis had been moved to safety, the building began to crumble, and Rex charged out of the structure with Altis, Vere, and Boro. While Ince headed to Coric's shuttle with Devis, Rex joined the fight against an incoming force of battle droids. In the ensuing battle, Vere was wounded beyond help, leaving Rex pained with the loss of the rookie trooper. Although Boro tried to revive Vere, Rex told him to continue fighting, as Boro endangered his own life with every second he spent trying to help Vere. Launching grenades at the droid infantry with his rifle, Rex prepared to lay charges and sacrifice himself so that the others could escape, despite protests from both Tano and Boro. Before Rex could execute his plan, Altis, Masana, and Tano focused through the Force, toppling an adjacent building onto the droids and barricading the enemy's path with rubble. Rex contacted Coric and was surprised to learn that the sergeant—despite having been ordered to wait only for Devis and the Jedi—was landing nearby to extract the rest of the team. Although Coric had disobeyed orders, Rex was grateful that he had decided to return for them.

Once all of the Jedi and clones were on board, Coric piloted the shuttle out of the area, barely evading the pursuant battle droids. En route to Leveler, Devis thanked Rex for his men's efforts, but he avoided initiating a conversation with her so as to reflect on Vere's death. He noticed that Ross, Boro, Joc, Hil, and Ince had opened up a private comlink frequency and respected their privacy, knowing they needed to discuss personal matters, including the painful loss of Vere, without him overhearing. He instead voiced his congratulations to his men on the successful rescue, though he noted that JanFathal was lost to the Republic. Meanwhile, the Separatist destroyer Reaper attacked Leveler and forced Pellaeon's warship to flee to hyperspace before Coric's shuttle could dock, leaving Rex and his team to fend for themselves. With their main source of life support—Leveler—gone, Rex ordered Coric to disable all nonessential systems. Boro calculated that with their limited oxygen supply, they would only be able to make it halfway to the shipyards at Kemla Yard, the closest Republic-allied location. Instead, they elected to return to Athar and mount a last stand against the Separatist army there. Shortly thereafter, Skywalker arrived in the system aboard the V-19 Torrent starfighter Echo-97 and contacted Rex, who updated him on their situation. Rex and the others rendezvoused with Skywalker in Athar, where Skywalker was introduced to the rookie clones and the Altisian Jedi.

Rex and his men's spirits were lifted when Skywalker told them he had spotted several of the Separatists' hyperdrive-equipped CR-20 troop carriers, which could be used to escape off-world. Altis presently received word from his colleague Ash Jarvee that Leveler was returning to the system from a miscalculated hyperspace jump. In the meantime, Skywalker sent Rex, Masana, and the clone troopers to a road bridge along the Cadaman Royal Highway while he and the other Jedi seized a CR-20. Rex and his comrades would provide covering fire until the troop carrier lifted off and would then board the ship. Once Rex, Masana, and the clones were in position, Skywalker commandeered the troop carrier with Tano, Altis, Eris, and Devis and arrived to rescue them. Yet Ince was injured in battle with the droids, and Hil hurriedly treated him for his wounds. A Vulture droid approached and fired at some paving behind them, but Masana diverted the falling debris with the Force and edged over to attend to Ince. While Masana and the others carried the injured Ince onto the hovering troop carrier, Rex and Ross remained on the ground to keep the droid starfighter occupied.

The Vulture droid landed and advanced on the two clones in walking mode, and Ross got the droid's attention while Rex tangled its legs with his rappel line, pulling himself toward the droid. He hung on despite its attempts to throw him off, causing the droid to become increasingly more tangled in the line. Rex and Ross's combined blasterfire brought down the droid, and they escaped to the CR-20, which Skywalker promptly piloted toward Leveler. While the wounded Ince was stabilized, the battle-weary Rex manned the CR-20's blaster cannons with Tano, returning fire at the attacking Separatist armada. As soon as their CR-20 landed aboard Leveler, the assault ship escaped to hyperspace; Ince, meanwhile, was rushed to the medbay. Rex joined his comrades there, trying to endure the aggravating wait for developments in Ince's case. When Ince died from blood loss, Rex, devastated and furious with the loss of a second soldier within a single day, took refuge in the mess hall. Tano found him there and consulted him about the Altisian Jedi views on the Clone Army, a discussion that soon undermined Rex's own beliefs as well as Tano's. Accepting that he and his comrades were making the best of an unwanted situation, Rex finally regained stability with his principles, though Tano found it more difficult to do so.

As the war continued, Rex participated in a battle on a world against anti-Republic forces with Skywalker and Tano. During the fighting, Rex oversaw the operation of the Republic's AV-7 Antivehicle Cannons and had them return bombardment to the enemy artillery. Eventually, Skywalker learned that Trade Federation Viceroy Nute Gunray, a member of the ruling Separatist Council, had been arrested on the planet Rodia. While Tano departed to assist Jedi Master Luminara Unduli in transporting Gunray to Coruscant for trial, Skywalker and Rex stayed to maintain the Republic's position on the embattled world. When the Republic launched a later campaign to capture Confederate Head of State Count Dooku, Rex served with Skywalker, Tano, and Kenobi aboard the Resolute, searching for traces of the Sith Lord in the hopes that removing him from the Confederate leadership would effect a quicker end to the war. Once they located Dooku's Munificent-class star frigate in the Vanqor system, Skywalker and Kenobi infiltrated the frigate to detain the Separatist leader while Rex, remaining behind with Tano, took Wullf Yularen's place of commanding the Resolute, as the admiral was recovering from the previous run-in with the Malevolence.

As soon as Skywalker and Kenobi were aboard Dooku's frigate, Rex had the Resolute move into position and open fire, crippling the enemy vessel. However, Dooku escaped aboard his solar sailer, and Skywalker and Kenobi gave pursuit in a stolen Sheathipede-class transport shuttle, ordering Rex and Tano to follow in any available craft. Although Skywalker and Kenobi crash-landed on the planet Vanqor alongside Dooku, a band of pirates brought the Sith Lord to their base on Florrum. After Tano retrieved Skywalker and Kenobi from Vanqor, Rex was present on the Resolutes bridge when Masters Yoda and Mace Windu of the Jedi Council delivered new orders to them. Hondo Ohnaka, the leader of the pirate gang that had captured Dooku, had issued a ransom of a million credits for their prisoner, and Skywalker and Kenobi were to verify that the Florrum pirates had custody of Dooku so that the Republic could pay the ransom. Yet Ohnaka's pirates also briefly captured Skywalker and Kenobi, who failed to prevent Dooku from escaping from Florrum.

While liberating the planet Queel from the Confederacy alongside Skywalker, Kenobi, and Tano, Rex accompanied the latter to eliminate the enemy's artillery encampment. Rex used a jetpack to cross a swamp to the artillery base, while Tano rode a large dragon-like creature. Attacking the battle droids guarding the blaster cannons, Tano threw a blaster battery at the artillery stations with the Force, and Rex detonated the explosive by shooting the flying target, annihilating the cannons. He and Tano then returned to the Republic's forward command post with Skywalker and Kenobi to receive an incoming message from the Jedi Temple on Coruscant. In a conference with Jedi Masters Yoda and Ki-Adi-Mundi, Skywalker and Tano were assigned to intercept the Separatist agent Messo—who had stolen a Republic data file—in the Mon Gazza system, while Kenobi was to finish the campaign on Queel. Rex went with Skywalker and Tano aboard the Twilight to undertake their assignment on the planet Mon Gazza, where Skywalker left to find Messo while Rex and Tano stayed behind to secure the freighter. After changing out of his usual armor, Rex donned a heavily covered-up disguise and traveled with Tano to find her Master. When Skywalker confronted Messo in a Podracing arena, he discovered that the enemy agent had already transferred the data file. To further complicate matters, Messo was killed in a collision with a Podracer before he could reveal any more information.

Rex and Tano joined Skywalker in the stands to watch the race and learned that Skywalker, who believed that Messo's contact belonged to one of the teams in the racing circuit, had entered Tano as a contestant to go undercover with the other racers. They proceeded to the Podracing stalls to begin outfitting Tano's Podracer, with Rex, Skywalker, and R2-D2 posing as her pit crew. The skilled Podracer Kidd Kareen became their prime suspect for being Messo's correspondent, as Tano learned via Jedi intelligence that several recent espionage incidents had coincided with the racing circuit's presence in the same system, with Kareen and his crew being present for each of the events. Once Kareen's crew had left their stall for the day, Tano kept Kareen occupied while Skywalker took a look around the stall, with Rex and R2-D2 on lookout. However, Kareen's fellow crew member San Maxus caught Skywalker snooping around, and a fistfight erupted between the Jedi and Kareen's crew. Shortly after Rex joined the fray, Tano and Kareen returned and halted the fight, and Tano was forced to apologize for her crew's actions. Rex and his comrades hurriedly left to prepare when they learned that the Padawan's debut race was next.

At the race, Rex and Skywalker tracked Tano's progress through the course via R2-D2's hololink, rushing to her aid when another Podracer rammed her from behind near the finish line. Although Tano's Podracer had been demolished in the crash, Kareen offered to loan her one of his spare Podracers. Rex and Skywalker later trailed Maxus into a pub and used R2-D2 to eavesdrop on him. They discovered that Maxus was the Separatist spy when he contacted Count Dooku, and they also overheard Dooku arranging to have another agent collect the stolen Republic datachip from Maxus the next day. That day, during Tano's next race alongside Kareen and Maxus, Rex and Skywalker noticed Maxus recovering the stolen datachip from the Podracing pits and chased after him. Though Maxus escaped, he left the rest of Kareen's crew to engage them in blaster combat. While Rex and R2-D2 fought off the Podracers, Skywalker departed to help his Padawan, and the Jedi managed to prevent Maxus from handing over the datachip to Asajj Ventress thanks to assistance from Kareen. With their task completed, Rex, Skywalker, and Tano bid farewell to Kareen before leaving Mon Gazza aboard the Twilight. The three reported their success to Kenobi, who was still on Queel.

When rumors abounded of a new Confederate project in the Outer Rim, Rex became involved with sending Denal on various missions to counter the menace. While Denal was on Rodia investigating the rumors, Rex contacted him and ordered him to make way for Republic reinforcements by purging a nearby jungle clearing of battle droids. Once Denal had done so, Rex sent him to destroy a transport factory by activating its self-destruct mechanism. At Rex's behest, Denal next took a squad to Tatooine to scout out an allegedly deserted Separatist base, which was discovered to be teeming with droid forces. After Denal's team cleared the outpost of hostiles, Rex relayed the news that another enemy base—this time a research station—had been discovered on Tatooine. As the outpost was reportedly connected to the new Separatist project, Rex told Denal to act quickly before the facility could be evacuated and any evidence destroyed. Denal infiltrated the station and uncovered plans for a superweapon that could cloak entire armies from the Republic. He later destroyed the superweapon at its construction site on the ice world Orto Plutonia. Shortly after Denal returned to the Republic fleet and received commendations from Kenobi, Rex dispatched the trooper on yet another assignment.

Rex was sent with Skywalker and Tano to the planet Taronda to secure raw materials that the Republic desperately needed. However, Taronda's resources were also of interest to the Separatists, who targeted a mining settlement on the world to divert the Republic's attention. With Vulture droid starfighters attacking from overhead, Skywalker had Rex gather the miners and prepare the encampment's deflector shield. Though Tano fell down a crevice leading to a mineshaft, Rex informed Skywalker of a more pressing matter: the arrival of a Separatist assault force composed of a C-9979 troopship, Multi-Troop Transports, and multiple Armored Assault Tanks. After bringing the wounded civilians to safety, Rex triggered the shield and called in Republic reinforcements. Asajj Ventress materialized just beyond the shield and revealed that she had sent dwarf spider droids after Tano, but Rex told Skywalker to have faith in his Padawan and restrained him from confronting Ventress. She withdrew her droid forces from Taronda upon discovering that a Republic Star Destroyer was inbound. Rex thereafter deemed it safe to disable the shield, and Tano, who had defeated the spider droids on her own, soon rejoined him and Skywalker.

When the Republic Ninth Fleet received a distress call from the Deyvus, a malfunctioning merchant starship locked on course with an unstable nebula, Rex, Skywalker, and Tano were sent to rescue the ship aboard the Twilight, as their craft was the nearest and fastest one available. On approach to the Deyvus, Rex noted that the damage appeared to be severe, with its ion drive gone critical and it's stabilizers offline. As they prepared to send R2-D2 to access the Deyvuss maintenance systems, the vessel revealed a number of battle droid–manned laser cannons, leading Rex, Skywalker, and Tano to realize that it was a Separatist trap. Before they could maneuver the Twilight out of range, the droids targeted its engines; Rex used a fire extinguisher to put out the accompanying flames in the cockpit. He informed Skywalker that another impact would cripple the Twilight, as its hull could not withstand further damage. While the Twilight began to be pulled toward the collapsing nebula, General Grievous holographically contacted Rex, Skywalker, and Tano and lured them aboard the Deyvus, from where he claimed to be watching their deaths. Skywalker had R2-D2 begin repairing the Twilights engines and took Rex with him to the Deyvus to capture Grievous.

Rex and Skywalker used a pair of grappling hooks to pull themselves toward the Deyvus through the void of space. Along the way, Rex questioned the boldness of their plan, to which Skywalker replied that it was boldness that distinguished them from the Separatists. Sneaking past the heavy laser cannons, Rex and Skywalker boarded the gun deck and proceeded into the Deyvuss system of hallways. Before they could get far, B1 battle droids and shielded droidekas surrounded them. Skywalker responded by slicing a hole in an adjacent wall with his lightsaber to blaze a detour to the bridge, where they assumed Grievous was sequestered. They passed through three floors, eliminating all of the battle droids in their path. On the bridge, they discovered that Grievous was not aboard the Deyvus; instead, a plethora of primed thermal detonators greeted them. Grievous contacted them from the safety of a Separatist cruiser and taunted their predictability before severing the connection. Skywalker quickly cut intersecting slices in the cockpit's roof with his lightsaber, and Rex blasted a hole through the weakened metal, allowing them to return to the Twilight moments before the Deyvus exploded. Though they failed to capture Grievous, they had foiled his trap for them.

Eventually, the Jedi Order learned—via a datachip that Ros Lai, an outcast of the Nightsisters clan of Dathomir, had provided—that the Confederacy had entered into an alliance with the Nightsisters. Rex returned to Christophsis with Republic Senator Padmé Amidala, her protocol droid C-3PO, and R2-D2 to pursue Lai's leads about the new enemy partnership for the Jedi High Council. During their investigations, Amidala discovered that the Separatist Droid Army was mining for something on Christophsis, though she was unable to determine what. Amidala reported her findings to the High Council and prepared to leave Christophsis with Rex and her droids. Before they could get off-world, enemy forces shot down their ship, and Rex was injured in the subsequent crash. He, Amidala, C-3PO, and R2-D2 were imprisoned in the Separatist base, where the battle droids were conducting their mining operation. While there, they overheard their guards saying that the Confederacy was harvesting crystals from the planet core, which were to be used to power the Devastation, a newly constructed warship and the sister ship of the Malevolence.

Skywalker and Kenobi—who had been sent with Clone Commander CC-1004, nicknamed "Gree," to rescue Amidala—soon freed Rex and his friends from their prison cell. While C-3PO and R2-D2 remained behind to assist in the Jedi's continuing investigation, Amidala helped Rex to Gree's LAAT/i gunship, which had a medical console on standby for him. The Jedi later destroyed the Devastation before it could assault Coruscant, killing the Nightsister leader, Sai Sircu, and terminating her alliance with Dooku and the Confederacy.

While stationed aboard the Resolute, Rex accompanied Skywalker, Tano, and Yularen to aid Jedi General Aayla Secura, whose fleet was being ambushed by Confederate forces in the Quell system. By the time the Resolute arrived over Quell, two of Secura's Star Destroyers had fallen to a fleet of Munificent-class frigates; only Secura's command ship, the Liberty, was maintaining altitude. As the Separatists launched jetpack-equipped B2-RP battle droids to board the Liberty, Rex, Skywalker, and Tano took several LAAT/i gunships with troops from the 501st Legion to evacuate Secura and her 327th Star Corps personnel from her crippled flagship. After Skywalker reached the cruiser ahead of the others, a B2-RP battle droid intercepted the gunship carrying Rex and Tano, who pulled their clone trooper pilot to safety in the troop bay after the battle droid forced him out of the cockpit. The droid also sabotaged the gunship's controls, plunging the craft uncontrollably toward Secura's flagship. As soon as they crashed through the Libertys hull, Rex, Tano, and their squad jumped out of the burning transport without pause and began sprinting through the cruiser's corridors, disabling droids on their way to rendezvous with Skywalker and Secura.

Rex and Tano caught up with Skywalker, Secura, and Marshal Commander CC-5052, nicknamed "Bly," in one of the Libertys hallways, and they headed to the ventral hangar to escape aboard a Consular-class cruiser that Skywalker had called in. As the gangway was extended to the frigate, the Confederate fleet's intensifying cannonades caused an inferno to rage through the Liberty. Sacrificing himself, Skywalker Force-pushed Rex and the others into the airlock, sealing the blast doors shut in both directions, then used the Force to hold back the advancing flames. Despite his efforts, the inferno finally blasted through, throwing him against the airlock. Once Tano and Secura had brought the wounded Skywalker aboard, Bly and a co-pilot detached their Consular-class cruiser from the Liberty. Just as Bly was docking their frigate to the Resolute, a Vulture droid attack inadvertently activated the frigate's hyperdrive. Although the Resolute maneuvered away in time, the frigate jumped to hyperspace with the Jedi, clone officers, and other troop evacuees aboard.

While Skywalker was treated in the medbay, Bly discovered that the navigation computer's incorrectly inputted coordinates had locked them on a collision course with a star in the Maridun system. Rex and Bly joined Secura and Tano on the bridge, and they decided to disengage the hyperdrive by shutting down all primary power units so that they could avoid colliding with the star. With Tano at the controls, Secura deactivated the frigate's power, bringing them out of hyperspace. Due to the vessel's uncontrollable speed and the lack of artificial gravity, Rex lost his grip on the back of Tano's seat and was smashed against Secura, breaking her hold on the power switch. Secura telekinetically reactivated the switch, enabling Tano to pilot the frigate out of its collision course with the star. Yet she could not stop the ship from heading toward the nearby planet Maridun. The frigate suffered damage while entering the planet's atmosphere before finally crash-landing. Rex, Bly, and the clones escaped first, and Rex helped another trooper out of the frigate while Tano and Secura jumped out with Skywalker, just before the ship exploded. Once they had erected a makeshift shelter for Skywalker from the wreckage, Secura, Tano, and Bly took their only surviving troopers—Cameron, Lucky, and Flash—to seek out medical aid for Skywalker while Rex stayed to watch over him. Before Tano left with the others, Rex assured her that he would take good care of her wounded Master and also wished her luck.

Rex diligently guarded Skywalker through the night. When Skywalker finally awoke and tried to get up, Rex ran over and checked on his condition. However, a carnivorous mastiff phalone that had been watching the two for hours attacked Rex, pinning him and trapping his blaster hand under one of its claws. Rex managed to fire a shot, startling the creature and scaring it away, and aimed several final blasts at its retreating form. Skywalker fell back asleep and did not reawaken until the next morning. When he did, Rex insisted that he maintain his rest, but Skywalker told him that he could hear the mastiff phalones returning. Both of them drew their weapons just as two of the creatures arrived and attacked. Rex gunned one of the beasts down, but the other charged into the makeshift shelter, knocking both him and Skywalker aside. At that moment, Tano and Bly returned with Wag Too, a healer from Maridun's village of Lurmen colonists. Too wrapped a rope around the feet of the remaining mastiff phalone, and Tano assisted Too—as did Rex, despite an arm injury—in tugging on the rope to topple the creature. Once it had fallen to the ground, Too secured the rope around its legs, preventing it from inflicting further harm. Rex then followed Tano, Bly, and Too back to the Lurmen village, with Skywalker in tow on a stretcher cobbled together from the shelter's remains.

While the Lurmen tended to Skywalker's wounds, Rex kept watch on the outskirts of the settlement. During his shift, he noticed the arrival of a Confederate troopship and reported it to Bly, who was back at the colony with the Jedi and ordered him to return. Rex joined the others in the seedpod hut where Skywalker was being treated. Given that Maridun was a neutral world, the Jedi and clones decided to abscond before the Separatists found them so as to ensure that the Lurmen did not suffer for hosting them. Rex and Bly aided Skywalker and, with Tano and Secura following behind, made for a nearby field of tall grass behind the village. While there, Rex and Tano discussed the Lurmen's pacifism, denouncing the colonists as cowardly until Secura intervened and asserted that it took courage to follow one's beliefs. When Skywalker suggested that they pilfer a shuttle from the Confederacy to escape off-world, Rex agreed with his Jedi General, eager to steal from the Separatists. Tano then noticed that a Separatist recon droid was spying on them. Rex joined her and Bly in pursuing the probe droid, but it was Secura who disabled the probe by maneuvering in front of it through the grasses. Searching for the probe's origin from atop a nearby tree, Rex and his comrades discovered the Separatists' base and watched as General Lok Durd held a test run of his Defoliator, an experimental cannon capable of liquidating organic matter while leaving mechanical units unharmed.

As Rex and Bly moved in for a closer look at the Defoliator, Durd sent two B1 battle droids—inadvertently, in the direction of the approaching clone troopers—to serve as test subjects. When the Defoliator Deployment Tank fired a capsule at the battle droids' location, it birthed an expanding wave of fire that decimated all life in the area, flora or otherwise. Rex and Bly turned and fled for higher ground, firing their blasters' ascension cables at the tree. Rex made it to safety, and though Bly tripped and misfired his cable, Secura swung down on a vine and pulled him to refuge. They watched as Durd departed with several squads of troops, and Skywalker concluded that Durd intended to test the Defoliator on the Lurmen village. Rex and the others resolved to protect the Lurmen, waiting until after nightfall to raid the Separatist base for a starship. Once Rex, Skywalker, and Bly had cut down the droid guards outside the facility, Tano and Secura opened the door, enabling the others to infiltrate the base. Using various crates as cover, Rex, Skywalker, and Bly reached the communication center and destroyed the droids in command. Rex noticed a pair of mobile shield generators and, at Skywalker's behest, helped Bly bring them aboard the Sheathipede-class shuttle that the Jedi had commandeered.

When Rex and the others landed at the Lurmen village at daybreak, the Lurmen chieftain, Tee Watt Kaa, did not appreciate their return, as he believed that they had brought the Clone Wars to Maridun. Rex soon caught sight of Durd's inbound battle group from the village's perimeter. In spite of protest from Kaa, Rex and his comrades formed a seedpod barrier to protect the village from the imminent engagement with Durd, working in teams to haul the seedpods in front of the settlement. Once Bly and Tano had moved the shield generators into place, Rex noted that Durd's battle droids were holding position a considerable distance away; Skywalker theorized that Durd would attempt to use his long-range artillery before mounting a charge. Sure enough, Durd had his droids fire a Defoliator shell, but the deflector shield proved effective in repelling the wave of destruction. Unable to do anything from afar, Durd sent in his first squad. While Skywalker, Tano, and Secura waded into the enemy ranks, Rex and Bly, remaining in front of the shield, provided covering fire with their DC-15A blaster rifles. Although they defeated the first wave of droids, the second wave—comprising Durd's second and third squads—swiftly followed.

Due to their superior numbers, numerous battle droids slipped past the three Jedi, forcing Rex and Bly to retreat behind the seedpod barrier. Despite the clones' efforts, the droids breached both the deflector shield and the seedpod wall and marched into the village, eliminating the shield generators. Secura and Tano joined Rex and Bly in defending the Lurmen, while Skywalker disabled the Defoliator Deployment Tank and captured Durd. Aided by Too and several other Lurmen, who sacrificed their pacifist upbringings to repel the invaders from their colony, Rex and his comrades eradicated the battle droids, preventing them from demolishing the village. With the battle over, Rex and Bly ushered the captured Durd and his Aqualish aide, Pune Zignat, into the Sheathipede-class shuttle. Too thanked the group for their efforts, as did Kaa, who nonetheless questioned the cost of the victory. As the Jedi and clones prepared to leave Maridun, Admiral Yularen arrived in orbit with a fleet of Star Destroyers, having finally tracked the Jedi there from Quell.

When the Republic lost contact with Glid Station, a base on Orto Plutonia, Rex went with Skywalker, Kenobi, and a detail of cold assault troops to investigate the lack of response. They were accompanied by Chairman Chi Cho and Senator Riyo Chuchi from the orbiting moon of Pantora, which claimed the ice world as a protectorate due to its lack of sentient life. Upon arrival over Orto Plutonia aboard the Resolute, Rex, Skywalker, Kenobi, and the Pantoran dignitaries proceeded to Glid Station aboard a landing force of LAAT/i gunships. Rex and his men were forced to use cold assault armor that, while necessary for protection from the icy conditions, heavily restricted their movements in battle. After landing at the base and having his men place sensor beacons to survey the area, Rex followed Kenobi inside, where they discovered that the clone troopers within had been slaughtered, though there was no evidence of a battle with Separatist droids. Following their scouts' discovery of a nearby Confederate base, Rex took several troopers aboard Freeco bikes to examine the facility with Skywalker and Kenobi.

At the enemy outpost, which was composed of two connected XT Beetle Transports, Rex assisted Skywalker in placing sensors around the building before entering the complex with his general. Sorting through the communication records in the control center, Kenobi uncovered a holorecording of a large life form attacking a B1 battle droid. While Skywalker and Kenobi speculated as to what had attacked the droid, Rex reported that the droids' log indicated that it had last been scouting the southern canyon. He returned to Glid Station with the other troopers while Skywalker and Kenobi followed up on the lead. As a storm brewed outside, the Jedi returned with news of their discovery—contrary to the findings of previous scouting parties, sentient life inhabited Orto Plutonia: a colony of the Talz species. Upon learning of the Talz, Cho sought to preserve Pantora's claim to Orto Plutonia and immediately ordered Rex to prepare his troops for battle with the Talz, but both Skywalker and Kenobi intervened and told him that they had arranged a meeting with the Talz to negotiate peace, much to Cho's chagrin. As the Republic forces prepared to leave for the rendezvous, Rex reported to Skywalker that their gunships would not be able to take off in the storm. Skywalker ordered the rest of the clone platoon to remain at Glid Station—despite Cho's aggressive claim to Orto Plutonia, the Jedi did not intend to go to war with the Talz.

Rex set off with Cho, Chuchi, Skywalker, Kenobi, and their clone troops for the Confederate base, which was to serve as the neutral meeting ground with the Talz. Once there, Cho told Rex to position his men on a nearby ridge from which to ambush the Talz, but Kenobi countermanded the order, as the Talz had already arrived. Leaving Rex and the clone troopers outside with an explicit directive to avoid provoking the Talz, the Jedi and Pantorans entered into negotiations with Chieftain Thi-Sen. Despite the efforts of all other parties to prevent armed conflict, Cho declared war on the Talz in an effort to expunge them from Orto Plutonia, with no one present holding sufficient political authority to revoke his decision. While Skywalker, Kenobi, and Chuchi returned to Glid Station to determine a solution for the hostilities, Rex and his men took Freeco bikes and BARC speeders to accompany and protect Cho. When they encountered several narglatch-mounted Talz scouts near an ice ridge, Cho ordered the clones to open fire on the spot. Although Rex reminded Cho that they were only there for his protection, not to fight his crusade against the Talz, the captain and his troops were forced into battle when more Talz appeared and ambushed them. After a Talz warrior and his narglatch forced him out of his Freeco swoop, Rex retaliated by gunning down his attackers. He kicked over his bike for cover, ordering his men to do the same to form a defensive perimeter around Cho and his bodyguards from the Pantoran Guard.

As the Talz flung spears at them, Rex ordered his men to retreat. Though Cho refused to pull back, one of the spears soon hit him, impaling him through the back. Acting with celerity, Rex slammed a BARC speeder into an advancing Talz and defended the wounded chairman from more of the warriors, doing his best to fend off Cho's attackers. He carried Cho onto a spare speeder and joined the rest of his men in their retreat. Yet further on, the collapse of an ice bridge across a gorge compromised their only path to safety. Despite being trapped between the ravine and the line of Talz warriors, Rex was ready to fight to the last man. As spears began to fly, he signaled the few survivors of his unit to use their vehicles as cover from the charging Talz. They countered the Talz's spears with blasterfire until Skywalker, Kenobi, and Chuchi presently landed at their position with several LAAT/i gunships and troop reinforcements.

Though the Talz were forced to halt their offensive, both they and the clone troopers had suffered devastating casualties. After Cho, who remained determined to eradicate the Talz to his last breath, succumbed to his injuries and died, Chuchi—having received proper jurisdiction from the Pantoran Assembly—negotiated an end to the bloodshed with Thi-Sen. She peaceably transferred control of Orto Plutonia to the Talz in recognition of their sovereign status. With the Battle of Orto Plutonia brought to an end, Rex and his men departed from the battlefield with Chuchi, Skywalker, and Kenobi aboard the gunships.

When the Separatist-allied Doctor Nuvo Vindi was discovered to be resurrecting the fatal Blue Shadow Virus in a laboratory on the planet Naboo, Rex was sent with Skywalker, Kenobi, Tano, and the clone units Snow Wolves, Calm Tree, and Wildfire to shut down Vindi's facility. Once Tano breached the underground lab with explosives, Rex and his men joined her in drawing the attention of the battle droid defenses so that Skywalker and Kenobi could infiltrate the lab from other locations without resistance. From an LAAT/i gunship, Rex and his men rappelled into one of the ruptured tunnels and followed Tano in cutting through a patrol of B1 and B2 battle droids. However, the arrival of two droidekas halted their charge, forcing them to retreat while returning the droids' fire. As their men fell one by one, Rex and Tano were saved by Kenobi and the clone bomb squad, who collapsed part of the roof on the droidekas. Rex and his two remaining troopers followed Tano and Kenobi to a junction, where they decided to split up upon encountering more droids: Kenobi took the bomb squad to find Vindi's virus bombs—which Vindi had designed to spread the Blue Shadow Virus to key Republic star systems—while Rex, Tano, and their squad stayed behind to engage the droids.

Shortly thereafter, Vindi remotely activated the virus bombs. Once Rex and Tano had defeated the battle droids, they ran into Skywalker, Senator Padmé Amidala, and Representative Jar Jar Binks of Naboo—the latter two of whom had been captured by Vindi before Skywalker rescued them—at another junction. Skywalker informed Rex and Tano that one of the active bombs was missing and ordered them to split up and find Vindi's LEP servant droid, LEP-86C8, who, as Amidala recalled, had taken the bomb. While Tano and Rex searched for the bomb, Skywalker and Kenobi chased down Vindi before the scientist could escape from Naboo. When Amidala reported that she and Binks had retrieved the missing bomb from LEP-86C8 in the arboretum, Tano and Rex quickly brought the bomb squad to deactivate it. The ordnance specialists finished disabling all of the virus bombs with only seconds to spare, much to the relief of Rex and the others. Meanwhile, Skywalker and Kenobi apprehended Vindi and left to escort him to Naboo's capital, Theed, for trial. Unbeknownst to the Republic forces, LEP-86C8 had removed the virus vial from the last bomb before escaping. The droid used a spare explosive in the bomb room to release the Blue Shadow Virus into the laboratory.

Rex was on patrol elsewhere in the lab with Tano and several troopers when LEP-86C8 detonated the virus bomb, and they rushed for a safe room before the airborne virus could catch up to them. They were nearly sealed out of the safe room when its blast doors were triggered, but Tano held the doors open with the Force, allowing Rex and the other soldiers to jump through the crack. They in turn pried open the doors long enough for Tano to clear the jump. However, they discovered that some of the virus had entered the safe room, exposing them to the plague. Despite being infected, Rex believed that they could still contain the laboratory's remaining battle droids—in total numbering over a hundred—before they broke out and released the virus to Naboo's surface, even if such an act would be his last. Soon, Amidala and Binks, clad in enviro-suits, let them out of the safe room, dismayed that they could not do anything to help their infected comrades. After offering a DC-15S to Amidala, Rex joined Tano and another trooper in cutting off the battle droids from the bunker's north corridor, while Amidala, Binks, and the other troops took the south passage. They met halfway at an exit hatch, where Rex helped Amidala gun down the last battle droid attempting to cut through the hatch.

Over the next six hours, Rex and his comrades continued through the compound. When they were faced with a pair of droidekas, Rex and the others provided covering fire for Tano as she charged at and engaged the droids. Although Tano finished off the droidekas, Amidala's enviro-suit was breached in the ambush, and she was consequently infected with the virus. Nevertheless, Amidala remained committed to eradicating the Separatist forces. Rex and the others did not stop until they had rooted out and eliminated the last of the droids, completing their objective within thirty hours—by which point, four clone troopers besides Rex had been exposed to the virus. As the disease took its toll, Rex aided Amidala in tending to the other infected soldiers. While Amidala lamented the clones' wasted lives, Rex replied that it was what they had been born to do. Tano thereafter fainted from the virus's effects, and Rex caught her as she collapsed.

Meanwhile, Skywalker and Kenobi collected a sample of reeksa root—a cure for the Blue Shadow Virus—from the planet Iego and returned to Naboo. They thus neutralized the virus with the antidote, just in time to save their friends. Expected to make a full recovery, Rex and the other afflicted were placed on mobile stretchers and brought onto the complex's landing pad, where 2-1B medical droids ushered them onto waiting LAAT/i gunships. Before departing, the ailing Rex made it clear to Kenobi that he did not intend to help train Binks, whom Amidala had recommended for blaster training. Rex later healed and returned to fighting shape. For his part in protecting the Naboo people from the virus, Naboo's Theed Arms gifted Rex with a set of specially chromium-plated blaster pistols dubbed the "Vigilance" and "Negotiator."

Rex was deployed aboard a Republic fleet led by Skywalker, Tano, and Yularen to the Twi'lek homeworld of Ryloth, which the Confederacy had earlier seized with the aid of the Techno Union. They were tasked with eliminating the Separatist blockade of Ryloth to secure passage to the surface for a Republic invasion force under the command of Kenobi and Mace Windu. During Skywalker and Tano's first assault on the blockade, the arrival of Separatist reinforcements forced the Star Destroyers Resolute and Defender to withdraw from the Ryloth system, while the Redeemer collapsed to enemy fire. Yularen was injured, and Tano, who led Blue Squadron in her first command position, lost the majority of her men. As the Resolute and Defender reached their staging area, Windu asked for a status update from the Resolute, prompting Rex to go looking for Skywalker. He found his Jedi General in the hangar with Tano, who was distraught from the loss of her squadron, and told him of the incoming transmission. After compiling a damage report for Skywalker, Rex joined him on the bridge to speak with Kenobi and Windu, who granted Skywalker a single planetary rotation to complete his assignment. At his general's request, Rex went to locate Tano and found her in the medbay visiting Yularen; she left with Rex upon hearing that her Master was looking for her. Rex later received word of a complication aboard the Defender, which had been hit heavily during the engagement, and notified Skywalker via comlink.

Due to the Defenders damages, Skywalker devised a plan to sacrifice the cruiser. He intended to pilot it into a collision with the lead ship of the Separatist blockade, which would leave the enemy fleet in disarray without its commander, Captain Mar Tuuk. Skywalker thus ordered the Defender evacuated, and Rex helped him supervise the processing of the Defenders supplies as LAAT/i gunships transferred its matériel to the Resolutes hangar bay. When Tano arrived, Rex stepped in to oversee the cargo sorting while Skywalker explained his plan to his Padawan. Tano's role involved her assuming command of the Resolute to assault the remainder of the blockade. Though she felt unprepared to do so, Skywalker continued on and gathered Rex and their men, informing them that Tano would fill them in on the full plan. Before Skywalker left for the Defender, Rex asked him to leave some battle droids for him and the clones, though Skywalker made no promises. With Yularen still out of action, Rex joined Tano and the Resolutes navigation officer on the bridge to coordinate their next move. Upon hearing Skywalker's plan from Tano, Rex, believing that the odds were not in their favor, voiced hesitancy along with the naval officer about the strategy's chance for success.

Once Skywalker had annihilated the blockade's command ship, the Resolute would be exposed to attack from the Confederacy's six remaining Munificent-class frigates. To counter the enemy firepower, Tano proposed that they angle the Resolutes hull toward the Confederate frigates, drawing them in with a classic Marg Sabl maneuver, at which point Republic starfighters would launch to outflank them. Both Rex and the naval officer were apprehensive about employing a risky Marg Sabl, but a convalescent Yularen arrived to support Tano's proposal. Upon their return to the Ryloth system, Tano delegated command of the Resolute to Rex and Yularen while she prepared to oversee the starfighter assault. The Resolute moved into place following the Defenders obliteration of the Confederate command ship, but the other frigates did not immediately converge on the Resolute. Though Rex and Yularen concluded that they would have to retreat if the Separatists did not attack, Tano advised them to be patient, believing that the frigates' droid commanders would take the bait. Sure enough, the frigates moved in just a few moments later, and Tano responded by leading several Y-wing bomber squadrons into battle against them. The Separatist blockade was outflanked, and Kenobi and Windu thereafter arrived with the invasion troops aboard a trio of Acclamator-class transports. After referring the Jedi Masters through to Tano, Rex sent a shuttle to retrieve Skywalker's escape pod.

With the blockade broken, Kenobi and Windu were able to land their forces and recaptured Ryloth's capital, Lessu. They also arrested Techno Union Foreman Wat Tambor, who had overseen the Confederate invasion. Following the Battle of Lessu, Rex, Skywalker, Tano, and the 501st Legion were tasked with clearing out the remaining Confederate holdouts on Ryloth, which—in spite of the capture of Tambor and their defeat at Lessu—were refusing to surrender to the Republic. Rex landed his troops in the wastelands near the city Resdin, where the Separatists were based, and led an assault on the battle droid infantry there. He waded into the fray and gunned down a number of battle droids before Skywalker and Tano joined him; the pair proceeded to infiltrate the enemy's position. Rex and ARF Sergeant Boomer caught up with the Jedi on the city outskirts after they had defeated an octuptarra magna tri-droid, reporting that all of the droids in the area had been eliminated. Rex then joined Skywalker, Tano, Clone Sergeant Kano, and trooper Rookie on an LAAT/i gunship into the ruined city, where their squad disembarked. Rex reported that their patrols had encountered stiff resistance from the Confederacy, and he cautioned Skywalker and Tano as they departed to reactivate the city's outer holo-bridges. They succeeded in restoring power to the bridges, allowing the 501st Legion to enter Resdin.

That night, Rex went on a patrol of Resdin with Boomer aboard All Terrain Recon Transports. They found a myriad of battle droids in the city streets and fought through the enemy squads. After they exited a narrow alley and reached a large area below, more groups of B1, B2, and DSD1 battle droids ambushed them. The two troopers used their AT-RT walkers' cannons to decimate the droids and entered another street. Rex and Boomer noticed a suspicious figure running out from behind a building amidst the shadows, and they dismounted for a closer look. Rex reported the strange activity to Skywalker and Tano, but just as he transmitted his coordinates, he and Boomer were attacked by the figure whom they had spied—notorious bounty hunter Cad Bane. Bane took the two clones hostage and brought them to an underground hangar, where they awoke in binders. With their binders wired with explosive charges, Rex and Boomer were forced to help Bane transport a crate he had stolen to his ship, though they first had to contend with a contingent of Separatist battle droids that broke into the facility. Once Bane unlinked their binders and let them retrieve their blasters, Rex and Boomer joined the bounty hunter in battling the droids, using several crates as cover.

Rex closed the main hangar door and several auxiliary hatches via computer terminals, sealing out the droids. A Vulture droid thereafter broke through, but Rex used a rocket launcher from Bane to make short work of the droid. Though Boomer believed they could defeat Bane, Rex kept him focused on the matter at hand when Separatist reinforcements turned up in the form of B1, B2, and sabotage droids. Skywalker and Tano soon arrived and grudgingly decided to assist Bane, helping to eliminate the incoming droids. Bane then opened fire on Rex and his comrades, but Skywalker rebounded his blasterfire, forcing the bounty hunter off a platform. Upon learning of Bane's "arrangement" with the cuffed Rex and Boomer, Skywalker severed their binders with his lightsaber, neutralizing Bane's bargaining chips, and had the clones disarm Bane of his LL-30 blaster pistols. As explosions began to shake the hangar, Bane offered his Telgorn dropship, the Sleight of Hand, as an escape craft. Skywalker accepted Bane's offer and sent Rex and Boomer to find an elevated position from where to provide covering fire from the surrounding battle droids. Rex and Boomer took a path overlooking Ryloth's wastes, gunning down numerous droids along the way, including several tri-droids.

Once they had cleared the way and were in position, Rex commed Skywalker, who came to join them with Tano, Bane, and the latter's crate, which Skywalker intended to have the Republic investigate. While Rex and Boomer engaged the droids above a canyon, the others pressed through enemy waves below. When the Jedi found starship wreckage blocking their path, Rex fired a rocket at the rubble, allowing them to climb over the debris. Skywalker, Tano, and Bane soon began to move out of range, and Skywalker thanked Rex for the assistance, ordering him and Boomer to rendezvous with them at the Sleight of Hand. They arrived at the dropship a short while later to find Skywalker and Tano in mid-battle with the Separatist scientist Kul Teska, from whom Bane had stolen the crate. Although Teska encased Skywalker and Tano inside an energy bubble, Skywalker told Rex and Boomer to focus on Teska instead of rescuing them; the two troopers complied and engaged him in combat. Teska issued to them an ultimatum: kill him or save their Jedi commanders, promptly programming the energy bubble to close in on Skywalker and Tano. Rex and Boomer came to the Jedi's aid and disabled the sphere, while Teska boarded the Sleight of Hand and escaped off-world with his retrieved crate. Though Rex was disheartened by his failure to prevent Teska's getaway, Skywalker thanked him and Boomer for rescuing them. Meanwhile, Tano discovered that Bane had also absconded.

Following the conclusion of the Battle of Ryloth, the Jedi High Council learned that Teska, based out of an underground base on the planet Behpour, was planning on collapsing the Naboo system's sun with a superweapon known as the gravitic polarization beam. Rex and Cody were dispatched alongside Skywalker, Tano, Kenobi, and Windu to destroy the facility with a clone battle group. Rex and Cody staged a diversionary assault, marching through a canyon on AT-RT walkers and demolishing all Separatist forces they encountered, so that Skywalker and Kenobi could infiltrate the base and disable its deflector shields. With Rex and Cody distracting the droids, Skywalker and Kenobi deactivated the shield barrier, in turn enabling Windu and Tano to enter the underground facility and secure the entrance with the main detachment of troops. Inside, Rex and Cody rendezvoused with Clone Commander CC-6454, nicknamed "Ponds," whom Windu had sent to help them set up an evacuation zone for their forces. The trio fought their way through the base and secured a landing pad, where Rex destroyed a Vulture droid with a series of rockets.

From a computer terminal, Cody used the base's emergency beacon to signal R2-D2, who piloted the Twilight to the platform to serve as an escape vessel. Eventually, Count Dooku came in person to confront Rex, Cody, and Ponds, and though they directed blasterfire at him, Dooku Force-pushed them into the Twilights cargo bay and sealed its hatch shut. Dooku then used the Force to topple a beam onto the Twilight, plunging the clones and their ship into the abyss below. However, Rex and his comrades survived the fall and returned to rescue Kenobi and Windu—who had begun a duel with Dooku—just as falling debris impacted the platform's supports. Once Kenobi and Windu had boarded the Twilight, Rex and the others withdrew from the base, which was beginning to collapse. At Kenobi's recommendation, they hovered above the entrance and waited around long enough for Skywalker and Tano, who were still inside, having been delegated the task of disabling the gravitic polarization beam. Skywalker and Tano soon arrived with Padmé Amidala, whom they had rescued from Teska's custody, and jumped aboard the Twilight from stolen STAPs. Rex congratulated them on their victory, and they left Behpour shortly before the sabotaged superweapon imploded the base, claiming Teska's life and the local site along with it.

Following a Confederate invasion of the contested world of Felucia, Rex was among the troops sent to defend the planet alongside Skywalker, Tano, Kenobi, and Cody. Their contingent of clone troopers became based in a jungle clearing, from where they launched strikes on the outlying droid infantry. However, Rex and his comrades were soon surrounded and overwhelmed, and they called for an evacuation. Once LAAT/i gunships led by Plo Koon had broken through the Separatists' orbital defenses and had landed in the clearing, Rex and Cody herded their men onto the gunships, backing into one of the vessels while returning blasterfire at the encroaching battle droids. As soon as Skywalker and Kenobi had joined them on the gunship, they went to retrieve Tano, who was overseeing a jungle patrol elsewhere. Although Tano initially refused to retreat, Skywalker had the gunships land between her patrol and the droid army, forcing her to disengage from the fight and join Rex and the others aboard their craft. They lifted off just as droid reinforcements annihilated the ground vehicles that Tano had abandoned.

Although the Republic was unable to hold Felucia, it was not long before Rex returned to the war zone. He next joined Skywalker, Tano, and Admiral Yularen aboard the Resolute on their assignment to intercept Cad Bane, who had stolen a holocron from the Jedi Temple Archives. They proceeded to the Devaron system, where Bane's next target, Jedi Master Bolla Ropal, had last been heard from. By the time the Resolute arrived at Devaron, Bane had already captured Ropal to access the Kyber memory crystal, a device whose safety had been entrusted to Ropal. As Bane was rendezvousing with a Trade Federation fleet of Munificent-class star frigates, the Resolute moved in and opened fire on the frigates, decimating Bane's naval escort and stranding him in-system by disabling his command ship's hyperdrive. Assembling their forces in the Resolutes hangar, Rex rounded up three brigades of troops for the impending mission. When he learned from Skywalker that they were to board the enemy frigate to rescue Ropal and the stolen holocron, he expressed hesitancy, as their only available assault craft were the Twilight and a few starfighters. In response, Skywalker decided that they would repurpose several available AT-TE walkers as landing craft. Although Yularen was appalled at the idea, both Rex and Tano recognized that the walkers were suitable for space and complimented Skywalker on his resourcefulness.

Rex assigned Execute Battalion to Walker ATAT300, while Carnivore Battalion was to use Walker 773. Once the boarding party was ready, the Resolute maneuvered into position over Bane's frigate and dropped ATAT300, 773, and a third walker with the Jedi and clones aboard onto the hull of the enemy craft. While the AT-TE clone tank gunners targeted several oncoming Vulture droid starfighters and droid-piloted STAPs, Rex and his men provided covering fire for Skywalker and Tano to eliminate the Vulture droids. Once the droids had been repelled, R2-D2 opened a hatch on the frigate's hull, allowing Rex and the rest of the boarding party to enter the vessel. They then stormed the bridge, swiftly eradicating the frigate's battle droid crew—yet Bane was nowhere to be found. R2-D2 soon uncovered a record of a holographic conversation between Bane and Trade Federation Viceroy Nute Gunray from the frigate's computer. Replaying part of the transmission, Rex, Skywalker, and Tano learned that Bane had now acquired the memory crystal as well as the holocron, having stolen the former from Ropal. On Skywalker's orders, Rex sent a squad of troopers to secure the hangar bay and disable the frigate's escape pods to prevent any enemy forces from escaping. Yet he refrained from accompanying the squad when explosions began to rock the ship as a result of Bane's remote activation of the self-destruct sequence. Rex instead joined Skywalker and Tano in searching the ship for Ropal.

When Tano found Ropal dead in one of the holding cells below decks, Skywalker ordered Rex to have some of his men transfer Ropal's body to the Resolute. The deck lights were suddenly extinguished, and R2-D2 used his headlamp to lead Rex and the others through the dark hallways in search of Bane. Upon blindly colliding with a protrusive pipe, Rex told his men to switch their helmet visors to night vision, doing so himself by pulling down his helmet scope. They soon caught sight of a fleeing Bane and pursued him to the gunnery deck, where Bane, having lured them there, revealed a detachment of battle-ready droids. As Rex and his comrades engaged the B1 and B2 battle droids with blasterfire, Bane decided to intensify the fight by switching off the artificial gravity. Rising off the ground, Rex and his men used their magnetic gripsoles to latch onto various footholds before resuming their efforts against the battle droids, with Rex securing himself on one of the artillery guns. When a blaster cannon–wielding trooper hit a disabled droid and inadvertently dislodged an ammunition canister from an artillery gun, Rex warned his men to check their aim to avoid detonating a shell. They continued the battle even after R2-D2 reactivated the gravity generators.

Shortly thereafter, Bane lured Tano into a trap, drawing her into a dead-end hallway and sealing the blast doors behind her. Skywalker rushed over and began to cut through the blast doors with his lightsaber to rescue his trapped Padawan. Presently, a battle droid tripped and misfired at an ammunition canister. The blast from the exploding shell caused debris to seal off Rex and the rest of his men from Skywalker. Unable to move the heavy mounds of rubble, Rex called out to his Jedi General and finally got a reply from him, confirming he was alive. At Skywalker's behest, Rex headed for the hangar bay with R2-D2 and their troops to secure a transport with which to evacuate from the frigate. In the hangar, Rex found that the squad he had sent earlier was already confronting B1 and DSD1 dwarf spider droids that were guarding a Sheathipede-class shuttle. He and the others joined the fight for the shuttle, using crates as cover to return the advancing droids' fire. Rex soon received word from Yularen that the frigate's main reactor was exposed and would implode at any moment. Splitting his forces, Rex sent troopers Denal and Koho to assist Skywalker and Tano in their pursuit of Bane. In the meantime, the captain and his men managed to cut a path through the droids and seized the shuttle.

As Rex began to herd his troops aboard, he finally received word from Skywalker, who had rescued Tano and was heading to the hangar with her. He informed Skywalker that due to the danger that the reactor posed, they had to leave as soon as possible. The clone troopers held out against more battle droids long enough for Skywalker and Tano to arrive; Rex immediately waved the two aboard the shuttle. Before jettisoning away from the frigate, the shuttle picked up Denal, whom Rex and his comrades had witnessed shoot Bane on an overhang above the hangar. However, the armor-clad trooper was, in fact, Bane, who had killed both Denal and Koho and had stolen the former's armor. When Skywalker questioned him, "Denal" alleged that he had been unable to retrieve the holocron from Bane. Rex's shuttle withdrew moments before the supply of ammunition aboard the frigate detonated, ripping the vessel apart.

After reaching the Resolute, the Jedi and clones disembarked from the shuttle, though Rex and another trooper discovered that someone had left behind green blood on the shuttle's deck. Rex called Skywalker back aboard the transport and showed him their discovery, stating that the blood was definitely not from any of the clone troopers. Skywalker and Tano simultaneously realized the exploits of Bane, who bowled over Tano and promptly fled for the hangar's nearby stock of starfighters. Skywalker jumped onto the V-19 Torrent starfighter that Bane was powering up, though since the bounty hunter was already in the cockpit, Skywalker was unable to do much interference. Rex, a recovered Tano, and the other present troopers could only watch as Bane forced Skywalker off his stolen starfighter and piloted it out of the Resolutes hangar. Despite being alerted by Skywalker, Yularen was unable to lock down the hyperspace booster rings in time, and Bane appropriated one to escape to hyperspace. Though Bane remained at large, the Jedi Order later recovered the stolen holocron from his hideout.

Following the Battle of Devaron, Rex returned to Coruscant with Skywalker and Tano. At one point, he was sent to take a priority message from the Jedi High Council to Jedi General Keelyvine Reus; her Padawan, Tyzen Xebec; Clone Commander Ganch; and the Agricultural Corps worker Sanya, who had just arrived at a local staging area aboard the Star Destroyer Selfless following a campaign on the planet Ukio. Rex informed Reus that she and Xebec were to report to Master Yoda at the Jedi Temple. He also offered to take Ganch, whom Reus had excused from duty, to spend some downtime at the Republic Service Organization center. Ganch accepted the invitation and brought along Sanya, while Xebec returned to the Temple with his Master. Ganch soon received word from Reus that he would not be required for her and Xebec's next operation.

At the Service Organization's headquarters, Rex found Cody at one of the tables in the mess hall and, after introducing Ganch and Sanya to Cody, settled down to have a drink with his comrades. However, their downtime was cut short when Sanya discovered that someone had wired all of their chairs with remotely activated detonite charges. Further investigation on Sanya's part revealed that only the clone soldiers' chairs had been wired and that the detonators were all linked in series. Because the charges required simultaneous defusing, all available personnel from the Service Organization volunteered their services for the task. Although Rex was concerned with the amount of coordination that such a maneuver would require, the workers were able to disable the detonators under Cody's close supervision. When one staff member hastily made an exit, revealing herself as the infiltrator who had planted the explosives, Ganch and Sanya quickly went in pursuit of the saboteur, though they were unable to capture her. Ganch received fresh orders for redeployment with Reus shortly thereafter.

When the Confederacy initiated a conquest of the planet Malastare, Rex accompanied Skywalker, Windu, and Commander Ponds to oversee the Republic's defense of the beleaguered planet, as the Grand Army coveted its vital fuel reserves. In what was to become one of the lengthiest and fiercest engagements of the war, the Separatists gained the upper hand with an army several thousand battle droids strong. Supreme Chancellor Palpatine responded by authorizing the use of the electro-proton bomb, a creation of Doctor Sionver Boll that would generate an electron field capable of deactivating the entire droid army. Rex was tasked with shoring up the fortifications of the Doge's Palace—the residence of Doge Nakha Urus, the leader of the Dugs—until the bomb was detonated, and he proceeded to the front of the palace's defense lines to command the Republic troops, monitoring the massive droid army's approach with a set of electrobinoculars. Once the battle droids launched their assault, Rex held the line with his men, working in tandem with squads of insectomorph-mounted Dug cavaliers to repel the droid infantry.

Presently, a starfighter squadron dropped the electro-proton bomb in the middle of the droid army, producing an explosion that transformed into an electromagnetic pulse. The enlarging pulse disabled all of the droids and disrupted the clone troopers' helmet systems for a short time. The bomb also destabilized the surrounding ground, and Rex and his troops turned tail and bolted away as the tremors birthed an enormous sinkhole. Rex nearly fell into the expanding sinkhole when he became trapped on an unstable plateau, but he managed to jump to higher ground with the help of his troops. While rescue teams searched for the Republic personnel trapped in the crater, Rex joined Skywalker, Windu, Urus, R2-D2, and Doctor Boll at the Doge's Palace, where they reestablished holographic communications with Palpatine. After Windu and Urus conferred with Palpatine on the status of the Republic's fuel treaty with the Dugs' council, Rex reported that they had lost contact with the rescue team in the crater. Windu and Skywalker thus departed to respectively aid the rescue team and attend to the Dug leaders. Both Jedi soon found that the electro-proton bomb had awakened a colossal Zillo Beast in the crater; not even Skywalker's lightsaber made so much as a dent on the creature's tough scales.

As night fell, Rex met with Skywalker, Windu, and Boll at Urus's palace to discuss the problem of the uncontrollable Zillo Beast with Palpatine. While the Dugs wanted to kill off the Zillo Beast on account of an ages-old enmity with its kind, the Jedi wanted to preserve the creature, as it was one of the last of its near-extinct species. To appease the Dugs and ensure the ratification of the fuel treaty while also saving the Zillo Beast, Skywalker devised a plan to knock out the creature with the Republic's RX-200 Falchion-class assault tanks and then transport it off-world, thereby concealing its survival from the Dugs. The following morning, Rex served with the unit that was sent to subdue the beast under the command of Skywalker and Windu. Once the Republic forces rendered the Zillo Beast unconscious using Skywalker's strategy, Rex returned with Skywalker and Windu to the Doge's Palace, where Urus and the other Dug leaders signed the fuel treaty. As the Republic forces prepared to depart from Malastare, complications arose regarding the matter of the Zillo Beast. Although the Jedi had planned to deliver the creature into serene solitude on an uninhabited world, Palpatine ordered that they bring it to Coruscant for study before its release into the wild.

Rex returned to Coruscant with Skywalker, Windu, and Boll aboard an Acclamator-class transport. Back on the capital, the Zillo Beast was transferred to the Republic Science and Technical Center, where Boll began to analyze the creature's unusually durable scales in the hopes of synthesizing them into a new, impenetrable clone trooper armor. That evening, despite substantial containment measures, the Zillo Beast broke out of the Science and Technical Center and began to rampage across the ecumenopolis of Coruscant. As the creature headed for the Republic Executive Building, Rex joined an LAAT/i gunship force led by Kenobi and Windu that had set out to contain the beast. He contacted Skywalker through R2-D2, both of whom were with Palpatine and Padmé Amidala in the Chancellor's Suite at the Executive Building, and confirmed that he was to serve with Kenobi for the time being. Yet when Rex, Kenobi, and Windu reached the Senate Plaza with their detachment of clone troopers and stun tanks, they found that the Zillo Beast had taken hold of the H-2 executive shuttle that Palpatine, Skywalker, and Amidala had been using to flee from the Executive Building with R2-D2 and C-3PO.

Rex, monitoring the Zillo Beast and its captives through a pair of macrobinoculars, noticed that Skywalker was cutting the shuttle in half with his lightsaber and notified Windu. Kenobi deduced that Skywalker intended to free himself and the other passengers by severing the ship in two. While the recently arrived Yoda and Aayla Secura ran interference to distract the Zillo Beast, Skywalker finished slicing the shuttle in half, freeing himself and the others from the creature's grip. Kenobi and Windu quickly used the Force to stabilize the section of the shuttle carrying Palpatine and a Senate Commando, preventing them from falling off the dome of the Executive Building. While the stun tanks targeted the Zillo Beast, the LAAT/i gunships launched with Rex, Kenobi, Windu, and their men aboard and also opened fire, though neither approach proved effective in subduing the rampant beast. With no other options, Palpatine ordered the gunships to release toxic gas bombs that Boll had developed to kill the creature. Though the gas bombs proved successful, thus saving the Coruscanti populace from the Zillo Beast, the victory came at the price of the beast's life. The next morning, the slain Zillo Beast was transported back to the Science and Technical Center. Rex and his comrades met with Palpatine in the Senate Plaza to debrief the disaster, mourning the loss of the creature. While Rex and the others departed from the Senate Plaza aboard the gunships, Palpatine secretly gave Boll orders to clone the Zillo Beast.

In late 22 BBY, the Republic learned that Geonosian Archduke Poggle the Lesser had overseen the reconstruction of a major battle droid foundry for the Confederacy on Geonosis, despite the Republic's capture of the planet following the First Battle of Geonosis. In response, Rex took a detachment from the 501st Legion to reconnoiter Geonosis in preparation for a Republic assault. Upon arrival in orbit, his task force tried to hail the clone troopers on the surface but failed to establish contact. Conducting a preliminary scan, Rex discovered that the Geonosians had built not one but several droid foundries that were either nearing completion or already operational. In his report to the Jedi High Council, Rex classified the Geonosians' actions as a major revolt and asserted that a full-scale planetary invasion would be necessary to retake the Outer Rim world. Before ending the transmission to Coruscant, he promised to provide a further analysis of the Geonosian defenses once he had completed his mission. Based on his findings, the Jedi Council authorized an immense invasion force to reclaim Geonosis and shut down its droid factories. Kenobi, Ki-Adi-Mundi, and Luminara Unduli were given overall command for the campaign and brought the invasion fleet to Geonosis, soon followed by the arrival of Skywalker and Tano, who had come from defending the planet Dorin from General Grievous.

As the Republic fleet held position in orbit of Geonosis, Rex, Cody, and Mundi's clone commander, CC-1993, joined their Jedi officers aboard one of the Star Destroyers to plan out their attack. Cody led the briefing in the war room, explaining their plan for a three-pronged assault on the Geonosian defenses. As their main target was the ray shield generator protecting the droid factories, the invasion team would establish a staging area—termed "Point Rain"—before launching an attack on the Ray Shield Fortress. While Mundi and CC-1993, nicknamed "Jet," would oversee the advance from the north, Kenobi and Cody would execute the central push, and Rex, Skywalker, and Tano would lead the assault from the south. All three teams would rendezvous at Point Rain and then assault the Ray Shield Fortress. With the plan set, the Jedi and their clone officers split up to begin preparations for the invasion. Once the fleet was ready, Rex, Skywalker, and Tano launched with their LAAT/i gunships and LAAT carriers, the latter craft hauling several AT-TE walkers; their deployment followed and preceded that of Kenobi and Mundi, respectively. All of the gunships encountered stiff resistance from the Geonosians' surface artillery and Nantex-class starfighter squadrons.

The gunship carrying Rex, Skywalker, and Tano was among the first to be shot down, and they crashed near an encampment of blaster cannon–equipped Geonosian warriors. Once Skywalker heaved away the wreckage of the gunship, Rex joined him, Tano, and their men in assailing the Geonosian lines. After they lost their AT-TE walkers, Rex tried to hail Kenobi for reinforcements, but he learned from Cody—whose team had so far been the only one to reach Point Rain—that Kenobi's gunship had crashed. Ducking behind some rock cover with Skywalker, Rex informed him and Tano that Kenobi would be unable to provide support. Making do with their available resources, Rex and the Jedi led their men in rushing the blaster cannons. They pressed on toward Point Rain, but their trek led them through a canyon blocked by a massive Separatist barricade, riddled with hordes of gun emplacements and battle droids. Rex and his comrades rushed for cover from the incoming blasterfire; several troopers were slain before they could reach safety. To collapse the wall and clear a path to Point Rain, Skywalker and Tano each took a backpack filled with thermal detonators and left Rex in command of the troops. While Skywalker and Tano ascended the barrier and fought through the thick droid defenses, Rex targeted one of the enemy cannons, gunning it down. He then had his men focus their fire on the battle droids atop the wall while he went to ascend the barrier himself.

Rex aided Skywalker and Tano in their fight with a pair of droidekas, sneaking up on the one attacking Tano. He walked right through its deflector shield and shot it in the head; the distraction also enabled Skywalker to eliminate the droid's companion. Skywalker and Tano wasted no time with tossing their primed detonator–laden backpacks into a nearby hatch, and they then used the Force to levitate Rex off the wall and into the air. They jumped off the barricade, with Rex falling close behind, just as the explosives tore through the wall. Skywalker and Tano used the Force to slow their descent as they landed, employing the same technique to cushion Rex's fall centimeters from the ground just as the barricade came crashing down around them. Rex and the others headed for Point Rain and soon caught sight of a number of smoldering Geonosians falling out of a clifftop cave close by. Skywalker recognized Mundi atop the cliff with his troopers and, via comlink, learned that Mundi's squad had taken a detour through the cave en route to the landing zone. Once Skywalker and Mundi had joined forces, all of them proceeded to Point Rain, where Cody and Kenobi were in desperate need of support against the Geonosians.

Shortly after a Y-wing bomber squadron drove away most of the Geonosians from Point Rain, Rex and his comrades arrived, repelling the last of the enemy insurgents. After Rex and his fellow officers decided on a plan, they set out for their final objective: destroying the Ray Shield Fortress. Once Skywalker, Tano, and a small squad had disabled the Geonosians' blaster cannons with EMP grenades, Cody moved in with the AT-TE walkers and took out the shield generator and its artillery stations. With the shield down, Rex, Mundi, and Jet landed at the Ray Shield Fortress with the main body of troops and forced the outnumbered Geonosians to surrender. Kenobi and Mundi, both wounded from the battle, returned to the fleet for treatment, leaving Rex, Skywalker, and Tano to eliminate the near-completed primary droid foundry, where Poggle the Lesser was holed up.

Rex, Skywalker, and Tano moved their troops to the cliff opposite the factory, which was on the other side of an immense canyon spanned by a single bridge. Luminara Unduli; her Padawan, Barriss Offee; and Commander Gree soon arrived with reinforcements, and Rex greeted Unduli and Offee when their gunship landed and directed them to Skywalker and Tano. Together, the four Jedi devised a plan to cripple the droid foundry: Skywalker and Unduli would spearhead an assault on the foundry, acting as decoys for Tano and Offee to infiltrate the facility via the network of catacombs beneath it and plant explosives at the main reactor. Although a full frontal offensive would be risky due to the lack of cover along the canyon bridge, Skywalker and Unduli hoped to consequently entice Poggle into engaging them in open warfare. After the two Padawans had departed, Skywalker and Unduli began the assault. Deployed factions of B1 and B2 battle droids intercepted them on the canyon bridge, and Rex and his fellow officers headed the charge on the Separatists. Despite a Geonosian offensive from the rear, the Jedi and clones maintained their parade-style march toward the factory. When several droidekas rolled into range and opened fire, Rex ordered trooper Draa forward with an RPS-6 rocket launcher. Draa blasted the droidekas to smithereens in one shot, and the heavy firepower from the battle group's AT-TE walkers impeded the remaining droid forces.

Rex and his troops were thereafter faced with the deployment of several droid-manned super tanks, which Poggle's foundry had just finished manufacturing. At Skywalker's behest, Rex mobilized four AV-7 Antivehicle Cannons, having them open fire on the super tanks just as they reached the opposite end of the bridge. However, the ray-shielded tanks withstood the dense cannonades and pressed onward. Rex was forced to take cover with Skywalker, Unduli, Gree, and their men when the super tanks released a multitude of warheads at their position. The ensuing bombardment obliterated the heavy cannons and AT-TE walkers, and the clone troopers also suffered significant casualties. When Skywalker ordered Rex to have the troops fall back, Rex was initially adamant against retreating, but he complied when Skywalker detailed his plan: After the tanks had reached the bridge, Skywalker and Unduli would collapse it with explosives. Once Rex and his men retreated, luring the tanks onto the span, Skywalker and Unduli swung under the pass hand by hand and planted thermal detonators on its underside. When they had reached the other side, Skywalker activated the charges, collapsing the bridge and plunging the super tanks into the deep chasm below.

While waiting with Unduli for their Padawans outside the foundry, Skywalker commed Rex and questioned whether he had spotted Tano or Offee from his side of the canyon. Rex replied that he had not yet sighted either Padawan and also urged Skywalker to board an evacuation ship, though Skywalker refused to leave without Tano. Meanwhile, Poggle and a squad of Geonosians intercepted Tano and Offee at the foundry's reactor. When the enemy soldiers stole their explosives, the two Padawans saw no other choice but to use a super tank to destroy the power generator, sacrificing themselves to liquidate the facility. Once the rubble settled, Rex and Gree found Skywalker and Unduli amidst the debris field aboard an LAAT/i gunship. Rex reported to his generals that the LAAT carriers were moving the debris to search for the Padawans, who had been buried with the remains of the factory. Though Rex and his men did their best to locate the trapped duo, it was Tano who signaled them to her and Offee's location by boosting her comlink's reception with a power cell from the super tank. Rex and his fellow officers proceeded to the indicated area, and Skywalker and Unduli elected to lift the debris with the Force, despite Rex's offer to have the gunships move the heavy rubble. Once their super tank had been freed, Tano and Offee emerged, grimy but otherwise unscathed. Rex and his men looked on as the Padawans enjoyed a reunion with their Masters.

Following the decimation of the main foundry, Rex went with Tano and Offee to one of the Republic's staging areas, where he sent them back to the fleet for a much-deserved rest. Before departing aboard a medical convoy of gunships, Tano and Offee promised to return soon. Meanwhile, as other key droid factories were eliminated, Kenobi and Unduli initiated a manhunt for Poggle to bring him to justice. They and Skywalker eventually captured the Separatist leader in the catacombs beneath the Progate Temple, the lair of Geonosian Queen Karina the Great, who perished during their escape from the catacombs. With Karina dead, the Republic triumphed over the Geonosians and cemented its control of Geonosis. Shortly thereafter, Tano and Offee were assigned to take the Republic Pelta-class frigate TB-73 on a supply run to a medical station near the planet Ord Cestus. In the meantime, Rex accompanied Skywalker, Kenobi, Mundi, and Unduli aboard a Venator-class Star Destroyer to escort the captive Poggle to Coruscant for trial. At one point during their voyage through hyperspace, Rex accompanied the four Jedi Generals to the bridge to discuss a complication. Unduli had discovered that the Padawans' transport had failed to check in on schedule, and when she tried to contact TB-73, the crew was unresponsive. While Skywalker concluded that something was wrong, Kenobi convinced him that it was not worth worrying over.

Mundi turned their attention back to Poggle, who was resisting their questioning and refused to disclose any Confederacy military intelligence. Before leaving to continue interrogating Poggle with the other Jedi, Skywalker privately told Rex to remain on the lookout for any contact from Tano, which he agreed to do. Rex soon contacted TB-73 himself, and Tano answered the transmission, expressing her relief to hear from him. Once Rex put Skywalker through, Tano reported that Geonosian brain worms had overrun her frigate. The worms, originating from Karina the Great's hive, were capable of mind control and had already infected most of TB-73's embarked troopers from Tango Company. After resolving to wheedle information on the worms from Poggle, Skywalker severed the connection and headed to the detention level. Skywalker soon rejoined Rex, Kenobi, Mundi, and Unduli on the bridge and reported Tano's predicament, continuing with the news that the worms were susceptible to cold temperatures. Since he had Force-choked the so-far-uncooperative Poggle to compel him to divulge the information, Skywalker evaded the other Jedi's inquiries as to how he had gleaned the information. He relayed the worms' weakness to Tano, who neutralized them before TB-73 reached the Ord Cestus medical station.

As the war entered its second year, the Jedi Order learned that General Grievous had captured Jedi Master Eeth Koth. Skywalker, Kenobi, and Master Adi Gallia mounted a rescue mission to save Koth from Grievous's clutches and also capture the cunning Separatist general. Rex and a squad of troopers accompanied Skywalker and Gallia aboard an Eta-class shuttle, which joined the rest of the assembled Republic fleet in orbit of Coruscant in preparation for the assault. From his Arquitens-class light cruiser, Kenobi contacted Rex, Skywalker, and Gallia aboard their shuttle and conveyed the plan: Kenobi himself would head to the Saleucami system with the Republic fleet, distract Grievous's forces there, and transmit the coordinates of Grievous's command ship, which the Jedi presumed was where Grievous was holding Koth captive. Skywalker's shuttle would then be able to jump into the system undetected, infiltrate the command ship, and rescue Koth. While Kenobi and the Republic fleet departed for Saleucami, Rex and the others waited above Coruscant for Kenobi's transmission. Once Kenobi and Cody had transmitted the exact coordinates of Grievous's Recusant-class light destroyer, Skywalker took their shuttle to join the battle over Saleucami.

With Kenobi, Yularen, the Resolute, and the rest of the Republic fleet keeping the Confederate armada occupied, Skywalker's shuttle emerged from hyperspace and sped unopposed through the ongoing battle, quickly rotating upside down to dock to Grievous's destroyer. After securing the shuttle, Skywalker cut a hole in one of the command ship's hatches with his lightsaber and boarded the destroyer with Rex, Gallia, and their men. On Skywalker's orders, Rex and his men assumed guard positions around the hatch, as it was their only escape off the ship. While Skywalker and Gallia rescued Koth from captivity on the bridge, Grievous broke off from his ongoing duel with Kenobi aboard the Republic light cruiser and headed back to his own ship. Gallia subsequently went to prevent Grievous from escaping while Skywalker brought the weakened Koth back to the escape hatch, where Rex and the clones helped him into the shuttle before boarding themselves. As Skywalker released the shuttle from the destroyer, he and his comrades were contacted by Kenobi, who had pursued Grievous back to his command ship with Gallia, Cody, and several other clones; Kenobi requested transport off the ship before they became trapped there, as Grievous was abandoning ship. Skywalker complied and took the shuttle to the destroyer's main hangar, where they retrieved Kenobi, Gallia, Cody, and another trooper before the destroyer was damaged by debris from the naval engagement.

Although Rex and his comrades had saved Koth, they had not succeeded with their secondary objective of capturing Grievous. Nonetheless, the cyborg general's attempted escape was foiled when his C-9979 troopship was hit by debris and forced to crash-land on Saleucami. Kenobi resolved to head to the surface with Rex and Cody to apprehend Grievous while Skywalker and Yularen continued the space battle. After Skywalker brought the shuttle to one of the Republic cruisers, Rex helped Koth onto the flight deck and then passed him on to Gallia and a 2-1B medical droid, who escorted him to a medical frigate. Rex and a contingent from the 501st Legion then joined Kenobi and Cody on an Acclamator-class assault ship for the voyage to Saleucami's surface. Once the transport had landed and unloaded its personnel and matériel, Kenobi briefed Rex on their plan: Instead of scattering their men to locate all of the enemy troopship's escape pods, they would investigate the crash site for leads about the escape pods' drop zones. Rex traveled on a BARC speeder as Kenobi deployed their biker scouts and AT-TE walkers in search of the downed troopship. Upon arrival at the crash site, Rex and 501st trooper Jesse found that the troop compartments were damaged and relayed their findings to Kenobi and Cody. Kenobi decided to send teams to search for the escape pods, with Rex leading a patrol of Saleucami's wetlands.

Before Rex departed with a 501st squad comprising troopers Jesse, Kix, and Hardcase, Kenobi instructed him to send back word before engaging Grievous if they happened to encounter the elusive general. While leading his men through the lush wetlands aboard BARC speeders, Rex became the target of a two-member droid commando sniper team. One of the droids fired at him with a sniper rifle, knocking him off his speeder with a shot through the chest. Rendered unconscious, Rex could only lie sprawled where he had fallen as his speeder crashed into some nearby brush. While Kix, the squad's medic, circled around to protect Rex, Jesse and Hardcase eliminated the droid commandos with rapid blasterfire. Lifting off Rex's helmet, Kix did a cursory examination but needed to remove his armor to discern the full extent of his wounds. Realizing that they were on farmland, Jesse, Hardcase, and Kix decided to head for the grounds' homestead to find a safe place to tend to their fallen captain. After assembling a makeshift litter for Rex and affixing it to his own BARC speeder, Jesse led the team to the homestead with Rex in tow. They received permission from the Twi'lek farmer Suu to use an eopie barn for Rex.

Jesse, Hardcase, and Kix carried the still-unconscious Rex onto a bench, removing his armor and the top half of his black body glove so that Kix could properly tend to him. Rex finally regained consciousness after Kix had dressed his chest wound with a pair of bacta patches, waking up to discover from Hardcase that had the potshot been two inches to the left, it would have passed straight through his heart and caused instantaneous death. He also found that he was unable to move his left arm due to nerve damage. Pulling himself up into a sitting position, Rex told Kix to patch him up so that they could continue the search for Grievous. However, Kix told him that his wound would take time and rest to heal, countermanding his orders with his authority as the team's medic. Rex's argument with Kix was cut short when Suu arrived at the barn with some food for the clones. Her daughter, Shaeeah, entered the room chasing a ball and, upon catching sight of Rex, blurted out that he resembled her own father, a comment that intrigued him and his comrades. Despite Suu's demonstration of kindness, Rex sensed that something was bothering her, though he could not fathom what it was. While Suu conferred with Jesse and gave him the plate of food, Kix dressed Rex in an arm sling to help avert his temporary paralysis. Hardcase retrieved one of the captain's DC-17 blaster pistols from the pile of his armor on the ground, placing it next to him on the bench for easy accessibility.

After Suu had left with Shaeeah, Rex—recognizing that he needed to rest if he wanted his injuries to heal—reluctantly ordered his men to continue searching for Grievous without him. He entrusted command of the squad to Jesse, who departed the farm with Kix and Hardcase, leaving Rex behind. As night fell, Rex fell asleep on his bench, but a nosy eopie interrupted his slumber, sniffing him and licking his face. He forced the animal away, sighing before returning to sleep. He was later awoken a second time by the furtive sounds of an approaching figure—the farmer, Suu's husband. Rex's eyes snapped open, but he decided to feign continued slumber while slowly reaching for his blaster pistol. Once the farmer was close enough, Rex struck out at his assailant with his blaster, but the farmer disarmed him with a staff. The unarmed Rex looked up at his host and was shocked to find himself staring at his own face—the farmer was also a clone trooper. Recognizing this as the cause of Suu's earlier unsettledness, Rex demanded to know the trooper's number and rank, but the clone instead introduced himself as Cut Lawquane, a simple farmer. Realizing that Lawquane was a deserter, Rex called him out on his sworn oath to the Republic, but Lawquane replied that his duty was to his family, not to killing as a soldier. Their heated argument was interrupted when Suu brought her and Lawquane's children, Shaeeah and Jek, to welcome their adoptive father home.

After greeting his children, Lawquane invited Rex to dinner with his family, which he accepted when Shaeeah and Jek begged him to come. Putting the top half of his body glove back on, Rex joined the Lawquanes at their home, with him and Lawquane debating their distinct ideologies over a meal of roast nuna. Though Lawquane argued that the clones deserved more individuality, Rex countered that he was making an individual and deliberate choice to serve the Republic. Despite disagreeing, Lawquane respected his opinion, believing that everyone had a right to his or her own beliefs. After dinner, Rex and Lawquane continued their discussion of principles over a game of dejarik holochess. Following Rex's inquiries into the cause of his desertion from the Republic Military, Lawquane recounted his service in an engagement shortly after the First Battle of Geonosis. A devastating ambush by enemy battle droids had caused him to flee the carnage-laden battlefield, and he had subsequently begun to question his apparent expendability in the war. The wayward deserter eventually found his way to Saleucami and married Suu.

A survivor of Geonosis himself, Rex sympathized with Lawquane and stated that he, too, had lost many brothers—whom he had come to regard as his family and home—during the course of his military career. They began to reach common ground, with Rex in particular gaining a newfound respect for the man he had at first labeled a disloyal deserter. In the meantime, Shaeeah and Jek received permission from Lawquane to play outside, prompting Rex to express his admiration of the children to their father. In response, Lawquane, perceiving that Rex believed he was a coward, voiced his determination to keep his children safe until his dying breath. Rex, Lawquane, and Suu jumped to their feet when Jek and Shaeeah returned to the homestead in screams. Learning from Shaeeah that "monsters" were following them, Lawquane grabbed a pair of electrobinoculars to discern what she meant. Training his binoculars through the dark fields, he spotted some twenty droid commandos, which had been deployed from a crashed Separatist escape pod that Shaeeah and Jek had happened upon. With the droid commandos beginning to surround the homestead, Lawquane prepared for a confrontation with the droids, locking the front door and sending Suu to take refuge upstairs with Jek and Shaeeah.

When Rex inquired after Lawquane's weapon supply, Lawquane headed over to a closet and pulled out a blaster pistol for the captain, taking a rifle and carbine for himself. Rex volunteered a plan to catch the droids in a crossfire, but Lawquane cited the captain's injuries as a weakness and refused. Though taken aback by Lawquane's assertion, Rex grasped his meaning when the farmer clarified it for him: He was asking Rex to serve as a last line of defense for his family while he himself took point against the droids. Assuring Lawquane that he would take care of them, Rex went to join Suu, Shaeeah, and Jek in the bedroom on the second floor. Presently, the droids launched their attack on the homestead. Although Lawquane eliminated a number of them, several made it past him, and he warned Rex about the approaching droids. While Suu hid with Jek and Shaeeah by the bunk beds, Rex took up position, waiting at the end of the hallway leading to the stairwell doorway. Once the droid commandos had entered the hallway, Rex forsook his hiding spot and opened fire on them, gunning down a pair of the enemy units. While exchanging blasterfire with another of the droids, he managed to hit the droid in the head but not before it released a barrage of fire at the platform he was crouching on.

Rex fell through the floor and landed beside Lawquane, losing his grip on his blaster in the process. One of the droid commandos seized Rex by the throat in a choke hold, but Lawquane grabbed the fallen blaster and shot the droid's head cleanly off. With that, the last of the droids was destroyed, ensuring the safety of Suu and the children. The next morning, Rex prepared to rendezvous with Kenobi's assault force, recovering his armor and borrowing one of Lawquane's eopies, onto which he loaded his other gear. When Suu asked if he was going to turn in Lawquane for his desertion from the Grand Army, he stated that doing so was his duty but that in his condition, he might not "remember" his meeting with them. His discretion earned him a relieved thanks from Suu, who was grateful that she would not be separated from her husband. Rex soon received a comlink contact from Kenobi, whose assault the previous night had failed to detain Grievous yet again. Kenobi was glad to hear that Rex was on the mend, informing him that their battle group was waiting for him before they left Saleucami. Although Lawquane offered Rex a place at his home, Rex politely refused, not intending to impose on the farmer's family, and stated that his own family was elsewhere. With that, he bade goodbye to the Lawquanes and set off to rejoin Kenobi, leaving with a broader view of a soldier's loyalties.

The Mandalorian Death Watch, a terrorist splinter group allied with the Confederacy, later emerged in opposition to Duchess Satine Kryze of Mandalore and her dominant regime, the pacifistic New Mandalorians. With Kryze's life in danger, Rex was assigned with Skywalker, Kenobi, and Cody to escort Kryze to Coruscant, where she intended to reaffirm her people's position of neutrality before the Galactic Senate. Rex, Skywalker, Cody, and their clone squad met with Kenobi—who had been conducting an investigation into false rumors that Kryze had joined the Confederacy—at a spaceport in Mandalore's capital city, Sundari, where Kryze's starship, the Coronet, was preparing to depart. After checking in with Kenobi, Rex and his comrades joined Kryze and her entourage aboard the Coronet, which then left for Coruscant. En route to the Republic capital, Skywalker and Kenobi gathered their troops in the cargo hold for a briefing. The Jedi told the clones to stay vigilant for the Death Watch, which would stop at nothing to assassinate Kryze before she reached Coruscant. Rex and Cody sent their men to begin their rounds of the cargo bay, patrolling for any signs of danger, while Skywalker and Kenobi left to meet with Kryze.

During their patrol, Rex and Cody bumped into R2-D2, who appeared to have been frightened by something. The two officers also found they were unable to make contact with two of their men, Mixer and Redeye. Rex contacted Kenobi, who sent Skywalker back to assist in investigating the disturbance. Bringing the rest of the squad with them, Rex and Cody followed Skywalker and R2-D2 with headlamps ablaze through the labyrinth of containers in search of Mixer and Redeye. Their focus shifted upon finding an open and overturned crate, with Skywalker ordering Rex, Cody, and their men to find the box's missing contents. The disappeared cargo manifested itself as a large assassin probe droid, which had killed Mixer and Redeye and now began to attack Skywalker. Rex and his comrades intercepted the droid during its fight with Skywalker, disabling it with blasterfire before it could crush their Jedi General with its large legs. However, a second assassin probe took advantage of their distraction to head for the turbolift shaft leading to the dining room, where Kenobi was guarding Kryze and her Senatorial colleagues. Rex and the others ran for the lift but were unable to prevent the assassin probe from climbing up to the dining room; Skywalker notified Kenobi of the impending danger via comlink.

As Skywalker speculated on the possibility that more assassin droids were aboard, the fallen assassin probe hatched an army of tiny but deadly probe killer droids. Rex, Cody, and their men opened fire on the probe killers and, despite some casualties, managed to repel the majority of the nuisances. Although Rex wondered aloud how the assassin probe had gotten aboard the Coronet, Skywalker instead focused on the more specific question of who had smuggled it aboard to assassinate Kryze. After finding the protocol droid in charge of the cargo manifest, Skywalker ascertained that someone had used a Senate stamp to approve the shipment of the crates containing the assassin droids. Acting on that lead, Kenobi launched into an interrogation of the four senators aboard the Coronet—Onaconda Farr, Kin Robb, Orn Free Taa, and Tal Merrik—to determine which one of them had smuggled the droids aboard, while Rex and his men joined Skywalker in scouring the cargo hold for the third and final assassin probe. While patrolling with Rex, Cody stopped to examine a trooper's abandoned helmet and became the victim of a probe killer that had been hiding inside it. Cody fell to the floor as he tried to fight off the probe killer, and when Rex tried to grab the droid off his comrade, two more of them jumped onto the captain. Both officers were saved by the timely arrival of Skywalker and R2-D2, who disabled the enemy droids with lightsaber and electric shocker, respectively.

Rex informed Skywalker that he still had not seen the remaining assassin probe, but a moment later, the droid jumped out from behind some nearby crates and bowled over the captain. With Rex taken by surprise, the assassin probe climbed on top of him and prepared to impale him with its front pincers. Recovering quickly, Rex grabbed the droid's legs and kicked his attacker off him before it could do any harm. He and Cody fired at the droid as it escaped up a wall, and though both of them landed hits, it was not until Skywalker threw his lightsaber at the droid and severed most of its legs that it toppled back to the floor. Running over, Rex slammed his foot down on the disabled probe and rained down blasterfire on its cranial unit, preventing it from releasing its probe killer spawn. A triad of Separatist Droch-class boarding ships—called in by Tal Merrik, whom Kenobi had exposed as the Death Watch agent—thereafter assaulted the Coronet, penetrating its hull to deploy a boarding party of super battle droids. Joining Skywalker in one of the hallways, Rex and Cody led their men in a firefight with the battle droids. Rex and the others were able to bring about the Separatists' defeat and left the hallway littered with droid parts.

The rest of the Coronets journey went uninterrupted, with Rex and his comrades safely transporting Kryze and her entourage to Coruscant. After they docked at a landing pad, Rex, Cody, and their men disembarked with Skywalker and Kenobi, their escort duty ending as a success.

During an assault on Separatist-loyal Trade Federation forces over the Bothan colony world of Kothlis, Rex served as the gunner of Tano's BTL-B Y-wing starfighter. Each in their own starfighter, Skywalker, Tano, and Kenobi led the Republic's attack on the Vulture droids deployed from a Federation Lucrehulk-class Droid Control Ship. Upon reaching the battleship, Tano released a volley of proton torpedoes at the vessel; Rex regarded the ship's subsequent destruction as a beautiful sight. The Separatist Dreadnaught-class heavy cruisers were forced to flee, securing the Republic's victory over Kothlis. Shortly thereafter, Rex accompanied Skywalker, Tano, and Kenobi to the planet Taloraan, where the Jedi were to undertake negotiations for Tibanna gas with the Denfrandi tribe, the dominant clan on the world. En route to Taloraan aboard the Resolute, Rex conferred with Tano on the prospect of the diplomacy that she would be engaging in over the next few days. Whereas Tano found diplomatic negotiations boring, Rex respected them as a different method of fighting, one for which he was not trained. While the three Jedi left for the capital, Taloraan City, in a Nu-class shuttle, Rex remained aboard the Resolute with Wullf Yularen to regularly check in with the Jedi.

To contact the Jedi, the Resolute had to routinely leave orbit for a closer signal range. Unbeknownst to the Republic, Denfrandi Magister Orlin Denache had secretly forged an alliance with the Confederacy and was housing battle droids on Taloraan. During one of the Resolutes regular trips into comm range, the Jedi—who had discovered the Separatist presence in Taloraan City—warned Yularen that the Resolute was heading into a trap: A Confederate Munificent-class frigate commanded by Captain Canteval was preparing to attack the cruiser. Yularen had his bridge crew raise the Resolutes shields just in time to deflect fire from the enemy frigate. While the Resolute battled Canteval's battlecruiser, Yularen sent Rex and a clone trooper detachment to rescue the Jedi, whose shuttle had been destroyed. After landing with several LAAT/i gunships at a platform in Taloraan City, Rex and his men fell under fire from the Separatist-allied Denfrandi, who had taken up positions behind some cargo boxes. The brief firefight ceased when Denache's emissary, Sech Govlinder, galvanized the rest of the Denfrandi into taking up arms and defeating the Separatists. The Jedi established an accord to abate hostilities between the Denfrandi and their rival tribe, the Wind Raiders, thanks to Tano's personal involvement in the matter. When Rex asked Tano if she had changed her mind about her disregard for diplomacy, she replied that she had indeed due to her firsthand experience in the field.

The Republic discovered from an intercepted transmission between General Grievous and Asajj Ventress that Grievous was plotting to stage another invasion of Kamino, mere months after his last attempt had been thwarted at Rishi Station. Examining the message aboard the Resolute, where the 501st had been stationed, Rex, Skywalker, Kenobi, and Cody learned of Grievous's plan to cripple Kamino, a prospect that both Rex and Cody found quite personal. To notify Kamino of the impending threat and aid in the defense of the critical world, Skywalker and Kenobi set course for Kamino. En route, Rex met with his 501st troops in the Resolutes hangar bay to inform them of their new assignment. He found Echo and Fives in the process of unloading supplies from a gunship and conferred with the new recruits, discovering that given their lengthy service since joining the 501st, they had expected that Cody would have already made them Advanced Recon Commandos. Partly as a rebuke for their restlessness, Rex told them they would earn such a promotion when they no longer had to ask for it.

After transferring to an Acclamator-class transport, the Jedi and the 501st landed at the Military Complex of Kamino's capital, Tipoca City, where Rex, Skywalker, Kenobi, and Cody met with Jedi General Shaak Ti and Prime Minister Lama Su to relay the news of the Separatists' plan. Though they quickly marshaled Kamino's defenses, it was not long before Grievous's fleet arrived to challenge the Republic's orbital blockade. While Skywalker and Admiral Yularen oversaw the space battle against Grievous's flotilla, Rex joined Cody, Kenobi, Ti, and Su in Tipoca City's command center to monitor their progress. However, as debris from the Separatist cruisers fell into Kamino's ocean, the space engagement proved to be a diversionary assault when the remains of the ships turned out to be disguised modules for Trident-class assault ships, which the Separatists secretly reassembled below sea level. Using the craft, Grievous and Ventress landed hundreds of droid troops in Tipoca City and rapidly beleaguered the vital cloning facilities. As the droids began to overrun the Military Complex, Rex and the others were joined by Skywalker, who returned to the war room to help organize the city's fortifications. Rex and his comrades agreed that the Separatists' primary target would be the DNA archive—which was crucial for future clone production, as it stored the limited remainder of Jango Fett's DNA.

While Skywalker and Kenobi headed off to guard the DNA archive chamber and oversee the main assault on the battle droids, respectively, Rex and Cody found Echo, Fives, and the maintenance clone 99 at the barracks with several young clone cadets, who had been separated from their group. Although the cadets did not believe they could be of help since they had not yet graduated from training, Fives and Echo rallied them to take up arms, underlining that it was their home that they were defending. With the droids nearing the barracks, Rex and Cody followed 99 to the nearby armory to retrieve weapons for the others so that they could stage a retaliatory assault. The cadets hid in the raised retractable sleeping chambers to provide extra firepower at the right moment. When a squad of B1 battle droids led by Grievous broke into the barracks, Rex, Cody, Echo, and Fives immediately gunned down the advance forces at the entrance, while Kenobi engaged Grievous in a lightsaber duel. However, Rex and his comrades could not eliminate all of the droids and retreated into the barracks, stampeding back along the main corridor with the droids in close pursuit. Rex quickly found cover behind several crates alongside Cody, Fives, and Echo to return the enemy fire. As the droids gained ground and pushed Echo, Fives, and Cody back toward Rex's position, 99 tossed Rex a thermal detonator, which he launched at the advancing droids. Yet he missed, instead hitting an adjacent crate.

Once the battle droids had passed by the cadets' hiding places, Rex commed the young trainees to open fire on the droids, which they did to great effect. As more droids fell in the ensuing crossfire, Cody used up the last of the thermal detonators. Though 99 opted to retrieve another supply of explosives from the armory, his decision to abandon his cover—despite protest from Rex and the others—cost him his life, as he took enemy fire to the back and died. Cody thereafter received word from Ti that the droids had been pushed back to the main hangar. The Republic forces soon secured a victory over the remaining Separatist forces, forcing Grievous and Ventress to retreat. However, the damage had been done: Rex, Cody, Fives, and Echo took some time to lament the loss of 99, whom they believed had been a true soldier in spite of his debilitative cloning malformations. While clone troopers and Kaminoan cloners alike began to repair the desolation wrought throughout Tipoca City, Rex and Cody found Fives and Echo in the Military Complex's hangar and commended them on the true valor they had displayed during the battle. Once again impressed with their efforts, Rex and Cody officially promoted both 501st troopers—who had been only cadets not that long ago—to the prestigious rank of Advanced Recon Commando, saluting the Grand Army's newest ARC troopers.

Later in the war, the Trade Federation blockaded Pantora, suspending all commerce with the system to pressure the Pantorans into an alliance with the Confederacy. While with Skywalker on Coruscant, Rex was with him and Padmé Amidala on a landing pad as the latter was preparing to leave the capital aboard her J-type diplomatic barge. The three of them soon received news from Tano that Chi Eekway and Che Amanwe—the daughters of Chi Cho's successor, Chairman Notluwiski Papanoida—had been kidnapped. Skywalker sent his Padawan to aid Riyo Chuchi in investigating the matter, and Tano and Chuchi helped Papanoida rescue his daughters from the Separatists. They restored relations between Pantora and the Trade Federation, repealing the blockade.

While on their way to rendezvous with Jedi General Kit Fisto, Rex and Skywalker made a brief stop on Mandalore. The reason for their visit was to drop off Tano, whom the Jedi High Council had delegated—at the request of Satine Kryze—to teach cadet classes at the Royal Academy of Government. Because the world had become engulfed in a black market crisis, Tano's involvement was intended to curb the planet's deeply rooted corruption among its future leaders. After arriving at the Sundari docks aboard an Eta-class shuttle, Rex and another trooper stood by while Kryze and her Prime Minister, Almec, welcomed Skywalker and Tano. With Fisto expecting them, Rex reminded Skywalker of their orders, and they soon left Mandalore to join up with Fisto. Meanwhile, Tano and her students found that Almec was behind the ongoing black market conspiracy and helped Kryze bring him to justice.

Shortly after returning to Coruscant, Skywalker was given command of the Third Legion for another assignment. A large-scale civil war had consumed the planet Balith, and in response to an appeal for Republic aid, the Jedi Council tasked Skywalker with intervening in the fighting. While Tano stayed at the Jedi Temple to focus on her studies, Rex and troops from Torrent Company were with Skywalker on a Nu-class attack shuttle, and then boarded a Venator-class Star Destroyer for the voyage to Balith.

When the Resolute was scheduled to undergo a refit, Rex and Torrent Company were transferred with Skywalker, Kenobi, Tano, and Yularen to the recently christened Star Destroyer Indomitable. Presently, the Jedi and their fleet—including the cruisers Indomitable, Pioneer, and Coruscant Sky—received intelligence from the Grand Army's Special Operations Brigade that General Grievous was planning on seizing Kothlis and its Bothan Spynet facility. While in Indomitables mess hall, Rex, Sergeant Coric, and trooper Checkers were joined by Tano, who reported that the fleet was heading to mount a defense of Kothlis. Rex learned from Tano that a ground assault on the planet was highly possible; if the Separatists had already begun to invade Kothlis, Kenobi and Tano would be leading the counterattack on the surface while Skywalker commanded the space battle. The captain then put his men on standby and had them begin preparations for the imminent battle. When Indomitable, Pioneer, and Coruscant Sky arrived at Kothlis, they found that Grievous had already begun to beleaguer the undefended planet. The Jedi additionally discovered that Grievous was employing a computer virus to jam all of the Republic's comm channels, terminating ship-to-ship communications.

Skywalker met with Rex, Tano, and their waiting men in their barracks and informed them of the Separatists' comm jammer. Although Rex was concerned with the news, Skywalker stated it was possible that comms would be restored in time; if necessary, reinforcements could be requested. Before proceeding to the gunship hangar with Tano and Torrent Company, Rex wished his general good hunting. Once Skywalker and his Gold Squadron pilots had initiated the space battle against Grievous, Rex and Tano were joined by Kenobi in their gunship and led the assault force's launch from the fleet. En route to the surface of Kothlis, Rex spared his men a few last-minute words for preparation. After landing, Kenobi ordered Rex and Tano into the fray while he led the assault on the Separatist-claimed Spynet facility. Rex, Tano, and Torrent Company engaged the entrenched droid infantry forces in the central plaza of Kothlis's capital, Tal'cara, battling super battle droids, droidekas, and STAP-mounted droids. However, with only one gunship for air support, Torrent Company took heavy losses—their highest since the Battle of Teth.

Rex was among the injured, taking wounds to his right arm and chest. Checkers, who was wounded less severely, stood with his captain, ready to support him if he needed it. After the fight against the droids in the plaza reached a temporary standstill, Tano ordered Rex and his men to fall back and tried to contact Yularen for assistance, but her attempt failed due to the Separatists' still-active comm jammer. Seeing no other options, she left to get help from Kenobi while the barely conscious Rex stayed to watch over his men. Tano rendezvoused with Kenobi and assisted him in reclaiming the Spynet facility from the Confederacy, thanks in part to the efforts—and sacrifices—of Torrent Company and other clone units. The Republic fleet also managed to repel Grievous's forces from Kothlis. Rex, Coric, and the other wounded soldiers were sent for treatment at the Republic's Kaliida Shoals Medical Center, one of the Republic Sector Armies' twenty Haven-class medical stations. Tano chose to be treated with them at the Outer Rim medcenter so that she could provide moral support.

Although the Kaminoan doctors quickly healed Tano's injuries, Rex, Coric, and several others had to undergo bacta treatment and received their own bacta tanks. Rex and Coric were among those who made full recoveries, though the Kaminoans did not have as much success with some of the other troopers. Eventually, Rex, Coric, Checkers, and the other survivors were discharged and returned to Coruscant's GAR clone barracks on furlough to rest up before their next assignment. Tano arrived at their barracks an hour after their return to welcome them back. She revealed to Rex and Coric that she was concerned for her Master, whose life had been put into grave danger while on a confidential mission with Kenobi. Unable to rescue their generals for the time being, Rex and Coric tried to cheer up Tano with a game of turbo-darts. Since they had not yet received their next orders, Rex only intended to take a few days of recuperation before resuming Torrent Company's training. Their next deployment came within a few days, a day after the Separatists launched a devastating bioweapon attack on the planet Chandrila. Although GAR command did not inform him of their destination, Rex learned about their complete assignment from Tano, who was to accompany them on their mission.

Tano explained that Torrent Company was joining a battle group bound for the Separatist-occupied planet Lanteeb to rescue Skywalker and Kenobi, who had been trapped there by forces under the command of General Lok Durd—a recent escapee from Republic incarceration. Durd was manufacturing a damotite-based bioweapon on Lanteeb, which had been responsible for the massacre on Chandrila, and the Republic intended to eliminate the weapon's stockpiles before it could strike again. Admiral Yularen was given command of the armada bound for Lanteeb, and Rex, Tano, and Torrent Company joined him aboard Indomitable, which had undergone repairs following the recapture of Kothlis. Their three-cruiser battle group—again consisting of Indomitable, Pioneer, and Coruscant Sky—received the addition of Mace Windu's Dagger, which came from safeguarding Kothlis in the wake of the Separatist invasion. Upon reaching Lanteeb in the Malor-77 system, the Republic forces found that not only were twenty-five enemy warships heavily blockading Lanteeb, but Grievous himself was leading the blockade. Among their scant good news was that Grievous's communications jammer virus had been temporarily nullified, restoring communications in the interim.

After executing three starfighter assaults on Grievous's flotilla, Yularen's battle group received reinforcements in the form of a large volunteer civilian fleet, which Senators Padmé Amidala and Bail Prestor Organa had worked tirelessly to organize in the absence of further support from the Republic Navy. Rex and the 501st prepared to aid in rescuing Skywalker, Kenobi, and Jedi Master Taria Damsin, who had slipped through the blockade to help the trapped generals. With the aid of the civilian ships, Yularen's fleet scattered the blockade, forcing Grievous to retreat. While Yularen oversaw the battle group's efforts to liberate Lanteeb from Separatist control, Rex joined Windu and Tano in leading the 501st and another Grand Army unit, the 95th, to the Lanteeban city Torbel, where Skywalker, Kenobi, and Damsin were desperately defending the local populace from Durd's droid army. The 501st and 95th took a squadron of thirty gunships to Torbel, with clone trooper pilot Jinx transporting Rex and Tano. Once they arrived in Torbel, Rex, Coric, and Checkers joined their comrades in cutting through the battle droids; the Separatist detachment was defeated in under an hour.

As Windu coordinated the Republic's various mopping-up operations, the sun began to set on Lanteeb, so Rex arranged for the floodlighted gunships to be positioned around the village square for additional light. Since the battle had reduced Torbel to little more than ruins, the Republic granted the villagers refugee status, and Amidala and Queen Jamillia offered to give them homes on Naboo. While Windu stayed behind to discuss the civilians' future with the village speaker, Rikkard, Rex and a clone medic escort shuttled Tano and the extremely injured Skywalker, Kenobi, and Damsin to Indomitable for proper medical treatment. Windu then took Skywalker, Kenobi, and Damsin back to Coruscant aboard Dagger, with Rex and Tano being entrusted with overseeing the remainder of the Republic's operations on Lanteeb with the 501st Legion.

When a group of clone troopers, having just pilfered the coordinates for the Separatist hypermatter generators, crashed on the Hutt Space world Asuin, Rex, Skywalker, and Kenobi were tasked with rescuing the clone squad before the Confederacy could recover the intelligence. After Rex pinpointed the location of the squad's escape pod on the surface via scanning, Skywalker and Kenobi moved in to secure the craft. While battling the Separatists, Rex made contact with his Jedi Generals and reported that battle droid reinforcements led by Asajj Ventress were heading for their position. Skywalker and Kenobi managed to rescue the sole surviving trooper of the crash, but Ventress then confronted them. Although she destroyed J-3PO, the protocol droid containing the hypermatter generator coordinates, Skywalker and Kenobi were able to escape from the battlefield.

Shortly after the planet Makem Te rejoined the Republic, the Separatists deployed an advanced tank known as the Bogg Behemoth on the world. The Jedi Council dispatched Rex, Skywalker, and Kenobi to combat the new threat. Taking a battle group of HAVw A6 Juggernaut tanks and a clone legion to Makem Te, Rex and his Jedi Generals found the Bogg Behemoth in the desert near the city Thousand Thousand. Even with commandos supporting their elite detachment, Rex voiced skepticism to Skywalker and Kenobi that they would be able to capture the Bogg Behemoth, as they had been ordered to do. Because intelligence alleged that the Bogg Behemoth was still undergoing final testing, Kenobi mobilized their forces in a preliminary strike before the tank came online. When Rex led his men against the Bogg Behemoth, their intelligence proved to be faulty—the tank, already functional, began to launch scores of missiles at the clone soldiers.

Though Rex had the Republic's AV-7 Antivehicle Cannons return fire at the Bogg Behemoth, the tank's shield and heavy armor afforded it sufficient protection to endure the thick bombardment. With their men taking losses, Skywalker and Kenobi elected to instead assault the Bogg Behemoth from above. Rex and the Jedi landed their troopers on the tank via LAAT/i gunships, but hundreds of DSD1 dwarf spider droids confronted them before they could secure the deck. As Rex and his soldiers held out against the dwarf spider droids, Skywalker and Kenobi infiltrated the tank and forced its Geonosian operator, Bogg, to deactivate the vehicle and its defenses. Despite the clones' capture of the Bogg Behemoth, Kenobi chose to destroy it, as he simply did not believe that the Republic could adapt such destructive weapons for proper ethical use.

On another occasion, Rex joined Kenobi, Cody, and a company from the 212th Attack Battalion to claim Bogoa, a world whose durable coral was coveted by the Confederacy for use as ship-building material. After battling the Separatists for three days, the Republic forces managed to compromise the enemy stranglehold. During the following interlude in fighting, Rex remained at the Republic's staging area with Kenobi and the 212th infantry while Cody embarked on roundup duty, searching for survivors amidst the carnage on the battlefield. Cody soon found the B1 battle droid Coppertop, whose battle protocols had been peculiarly overridden; the droid had subsequently deserted the Separatist Droid Army to aid the wounded from both sides of the conflict. When Asajj Ventress and the bounty hunter Cyreltov attempted to reclaim Coppertop for Count Dooku, who had issued the experimental Order 99 directive that had modified Coppertop's objectives, Coppertop sacrificed himself to prevent Kenobi and Ventress from fighting over him. Ventress and Cyreltov thereafter retreated from Bogoa, having failed to retrieve Coppertop, while Kenobi and the clone troopers recovered from the battle.

Rex joined Skywalker and Tano in contesting the Confederacy's claim to the jungle planet Zeenada, where a large Separatist invasion force soon outgunned them. In response, Skywalker had Rex and Tano take a squad around the battle droid lines and stage a diversionary assault on the enemy's rear position. Doing so would cause the Separatists to believe that the Republic's main force was behind them, allowing Skywalker to capture the droids in a pincer maneuver. While circling around the enemy infantry, Rex and Tano encountered a droid patrol. By the time the droids had been eliminated, only Rex, Tano, and two other troopers—Gunner and Sarge—remained of their squad. Rex advised that they abort the mission and return to Skywalker for reinforcements, but Tano reminded them that Skywalker was depending on them to fulfill their objective. When they came across a wild feline predator, Tano ordered Rex, Gunner, and Sarge to avoid firing at it unless absolutely necessary while she distracted the creature. Yet she was unable to defeat the predator, and when she felt the ground shaking underneath them, she quickly Force-pushed Rex and the others aside. The threat turned out to be an incoming pack of wild animals, but Rex and the others were able to avoid the stampede.

Although Sarge and Gunner were skeptical of Tano's experience on the battlefield, Rex ordered them to respect her command, as she was in charge. They proceeded through the Zeenada jungle, eventually arriving at a swamp right behind the Separatists' rear flank. Rex was not enthusiastic about having to trudge through the swamp, but Tano believed that they could cross it via several rocks running through the marsh. However, the rocks—which were actually reptilian eggs—turned out to be yet another example of Zeenada's native wildlife: They hatched into massive swamp beasts, whose parent proceeded to attack Tano. While Tano ordered Rex and his men to safety, she had the idea to lure the beast onto the battlefield to attack the battle droids. Her plan worked, and while Skywalker ordered his forces to assault the droids' frontal flank, Rex, Gunner, and Sarge crossed the swamp and jumped into battle alongside Tano.

When Republic Admiral Tenant and the crew of his Star Destroyer crew intercepted a message containing a 2,000-year-old Jedi distress code, the Jedi High Council sent Skywalker, Tano, and Kenobi to investigate the location of its origin: the remote Chrelythiumn system, a site far beyond the Outer Rim Territories in the relatively unexplored region of the galaxy termed Wild Space. Since the Jedi Council suspected a Separatist scheme, Rex was dispatched aboard a heavily armed Venator-class Star Destroyer to meet up with the three Jedi at the source. Although both Rex's Star Destroyer and Skywalker's Eta-class shuttle arrived at the rendezvous point and established contact via the HoloNet, a peculiar situation arose: Neither Rex's cruiser nor the Jedi's shuttle were able to locate each other on their scanners. The peculiarity of the situation escalated when an outside source cut off Skywalker's holographic connection to the warship. While the concerned Rex continued his attempts to locate them, the Father—a powerful Force wielder who maintained the mysterious world known as Mortis—transported Skywalker, Tano, and Kenobi there. The Father wished to test Skywalker, who was believed to be the Chosen One of an ancient Jedi prophecy.

After Skywalker, Tano, and Kenobi underwent a series of tribulations on Mortis, they awoke aboard their shuttle. Seeing their craft reappear on his scanners, Rex reestablished holographic contact with them, confirming that they were all right. Although Rex did not understand when Skywalker stated that their communications blackout had lasted for more than a moment, Skywalker, commenting that they could not explain their ordeal, brought in their shuttle to join Rex aboard his Star Destroyer.

Following the Confederacy's capture of Jedi Master Even Piell, the Jedi Order sanctioned a mission to free the senior High Council member from incarceration in the Citadel, the most feared prison installation in the galaxy. Because Piell had just discovered the coordinates of the strategic Nexus Route, a secret hyperspace lane that spanned from Coruscant to the heart of Separatist space, his findings were of great value to both sides of the war. Rex was assigned to Skywalker and Kenobi's elite team to rescue Piell alongside Cody, Fives, Echo, and several other clone troopers. When Plo Koon headed a briefing on the mission at the Jedi Temple's communication center, Rex was present at the conference via hologram. The task ahead would become one of Rex's most difficult ones since the outset of the war: Because the Citadel had originally been designed to hold rogue Jedi who had fallen to the dark side of the Force, no team had ever been able to infiltrate the highly guarded prison. Although Rex was skeptical that the Separatists were still keeping Piell alive, the Jedi firmly believed that the Separatists would not kill Piell until they had extracted the Nexus Route coordinates, which were too valuable to waste. Once the Jedi had established a plan for infiltrating the Citadel on the planet Lola Sayu, Rex joined the others at a carbon-freezing chamber in the Jedi Temple Hangar, where they were to be encased in carbonite to circumvent the Citadel's life-form scanners.

After the Republic engineer Erk Zallis froze them in carbonite, Rex and his comrades were ushered onto Shuttle 81572, a captured Separatist Class Type B escort shuttle, which R2-D2 and a squad of reprogrammed B1 battle droids would pilot to Lola Sayu. R2-D2's battle droids transported the infiltration team—including the unauthorized addition of Ahsoka Tano—to Lola Sayu, gaining clearance from Citadel Command to proceed to the prison. At a site amidst the Citadel's maintenance pipes, Rex and the others were unfrozen from the carbonite, taking some time to recover from the encasement process before heading out for the facility. In the meantime, R2-D2 and his battle droids remained behind to guard the shuttle. Separated from the cliff-side entry point to the Citadel by a river of sulfurous lava, the squad was forced to ascend the cliff to the lookout balcony. However, strong winds hampered the use of jetpacks, and sensitive electro-mines thwarted ascension cables, so the Jedi and clones resolved to free-climb the cliff. Rex and his companions braved the dangerous conditions and reached the lookout balcony, where Tano disabled the door's ray shield from the inside by slipping through a ventilation shaft.

Just as Rex, Cody, and their men were joining Skywalker, Tano, and Kenobi on the balcony, trooper Charger lost his footing and fell down the cliff, activating an electro-mine and consequently being shocked to death. With alarms blaring and the Citadel's warden, Osi Sobeck, alerted to the Republic team's presence due to the tripped electro-mine, the Jedi and clones crept into the prison on the lookout for battle droid patrols. Avoiding droid guards and eliminating surveillance cameras along one of the hallways, the team cut through laser emplacements lining the walls. However, they soon discovered that the hallway was electrified when Sobeck remotely activated that trap. The others reached a safe passageway, but trooper Longshot was killed before he could make it to safety. After locating and breaking into Piell's holding cell with his comrades, Rex gunned down the A4 laboratory assistant droid that had been on the verge of gouging out Piell's sole remaining eye. Once Skywalker and Kenobi had freed him from his containment field, Piell revealed that he only possessed half of the Nexus Routes coordinates—the rest laid with his Republic Navy captain, Wilhuff Tarkin, who had committed them to memory and would also require rescuing, along with the clone trooper crew captured from Piell's flagship.

En route to free Tarkin and the other officers, Rex and his comrades were intercepted and surrounded from both directions by a squad of the Citadel's elite BX-series droid commandos. Though Rex assisted Skywalker and Tano in eliminating the droids at their end, the entire team fell prey to the powerfully magnetized ceiling, which pilfered their weapons and held them out of reach some meters above them. As Kenobi, Tano, and Piell used the Force to hold droid commando reinforcements at bay, Skywalker, who had been pulled up to the ceiling because of his prosthetic hand, managed to reclaim his lightsaber and sliced through the magnet. Rex and his comrades quickly rearmed themselves and cut through the droids. Before continuing on with the others, Rex disabled the surveillance cameras in the area, through which Sobeck had been watching them. Once Tarkin and the clone officers had been liberated from their cell, the Jedi decided on a new plan to escape from the Citadel: While Kenobi and Piell took one group to create a diversion, another team led by Rex, Skywalker, Tano, and Tarkin would find an escape route from the fortress. An advantage of such a tactic was that Piell's and Tarkin's halves of the Nexus Route intelligence would remain separated should Sobeck recapture one of them.

Using dated data from the Jedi Archives, Skywalker located a hallway adjacent to one of the Citadel's original fortress tunnels. He cut a hole through the wall with his lightsaber, and Rex and the others entered the tunnels, with Rex having Fives and Echo replace the severed hole behind them to avoid detection by Sobeck's pursuant forces. As they headed for the entrance to a pipeline network, Skywalker took up position at the rear to guard their flank from the droids sent to recapture them, while Tano led the group onward. Along the way, Rex defended Tano's abilities from Tarkin, who doubted that the young Padawan was capable of leading them to safety. After they found themselves at a dead end in the caverns, B2 super battle droids and droid commandos caught up with them, with the commandos sporting personal energy shields to counter the clone troopers' blasters. While Rex, Skywalker, and their soldiers faced down the droids, Tano used thermal detonators that Rex had been carrying in a supply backpack to rupture the obstructive wall, saving two of the explosives to use on the shield-wielding droid commandos. Both the wall and the droids were blasted apart, allowing Rex and his comrades to travel on toward the pipeline.

Rex and the others entered the large fuel line to ascend a ridge; they were to meet R2-D2 and their escape shuttle at the cliff's zenith. Due to the risk of igniting the flammable fuel within the pipe, Rex and the other troopers deactivated their lights and locked their weapons during their climb. Upon exiting the fuel line at the top of the cliff, Rex and his comrades were faced with a squad of B1 battle droids and LM-432 crab droids. While Skywalker and Tano deflected the battle droids' fire, Rex and Tarkin headed for cover with their men behind a series of nearby hills. After joining them, Skywalker used a thermal detonator from Rex to explode the section of the fuel line that they had just exited, leaving the droids in pieces. As Kenobi and the shuttle had not yet reached the pipeline, Rex and the others resorted to their backup plan—meeting Kenobi at his position instead. Rex helped one of Piell's injured clone officers to the Citadel's rear landing platform, where Kenobi, Piell, and their soldiers were battling Sobeck's forces to reclaim their shuttle, from which the droids had separated them. Rex, Skywalker, Tano, Tarkin, and their group joined Kenobi's squad at their cover behind several crates, but their refuge was compromised with the arrival of battle droids aboard STAPs, which soared in to attack them from behind.

When Echo attempted to commandeer the shuttle, one of the platform's droid-manned blaster turrets blew apart the craft. The resulting explosion claimed Echo's life as well as the shuttle. Their only means of escaping off-world now gone with their comrade-in-arms, the Republic team was forced to retreat from the Citadel. Once Skywalker and Kenobi had requested retrieval from Koon and the High Council, Rex and his comrades proceeded away from the prison, across the perilous and barely navigable landscape of Lola Sayu. Rex, Cody, and Fives scouted ahead for the team as they traveled through a series of caves partitioned by rivers of sulfur. Taking advantage of the brief lack of pursuant droids, Piell contacted Yoda and Mace Windu at the Jedi Temple. With Koon's rescue fleet of cruisers already en route to Lola Sayu, Yoda and Windu informed Piell and the others that their rendezvous point with Koon's evacuation ships would be a small island in the middle of a lake of lava. When a trio of droid commandos caught up with them, Fives tossed a thermal detonator, making quick work of their pursuers. Yet Sobeck's forces did not relent in their pursuit and next tried to surround Rex and his comrades at a cliff, with battle droids approaching from the rear and a crab droid attacking from a nearby cliff face.

While R2-D2's reprogrammed battle droids delayed Sobeck's forces, Rex and the others used ascension cables to descend the cliff; Rex helped a clone officer down the ridge. Despite losing two troopers, they pressed on along a river of lava leading to the island rendezvous point. The group soon heard distant howling and realized that Sobeck had released a pack of hunters to lead his battle droids to them—specifically, the hunters were dangerous anooba trackers. As the anoobas were not far behind, the Jedi decided to use a nearby cave to their advantage: Once Skywalker and Kenobi had led the anoobas past the cave, Rex, Tano, Piell, and their men would surprise them and their accompanying battle droids from behind. After the anooba pack passed by, Rex and his team rushed to join Skywalker and Kenobi, but several crab droids intercepted them. While Tano and Piell held off the crab droids, Rex pushed on with Tarkin, Cody, and the clones to Skywalker's position, where they found him and Kenobi in battle with the anoobas and a squadron of STAPs. Although the anoobas and droids were defeated, the victory came at a high cost: Piell died in combat with the anoobas. Tano—to whom Piell, with his final breath, had designated his half of the Nexus Route coordinates—brought the body back to the others, who were saddened to learn of the Jedi Councilor's sacrifice.

Even with Sobeck pursuing them, Rex and his comrades paused to honor the fallen Piell, cremating his body in the lava of Lola Sayu. Once Piell had joined with the landscape, the Republic team continued on to the island. With sulfurous lava separating them from the island, Skywalker and Cody each connected a cable to the opposite shore, erecting a line across the magma, and Rex and Tarkin were the first to climb across. As the others traversed the cables, Sobeck personally arrived with a squad of STAP-mounted droid commandos to reclaim his prisoners. A fierce lightfight ensued, with Rex and his men battling Sobeck's forces in a final stand. Unwilling to let the Nexus Route coordinates reach the Republic, Sobeck tried to murder Tarkin, but Tano killed the warden before he could do so. Just as Koon and Clone Commander CC-3636, nicknamed "Wolffe," arrived aboard a gunship to rescue the Republic team, hordes of crab droids appeared and surrounded the Jedi and clones. After providing cover fire for the Jedi, Rex and his men boarded Koon's space gunship and lifted off from Lola Sayu. They and their starfighter escort—provided by Adi Gallia, Saesee Tiin, and Kit Fisto—reached Koon's fleet of Star Destroyers, which withdrew to hyperspace.

Rex and the other survivors of the Citadel mission returned to Coruscant with Koon's fleet. During debriefing, the Jedi High Council encountered problems with processing the Nexus Route intelligence, as Tarkin had been instructed to take his half of the information directly to the Supreme Chancellor, while Tano, obeying Piell's dying wishes, intended to see that it was entrusted to the High Council. To resolve the matter, Yoda entered into discussions with Palpatine to determine the best way to debrief the information for Republic use.

Having become a foothold of Separatist strength since the onset of the Clone Wars, Felucia was engulfed in conflict for a second time on account of being situated near the valuable hyperlane known as the Perlemian Trade Route. Rex went with Skywalker and Tano to repel the Confederacy from Felucia, leading a clone trooper division of AT-TE walkers into the heart of enemy territory. They encountered squads of battle droids as they went but gained much ground, eventually joining forces with Plo Koon and Commander Wolffe to capture a Confederate outpost, to which General Grievous was sending reinforcements to fortify his hold on the system. As night fell, the Jedi and clones moved their forces to a ridge overlooking the outpost just as a C-9979 landing craft arrived with the droid reinforcements. Koon decided on a three-pronged assault plan to secure the outpost: While Koon and Wolffe attacked the base's left flank, Tano would breach the rear entrance with troops from Wolffe's Wolfpack, a squad within the Grand Army's 104th Battalion. Meanwhile, Rex and Skywalker would spearhead the frontal assault on the station. Once Skywalker's Felucian scouts had found them a secure way to the path leading to the outpost, Rex positioned half of their soldiers amidst the dense foliage on one side of the path, while Skywalker did the same along the other side.

With all of their forces in place, Koon had their AT-TE walkers deliver long-range fire at the outpost from the ridge. The cannonades baited tactical droid commander TZ-33's droid defenders out of the front entrance, and Rex and Skywalker began their attack once several DSD1 dwarf spider droids had been lured out into the jungle. Rex and Skywalker cut through the battle droids and joined Koon in capturing the base's command center, eliminating TZ-33. Although the enemy station had been secured, Tano was nowhere to be found—unbeknownst to her comrades, Trandoshan hunters had captured her for a ritualistic hunt on the moon Wasskah. Rex and his team received orders to return to Coruscant the next morning. As they prepared to leave Felucia, Skywalker had Rex and his men search the conquered outpost and the surrounding area for Tano several times, to no avail. With gunships waiting for them, Skywalker was forced to call off the search, hoping that Republic forces or spies in the Confederacy would locate his Padawan. Tano was later rescued from Wasskah and safely returned to the Jedi Temple.

Following the Second Battle of Felucia, Grievous oversaw a Separatist invasion of the Calamari system, home to the Mon Calamari shipbuilders who were key to the Republic war effort. After the King of Mon Cala, Yos Kolina, was assassinated, Skywalker and Padmé Amidala were sent to quell the political tensions between the Mon Calamari and the Quarren in the wake of his death, hoping to stem the impending threat of a Mon Calamari–Quarren civil war. Despite their best efforts to peacefully resolve the conflict, Skywalker and Amidala were unable to stop the Quarren from seceding from the Republic in favor of an alliance with Commander Riff Tamson of the Confederacy. Upon learning that civil war on Mon Cala was now inevitable and imminent, the Jedi High Council immediately commissioned a company of clone troopers for underwater combat to prevent the world from falling to Separatist control. Rex, Tano, and Kit Fisto were appointed to oversee the reinforcements for the Mon Calamari. Yet the battle began before they could arrive when Tamson and Quarren chieftain Nossor Ri led an assault on the undersea capital, Mon Calamari City, where Captain Gial Ackbar of the Mon Calamari Guard was hosting Skywalker and Amidala.

After arriving in the Calamari system aboard a Venator-class Star Destroyer, Rex remained on the bridge to supervise the clone detachment's deployment into the Calamari Sea. LAAT/i gunships took Tano, Fisto, Clone Commander Monnk, and their clone SCUBA troopers, all outfitted in submersible gear, to sea level, where they dove into the waters of Mon Cala. Using OMS Devilfish subs to reach Mon Calamari City, Tano, Fisto, and their men joined Skywalker, Amidala, Ackbar, and Kolina's son, Prince Lee-Char, in the ongoing battle against the allied forces of the Separatists and Quarren. Thanks to further reinforcements from Naboo's Gungan Grand Army, the Jedi and clones bested Tamson's forces, with Nossor Ri and the Quarren realigning with the Mon Calamari and the Republic under newly appointed King Lee-Char.

As the war progressed, Rex made the jump from the old Phase I armor to the more advanced Phase II equipment. Despite not being partial to the new gear, he developed a unique personal suit of Phase II armor, integrating the advanced equipment with salvaged Phase I parts. His troops in the 501st Legion and Torrent Company also adopted Phase II armor, carrying over their famous blue-marked design.

Rex and Sergeant Coric were dispatched to review security on the agriworld Biitu, where the Biituians were repurposing Separatist battle droid scrap as raw materials to be sold to the Republic Senate. Rex and Coric brought along a detachment from Torrent Company aboard an LAAT/i gunship to the Pitor Processing Plantworks, where a disturbance had been reported, though GAR command did not provide specifics. As they approached the Plantworks, Coric voiced his disregard for war profiteers like the Biituians, though Rex admonished him for his disrespectful attitude. Upon landing, they were greeted by Pitor, the foreman in charge of operations. Pitor brushed off the report of a "disturbance" and took the opportunity to give Rex and his squad a tour of the large facility, which, being the largest of its kind in the Outer Rim, received huge quantities of dismembered battle droids by the day. When Rex questioned Pitor as to why his men's presence had been requested, Pitor revealed that a battle droid calling itself the Reanimator, having forged himself from the bodies of his fallen comrades, had begun to bring the scrap droids back to life. Although Rex and Coric initially had trouble believing Pitor's tale, the Reanimator—an IG-100 MagnaGuard with a faulty neural processor—attacked Torrent Company at that moment, forcing them to take cover. While Pitor barricaded himself in his office, Rex's men fell one by one to the Reanimator and his droid army until only Rex, Coric, and a third trooper remained.

Rex ordered a retreat so that they could find one of the Reanimator's weaknesses and exploit it. He and Coric helped their injured comrade to Pitor's office, where Coric forced Pitor to let them inside. As the enemy droids closed in, Rex devised a plan that would combine Pitor's skills with Coric's suicidal sense of duty. Proceeding to the roof, Rex and Pitor manned magnetic grapples that would allow Coric to pose as a clone trooper with Force powers. When the Reanimator arrived with his droids, Rex's ruse distracted the Reanimator long enough for Coric to place a blaster shot through the droid's head. The clone soldiers remained at the Plantworks for another day to eliminate the rest of the droids. Their report of the incident resulted in the Senate agreeing to implement stringent checks on all Biitu-bound salvage shipments to prevent further complications, as deliveries of still-operable battle droids had been the agent of the catastrophe. Rex, Coric, and their men received Pitor's thanks before departing. As they lifted off, Coric commented to Rex that despite his still-low opinion of profiteers like Pitor, he had learned that the only reliable battle droid was a properly recycled one.

On another assignment without Skywalker, Rex and Torrent Company traveled to the planet Ereesus in the Outer Rim, where they entered into a collaboration with the local Ereesus Planetary Security Forces to repel a Confederate invasion. After establishing a forward operating base, Rex and his soldiers initiated an assault on the droid battle group, which was being overseen by a number of T-series tactical droids. The Republic's campaign soon took a turn for the worst, as the Separatists captured a squad led by Planetary Security Forces Sergeant Palola—along with their Torrent Company liaison, Oz—while gaining substantial ground, threatening to collapse the 501st Legion's left flank. The same night, Rex and his men learned of the Separatists' demands for the hostage militiamen via a two-minute holographic transmission from the tactical droid who had seized the squad. Adding to Rex's growing headache were numerous rebukes from generals in Sector Command concerning the fragile and crumbling situation.

Rex was soon sought out at the forward base by Lieutenant Sollaw ap-Orwien and Corporal Dafyd, the former of whom asked to view the holorecording of the captive squad to see what Palola had said. Rex mistook ap-Orwien's entreaty for a misconceived notion, as the tactical droid had not allowed Palola to utter a single word during the transmission, but ap-Orwien insisted that due to being a Lorrdian like Palola, he could discern a message. As Rex brought ap-Orwien and Dafyd to the operations room, the former explained that during the Kanz Disorders of millennia prior, the Argazdan Myrialites had enslaved the Lorrdians and barred them from speaking. To the stupefaction of Rex and troopers Jesse and Ringo, ap-Orwien—instantly after taking his eyes off the transmission—relayed key intelligence from Palola. The Lorrdian sergeant, Oz, and their five comrades were being held in a depot at the top of the Hidaci Ridge; the tactical droid's base of operations was a granary halfway up; and the Separatists had stockpiled fuel and artillery on the road along the ridge.

Ap-Orwien continued his explanation of the kinetic communication that the Lorrdians had developed during the Kanz Disorders, which had allowed them to communicate via the most minuscule movements and gestures ever since. As an example, ap-Orwien left the room, with Dafyd listening in as Rex relayed some made-up tactical information to Jesse and Ringo. They were further impressed when ap-Orwien reentered and, after exchanging wordless kinetic communication with Dafyd that almost missed Rex's scrutiny, repeated the fictitious orders word-for-word. After confirming with Sector Command, Rex devised a strategy to rescue Palola's squad from the Hidaci Ridge depot. To divert the Separatists' attention, he dispatched a squadron of BTL-B Y-wing starfighters to launch a bombing run on the fuel and artillery dumps. A sham 501st advance would further draw the battle droids south and allow the extraction team's gunship to move in on the hostage site from the north. Rex selected Jesse, Ringo, and Dogma, one of their recent recruits, to accompany himself, ap-Orwien, and Dafyd on the team, with Kix serving as their medic. Rex set the plan into motion that night, deploying the starfighters to deliver their ordnance while he departed with ap-Orwien, Dafyd, and the others on a stealth-outfitted gunship.

By the light of Ereesus's moon, Rex and his comrades flew to the Hidaci Ridge and lowered cables to the surface, fast-roping from the gunship into the depot. They landed at a speeder truck loading dock, where Rex and his soldiers switched on their night vision filters while the Lorrdian militiamen strapped night vision goggles over their eyes. Once they scanned the yard for hostiles, the team used explosives to blow open the main door and proceeded into the depot. Jesse and Ringo set a second set of charges to breach another door in the facility's office, which led downstairs to where Palola had reported that he and the other captives were being held. Immediately after the explosives did their work, Rex had Dogma toss an EMP grenade down the stairwell leading into the basement to deactivate the droid forces within. Following Jesse and Ringo into the basement, Rex placed a blaster bolt through the head of a still-twitching battle droid. However, as the troopers and militiamen discovered, Dogma's electromagnetic pulse had not disabled all of the droids. While Rex and the others deactivated their night vision filters, Jesse yelled out from further down the stairs that there were still-active droid commandos. Rex rushed down the stairs in an attempt to spot the enemy droids, but in doing so, he narrowly avoided a commando that detached itself from the pipes on the ceiling and brought its vibrosword through where his head had been a moment prior.

The droid commando landed behind Rex and kicked him down the stairwell, then pinned him chest-down on the ground—resulting in a bloody mouth on his part, with his hands and blaster pistols trapped beneath him. Ap-Orwien came to his aid, decapitating the commando with a blaster bolt and allowing Rex to free himself from under the now-defunct droid's body. With the rest of the droid commandos disabled, Rex and his team headed for the locked door at the bottom of the stairwell. He had explosive charges placed to blow open the door, with Dogma again tossing an EMP grenade through the rupture. On the other side, Rex smartly gunned down a droid commando that tried to pounce on them from the ceiling. He and his comrades were relieved to find Palola, Oz, and the other five hostages safe with minimal injuries.

Although Rex was about to radio the gunship for an immediate retrieval, he instead decided to act on Palola's findings, confirming from the Lorrdian that their tactical droid captor was headquartered in the nearby granary. Rex led his team and the former hostages to the granary, where they raided the droid encampment and captured the tactical droid's cranial unit. He and the others then returned to Torrent Company's base. When ap-Orwien asked if he and his fellow militiamen could spend the night at the 501st's base, since it was too late for them to return to their own headquarters, Rex told them it would be an honor to have them bunk with Torrent Company. Still, he smiled and declined ap-Orwien's offer for a game of sabacc, not willing to gamble with such masters of nonverbal communication as the Lorrdians.

In late 21 BBY, a major point of contention in the war became the planet Umbara, whose Umbaran people had recently seceded from the Republic and were arming the Confederacy with their extremely advanced military weaponry. The Republic responded to Umbara's defection by sending a full invasion force from the Grand Army to conquer the strategic Umbara system, which was located in the Expansion Region's remote Ghost Nebula. As part of the numerous units dispatched to Umbara, Rex and the 501st Legion joined Skywalker and Kenobi aboard one of the Republic fleet's lead Acclamator-class transports. After Tano and Barriss Offee breached the Separatist blockade of Umbara, Skywalker and Kenobi's assault ship moved in on the Shadow World, so named because the Ghost Nebula eternally shrouded it in night. While their troops prepared to land on Umbara, Skywalker and Kenobi held a briefing in the hangar bay with Rex, Cody, and other troopers to outline the plan for capturing the capital city. Jedi Generals Saesee Tiin and Pong Krell would be supporting Kenobi and Cody's battle group in their attack on the Umbaran capital from the south, while Rex, Skywalker, and the 501st Legion were tasked with intercepting enemy reinforcements to the north of the city. Opposing the Republic forces would be the heavily armed Umbaran Soldiers of the Umbaran militia.

Rex was pleased to learn that he and Skywalker would be assisted by an old friend, Advanced Recon Commando Fives, who was on special assignment to the 501st for the campaign. Once all of the Republic forces were ready for deployment, the Jedi and clones began their landing, taking space gunships to the planetary surface. Lieutenant Hawk piloted Rex, Skywalker, Fives, and some of the 501st troops—including veterans Hardcase and Jesse and new generation recruits Dogma and CT-5385, nicknamed "Tup"—through the atmosphere's thick fog, with clone Z-95 starfighters providing support against enemy Umbaran starfighters. When the gunships were met with dense surface cannon-fire from the Umbaran militia, Hawk struggled to reach the predetermined landing site through the difficult conditions. After All Terrain Recon Transports and 501st AT-RT drivers were deployed to secure the landing zone against approaching Umbaran Soldiers and Umbaran hover tanks, Hawk brought Rex, Skywalker, and their men to the drop site, where they joined the battle and led the 501st Legion's charge on the Umbaran lines. During their advance, Rex took notice of a nearby ridge, which Skywalker elected to claim for use as a staging area.

The Umbarans and their hover tanks were relentless in defending their positions, and Umbaran starfighters proved an even greater danger, executing strafing runs on the 501st troops. Even with the added threat of an esurient vixus creature, Rex and his men prevailed, taking the ridge and converting it into a temporary post. While monitoring the ongoing battle's progress from the trenches along the ridge, Skywalker noted that Kenobi's battalion was nearing the capital. However, the interlude in fighting did not last long, as Umbaran Soldiers had infiltrated the thick foliage behind the 501st lines to catch them off-guard. One of the enemy soldiers released a small but lethal millicreep droid, and the Umbarans took advantage of the clones' following distraction to ambush them. In the ensuing engagement, Skywalker cut through the millicreep, while Rex called in an airstrike on the enemy's position. Seeing an opening to the south of the ridge, Rex advised that they move their men off the ridge in case the airstrike overshot, and Skywalker heeded his captain's advice. While Skywalker defended their flank, Rex led the 501st platoons out of the trenches to take cover amidst the scattered vegetation just below the hill. They were glad that they had done so, for a pair of BTL-B Y-wing starfighters arrived only moments later.

Led by clone trooper pilot Odd Ball, who had been spared from General Krell's assault, the Y-wing bombers dropped munitions on the ridge, eliminating all of the Umbarans there. Shortly thereafter, Krell himself landed at Skywalker's position aboard a gunship to deliver new orders: In response to a request from Supreme Chancellor Palpatine, the Jedi High Council had ordered Skywalker back to Coruscant without delay. In the interim, Krell would assume command of the 501st Legion for the campaign on Umbara. Skywalker was concerned about leaving his troops in the middle of the battle, but Rex assured him that they would have the Umbaran capital under Republic control by the time he returned. Before departing aboard the gunship that had dropped off Krell, Skywalker introduced Rex to Krell, speaking highly of his captain. Although Rex told Krell that it was an honor to serve with him, as the Jedi Master had amassed an impressive record of victories throughout the war, Krell—a hard leader who strictly observed protocol—dismissed his words as mere flattery and made it clear that his command style was of a much different temperament than that of Skywalker. Despite recognizing that Krell would be difficult to work with, Rex readied his men to move out with their new general for the capital.

While on an overland march through the hills, Rex and his men were attacked by a trio of flying banshees and raised their blasters in defense. They were unable to kill the banshees, which each grabbed a trooper and carried them into the air; only Krell's intervention stopped the creatures' rampage and saved their clone victims. Krell did not sympathize with the troops' plight and briskly led them onward. Rex and his men trekked across the rough terrain for twelve hours straight, with Kix, the unit medic, soon voicing concerns for the soldiers' increasing fatigue. Although Rex suggested to Krell that they make camp on a nearby ridge, Krell asserted the necessity of taking the capital as swiftly as possible—to him, the clones' comfort was not as important as completing their mission, since the other Republic battalions were relying on their success. They eventually reached the main road leading to the capital, at which point Rex and Krell met to resolve their plan of attack.

Rather than utilizing Skywalker's original plan for a myriad of surgical strikes, Krell opted to pit the entirety of the 501st platoons against the city's defenses in a full frontal assault—a plan that Rex saw as misguided, as it would surely engender high casualties. Despite Rex's concerns that they did not know the extent of the Umbaran defenses, Krell refused to let his orders be questioned and directed the captain to lead the 501st toward the capital, explicitly instructing him to continue marching regardless of Umbaran resistance. Rex reluctantly obeyed Krell's command and led the 501st platoons and AT-RT walkers on the route to the city, while Krell remained behind to command them from a distance. Tup and Fives saw the plan as reckless, but though Rex acknowledged that he, too, disagreed with Krell's strategy, he focused his men on staying alert on the battlefield. They soon encountered mines that had been planted along the road, and Ringo and Oz died in the detonations. While everyone else laid low, Rex had Fives execute a sensor sweep of the road ahead to root out any more waiting mines.

There were indeed more explosives, and Rex and his men were careful to avoid setting them off. However, Umbaran Soldiers subsequently ambushed them from the surrounding forest. In spite of lacking cover from the Umbarans, Rex ordered his men to maintain their position on the road. He took out several Umbarans himself, but the 501st's casualties mounted as the enemy advanced on them, attacking from all sides. With his men surrounded, Rex ordered a retreat so that they could draw the Umbarans out of the darkened jungle. Although the 501st's rear flank endured heavy losses, Rex's plan worked, and his platoons were able to return many of the casualties to the Umbarans, forcing them to abandon their pursuit. Immediately thereafter, Rex was confronted by a greatly displeased Krell, who was outraged that the captain's retreat had ceded control of the road to the Umbarans. Fives protested to Krell's accusations, only to have his defiance silenced when Krell ignited one of his lightsabers and ordered him to stand down. Yet Rex stood his ground, stating that he had followed Krell's orders and, as a result, had lost many men, whose well-being it was his duty to defend. Noting Rex's opinion, Krell acquiesced, deactivating his lightsaber and dismissing him, though Rex and Fives were unable to ascertain if the general's words had been meant as a compliment. The Umbarans had meanwhile regrouped and resumed their assault, and Rex mobilized his men to defend their position.

Upon entering the jungle to combat the Umbarans, Rex and the 501st Legion were faced with the further threat of Umbaran starfighters, whose ray shields effectively repelled their blasterfire. One of the starfighters moved in low to strafe them, and Rex and his men were unable to shoot it down before it pulled out of the vegetation. Rex elected to press toward the Umbaran lines before more starfighters could assail them. When Kix called for support to save some of the wounded, Rex led his men forward to cover Kix's position, having Jesse protect their right flank and Dogma their left. Kix rescued several of the fallen troopers and administered temporary stimulants until they could receive proper medical treatment. In the midst of the fighting, Krell received word that Kenobi was unable to secure the capital due to its overpowering defenses, which were being resupplied by an Umbaran airbase to the west of the city. Before his battalion could advance on the capital, Kenobi required the 501st to capture the airbase so that the city's supply lines would be severed. Krell obliged, and Rex and his men set off with their general for the airbase, stopping when they reached a steep cliff overlooking the ravine that led to the enemy encampment. Rex examined the Umbaran defenses with a set of electrobinoculars and observed that the base was heavily guarded, with at least three tank divisions and a plethora of cannon installments contributing to its fortifications.

Krell decided that they would besiege the airbase in another full forward assault, as they had without success against the capital's defenses. As Rex pointed out, the narrow ravine would force them into single squads, which would make them easy targets for enemy fire. Although Rex recommended that they look for a more secure route, Krell decreed that they did not have time to do so because Kenobi was urgently depending on their success. Despite again disagreeing, Rex heeded his orders. While 501st Sergeant CC-1119, nicknamed "Appo," remained with Krell, Rex gathered his men at the bottom of the cliff and organized them into two divisions, one that he would personally lead and another that Fives and Hardcase would oversee. Many of the troops—including Jesse, Kix, Tup, and Fives—objected to Krell's tactics, and though Rex tried to defend Krell's recklessness by citing Skywalker's similar traits, Fives remained opposed to their interim general's decisions. Taking Fives aside, Rex tried to convince his comrade to ease the others' minds. When Fives argued that Krell's plan was too costly and not worth following, Rex reminded him that their duty was to follow orders, even if that meant sacrificing their lives for victory.

Rex led his men into the canyon and, after stopping to survey the airbase's defenses one last time with Hardcase and Fives, split the 501st squads into the two groups. While Rex and his team marched along the outskirts of the canyon, Fives took his division through the other side of the gorge. Fives' detachment was the first to meet Umbaran resistance in the form of an Impeding Assault Tank, a deadly crawler tank that burrowed out of the ground to ambush them. As several of the ray-shielded tanks surrounded them, Fives requested rocket launcher support from Rex, who sent one of his men forward with an RPS-6 launcher. When another Impeding Assault Tank injured that soldier, Kix tended to the fallen trooper while Hardcase took up the rocket launcher. By firing a missile directly into the cockpit of one of the tanks, Hardcase set off a chain reaction that blew apart the vehicle. However, with four more Impending Assault Tanks still operational, Rex ordered his men to regroup and take cover from the mechanical monstrosities. With only a few seconds' lead over the tanks, Rex had his troops plant thermal detonators along the ravine corridor through which the tanks were advancing. The soldiers then retreated into the bottleneck, luring the crawlers into the booby-trapped passage.

Once the tanks had fallen into their trap, Rex detonated the explosives, and he was blown into the air from the resulting blast, which consumed the four tanks. He and his men continued on in a single group, making their way through the seared wreckage of the tanks, one of which was still active. At Rex's word, Hardcase blasted its cockpit apart with a missile, and Rex made quick work of its Umbaran pilot. The clones also cut through several banshees that had been picking at some of their slain comrades, though Rex had to order Kix to leave behind the fallen and move on. As they neared the airbase, Rex and his men halted when they felt the ground shudder from doubtlessly more Umbaran forces. Sure enough, when Rex surveyed the area ahead with electrobinoculars, he saw that a far more deadly threat had been unleashed upon them: titanic six-legged juggernauts known as Umbaran mobile heavy cannons, each fitted with a powerful electromagnetic plasma cannon. He hurriedly ordered his men to fall back as the mobile heavy cannons opened fire, but the 501st platoons suffered severe casualties. Despite soliciting reinforcements from Krell, Rex was told that the rest of the 501st was guarding the entrance to the gorge so that his men could press forward to the airbase.

Forced to obey Krell's direct order to stand his ground against the cannons, Rex mobilized his men, directing Kix to keep the wounded as quiet as possible. Although Fives and Jesse objected to Krell's head-on plan, neither of them had any ideas for an alternative strategy, so they fell in line with Rex in spite of their misgivings. Their RPS-6 launchers proved ineffective against the mobile cannons' armor, and the 501st troops continued to endure egregious losses. In the tumult, Kix called out for help with getting the wounded to safety, and Rex helped him carry one of the injured troopers to cover in nearby vegetation. When Kix made to rescue more of the wounded and resented Rex's orders for the contrary, Rex told Kix that he needed to survive the current crisis to be able to administer aid later. Although Tup was losing hope that they would be able to hold out, Rex, surveying the airbase once more, had an idea about how to destroy the juggernauts. He sent Fives and Hardcase to commandeer two of the base's Umbaran starfighters, which would provide some much-needed air support. Krell was infuriated when he learned of Rex's alternative plan and ordered him to continue his frontal strike under threat of being relieved of duty. Rex did so with the intention of distracting the Umbarans long enough for Fives and Hardcase to complete their stealth incursion, placing his trust in them.

Rex took up an RPS-6 rocket launcher and used it against one of the tanks, to no avail. He narrowly avoided being crushed and managed to disable one juggernaut's plasma cannon with a rocket, which prompted the Umbaran pilot to advance his vehicle on Rex's position. The return of Hardcase and Fives aboard their pilfered starfighters saved him from the tank, their artillery succeeding where the rocket launchers had failed. Hardcase and Fives' success with eliminating the mobile heavy cannons elicited cheers from Rex and his comrades on the ground. With the juggernauts destroyed, Krell sent Appo forward with the rest of the 501st Legion to capture the airbase, where the Umbarans were using four more juggernauts to beleaguer the Republic fleet in orbit. After setting up an outpost to the south of the airfield, Rex had the 501st move in. With the aid of a Jedi Knight, they eradicated the airfield's mobile heavy cannons along with its supply lines to the capital. The Umbaran Soldiers at the base were taken prisoner and were locked in the prison levels. While reporting their hard-won success to Krell, Rex recalled that many men had died to take the enemy facility, to which Krell dismissed the captain as myopic, replying that he had yet to understand the price of victory. None of his comrades approved of Krell's sentiment, and as the general walked away, Rex agreed with Fives that it was Krell who would never comprehend the depth of the clone troopers' sacrifices.

The 501st Legion established a staging area at the Umbaran airbase, making use of its barracks and attempting to crack the Umbaran starfighter access codes so that they could be converted for Republic use. However, the capture of the base had come at high casualties, further sowing mistrust with Krell's leadership within the 501st ranks. Furthermore, Rex and Krell soon discovered from Kenobi that the seizure of the airbase had not, ultimately, severed the capital's supply lines as they had hoped. Holographically conferring with Kenobi at the airbase's command center, Rex and Krell learned that the Umbarans had begun to receive arms shipments from a Separatist supply ship in orbit. With that new source, the Umbarans were continuing long-range missile attacks on Kenobi's position, preventing him from reaching the capital. When Rex inquired after the possibility of destroying the orbital supply ship, Kenobi stated that they had been unable to do so thus far due to the Separatist fleet's greater strength, leading Krell to resolve to take the capital regardless of the threat of the missiles. Before Kenobi could respond, the connection was severed due to enemy interference. Proceeding to ground level, Krell ordered that the 501st Legion be ready to move out in twelve hours for an assault on the capital, ignoring Rex's concerns that they should coordinate their attack with Kenobi's battalion even as the Umbaran missile strikes targeted an area adjacent to the airbase.

Rex joined his men in Hangar 9-4, where the clones were working to break the starfighter access codes. Upon learning of Krell's decision to continue the push toward the capital, Fives, Jesse, and Tup were disgusted with their general's head-on tactics. Rex did not agree with Krell's plan either but could not think of a better option to suggest to him. Fives solved that dilemma when he revealed that Jesse had cracked the starfighter access codes—they now had the ability to infiltrate the Separatist blockade as friendlies and eliminate the supply ship. Rex took Fives' proposal to Krell, who—obstinate as ever—dismissed it out of a lack of faith in the clone troopers' ability to pilot the alien-designed starfighters, in spite of Rex's belief in his men's faculty for adaptivity. When Rex broke the news to Hardcase, Tup, Jesse, and Fives in the barracks, Fives proposed that they carry on with their illegal plan and accept the consequences, which would, at the very least, involve being court-martialed. Although he stated that he would have given the strategy his support if they had more time and training, Rex resolved that they lacked both. He continued to argue with Fives outside of the barracks, seeing his comrade's intention to disobey orders as bereft of honor.

Unable to convince Rex that Krell's orders were not worth following, Fives stubbornly left to round up some volunteers for the mission. He recruited Jesse and Hardcase as pilots for the Umbaran starfighters, but they drew Krell's attention when Hardcase accidentally liquidated the door of Hangar 9-4 while test-piloting one of the starfighters. Although Fives and Hardcase managed to convince Krell that the incident was a result of an enemy booby trap encoded in the starfighter, Krell simply cited it to Rex and Fives as further reason that the craft were too dangerous for their use. Krell consequently grounded the fighters, leaving Rex exasperated with Fives and Hardcase's actions. That night, while leading a full perimeter sweep to patrol for enemy activity in the outlying forest, Rex was sought out by Fives, Hardcase, and Jesse, who revealed that they were going to attack the supply ship in spite of the consequences for disobedience. When Fives asked him if he intended to stop them, Rex resignedly replied that he would not be able to help them when they got caught. After returning to the airbase, Rex witnessed the trio's launch from the hangar bay, and Krell thereafter confronted him about the illegal launch. Covering for his men, Rex claimed that he had authorized their launch so that they could reconnoiter the delta in preparation for the march on the capital, promising a full report to Krell once his men returned.

Having concealed Fives' plan from Krell, Rex was next challenged by Dogma and Tup, who sought to report their comrades to avoid being found complicit in their insubordination. Rex intercepted the two young troopers and managed to turn them away before they could speak with Krell, forcing them to go through him before they approached the general. Eventually, Rex witnessed with Tup a massive explosion through the clouds overhead, and he realized that Fives, Jesse, and Hardcase had destroyed the supply ship. When only Fives and Jesse returned, Rex learned that Hardcase had sacrificed himself to eliminate the orbital transport. They were then interrupted by Sergeant Appo, who reported that Krell had summoned them to the command tower. Standing before the general, Rex attempted to claim responsibility for his men's actions, but Fives insisted that he be punished instead, since he had committed the offense. Krell, caring little for the Advanced Recon Commando's display of honor, proclaimed that they would be court-martialed, for he brooked no insubordination among his troops. While Fives and Jesse were stripped of their weaponry and locked in the airbase's brig, Rex tried to convince Krell against court-martialing them. Krell came to agree with him, but not for the same reasons—believing that Fives and Jesse were defective, and convinced of the need to set an example for the rest of the men, he decided that the pair's punishment would instead be execution.

Krell ordered Rex to immediately prepare a firing squad for the execution, leaving the captain shocked with his orders. He and several other clone troopers reluctantly went to retrieve Fives and Jesse from the prison levels. Although the two soldiers were disgusted when they learned of their punishment, they resigned to their fates and did not bear Rex blame for Krell's decision. Locked in binders, Fives and Jesse were brought outside for the execution, to be delivered by a firing squad that included Kix and Tup. However, when Dogma gave the order to fire, Kix, Tup, and their comrades could not bring themselves to shoot at their own brothers and misfired, instead perforating the wall behind them. Although Dogma insisted that they follow Krell's orders, Rex overrode him, having realized that Fives and Jesse did not deserve to be executed for their insubordinate yet heroic actions. While everyone save for Dogma stood with him, Rex had Fives and Jesse freed from their binders, telling Dogma that he would have little success with finding others to conduct the execution.

Krell called Rex and Dogma back to the command tower, where they faced his extreme displeasure at their disobedience. Rex stood up to Krell a second time, meeting his threats for retribution with stoic determination of his own. Their standoff was interrupted by an incoming transmission from trooper Waxer of Cody's 212th Attack Battalion, who, like Rex, was a veteran of the Battle of Ryloth and the Second Battle of Geonosis. Rex was unaware that the message had been forged. Waxer alleged that the Umbarans had ambushed a clone platoon and had pilfered weapons and armor, warning that they could be gearing up for a devastating attack. Postponing Jesse and Fives' punishment and ordering them back to confinement, Krell had Rex mobilize his men to preempt the Umbarans with a preliminary strike, making a point to warn the clones not to be confused by the enemies' armor. Rex then set off with Tup, Dogma, and a forward platoon into the briar fens of the forest.

Rex's platoon was soon assaulted by enemy forces, though the shrouded environment prevented them from identifying their attackers. He sent his men forward with mortar launchers, and they bombarded the enemy lines with artillery rounds. Kix, using his night vision filters, saw that the opposing soldiers were wearing 212th armor and concluded that they were disguised Umbarans, just as Krell had cautioned. The ensuing battle saw both the 501st and their enemies sustain scores of casualties. Yet as Rex was to soon discover, the attacking soldiers were not Umbarans. While heading through the battlefield, he noticed a fallen enemy soldier in a nearby grove and removed the trooper's helmet to verify his identity. To his abject horror, the face underneath was not Umbaran, but that of another clone trooper. Distraught, Rex ran out onto the battlefield, frantically ordering his men to cease their fire and take off their helmets to show that they were not enemies. He took the risk of doing so himself to halt the rising carnage, even tackling one of the enemy soldiers and removing the trooper's helmet to further show both sides that all of them were clones, none of them enemies. The 212th-marked soldiers took off their helmets as well, equally aghast that they had attacked their brethren from the 501st.

As the hostilities dissolved into shock about the wrongful massacre, the 501st and the 212th tended to the many wounded and fallen. While a distressed Tup and Dogma questioned why their fellow soldiers had attacked them, Kix sought out Rex and reported that he had found Waxer, who had served as the platoon leader from the 212th and would surely have some answers to their questions. Kix led Rex and Dogma to Waxer, who was on the brink of death, being tended to by another 212th trooper. Removing his fellow veteran's helmet, Rex spoke face-to-face with the ailing Waxer and asked him who had ordered the 212th to attack the 501st. With his final breaths, Waxer revealed that Krell was responsible. The general had supplied the coordinates to assault alleged enemy forces who, they had been told, were disguised in clone trooper armor. While Waxer died, Rex—having long suspected that Krell's recklessness was rooted in darkness—realized that Krell was, in fact, a traitor to the Republic, and he resolved to arrest their general on charges of treason. Gathering the 501st and 212th survivors, Rex told them of his intentions and mobilized them to bring Krell to justice. Knowing that what he proposed was highly treasonous, he gave his troops the option to opt out, though all of them decided to stand by him.

Leading his men back to the airbase, Rex first stopped by the prison block with Kix and Tup to release and rearm Fives and Jesse, who fell in line with the others. They all proceeded to the command tower, where they stormed into the control room and surrounded Krell, training their blasters on him. Rex informed Krell that he was being relieved of duty and demanded his surrender, though Krell responded by proclaiming the clones' inferiority and releasing a massive Force pulse against his would-be captors. Krell activated his double-bladed lightsabers and used them to great effect, cutting through many of the soldiers in a matter of moments. Rex himself narrowly avoided being hit by a corpse that Krell kicked in his direction. Refusing to let Rex and the clone troopers undermine him, Krell broke out of the command tower, smashing through the viewing window and forcing his way through the troops who confronted him below. By the time Rex made it to ground level with Jesse, Fives, and the others, Krell had escaped into the forest, leaving behind a long trail of carnage. Before they could pursue, Rex and his comrades were challenged by Dogma, who tried to retain his loyalties to his general, proclaiming that all of the clone troopers were traitors for turning on Krell.

Dogma raised his blaster at his fellow troopers, who did the same to him, but Dogma's uncertainty with his own position grew when Rex told him that they were not mindless, obedient soldiers—they were more than droids, and they had a duty to make their own decisions when faced with ill-natured orders. Dogma hesitated, then lowered his blaster, and several other troopers subdued him. Ordering that Dogma be taken to the prison block, Rex led the remainder of his men into the jungle after Krell, splitting them into groups to search for their rogue general. After a while, Rex checked with the other squads to see if anyone had found any sign of Krell. One of the other units had encountered him, and Fives spotted them up ahead, but all of them fell to Krell's blades. Approaching Rex and his squad, Krell jumped into the trees and used the Force to magnify his voice, taunting the clone troopers and their loyalty to him. Krell then revealed himself and attacked, dealing a great number of losses. While Rex tried to hold the line with Fives and their rapidly diminishing troops, he was contacted via comlink by Tup, who had a plan to defeat Krell that required the general being lured toward him. Rex observed Tup's request to trust him and ordered everyone to circle around Krell and lead him in Tup's direction. They soon saw Tup's idea: to maneuver Krell into the waiting tentacles of a ravenous vixus, a threat that even the Jedi Master did not expect to encounter.

Tup succeeded, and although the hungry creature did not digest Krell, he was left winded upon breaking free of its tentacles. Tup killed the vixus and stunned Krell at point-blank range, and Rex congratulated the rookie trooper on his canniness. Locked in a set of binders, Krell was brought back to the airbase, where Rex and his men installed him in a detention cell adjacent to Dogma's. Confronting the shackled Krell, Rex discovered that the Jedi Master had fallen to the dark side. Krell had foreseen that the Jedi were going to lose the Clone Wars and strove to become Count Dooku's new apprentice, intending to curry favor with the Sith Lord by driving the Republic from Umbara. Although Rex refused to let Krell's ambitious plans come to fruition, the Jedi Master believed that the Umbarans would soon retake the airbase, at which point the Separatists would set him free. Troubled by their deposed general's resolve, Rex, Fives, Jesse, and Tup returned to ground level, where they witnessed bombings overhead from the Umbarans' long-range missiles. Appo reported to Rex that the command center's transmitter had been repaired, as it had been offline not due to enemy interference, but because of sabotage. Appo went on to convey that Kenobi's forces had conquered the capital city, though the remaining Umbarans were now regrouping to retake the airbase. Rex ordered Appo to mobilize all of their men on the perimeter in preparation for what looked to be a full-scale enemy assault.

Rex realized that Krell, having sabotaged the transmitter, had been against the clone troopers from the beginning, leading Fives to conclude that if the Umbarans took custody of Krell, he would betray all of the Republic intelligence in his possession. Jesse and Tup agreed that they had to do something to silence Krell, and Rex reluctantly conceded that they would have to execute him. The captain returned to the prison block with Fives and Jesse to carry out the task at hand. While Fives brought Dogma out of his cell, Rex told Krell to turn around and step toward the back wall, then ordered him onto his knees. He drew one of his blaster pistols and had Jesse deactivate the shielded door of Krell's cell. Despite the necessity of executing the Jedi Master to prevent his information from falling into Separatist hands, Rex hesitated with killing an unarmed Jedi, even in spite of his crimes against the 501st and the 212th. Krell sensed his hesitation and savored his fear, calling out the captain on his inability to deliver the killing shot. In the end, the fatal shot came not from Rex, but from Dogma, who had lifted one of Fives' blaster pistols. Having been one of Krell's most ardent supporters, Dogma had consequently been devastated by his betrayal.

Their general permanently removed from duty, Rex and the others exited from the detention level. Republic LAAT/i gunships soon landed at the airbase, and Dogma was taken away on one of them, exchanging a respectful nod with Rex before leaving. Fives informed Rex that Kenobi's battalions had routed the final Umbaran holdouts—the Battle of Umbara was over, and the Republic was now in control of the Shadow World. With the hostilities abated, Rex wondered aloud why they were fighting the war and what would happen to the clone troopers when it ended. Fives, Jesse, Tup, and the others did not have an answer for him, and they simply watched as Dogma's gunship lifted off into the darkened Umbara sky. Following the campaign, Rex reported to his superiors on Krell's treason against the Republic and his betrayal of the Jedi Order, though responsibility for his execution remained with the arrested Dogma.

Following the Confederacy's invasion of the Togrutan artisan colony of Kiros—a peaceful society that had, up until that point, avoided being ensnared in the war—the Jedi High Council sent a Grand Army detachment led by Skywalker, Tano, and Kenobi to liberate the world. Troops from Rex's 501st Legion and Cody's 212th Attack Battalion were assigned to the joint task force, which arrived at Kiros aboard a Republic Navy fleet ten rotations after the Separatists' takeover of the world. Rex served as one of the officers aboard a Venator-class Star Destroyer that had replaced the Resolute, which had fallen at the previous Battle of Sullust. Rex discovered that there were no Separatist craft in the system from the earlier invasion force and, on Kenobi's order, moved their Star Destroyer into position for deployment. The Republic troops transferred to an Acclamator-class transport, whereupon they departed for the surface with AT-TE and AT-RT walkers aboard LAAT/i gunships. Upon landing in the capital city, Skywalker and Kenobi elected to patrol the city for Separatist activity on BARC speeders. Rex manned the sidecar of Kenobi's speeder while Tano rode with Skywalker, with other speeder-mounted 501st troopers falling into line behind them as they proceeded through the city streets.

Speeding through the city, Rex and his comrades were surprised to encounter an utter lack of Togruta colonists, who Skywalker and Kenobi assumed were hiding to wait out the fighting. Kenobi believed that they would have an easier time repelling the Separatists without having to worry about the risk of civilian casualties, but Rex was apprehensive about the situation, noting that the Separatists had never hesitated in the past to exploit civilians as living shields. As they headed for the city center, the silence from the absent colonists was broken by the appearance of Separatist forces ahead, taking the form of BX-series droid commandos riding Flitknot speeders. Rex and his men quickly returned the approaching biker droids' fire with their BARC speeders' repeating blasters, and they cut through a number of the droid commandos before passing by them. When the battle droids caught up with them again from behind, Rex and Tano revolved their sidecars and focused their blasterfire on the enemy units, eliminating the remainder of the droids between the two of them.

As they approaching the governor's tower at the city center, Rex and his comrades encountered more Separatist defenses, this time including two Armored Assault Tanks. While the others took care of the battle droids, Rex made quick work of one of the tanks, blowing it to pieces with a warhead from his RPS-6 rocket launcher before it could fire at his men. Tano destroyed the other tank with a pair of thermal detonators, and the last of the battle droids in the area were eradicated. At Kenobi's behest, Rex deployed his 501st troops to secure the vicinity around the city center. AT-TE walkers were brought in as the Republic forces established a perimeter around the governor's tower, wherein the Separatist commander, a Zygerrian known as Darts D'Nar, had barricaded himself. When Kenobi went to negotiate terms for surrender with D'Nar, he discovered that D'Nar had set up thermal annihilator bombs all over the city to be used as last-resort leverage against the Republic forces. Skywalker and Tano deactivated all nine of the annihilator bombs before D'Nar could use them to destroy the capital, and they also managed to prevent D'Nar from escaping off-world aboard his Zygerrian slave ship, the Tecora.

Although the Republic succeeded in securing Kiros, a planetary bioscan conducted by Admiral Yularen revealed that the Togruta colonists, all 50,000 of them, had completely vanished from their world. When Skywalker and Tano interrogated him, D'Nar revealed that the Zygerrian queen was reviving the Zygerrian Slave Empire of old, a slave-trading government that had prospered for centuries before the Jedi Order had dismantled it, forcing its slave trade to fester in the criminal underworld. The Togruta were to be auctioned off into slavery on Zygerria, but the Jedi were determined to prevent the colonists from becoming slaves. To that end, Rex, Skywalker, Tano, and Kenobi took the Tecora to Zygerria, where they intended to infiltrate the Slave Empire and locate the missing Togruta. En route to the Zygerria system, Rex, Skywalker, and Kenobi assumed uniforms to pose as Zygerrian slave traders, while Tano masqueraded as a Togruta slave. After landing at a Zygerrian slave market, Rex and his comrades set off on their mission. While Skywalker distracted the Zygerrian queen, Miraj Scintel, Rex and Kenobi were to find the Togruta colonists. Splitting up from Skywalker and Tano, whom Prime Minister Atai Molec escorted to the Zygerrian Royal Palace, Rex and Kenobi proceeded to the Royal Palace's outdoor slave cells, where they discovered only one Togruta prisoner, an ailing Governor Roshti of Kiros.

With royal Zygerrian guards patrolling the compound, Rex kept watch for Kenobi to retrieve Roshti, who was too weak to reveal anything about the whereabouts of the other missing Togruta. Recognizing the need to spirit Roshti away from the Royal Palace, Kenobi commandeered a brezak lizard mount from a Zygerrian guard and helped Rex bring Roshti onto the creature's back. As other Zygerrian guards in the vicinity caught sight and ordered them to stop, Rex took up the brezak's reins and steered their mount for the other end of the compound. However, a Zygerrian guard shot Kenobi in the shoulder, and both he and Roshti fell off the brezak. Rex was forced to leave them behind and escaped while Kenobi and Roshti were captured. That evening, Rex proceeded to the royal auction house to provide support for Skywalker and Tano at Queen Scintel's Royal Slave Auction, in which the Togruta colonists were to be sold into slavery. While a Zygerrian auctioneer introduced the recaptured Roshti as a sample of the Togruta, Rex caught the eye of Skywalker, who was with Tano and Scintel in the queen's private viewing box, and showed him his acquired Zygerrian blaster rifle as a gesture of being ready for action. However, Rex and his comrades were met with a grim surprise when Kenobi was brought out onto the auction block as a "special guest" of the queen.

Denouncing the Jedi as slaves to a corrupt Republic Senate, Scintel ordered Skywalker to whip Kenobi to teach the Jedi Master his place. Just as he activated his shock whip, Skywalker checked that both Rex and Tano were prepared for action, then joined Kenobi in attacking the Zygerrian guards on the auction block. As the guards in the stands opened fire on his comrades below, Rex disarmed one of the Zygerrians and shot at another group of them, exploding that part of the floor. With two blaster rifles in hand, he was stopped by a trio of royal guards and was then attacked from behind by another. Both Rex and his assailant fell out of the stands, landing on the ground several stories below. Before Rex had much time to recover, Scintel sent in reinforcements to subdue the infiltrators. The touch of a shock whip electrified Rex into unconsciousness, and Skywalker, Tano, and Kenobi were similarly defeated. The Zygerrians sent all four of them into slavery: While Scintel forced Skywalker to become her personal bodyguard, Rex and the others became her leverage to keep Skywalker in his place. Tano was imprisoned outside the Royal Palace, and Rex and Kenobi, fitted with shock collars, were meanwhile sent to be processed as slaves with Roshti.

The Zygerrian slave ship Delta-T-3 transported Rex, Kenobi, and Roshti to the volcanic world of Kadavo, where the Zygerrians maintained a mining complex over a volcanic crater. Rex and the others laid eyes on the population of Kiros, whom Agruss, the keeper of the facility, was subjugating into slavery for processing by the Zygerrian Slave Empire. As part of his welcome for his newest charges, Agruss dropped seven of the Togruta colonists into the crater below, making it clear that the Togruta would suffer for any trace of defiance from Kenobi. Rex and Kenobi were quickly forced into work alongside the Togruta in mining materials at the facility. On one occasion, while Kenobi was commenting to Rex on the state of the despairing Togruta, one of the Zygerrian slave masters interrupted him, whipping Kenobi as punishment for speaking. The Zygerrian then turned his shock whip on a nearby Togruta slave, forcing Kenobi to submit to save the colonist's life. Rex and Kenobi thus realized that the Zygerrians intended to break Kenobi's spirit by punishing the Togruta instead of him. As Rex and Kenobi's days in slavery continued, they were shackled in handcuffs and brought before Agruss in the facility's command center to speak with none other than Count Dooku via holoconnection. Having learned of the Zygerrians' capture of the Jedi, Dooku had ousted an uncooperative Scintel from power and had ordered the immediate execution of Rex and Kenobi.

Just then, the Tecora made an unscheduled landing at the Kadavo mining complex. Aboard were Skywalker, Tano, and R2-D2, who had escaped from Scintel's custody on Zygerria and had come to rescue Rex, Kenobi, and the Togruta. The Zygerrians destroyed the Tecora, though an unfazed Skywalker and Tano began to cut through the facility's outer blast door with their lightsabers. Meanwhile, the Zygerrians rounded up all of the Togruta colonists in a holding cell and prepared to dump them into the crater below if Skywalker did not call off his forces. Nevertheless, Skywalker continued his efforts when his reinforcements arrived: Plo Koon and a Republic Star Destroyer under the command of Admiral Coburn. With the complex under attack by Koon's starfighter forces, Kenobi used the Force to sever his and Rex's shock collars, and the two attacked their Zygerrian captors. Rex disabled his handcuffs with a Zygerrian's electrostaff and took down several slavers on his own, pilfering an electrostaff from one and head-butting another. In response to the outbreak of hostilities, Agruss activated the mechanism that would open the Togruta slaves' holding cell over the crater, jamming the controls so that Rex and Kenobi could not deactivate it.

As Rex and Kenobi finished off the Zygerrian guards, the cornered Agruss attempted to barter for his life, taunting Kenobi that a Jedi would not kill an unarmed man such as himself. Though Kenobi was unable to pass judgment on him, Agruss failed to account for Rex, who did not share Kenobi's reservations and threw an electrostaff at Agruss. The staff plunged straight through Agruss and the back of his hoverchair, killing him. Rex and Kenobi then left the command center and joined Skywalker out on the landing pad, where Koon's Wolfpack landed an LAAT/i gunship to retrieve them. In the meantime, Coburn took the Arquitens-class light cruiser Hand of Justice to assist Tano in rescuing the Togruta slaves from their holding cell. Once all of the Togruta were safely aboard the Hand of Justice, the Republic's LAAT/i gunships moved in and compromised the building's supports, plunging the entire complex into the crater below. Following the successful rescue, Rex, Skywalker, Tano and Kenobi were taken to Koon's Star Destroyer with the Togruta colonists, who began to receive treatment to recover from their ordeal in enslavement. After receiving Roshti's thanks for their efforts, Rex and Commander Wolffe convened in the main hangar with their Jedi commanders to debrief the operation.

When Supreme Chancellor Palpatine became the target of a Separatist kidnapping plot, Rex and some of his men from the 501st were assigned to be bodyguards for him, serving as extra security at the Chancellor's Suite on Coruscant. Meanwhile, the Jedi High Council authorized an operation to infiltrate the enemy plot. The sniper Rako Hardeen was allowed to appear to kill Kenobi, who then went undercover as Hardeen to gain the trust of Moralo Eval, the mastermind behind the conspiracy. After learning from Palpatine that Hardeen—actually Kenobi in disguise—had escaped to the planet Nal Hutta with Eval and Cad Bane, Skywalker went after the sniper who had murdered his former Master, while Rex and two of his soldiers remained behind to guard Palpatine. That night, Mace Windu contacted Rex via the latter's Imagecaster and asked for Skywalker, who had failed to respond to his calls. Although Rex tried to hide his general's unsanctioned departure from the capital, Palpatine revealed that he had personally sent Skywalker to Nal Hutta, believing that the High Council should have more faith in Skywalker and his abilities. Palpatine ended the exchange with Windu by informing Rex that he was withdrawing for the night, and Rex and his men escorted him back to his apartment. Thanks to Kenobi's undercover efforts, the Jedi Order thwarted the kidnapping plot two days later at the Festival of Light on Naboo, preventing Eval and Bane from capturing Palpatine.

In 20 BBY, as the Clone Wars entered their third year, Rex accompanied Kenobi to the Jedi Temple to watch a sparring duel between Jedi Master Quinlan Vos and a Jedi Knight. New orders came in soon enough for Rex when the High Council received a plea for aid from the Onderon rebels, a grass-roots insurgency based on the planet Onderon. Despite their world's alignment with the Confederacy, the rebels refused to recognize the legitimacy of their Separatist-loyal monarch, King Sanjay Rash, and sought to deliver Onderon from battle droid occupation. Instead of direct intervention by way of the Grand Army, Skywalker developed the idea of sponsoring training for the local rebels, the objective being to teach them self-sufficiency while also engaging the Separatists on another front. Rex joined Skywalker, Tano, and Kenobi as the fourth member of the team of advisors who would be instructing the rebels. Once they had prepared for the journey to Onderon, Lieutenant Hawk transported them to the night side of Onderon aboard the Republic shuttle Valkyrie 2929, hovering over the drop zone in the Onderonian jungle long enough for Rex and his robed Jedi comrades to reach the ground via a jetpack and the Force, respectively. They were soon found by a dalgo-back patrol of guerrillas led by the young Steela Gerrera, who took Rex and the others to the insurgency's secret base a half-kilometer to the east.

Rex and his comrades arrived at the rebel camp at daybreak, at which point Steela introduced them to her brother, Saw, the self-proclaimed leader of the insurgency. Among the other rebels was Lux Bonteri, the quondam senator of Onderon and an old friend of Tano. Skywalker and Kenobi wasted no time in launching the insurgency's training, calling a gathering to introduce themselves to their new trainees. After Rex took a group of volunteers to retrieve supplies from their entry point, the Jedi decided to begin with a session on countering an Armored Assault Tank, a common sight amidst the Separatists' forward infantry. Using a captured tank as a visual aid, Tano laid out the vehicle's schematics to their rebel trainees, explaining that both the top and front hatches had to be disabled to fully immobilize the tank. As a demonstration, Rex, taking an EMP grenade in each hand, tossed one charge into the front cabin and then swung onto the main cannon to reach the topside chamber. He somersaulted off the tank a moment before it was disabled by the combined electromagnetic pulse. To practice the maneuver, Skywalker organized the rebels into teams of two, as each soldier would be able to target a separate port. Although the first pair, Saw and Bonteri, botched their attempt when the latter lost his hold on the main turret, Rex kept the exercise moving, supplying the next few groups with EMP grenades. He rallied each pair through the drill, treating them as soldiers and pushing them to give it their all.

In the next lesson, Rex, Skywalker, Tano, and Kenobi taught the insurgents how to disable a shielded droideka. Controlling three reprogrammed units from a wrist remote, Rex activated the shield of one of the sample droidekas, then released several blaster shots at the shield to demonstrate its ability to repel high-velocity attacks. Tano presented the solution to the shield: a stationary or slow-moving object, such as a carefully tossed EMP grenade, one of which she lobbed through the shield, deactivating the destroyer droid. When it was time for the rebels to conduct the exercise, only Bonteri mastered it on the first try. Rex broke the soldiers into pairs for further practice, in which others, including Saw, were able to perfect the maneuver. Following that, the Jedi moved on to firearm practice, with Steela exemplifying her natural abilities with a sniper rifle. Rex made sure to inform the rebels that a headshot was the only effective way to deactivate a battle droid, as the enemy units would otherwise continue relaying intelligence to central command. At that point, the insurgency's training escalated into full-blown combat, as a patrol of droids stormed out of the surrounding trees to quash the fledgling rebellion. Rex shouted for everyone to take cover as enemy rockets and cannonades began to fly into the camp.

Jumping behind a wall with several of the rebels, Rex opened fire on the invading droids, the first wave of which was demolished thanks to the insurgents' homemade disruptors. The next wave of enemy infantry was headed by an Armored Assault Tank, which spawned considerable devastation across the camp until Bonteri and Saw worked as a team to disable it with thermal detonators, just as Rex and his comrades had taught them. Despite several casualties, the young insurgents emerged victorious over the droids. Emboldened by their success, the rebels decided to infiltrate the capital city of Iziz, where they would bring the fight directly to King Rash and his Confederate supporters. Posing as game hunters with a dalgo-drawn caravan, Rex and the others gained access to the walled Iziz from the battle droid guards at the city gates, then split up to avoid detection. Rex accompanied Tano on her dalgo-drawn cart to find supplies for the rebels, rendezvousing with the others after nightfall.

The rebels' next course of action was to carry out a series of small-target strikes on battle droid patrols throughout Iziz. Rex helped coordinate one of the assaults, targeting a Separatist checkpoint in the city, while Skywalker, waiting with Steela on a nearby rooftop, observed their performance. After Steela sniped at the B1 battle droid manning the checkpoint, then disabled the security shield's controls with another blast, a DSD1 dwarf spider droid emerged and targeted her from street level. At that point, Rex signaled to the two soldiers accompanying him, and he watched as the insurgents used an EMP grenade to disable the dwarf spider droid. Rex, Skywalker, and the others proceeded with Tano, Kenobi, and the rebels to their safe house in Iziz to review their progress. Although Bonteri, the Gerreras, and the other rebels were proud of their growing number of successes, Kenobi and Tano—who, like Skywalker, had been monitoring the strikes as well as civilian reactions—voiced their concern that the local citizenry was frightened by the outbreaks of violence. While Bonteri proposed that they make a show of strength to garner public support, Rex withdrew from the safe house with Skywalker, Tano, and Kenobi.

The group decided that Skywalker and Kenobi would return to Coruscant to report back to the High Council. Meanwhile, Tano would remain on Onderon as an advisor for the rebellion while also providing firsthand developments to the Council. With that, Rex left for Coruscant with Skywalker and Kenobi. After the rebels won a major victory by destroying Iziz's power generator, Rex was present at their following celebration via hologram with Skywalker and Kenobi, who offered encouragement and advice to the insurgents. In particular, Rex noted that Steela was emerging as a born leader, to which Kenobi agreed. Thanks to their training from Rex and the Jedi, the rebels were able to liberate Onderon from the Confederacy. Although Steela was elected to replace Saw as the rebel leader, she died during their decisive clash with the Separatists, becoming the final casualty in the rebellion's campaign for freedom.

While stationed aboard a Venator-class Star Destroyer, Rex joined Skywalker, Kenobi, and Cody on the bridge to review an intercepted transmission from General Grievous. Due to a new encryption code that the Separatists had recently developed, the bridge team was unable to decipher the audio of Grievous's message. When Republic Intelligence encountered similar results, the Jedi High Council formed a squad of Republic droids to retrieve the Separatist encryption module responsible for encoding the transmission. Not only did the so-called D-Squad complete its mission, but it also thwarted a Separatist plot to sabotage the Republic strategy conference.

When Republic Intelligence got wind of a new Subjugator-class heavy cruiser—of the same class as the Malevolence, which had terrorized Republic systems earlier in the war—that the Confederacy was constructing over a planet in the Enoth system, Rex was among the clone forces that went to target the nearly completed warship. He was present when Skywalker led a briefing for the assembled troops aboard his Star Destroyer. While Rex was to lead the ground unit that would destroy the heavy cruiser's energy shield generator, located on the planet below, Skywalker would lead the starfighters of Red Group and Blue Group in eliminating the battleship itself. After they reached the Enoth system, Rex led his battle group to the planet's surface with a pair of AT-TE walkers. As he reported to Skywalker, who was leading the space forces against the battleship's Vulture droid defenses, the clone infantry made progress toward the generator site, albeit slowly. Once they were within optimal firing range, Rex ordered the AT-TE walkers to open fire on the shield generator, to great effect. He then gave Skywalker the all-clear, and Skywalker's squadrons were able to obliterate the heavy cruiser—mainly due to the sacrifice of clone Z-95 pilot Shooter.

In 19.1 BBY, in what was to become the final month of the Clone Wars, Rex and the 501st were assigned to respond to a Separatist invasion of Cato Neimoidia, a former Neimoidian purse world and major holding of the Trade Federation. While Skywalker and Tano led a starfighter assault on the Confederate aerial defenses, Rex followed closely behind, overseeing the main body of troops from the gunship Lucky Lekku, which launched from the Republic fleet in orbit. Once his 501st landing force had reached Cato Neimoidia's bridge cities aboard its squadron of LAAT/i gunships, Rex received a request for retrieval from Skywalker, who had been stranded with Tano on an outcrop after Pistoeka sabotage droids, also known as buzz droids, destroyed his Eta-2 interceptor. Rex diverted the Lucky Lekku to the cliff to pick up Skywalker and Tano. The two Jedi were thereafter recalled to the Jedi Temple to investigate a terrorist bombing there, and they returned to Coruscant, as did Rex. Although Skywalker and Tano apprehended Letta Turmond, a Republic citizen who had engineered the bombing, Turmond was murdered while in Republic custody. Tano was framed for the crime, and as a result, newly promoted Admiral Wilhuff Tarkin, who was leading the Republic Military's investigation into the bombing, arrested and incarcerated her in the Republic military base.

Despite an attempt on Skywalker's part to speak with his detained Padawan, the base's security staff—headed by Clone Commander CC-1010 of the Coruscant Guard—withheld Skywalker from seeing her as per Tarkin's orders. When Rex received word that Tano had escaped from her prison cell, he rushed to the military base with Skywalker aboard a Praxis Mk. I turbo speeder. Once there, he and Skywalker hurried after CC-1010, nicknamed "Fox," who was pursuing Tano through the corridors of the compound. Upon discovering the bodies of three of his clone shock troopers, killed by lightsaber wounds and left in Tano's path, Fox concluded that Tano had slaughtered his men and ordered his search team of shock troopers to shoot to kill if they found her. Catching up with Fox, Skywalker promptly countermanded the order, while Rex argued with the commander, refusing to believe that Tano would have killed the troopers. Skywalker silenced Rex and Fox in mid-argument and called out to Tano, who was still inside the base. Tano claimed that she was being framed her for the murders, and though Skywalker assured her that he believed in her innocence, she was convinced that no one else would and refused to capitulate. Assuming command of the manhunt for his Padawan, Skywalker ordered Rex to relay an all-points bulletin to the base's security team. In light of the current evidence, Rex was forced to report that Tano had killed the three troopers and classified her as armed and dangerous.

As Rex and Skywalker joined Fox outside the base to oversee the external security patrols, Fox reported that they had spotted Tano heading for the industrial pipeline that led away from the complex. Skywalker ordered all of the shock troopers to set their blasters to stun mode, intending to take her alive. Rex, Skywalker, and Fox caught up on foot with the search teams just as they surrounded Tano near the pipeline's central viaduct. In spite of being outnumbered, Tano continued to evade capture, carving a hole into an adjacent pipe with her lightsaber and jumping into it. Rex followed his comrades in rappelling down into the pipe network in pursuit of Tano. With spotlights activated, he and Fox searched for the fugitive Padawan amidst the shadows of the sewers. During the hunt, they were separated from Skywalker, who found Tano first and tried to convince her to turn herself in. However, Tano was adamant against doing so and was determined to clear her name. Just as Rex and Fox found Master and Padawan at the edge of the water pipe, they were unable to prevent the latter from jumping out of the shaft. Rex and the others could do nothing but watch as she landed on a freighter far below, descending into the cavernous shipping portal of the Coruscant underworld.

With Tano now being framed for the murder of the clone officers at the military base in addition to the homicide of Letta Turmond, Tarkin concluded that Tano was further responsible for the bombing of the Jedi Temple, given that Turmond had admitted to collaborating with a dissident Jedi while Tano was interrogating her. The evidence even compelled the Jedi High Council to consider the possibility that Tano was guilty, resulting in Master Yoda dispatching two teams of Coruscant Guard shock troopers to detain Tano. Rex and Skywalker headed the first team, while Plo Koon and Commander Wolffe received command of the second. Both squads set out for the Coruscant underworld aboard a pair of Republic police gunships. As they crossed the ecumenopolis en route to the underworld's shipping portal, Rex interfaced with the local Coruscant Underworld Police, who oversaw security on the lower levels and claimed to have sighted Tano in the vicinity of Level 1312. Rex relayed the report to Skywalker, who ordered their search party's pilots to set course for that area as they descended into the underworld. Just as they neared the landing deck of Level 1313, Skywalker ordered the police gunships to train their spotlights on terminal 24, where Rex and the others spotted Tano in mid-conversation with an unexpected confederate: Asajj Ventress, who had ventured into bounty hunting and reformed her ways—to a degree—since being jilted by Count Dooku.

Skywalker immediately jumped out of the police gunship and gave pursuit on foot, though Ventress cut him off by activating terminal 24's ray shield before bolting out of sight with Tano. In response, Skywalker sent out the search party's probe droids in search of the fugitive pair. The probes eventually located Tano and Ventress on Level 1312, where Wolffe and his team of Coruscant Guard troops attempted but failed to subdue the pair. In the meantime, Rex remained with his shock troopers aboard their police gunship and continued to monitor reports from the Underworld Police, hoping to come across another lead as to Tano and Ventress's whereabouts. When Rex heard word of suspicious activity on Level 1315, Skywalker had their police gunship adjust course for that area. After regrouping en route with Koon and Wolffe, Rex and Skywalker proceeded with their soldiers to the abandoned munitions warehouse where the police report had originated. Wolffe was the first one on the scene and—upon sighting Tano—stunned her at point-blank range before she could emit more than a few words. Upon further examination of the vicinity, Wolffe found that Tano had been inspecting several crates of nano-droids, identical to the ones that had been used in the bombing of the Jedi Temple.

Rex and his comrades took Tano into custody and withdrew from Level 1315, with Rex and Wolffe joining Skywalker, Koon, and the detained Tano aboard one of the police gunships while their shock troopers rode aboard the second gunship. During the flight to the Jedi Temple, Rex and Wolffe held the comatose Padawan upright while Skywalker and Koon holographically reported back to the High Council. Though Ventress's exact role in the situation remained a mystery, as she had not been present at the Level 1315 warehouse, Tano was still suspected of sedition on account of being found with the nano-droids. By all accounts, the case against Tano was gaining more momentum, since she had nothing but her word to defend her innocence. As a result, the Jedi Council expelled her from the Jedi Order so that she could be put to trial under a Republic military tribunal. Skywalker eventually discovered that Barriss Offee was the true culprit, having orchestrated the Jedi Temple bombing and then framed Tano for her own crimes. Although Offee was arrested and later confessed to her machinations, Tano ultimately decided not to rejoin the Order, resigning her Padawan status and her rank in the Grand Army to find a new path for herself.

When the Republic set its sights on seizing the planet Ringo Vinda, Rex helped Skywalker lead the 501st infantry that was assigned to the campaign. The Republic and Separatist forces clashed for control of the orbital space station that encircled the entire world, eventually becoming based out of opposite sections of the facility. Rex and his comrades became locked in combat with the Separatist battle group for at least five rotations, but it was not until the arrival of reinforcements under the command of twin Jedi Generals Tiplee and Tiplar that they began to make headway toward breaking the ongoing stalemate. As part of their renewed offensive, Rex and Skywalker led the 501st in pressing through one of the station's hallways, while Tiplee and Tiplar's men concentrated on repulsing the droid forces in an adjacent passage. Once they had reached a communications center, Rex and Skywalker regrouped with the twin Jedi Generals and claimed the facility for their own use. They next set their sights on a command center up ahead, out of which the Separatist commander, Admiral Trench, was operating.

The Jedi initiated phase two of their battle strategy: While Tiplee and Tiplar would each lead their men to Trench's command post via the outer two of three passageways, Rex and Skywalker would oversee a 501st advance through the middle corridor. Upon learning from Tiplee and Tiplar's clone officer, Commander Doom, that his men were severely depleted, Skywalker transferred Fives, Tup, and ten other soldiers from the 501st to Doom and Tiplar's squad. With that, Rex joined Skywalker in spearheading the 501st's push, blasting through a number of B1 battle droids in the central passage. The hallway eventually opened into a large room in front of Trench's post, and Rex and the others were faced with DSD1 dwarf spider droids and super battle droid rocket troopers. As they made progress toward Trench's position, Tup—in a trance-like state—executed Tiplar at point-blank range. Tup's shocking exploit, combined with the appearance of a squad of droidekas, crumbled the Republic's advance, and Skywalker ordered a full retreat, with Fives taking Tup into custody. Once Rex and the others had fallen back to the communications center, they welded shut the blast doors to cut off the pursuant battle droids, then turned to the perplexing matter of Tup.

Alongside Fives, Kix, and Skywalker, Rex proceeded to interrogate the restrained Tup. Slipping back into his puzzling trance, Tup began to state that "good soldiers follow orders" before attacking Tiplee, who, undeterred, telekinetically repelled him with the Force. Skywalker decided to have Tup transferred to the medical bay of one of the Republic fleet's Star Destroyers before he tried to harm anyone else. Once Kix had completed a series of scans on Tup, the mystery deepened. After Rex, Skywalker, Fives, and Tiplee entered the ward, Tup—who had been strapped to a bed—questioned Fives about what had happened to him, evidently displaying no knowledge of his murder of Tiplar. Tup then began to panic, and a 2-1B medical droid promptly sedated him. At Skywalker's prompting, Kix reported that Tup had passed all of his scans, so Kix believed that Tup's behavior was the result of combat-related stress. Rex disagreed with Kix's diagnosis of an emotional breakdown, since all of them as clone troopers had been designed to withstand high amounts of stress, and Fives agreed. Rex and the others continued their conversation in the hallway outside, entertaining the possibility that the Separatists could have engineered Tup's breakdown by way of a virus—as Tiplee put it, biological warfare. Still, Kix advised that Tup undergo extensive examination back on Kamino, the only place with facilities that were equipped for that level of surgical scrutiny.

With Skywalker's approval, Tup and his hovergurney were moved to the Star Destroyer's hangar. Rex, Fives, and Skywalker saw Tup off as he was ushered onto a waiting Nu-class attack shuttle for transport back to Kamino. Just as Tup's shuttle was about to leave the system with an escorting quartet of ARC-170 starfighters, Admiral Yularen and the bridge team aboard Skywalker's flagship lost contact with the craft. Rex joined Fives and Skywalker aboard an Eta-class shuttle to investigate the last known location of Tup's transport, and there they were met with a grim surprise: The shuttle's hull had been breached, with Rex theorizing that it was the work of Separatist buzz droids. Once they had outfitted themselves in breathmask survival gear, Rex and Fives joined Skywalker in entering the drifting Nu-class shuttle, finding nothing but carnage within, as the crew and embarked clone trooper detail had all been massacred. Amidst the floating bodies, Skywalker found Tup's hovergurney with its restraints severed. Fives believed that the Separatists' kidnapping of Tup indicated that they were responsible for his breakdown, and Skywalker did not rule out that possibility. Returning to their Eta-class shuttle, Rex and his comrades followed Tup's exceedingly faint tracking signal to the Separatist-held side of the space station, specifically the enemy's principal hangar. Skywalker decided that the shuttle would drop them off at the hangar, and he, Rex, and Fives would space-walk on their own from there.

Upon reaching the Separatists' hangar, Rex and his comrades found it was occupied with hundreds of battle droids, some of which were loading Tup onto a Maxillipede shuttle. Rex voiced skepticism regarding their chances of surviving a direct confrontation with the droid army, earning Skywalker's comparison of his sentiment to that of the perpetually cautions Kenobi. As Tup's shuttle took off, Fives devised the idea of boarding the vessel via ascension cables, thereby avoiding the numerous droids in the hangar. Rex and Fives each attached a grappling extension to one of their blaster pistols and rappelled onto the shuttle as it passed overhead, with Rex bringing along Skywalker. After entering the airlock, Rex and the others broke into the main cabin and took down the BX-series droid commandos guarding the barely conscious Tup. While Skywalker defeated the shuttle's commander, the super tactical droid Kraken, Rex fought his way to the cockpit and gunned down the pair of OOM pilot battle droids at the controls. With Rex at the helm, they immediately piloted the captured shuttle to Skywalker's flagship, since Fives noted that the ailing Tup's life signs were dropping, indicating that he was close to death. Sending Tup to Kamino was paramount for him to be cured.

Once Rex and the others were back aboard Skywalker's flagship, a Consular-class cruiser designated as medical frigate 517 was prepared as Tup's transport. Skywalker assigned Rex to oversee the transfer, requiring a full report upon his return from Kamino. Prior to their departure, Fives asked for permission to accompany Rex to Kamino, as Tup was his best friend. Rex granted Fives' request but ordered him to proceed by the book so as to avoid further setbacks. Once they had arrived on rainy Kamino, Rex and Fives ushered Tup and his hovergurney into Tipoca City's Military Complex, where they were received by Shaak Ti and Doctor Nala Se, Chief Medical Scientist of Kamino and one of the principal engineers of the Grand Army's cloning program. While Se and a team of clone troopers took Tup to an observation room, Ti informed Fives that he would be undergoing a complete medical exam. She reasoned that if a virus was the cause of Tup's behavior, then Fives had likely been exposed to the same contagion. Although apprehensive about leaving his friend's side, Fives agreed to do so if it would help pinpoint a cure for Tup. After Ti informed him that Skywalker had ordered him back to the war zone, Rex told Fives to take care of himself as well as Tup before departing from Kamino.

Following the Battle of Ringo Vinda, Rex and the 501st returned to Coruscant. In the intervening time, Tup died after a tumor was removed from his brain due to Fives' intervention. After disobeying orders and evading arrest on Kamino, Fives discovered that the tumor was actually an inhibitor chip—an inorganic cerebral implant that the Kaminoans had inserted into all of the clone troopers at the embryonic stage. In Tup's case, his inhibitor chip had corroded and malfunctioned, leading to his unstable behavior. Upon arriving on Coruscant with Ti to plead his case to Chancellor Palpatine, Fives allegedly attempted to assassinate Palpatine and escaped into the lower levels of the ecumenopolis. Following Fives' getaway, the entirety of Coruscant's security and clone trooper forces were allocated to a manhunt for the rogue ARC trooper, but Jedi involvement was not requested. As a result, Skywalker volunteered to head the Order's undercover investigation into the matter, with Rex joining his Jedi General in the search for Fives. According to Ti, Fives believed that he was the victim of a conspiracy, Separatist or otherwise. Ti also warned Skywalker that since Fives had extracted his inhibitor chip—as he had done for Tup—his behavior might be as erratic as that of his late comrade.

Rex and Skywalker soon received a promising lead in the form of a communiqué from Kix, who had run into Fives at the clone sports bar known as 79's. Kix relayed a set of coordinates where Fives had requested a meeting with Rex and, by extension, Skywalker. Rex and Skywalker took a police gunship to the specified location, a portal warehouse on Level 1325. After disembarking, Rex and Skywalker warily entered the darkened warehouse, blaster pistols drawn and lightsaber ignited, respectively. Inside the building, they called out to Fives, who responded by thanking them for trusting him and then asked them to drop their weapons. Once Fives said he was unarmed, Rex and Skywalker complied, setting down their weaponry on a nearby crate. However, Fives, appearing disheveled and deranged, did not emerge from the shadows until he had trapped the pair in a ray shield. The beleaguered clone appealed to his irate comrades that he did not have a choice, saying he had been framed because he had uncovered a massive deception, the scope of which reached the highest echelons of the Republic. Fives claimed that the inhibitor chip in every clone trooper would even make them follow orders to kill the Jedi—as Tup had done to Tiplar.

Rex and Skywalker did not know how to react to Fives' improbable claims, and their visible skepticism left Fives frustrated with their lack of belief in him. After Skywalker asked Fives to come with them, Rex assured Fives that they were listening to him and that their only intention was to provide help. Nevertheless, Fives refused, claiming that Palpatine would kill him. Fives implicated the Supreme Chancellor in the conspiracy, an allegation that Skywalker refuted without a second's hesitation. At that moment, Commander Fox and a contingent of Coruscant Guard shock troopers stormed into the warehouse, having pinpointed Fives' location via a probe droid. Although Fox ordered Fives to surrender, the rogue ARC trooper refused to do so and seized one of Rex's blaster pistols from the adjacent crate. Before Fives could fire his pilfered blaster, Fox shot first. Aghast, Rex and Skywalker watched from the inside of the ray shield as Fives collapsed to the floor, clutching at the lethal wound to his chest that Fox had inflicted. Once one of the shock troopers disabled the shield at Skywalker's behest, Rex rushed to Fives' side, shouting that he needed a medic, but it was too late. Fives told Rex that the conspiracy was larger than anyone could have imagined, and his dying words made mention to a mission and nightmares that, for him, were finally over. Rex was devastated by the loss of his longtime comrade. All of Fox's Coruscant Guard troopers took off their helmets in honor of the fallen soldier.

In the wake of Fives' death, Palpatine's personal medical staff concluded via autopsies that the source of Tup's and Fives' disturbing breakdowns had been a parasite native to Ringo Vinda, which had led to the deterioration of their inhibitor chips and, consequently, their volatile behavior. Unbeknownst to Rex and his comrades, the truth was just as Fives had said: Palpatine's explanation was a cover-up on the part of his alter ego, the Dark Lord of the Sith Darth Sidious, to mask an anti-Jedi directive that he and Count Dooku intended to execute via the clone troopers.

When the Confederacy invaded the planet Scipio, the headquarters of the InterGalactic Banking Clan, the Republic Senate authorized a mercy mission to secure the banks and prevent Count Dooku from wresting control of the entire galactic economy. Skywalker was appointed as the general in charge of the Republic fleet, joined by Rex and their men from the 501st. One of their primary objectives was to rescue Padmé Amidala, who had been on-world to recognize the inauguration of the Banking Clan's new leader, Rush Clovis, but had been trapped when the Separatists invaded and obliterated her Coruscant Guard security garrison. After their three-cruiser fleet reached the Scipio system, Rex, Skywalker, and their troops deployed from Skywalker's flagship in a squadron of LAAT/i gunships. En route to bypass the Separatist blockade, Rex used a datapad to review initial scans of the city that housed the Banking Clan's Main Vault and concluded that Amidala was there, still alive. Lieutenant Hawk and other pilots, flying clone Z-95 starfighters, provided escort for Rex and the others to blast through the enemy droid starfighters and enter Scipio's atmosphere. Dooku thereafter withdrew his Confederate flotilla from the planet, abandoning his remaining droid forces stationed at the Main Vault.

Upon arrival at one of the Main Vault's landing platforms, Rex stormed out of the gunship with Skywalker and their men and opened fire on the squads of Separatist troops in the vicinity, including droid commandos, B2 super battle droids, and Vulture droids in walking mode. Rex and Skywalker soon found what remained of Amidala's felled security garrison, including the corpse of the officer in charge of the detachment, Clone Commander Thorn, buried under several super battle droids. In the ensuing lightfight, Rex and his men accepted the task of occupying the droid infantry on the landing platform and also provided covering fire for Skywalker, who pressed past the enemy forces and into the city to retrieve Amidala on his own. Skywalker reached Clovis's office and freed Amidala from Separatist custody there, but after a careening Vulture droid crashed into the spire atop of which the office was situated, Clovis sacrificed himself so that Skywalker could pull Amidala to safety. Following the Republic's triumphant seizure of Scipio, the remnants of the Banking Clan leadership blamed the late Clovis for the incident and conceded command of the banks to the Office of the Supreme Chancellor, transferring full economic power to Palpatine.

When Master Yoda made a later visit to the Sith homeworld of Korriban, known at that time as Moraband, the Sith Lords Darth Sidious and Darth Tyranus—the latter being Dooku's alter ego—engaged in an ancient ritual as a means of turning Yoda to the dark side. In the vision that Sidious and Tyranus concocted, Yoda found himself in a gunship with Rex, Skywalker, and a squad of four 501st troopers. The manifestation of Rex reported to Skywalker that they had detected a rogue shuttle slipping through Coruscant's security grid and that Dooku had been aboard the craft. Rex also revealed that, according to their scans of an industrial sector on Coruscant, Dooku was meeting with a second person inside of the LiMerge Building, to where their gunship was headed. Though at first disoriented, Yoda ordered the mission to proceed. Since Dooku was allegedly meeting with his Sith Master, Yoda believed it was imperative that they capture or else execute both Sith Lords. Upon touching down inside the building, Rex led the charge into the tower and sighted the two Sith Lords huddled over an altar basin, ordering his men to be wary of additional enemies. At Skywalker's word, Rex and his troopers opened fire on the Sith, but Tyranus reached out with tendrils of Force lightning to incapacitate Rex and his soldiers. Yoda's vision on Korriban ended after he sacrificed himself to defeat the hooded apparition of Sidious, with Sidious and Tyranus ultimately failing to break Yoda's spirit.

As the Republic targeted remote Separatist strongholds in a campaign that was termed the Outer Rim Sieges, Republic forces tracked Nute Gunray to Cato Neimoidia, where he sought to retrieve some possessions from a citadel that he owned on the purse world. In response, Rex joined Skywalker, Kenobi, and Cody in an assault on Gunray's citadel in an effort to detain the elusive viceroy. Though Gunray escaped, the Republic forces captured his mechno-chair, which proved to be a valuable asset in unearthing the identity of Darth Sidious.

Eventually, Rex relinquished his command of the 501st Legion, and the newly promoted Commander Appo assumed his leadership position. As a result, it was Appo and not Rex who oversaw the 501st through the end of the Clone Wars and into the time of the first Galactic Empire, the product of Palpatine's reorganization of the Republic.

Gruff, no-nonsense, and tough as carbonite nails, the elite Rex was an aggressive and battle-scarred veteran of the Clone Wars. Hardened by countless engagements with the Confederacy of Independent Systems, Rex—as he chose to be named—retained a reputation as one of the best and toughest clone troopers in the galaxy, particularly due to his near-flawless military record. Freethinking, fearless, and resilient, he preferred to be more diplomatic than the headstrong Advanced Recon Commandos when it came to operating with his superiors, though he would not hesitate to give higher-ranking Jedi officers his blunt opinion. He regarded his assignments with the utmost priority, and true to his genetic engineering, he often put them before his own safety, recognizing the importance of doing his part to ensure an objective's completion. A cunning warrior who was versed in military strategy, Rex led from the front and, in some cases, would have fought ahead of his Jedi General, Anakin Skywalker. Far from being reckless, his courage and willingness to jump into the fray helped the Republic win numerous victories. His outspokenness and aggression notwithstanding, he held that it was a soldier's duty to follow orders, faithfully executing them even when he disagreed, with little concern for his own well-being. Although he was willing to lay down his life for victory if need be, he came to acknowledge that in some cases, soldiers had to make their own decisions.

Brave and selfless, Rex was resolute in his dedication to his comrades. He recognized the need for galactic order and believed that the war was crucial to preserve the civilization that the Republic safeguarded. In spite of sometimes disagreeing with the management of the Republic's war effort by the Jedi High Council and the Galactic Senate, he remained committed in his service to the Republic. While on the war's front lines, he often became concerned for the safety of his Jedi officers, particularly for Skywalker, Ahsoka Tano, and Obi-Wan Kenobi. As such, Rex was hesitant to follow orders that put the Jedi in danger, especially those that came from the Jedi themselves, and was willing to sacrifice his life for the Jedi. He came to regard his clone brethren as his home and family, and he never forgot the many brothers whom he had lost to the war. His first loss of a unit, Torrent Company, at the Battle of Teth hardened him even further, and that he survived the ordeal was visible in his character from then on. During that campaign, Rex did not waver in his commitment to the mission, in spite of the possibility that the battle could be his last. While leading a squad of rookie soldiers against a full Separatist detachment for control of Rishi Station, he disregarded the odds against him, focusing only on his objective to retake the Republic base.

Despite witnessing enough of his comrades die to know that there was nothing glorious about war, Rex was unafraid to do his duty as a soldier of the Republic, even if it meant placing his own life and those of his troops in jeopardy. He made tough decisions calmly, would never back down from a fight, and was willing to fight to the last man if necessary; during the Second Battle of Geonosis, he even denounced a retreat as a cowardly tactic. Toughness aside, he viewed military service as an honor and greatly cared for the troops under his command, refusing to leave anyone behind if at all possible. He held the Separatist battle droids in contempt for all the damage that they had wrought on both him and his clone brethren, and cutting through droids on the battlefield frequently became an outlet for his rage and a way to avenge his fallen brothers. Despite his enmity with the Separatists, he assiduously lived by rules of engagement that transcended unwarranted behavior, regardless of provocation. After the loss of troopers Vere and Ince during a rescue mission, Rex pushed his anger to one side so that it would serve as fuel for the job at hand, intending to surrender to his feelings when in private. Sometimes, he even saw death as a method to assuage his belief that he had failed his men and to stop wondering how many more of them he would lose the next day. Yet he never gave up, watching over his troops throughout the pan-galactic conflict. Rex's care for his rookie 501st troopers on JanFathal was so substantial that he was surprised that his first instinct was not to look after Tano, whom he usually guided and mentored, but instead to take care of his men.

A seasoned soldier born to fight for the Republic, Rex was not often given to softness or sentimentality of any kind. He possessed an unusual individualism as a clone trooper, encouraged early on in his career during his participation in Alpha's ARC training program. Though Rex took on a unique nickname, he opted to keep its origins to himself. Unlike most clone troopers, he even kept the name's origins private from his Jedi commanders. According to Skywalker, he was wound very tight as a rookie soldier, eager to carry out orders to the letter, but became less stiff as time progressed. He made a habit of reviewing mission parameters and objectives in his head prior to an operation, a trait that he shared with much of his clone brethren, since it had been drilled into them thousands of times during training on Kamino. He did not allow himself to be intimidated by his enemies, from battle droids to Dark Jedi like Asajj Ventress, though he did—at rare moments—acknowledge being afraid. Although he recognized that fear was necessary to understand the severity of a situation, he refused to let such feelings prevent him from doing his job. He even expressed humor in the direst situations, such as during the Battles of Christophsis and Teth, as he believed that humor had many uses. In some ways, he could not imagine how the Republic had survived in antebellum times, without himself and his clone brethren in the Grand Army providing support and security.

Rex relied on instinct, sometimes preferring to shoot first without bothering to ask questions. Like many clone troopers, he regarded his homeworld of Kamino with a degree of personal importance. As such, he fought proudly alongside Commander Cody and their brethren to repel a Confederate invasion of Kamino, even rallying a group of young clone cadets to join the fight for their homeworld. Rex did not always look to a soldier's rank for information and instead judged by experience, which outranked everything in his system of beliefs, even the seniority of his superiors. When addressing the rookie soldiers of Rishi Station, he used the derogatory "shinie" slang to underline their inexperience in combat. He was pleased when the rookies rose to the challenge and acquitted themselves well in their first battle; he placed a handprint of Rishi eel blood on Echo's armor to recognize the trooper's transition to a seasoned warrior, and he also honored Hevy's ultimate sacrifice to destroy Rishi Station. He and Cody succeeded in sharpening the rookie clones into an effective fighting force. Rex inducted both Echo and Fives into the 501st Legion for their valiant service, and he later promoted them to Advanced Recon Commandos for their courage and determination during the defense of Kamino. Rex even saw a bit of himself in the two troopers.

A disciplined captain, Rex was good at preserving a stoical front around his troops when facing setbacks. Even when deeply unsettled about the comm jammer situation at Kothlis, he was careful to maintain a focused outward attitude, to the point that Skywalker could only sense his unease through the Force. Although Rex was not easy to rattle, he was visibly startled when he overheard trooper Checkers complimenting his skills as an officer, and he snapped at Tano and Checkers to "stow the chatter" after that comment. As a commanding officer, Rex was efficient and thoughtful, and his decisions and conduct reflected his assiduity. He often stayed focused on the current situation by keeping himself busy, which he found easy to do on account of his countless day-to-day tasks as a soldier. He knew that over-preparation never hurt and kept his men ready for battle at all times. Opting for maximum situational awareness on the battlefield, Rex was not partial to the Republic's spacegoing navy. He preferred to have ground under his boots whenever possible, where he could use his natural senses to take in the environment around him, free of a starship's viewports. Even so, he learned to respect the willingness of civilian starship contractors to live or die by their workmanship's quality, since such workers often went space-side with assault craft in the war zone. He fell back on old-fashioned soldering whenever necessary, using hand signals to convey orders depending on the situation.

Rex learned what he could from the Republic's HoloNet News information bulletins, being used to absorbing information in that manner from his early Kaminoan flash training. He sometimes made judgments based on the contents of his training; for example, he respected diplomacy as a kind of fighting for which he lacked training. On the other hand, he saw fighting simply as a skill in which he was versed, not claiming to absolutely like it. Unlike some other officers in the Grand Army, he respected malformed clones like 99, whose strong spirit earned his admiration, and was greatly saddened when 99 died during the Battle of Kamino. Some of Rex's views were less open-minded, particularly as he encountered different cultures on his tour of duty. At times he did not pay much attention to history or culture; he initially could not understand the Lurmen of Maridun and their pacifistic choice to avoid fighting, attributing such behavior to a lack of pride. He also looked down on the Lorrdian militiamen during the battle for Ereesus, though he learned to trust and respect their aptitude for kinetic communication. When it was too late for the Lorrdians to return to their own base, he welcomed them to bunk with his own men. The experience additionally led him to form a close working relationship with one of the Lorrdian officers, Sollaw ap-Orwien. On Onderon, Rex embraced his leadership role in training the local rebels, treating them as he would the troops under his command. He did not hesitate to push them, impelling them to perform maneuvers like the soldiers they strove to become. When the time came to leave Onderon, Rex was impressed with the rebels' efforts.

Rex was tan-skinned and stood 1.83 meters tall, weighing eighty kilograms. He was versed in Galactic Basic Standard, the primary language of the Republic. Due to his naturally accelerated age, he was ten years old by the time of the Battle of Christophsis in 22 BBY, though his physical development was that of an older Human man. He paid considerable attention to his hairstyle, as he found hair under a helmet to be bothersome and annoying. As such, he regularly kept his naturally black hair shaved to a fine polish to prevent it from interfering with his concentration on the battlefield. Even so, he dyed his hair a light blond, his most obvious unique trait, and let it grow out to a certain extent on various occasions. He experimented with other hairstyles as well, briefly dying his hair blue after choosing to support the Bylluran Athletic bolo-ball team when it reached the finals. However, he eventually deemed his new hairstyle undignified and inappropriate for a commanding officer, and he shaved it off to better fit in with his black-haired troops. Rex had a small scar beneath his lower lip. He sometimes bared his allegedly perfect teeth in a feral smile when adrenalized for a coming engagement with the Separatists.

A well-respected clone trooper captain, Rex viewed military service as an honor and acquitted himself as the leader of the 501st Legion. He projected an air of authority to his troops and earned their respect and obedience in that fashion. Leading by example, he saw the importance of being confident on the battlefield and motivating his men to fight for victory. To him, honor and service were the hallmarks of being a clone trooper. He trusted the men under his command and was a role model to them. He remained determined to achieve success in the face of danger, from frequently overwhelming enemy numbers to the life-threatening Blue Shadow Virus. Though he staked his life by the chain of command and did his best to honor superiors' orders, he also came to recognize the importance of a soldier's independence: He questioned orders instead of mindlessly obeying them and would adapt to shifting situations and plans as required.

Rex had several manners of etiquette as a commander that he strictly observed. He made a conscious effort to spend time getting to know all of his men on a personal level, and he consequently despised using the inconsiderate tally sensor to remember his charges' names because it was an admission that he could not tell his men apart from one another. He also valued his troops' privacy while not in combat. During the JanFathal operation, after the five rookie clones under his command opened up their own comlink channel, Rex avoided intruding on their conversation, even if they were cursing him for the recent loss of trooper Vere, and would have only overrode the frequency in an emergency. Outside of life-or-death situations, he abstained from barking out orders to his subordinates or superiors, believing that such conduct was improper.

In the absence of orders from superiors, Rex took matters into his own hands to ensure the survival of himself and his men. Despite generally being cautious and acting on certainty instead of hunches, he realized that in some situations there were no other options besides guesswork and improvisation. He was loyal to his men and genuinely cared for their well-being, for which he earned their admiration. All of Rex's traits in leadership were a testament to his effectiveness as a military leader, which was noticed by many of his colleagues, from troopers Checkers and Tup to Jedi General Pong Krell. Rex was well aware of his own talents as a leader and did his best to use them for the betterment of his men. His leadership skills were put to the ultimate test during the Battle of Umbara, where he was forced to balance the well-being of his troops with his commanding officer's strict orders. During that campaign, Rex found difficulty with uniting the 501st Legion under interim General Krell's leadership. Krell was focused on completing his mandates regardless of the cost, and he frequently employed strategies that the 501st perceived as reckless and costly. Though not afraid to speak out when he believed that he and his men were being treated inhumanely, Rex kept his men focused on their objectives and tried to set an example for his charges. He made an effort to respectfully cooperate with Krell despite the Jedi General's disagreeable behavior toward the clones.

Rex was tenacious in safeguarding his men's lives, even if that meant deviating from Krell's often reckless plans. At times he had more faith in his men than Krell did, trusting that Fives and Hardcase would be able to co-opt Umbaran starfighters from the nearby airbase—unlike Krell, who threatened to relieve Rex of his rank should he stray from the original assault plan. Rex was receptive to his subordinates' concerns and welfare in ways that Krell was not, requesting a respite for the battalion after a twelve-hour overland march. Whereas Krell simply activated one of his lightsabers to silence dissenters, Rex listened to his soldiers' grievances even when he did not agree, such as during their preparations to seize the Umbaran airbase. As time went on, he grew more open to defying Krell's orders in order to preserve his men's lives. After Fives, Jesse, and Hardcase refused to abandon their plan to eliminate the orbital Separatist supply ship, even though Krell had outright rejected their proposal, Rex did not attempt to restrain the three soldiers from leaving, but he also made it clear that he would not be able to save them from Krell's wrath once they were caught. Nevertheless, Rex covered up the trio's departure from Krell and also prevented Dogma and Tup from reporting their insubordination to Krell.

As the dissenting trio's commanding officer, Rex displayed a measure of responsibility for his subordinates' exploits, even though the decision to disobey orders had been theirs and not his. When Fives and Jesse returned, Rex tried to take the full blame and punishment for their actions, claiming that he had ordered them to disregard Krell's decree, though Fives returned the gesture by honorably reporting the truth of their disobedience to Krell. In the end, Rex's concern for his troops' welfare outshone his adherence to Krell's authority: He openly disobeyed Krell's subsequent orders to execute Fives and Jesse. He knew that if such punishment was rendered even once, then all of the 501st Legion could eventually face a similar demise, and he refused to let his men be subjected to fear of execution. He was horrified when Krell manipulated the 501st into attacking fellow clone troopers from the 212th Attack Battalion; the incident instilled in him the need for justice to prevent a recurrence of such an atrocity. He thus resolved to lead his men into the "uncharted territory" of arresting Krell for treason against the Republic. Given the mutinous nature of his proposal, Rex knew that he could not force his men into participating and gave them the option to opt out, though all of them except for Dogma supported his decision. For the entirety of the episode, Rex persevered in his commitment to his men, for whose safety he sought to detain Krell.

During the war, Rex swore to protect all Republic citizens from harm, including the ill-advised Chairman Chi Cho. At the Battle of Orto Plutonia, Rex knew that his men were risking their lives because of Cho's foolishness, but he nevertheless respected Cho's authority. Yet for all his wartime service, Rex's challenges were not only posed by his enemies. His loyalties and resolve were tested multiple times simply from his battlefield career. While he was aware that he and his clone brothers had been bred to fight for the Republic without a choice, he made the best of the situation. He knew that the politics and ideology of fighting were beyond his influence and instead focused on the day-to-day activities of looking out for his brothers in arms. When it came down to the nature of his commitment, it was not his relentless Kaminoan training or his loyalty to the Republic, but his dedication to his soldiers and Jedi officers that kept him in service. His compassion and selflessness as a commander was evidenced at Kothlis when, despite being severely injured, his first concern was for the welfare of his troops and comrades, not his own. His loyalty was so potent that even if he had not been born to serve, he could not imagine the prospect of abandoning his brothers and friends.

Over time, Rex learned to cope with his doubts about his origins as a clone trooper. Whenever the morality behind his manufactured birth was tested and his indoctrinated loyalty to the Jedi and the Republic challenged, he recalled that the men under his command depended on him to lead them—and that he would never be able to fight for the Republic if he questioned or scrutinized his birth's ethics. In that way, Rex put aside his insecurities for the greater good of the Republic. His strong loyalty to the Republic and the Jedi came into stark contrast with Sergeant Slick's hatred of the Jedi and betrayal of his comrades during the Battle of Christophsis. Rex had no respect for traitors like Slick and was visibly unsettled with Slick's perspective that the clone troopers were slaves to their Jedi commanders. Despite Slick's claim that he had been striking a blow for all clones, Rex drew the conclusion that the sergeant's actions—particularly putting his brothers' lives at risk by performing espionage for the Separatists—evidenced that he did not love and care for them as he so believed.

Rex's commitment to the Republic remained undeterred during his later encounter with the clone deserter Cut Lawquane, who had left the Grand Army relatively early on in the war. After first meeting Lawquane, Rex displayed a lack of patience for those who would abandon their duty, and he made his contempt for the deserter known. Once he had assumed a more respectful attitude toward Lawquane, Rex maintained that his beliefs had not been programmed into him, as Lawquane suggested, and that they were undeniably his own. He believed that his military service made him part of the most pivotal moment in the Republic's history and that the Grand Army's failure to defeat the Confederacy would mean the insurrection of an inconceivable evil. Despite disagreeing with Lawquane's outlook and disapproval of the war, Rex came to respect Lawquane as possessing a different type of loyalty—not to the Republic, but to his adopted family. Adding to his grudging but sincere regard for Lawquane was the deserter's brave effort to safeguard his family from invading droid commandos. When the time came to end his stay with Lawquane's family, Rex forwent his initial adamancy on turning in the fugitive Lawquane, opting not to report him as a deserter. He concluded that Lawquane was certainly not a coward and, before departing, politely refused his offer of a place at his farm.

As the Clone Wars continued, Rex feared that the Republic was beginning to view the clone troopers as a deindividualized, disposable army. He nevertheless upheld the mindset that the clone troopers' responsibility was to carry out and die for their missions when necessary. As he argued with Fives during the Battle of Umbara, that belief stemmed from his own code, not from the Kaminoans engineering him to think as such. In spite of his doubts about the clones' place in the Republic, he preserved his belief in the system for which he and his men were fighting. He held that the clone troopers were not independent of one another, that they were part of something larger than themselves, and it was thus not up to them to disobey orders in favor of strategies that they deemed more effective. Yet he was forced to draw the line when his loyalty to orders required that he see out General Pong Krell's decree to execute troopers Fives and Jesse for insubordination. Rex consequently realized that in some cases, it was necessary to make one's own decisions instead of blindly following orders like battle droids. Although he retained his loyalty to the Republic despite the incident with Krell, the Battle of Umbara left a lasting impression on his outlook as a clone trooper. In the face of so many casualties, he questioned the point of the war and wondered what would happen to the clones when the conflict ended, when they would no longer be needed as soldiers to fight the Clone Wars.

During the war, Rex became acquainted with a number of his brethren. He was good friends with Commander Cody, their friendship stemming from their mutual ARC training under Alpha. Their close relationship mirrored that of Skywalker and Kenobi—Rex's impulsiveness and superb instincts in battle won Cody's admiration, though Cody often worried that he put too much faith in them and rushed into danger too frequently. Still, Cody's penchant for procedure tempered Rex's impulsiveness, making them a good fit. After Rex fought alongside Sergeant Boomer countless times, Boomer became one of his trusted allies and close friends, as did Sergeant Coric of Torrent Company and Advanced Recon Commando Fives. Rex also shared an acquaintance with Commander Ponds and came to rely on fellow 501st trooper Denal for his instincts and expertise in combat.

Aboard Captain Gilad Pellaeon's Leveler, Rex found that he was comfortable with others who understood him as a fellow soldier, as opposed to Coruscant civilians who never would. Pellaeon described Rex as a solid, sensible chap who told very good jokes when not being the obedient soldier around Skywalker. Cody admired Rex as a smart man, and Kenobi believed he always thought on his feet. Tup held his leadership in high regard, and Checkers saw him as one of the Republic's best commanding officers. Callista Masana interpreted Rex as a hands-on commander who did not want to look like he was letting others do the dirty work by not taking part in the reconnaissance of JanFathal's capital of Athar.

Serving closely with Skywalker throughout the Clone Wars, Rex absorbed much from the Jedi General's style of leadership and daring improvisation. He learned to think on his feet, to consider methods outside of the regulation manuals, and to never surrender or let seemingly overwhelming odds dissuade him on the battlefield. He adopted Skywalker's inclination for unorthodox combat tactics, which often yielded spectacular results against the enemy. Rex was as headstrong and as brave as Skywalker, with full confidence in his own abilities, and it was the duo's similar lack of "by-the-book" methods that made them such an excellent team. He shared Skywalker's aggression, free thought, and occasional recklessness—a combination that got them both in and out of trouble. From his service with Jedi officers on the war front, Rex regarded them as figures of authority and learned to both respect and never doubt their resolve or powers. In turn, the Republic's Jedi Generals came to rely on him on the front lines, and his performance as an honorable military leader effected him becoming well-respected by Jedi officers and clone troopers alike. However, he sometimes disapproved of the preference to debating over fighting that some Jedi possessed. On the other hand, Skywalker matched Rex in bravery, aggression, and decisiveness, and the general's "soldiery" traits helped Rex to form something of a friendship with him.

Rex worked closely with Skywalker on the battlefield, offering thought-out suggestions about strategy as he saw fit, and respected Skywalker because he put himself on the line with his troops. Even though Skywalker at times maintained an authoritative demeanor of command, Rex did not resent such conduct on his part, knowing that respecting the chain of command was an integral component of an officer's performance. Like the rest of the 501st's Torrent Company, he was truly devoted to Skywalker and was proud of the trust that his general invested in him. Skywalker in turn thought highly of Rex, believing him to be the finest and most loyal trooper with whom he had worked, and introduced him as such to General Pong Krell. As a soldier, Rex was loyal to Skywalker not only on the battlefield, but also on a personal level. When Skywalker was away during Levelers shakedown cruise, Rex kept him regularly apprised with the situation to prevent his general from being caught out of the loop. In addition, when Skywalker pursued fugitives Rako Hardeen, Cad Bane, and Moralo Eval to Nal Hutta without the consent of the Jedi High Council, Rex made an effort to conceal his general's unauthorized undertaking from Mace Windu.

Rex was not upset when Skywalker was unable to aid Torrent Company during the Battle of Teth. True to his belief that the mission always came first, he understood his general's mandate to return Rotta the Huttlet to Tatooine. Furthermore, he looked up to Skywalker as a role model; when serving away from his general, he would sometimes consider, as he did more than once during the battle on Ereesus, what Skywalker would have done in his position to ensure success. The time that Rex spent with Skywalker was such that he even became aware that his general had feelings for Senator Padmé Amidala, though he was unaware of the full extent of their attachment. On some occasions, he pitied Skywalker, who was often prone to guilt and regret when forced to prioritize other assignments over serving alongside his captain. He became used to Skywalker's personal style of command and worked well with his Jedi General.

Besides his friendship with Skywalker, Rex was acquainted with Obi-Wan Kenobi, Skywalker's own former Master. Rex made it a goal to procure a laugh from Kenobi on the battlefield with his sarcastic jokes, though he did not have much success. In spite of his respect for his Jedi officers, Rex did not share all of their beliefs, particularly regarding the Jedi Code. Whereas Kenobi restrained himself from taking the life of the unarmed Keeper Agruss despite the Zygerrian's crimes as a slaver, Rex had no such reservations and acted decisively, killing the keeper. Rex also came to fully trust R2-D2, Skywalker's personal astromech droid.

After meeting Ahsoka Tano on Christophsis, Rex admired her spirit, though he was concerned with her initial naivety and arrogance toward her commanders, particularly Skywalker. Once the captain and Padawan reached an understanding of each other, they began to form a strong bond and supported each other as the galaxy-shaking war progressed. Rex often addressed Tano as "kid" in lieu of a more formal title. As Tano's teacher in military matters when Skywalker was absent, Rex preferred to train by example, and it was in that manner that he often instructed Tano. Among his lessons for her was that smart remarks were unhelpful and disruptive in times of protocol, especially when they were directed at her Master. They came to respect each other, and he earned her trust with her life. He defended her proficiency from others who expressed hesitancy with her competence, including fellow officers like Gilad Pellaeon and Wilhuff Tarkin. In addition, Rex encouraged Skywalker himself to maintain his faith in his Padawan during a confrontation with Asajj Ventress on Taronda. Rex's attitude toward Tano was such that Skywalker came to trust him with her, and Skywalker additionally recognized that some of the Padawan's lessons were better learned from the captain instead of himself.

Rex helped Tano through several tough situations, including on Maridun, where their team was forced to find medical attention for a grievously wounded Skywalker, and at JanFathal, when their encounter with the Altisian Jedi challenged her beliefs in the Jedi Code. Rex also guided Tano in her first command position at Ryloth, even though she expressed insecurity with the role. Although he was skilled in strategy and carefully identified the obstacles that hindered Tano's plan to break the Separatist blockade of Ryloth, he remained respectful toward her and did not outright criticize her proposed tactic. He mentored her in leadership as time went on, instilling in her the importance of inspiring one's troops and leading by example on the battlefield, no matter the situation. On occasions when Tano was unable to voice her full concerns to him because of security or protocol surrounding certain assignments, Rex fully understood the reasons behind her withholding of confidential information, and he did not take it personally. Although in some cases he knew when she was concealing her fears from him, including those about her Master's life, he did not criticize her for being afraid; instead, he supported her in what ways he could.

During the search for the fugitive Tano at the Republic military base, Rex refused to believe that she had slaughtered three clone troopers while escaping, even though the lightsaber cuts on the corpses indicated that she was responsible. Nevertheless, he was forced to set aside his personal beliefs in favor of the evidence at hand, stating in a following all-points bulletin that Tano had killed the three soldiers. Rex's instincts were later upheld when it was revealed that Barriss Offee had committed all the crimes for which Tano had been accused.

By the time of the Battle of Umbara, Rex had become used to Skywalker's more personal style of command. He thus came into conflict with the 501st Legion's interim Jedi General on Umbara, Pong Krell, a hard leader who strictly adhered to the chain of command. Rex initially respected Krell for his impressive military record, but he found that Krell was difficult to work with because of his apparent lack of regard for clone troopers—Krell preferred to address them by their numerical designations instead of their individually chosen names, with which Rex took issue. Although he did his best to cooperate with Krell, he found that the Jedi Master rarely responded positively to suggestions as Skywalker did. Furthermore, he frequently viewed Krell's methods as flawed and reckless, since they often involved head-on assaults with high casualties. Even after Krell forced an uncooperative Fives to stand down by igniting his lightsaber, Rex firmly stood his ground against the Jedi General. He defended his troops' well-being and removed his helmet to speak to Krell face-to-face, asserting that the clones were men rather than faceless, rank-and-file soldiers. Though his tenacity and loyalty to his subordinates won Krell's respect, Rex still failed to see eye-to-eye with Krell as the Umbara campaign continued.

Over time, Rex became more willing to disobey Krell's orders. During the battle to reach the Umbaran airbase, Rex developed a secondary plan to have Fives and Hardcase seize two starfighters from the enemy outpost to use against the Umbaran mobile heavy cannons. Though Krell did not approve of his strategy and even threatened to relieve him of duty for insubordination, Rex allowed Fives and Hardcase to carry out their stealth incursion. When Krell claimed that Rex had yet to understand that copious casualties were the price of victory, the captain's respect for Krell waned, and he agreed with Fives that it was Krell who would never understand the clones' sacrifices. After Fives, Hardcase, and Jesse slipped away on their illegal plan to target the Separatist supply ship in orbit of Umbara, Rex covered for them during their absence. He outright lied to Krell, providing a fake cover story that he had authorized the trio's use of the locked-down Umbaran starfighters and kept the Jedi General in the dark about the nature of their departure. Ultimately, he overtly defied Krell's orders to execute Jesse and Fives for their insubordination, and his respect for Krell eroded even further as he refused to be intimidated by the general's threats for retribution.

Rex began to question Krell's authority as well as his sanity, even suspecting that the Jedi Master had betrayed the Republic, and his suspicions were proven correct when the general turned the clone troopers against one another on the battlefield. He was appalled at Krell's crimes against his soldiers, especially since Krell was a Jedi Master. From that point onward, he resolved to treat Krell as a traitor, risking charges of mutiny to arrest the Jedi General for treason against the Republic. Rex deplored Krell's fall from the ideals of the Republic and his quest to become Count Dooku's new apprentice. With the imminent danger of the Umbaran militia advancing on the airfield, Rex reluctantly agreed with Fives, Jesse, and Tup that Krell needed to be executed before he could convey the Republic intelligence in his possession to the Confederacy. When about to shoot Krell, Rex remained undeterred by his taunts about being in a position of power. Yet for all the casualties that Krell had caused, Rex was unwilling to pull the trigger on an unarmed Jedi, and Dogma instead terminated Krell.

Rex's gifts in critical thinking and leading his brethren into battle reached the attention of the Kaminoan cloners, and he thus underwent command training and intensive programmed learning on Kamino. Further ARC training under Alpha sharpened him into a cunning and lethal soldier. As an expert in multiple forms of combat, Rex was skilled in armed and unarmed fighting. He was knowledgeable in the use of a jetpack, taking squads through the most difficult of flight paths. He was additionally well-versed in reconnaissance and military tactics and was capable of leading specialty clone trooper units in various operations when the need arose. His abilities were such that he came to be considered one of the best soldiers in the Grand Army. Rex valued being an accurate shot with a blaster and became proficient in marksmanship. He was able to hit both fast-moving targets—such as a flying fuel cell on Skytop Station or a Single Trooper Aerial Platform on Lola Sayu—and distanced marks alike, eliminating a gun emplacement on Geonosis from several hundred meters away.

Like any good soldier, Rex knew his weapons and swore by his armor and gear, but he also recognized that equipment alone could not win a battle—a soldier's greatest tool was his mind. Relying on intelligence over weaponry, he combined a commando's gift of improvisation with the toughness of an infantryman. Having been trained to resist interrogation as a prisoner of war, he was adept in mental resistance and was able to shield himself from a Force mind trick performed by the Dark Acolyte Asajj Ventress, due in part to his strong will and focus. He was relentless in using his abilities and equipment against his adversaries, whether they were Separatist droids on Ryloth or aggressive Talz warriors on Orto Plutonia, the latter of whom he faced with steely determination. He had a fast reaction time even when not in combat: He responded instantly with his blaster to the appearance of a Rishi eel on the Rishi moon, killing the predator with a single shot to the eye. He recognized the danger of hesitating in battle, even for a split second, and resolved to eliminate all of the enemies in his path before they could gain the upper hand. As Skywalker noted during the Battle of Christophsis, he did so without even having to think about his maneuvers.

Rex was able to hold his own against the larger units within the Separatist Droid Army, including octuptarra magna tri-droids and heavily armed Vulture droid starfighters. Though he dreaded the latter the most of all of the Separatists' combat droid models, he stood his ground against them. He was quite strong and was able to lift the injured Chairman Chi Cho without aid. He was also able to escape defeat at the hands of a menacing assassin probe aboard the Coronet by grabbing the attacking droid's pincers before they impaled him; he then managed to kick the large droid off himself. Against ruthless winds and menacing electro-mines on Lola Sayu, he was able to free-climb the cliff to an entry point to the Citadel. Despite having a temporarily paralyzed arm during the Battle of Saleucami, Rex was able to roll and fight in blaster combat against several droid commandos.

During the first months of the war, Rex used a suit of plastoid Phase I clone trooper armor that was customized with the white and blue of the 501st Legion. His polarized T-visor helmet sported Mandalorian Jaig eyes as battle honors and was equipped with a fold-down rangefinder scope that included a night vision filter. For supplemental head gear, he used a visor with an inbuilt telemetry system and a pair of removable spot lamps that boasted a viewing range of forty feet. His helmet systems included infrared vision; an array of sensors; an internal comlink; visual and auditory buffers; and a heads-up display with thermal imaging and biosign indicators.

To complement his body armor, Rex sported a traditional kama half kilt, constructed out of leather and thick anti-blast armor, to repel low-flying shrapnel and debris. He also wore over his left shoulder a semi-blue pauldron armor plate, which was reserved for clone officers. It was punctured through the chest plate by an enemy droid sniper during the Battle of Saleucami. Besides boots with magnetic gripsoles, Rex used a variety of other tools: a vibroblade in one of his gauntlets; a wrist comlink for his left gauntlet; a medpac and high-calorie dry rations in his utility belt; and a rappel line with a winch control motor for climbing during combat. His armor suit had an airtight seal and a limited oxygen supply, which allowed him to survive in the vacuum of space for brief intervals, such as during the Battle of Devaron. For some operations, he wore standard-issue white clone trooper armor. While on Orto Plutonia, he donned cold-weather armor—including a thermal suit and rebreather hood, the latter of which was decorated with his Jaig eyes—for protection from the cold. Although necessary for surviving Orto Plutonia's hazardous conditions, the extra gear dangerously limited his movements in battle.

Being skilled in marksmanship, Rex never underestimated the capabilities of a good old-fashioned blaster and used a variety of weapons in combat. He preferred to wield a pair of DC-17 hand blasters for their speed, a trait that he shared with the dual pistol–using Jango Fett, the bounty hunter from whom he was cloned. Rex cut his blasters' holsters at his waist to be able to draw them more quickly. Although his two DC-17s were his signature choice of weaponry, he sometimes used a DC-15S or a DC-15A blaster rifle. On JanFathal, he used a DC-15 with a customized detonite grenade launcher attachment. He also used a grappling hook extension as required. As thanks for helping to contain the Blue Shadow Virus on Naboo, Rex received a set of modified DC-17s from Theed Arms. The pistols, dubbed the "Vigilance" and "Negotiator," were specially plated with metallic chromium, a prerogative of the Naboo royalty. When it came to heavy weaponry, Rex was capable with using missile launchers like the RPS-6 rocket launcher, which he employed against enemy ground vehicles.

Rex carried a set of electrobinoculars for expanding his viewing range on the battlefield. When the situation called for it, he used a JT-12 jetpack and accompanying flight equipment, as he possessed expertise with the gear. He used a space combat propulsion pack to boost his jetpack's range for high elevations, for as far reaches as realspace. While away from the front lines, Rex made himself comfortable with black fatigues instead of his usual hefty armor.

When the Republic began to have its clone soldiers transition to the Phase II set of clone trooper armor, Rex did not particularly care for the new equipment, as he believed that it was prefabricated and too disposable. He did not immediately switch over to Phase II, but when he did, he developed his own unique version of Phase II armor, combining elements of his old Phase I suit and the latest Phase II technology into a hybrid of both armor sets. Salvaging the middle portion of his old Phase I helmet, including his rangefinder scope and original T-visor, he welded them together with the new Phase II helmet's upgraded breath filters and voice output annunciator. He did the same for portions of his chest plates, and the resulting weld marks became another of his armor suit's distinctions.

Although Rex modified his helmet, he retained his Jaig eyes from his Phase I suit. Aside from a redesigned pauldron with an ammunition pack and an updated wrist comlink that he transferred to his right arm, he continued to use the rest of his Phase I equipment, including his kama, utility belt, removable spot lamps, and quick-draw blaster holsters. Though he still carried electrobinoculars, he began to use a polarized macrobinoculars attachment with his helmet. He even began to engrave tally marks into his helmet, gauntlet, and forearm and leg plates. In addition, he started carrying an Imagecaster holoprojector. He used a JT-12 jetpack with his Phase II armor as required, as well as a SCUBA trooper mask, decorated with his Jaig eyes and blue 501st markings, for underwater combat. For space-walking, he used breathmask survival gear, which consisted of a back-mounted pack with breathing tubes that connected to both of his helmet's breath filters.

For the assignment of helping the Jedi train the Onderon rebels, Rex adopted a new suit of armor to avoid using his usual, distinguishable set of 501st white and blue. The result was a set of black fatigues with a limited amount of equipment, including a jetpack for the deployment into the Onderonian jungle. Although he chose a different helmet with a visor and goggles, he made sure to have a rangefinder for his helmet and also sported his Jaig eyes on his chest plate.

The character of Captain Rex was created for the 2008 Star Wars: The Clone Wars film and television series, with his place in the spotlight turning him into a fan favorite among Star Wars enthusiasts of all ages. Prior to his debut in the television series, he was featured in February 2008 as a promotional mail-order figure that kicked off Hasbro's Star Wars: The Clone Wars toy line. After his "CC-7567" designation was attributed in his Databank entry on StarWars.com in May 2008, Rex made his first appearance in Star Wars canon in The Clone Wars film's novelization and junior novelization, which were published on July 26, 2008. As the television series' primary clone trooper character, Rex played a part throughout the series' five broadcast seasons, which aired from October 2008 to March 2013. He also appeared in several episodes of the series' sixth season, which was released on Netflix in March 2014.

Voice actor Dee Bradley Baker provided Rex's voice, as well as those of all other clone troopers, throughout the television series. To make Rex distinctive, Baker portrayed him with a somewhat deeper voice than the other clone characters based on his confidence and aggression. Baker and Series Supervising Director Dave Filoni developed the idea that Rex was the central personality type of all clone characters, whom they all aspired to embody, while others had an excess of various traits. Baker's intended distinction for Rex was prominent during clone-centric episodes, such as "Rookies" and "The Hidden Enemy" from the first season, as well as "The Deserter" from the second season, all of which featured Rex as a lead character. The latter two episodes contrasted him with Sergeant Slick and Cut Lawquane, two clone characters who were shown to have abandoned their service to the Republic for different reasons.

Rex's popularity and character development over time were such that Filoni voiced the production team's conscious effort to continue exploring his story within the series. In April 2011, Filoni stated that the fates of Rex and Ahsoka Tano were the two storylines that he was the most intent on pursuing, given both characters' inseparability and their absence from the chronologically later film Star Wars: Episode III Revenge of the Sith.

In the series' fourth season, Rex was spotlighted in a four-part story arc, which focused on the Battle of Umbara in the episodes "Darkness on Umbara," "The General," "Plan of Dissent," and "Carnage of Krell." The episode arc evolved his character by bringing him into conflict with General Pong Krell, while also showcasing his performance as a leader.

A heroic character in the television series, Rex has achieved considerable popularity with the Star Wars fan base, particularly with younger fans. In August 2010, he was voted the thirty-sixth most popular character in Star Wars canon on IGN.com, beating Ahsoka Tano, who was ranked as forty-third most popular. In the Star Wars: The Clone Wars Magazines 2014 "Reader Awards" contest, Rex—alongside Yoda—was a runner-up in the "Most Heroic Hero" category, which fans chose from the television series' cast of characters; the overall category winner was Obi-Wan Kenobi. Rex has also been included in StarWars.com's This Is Madness, an annual character popularity tournament imitating March Madness. In the 2013 bracket, he lost within the first round to Ahsoka Tano, but the 2014 bracket saw him reach the "Duel of the Eights" quarterfinal round, in which he lost to Han Solo.

At first, the creators of The Clone Wars series planned to use Alpha, the Advanced Recon Commando featured throughout the Star Wars: Republic comic book series, as the television series' primary clone trooper character. Series Producer George Lucas objected to the selection of Alpha because his name would perpetuate too much of an alliteration between several main characters—Anakin, Ahsoka, Artoo/R2-D2, and now "Alpha"—hence, another clone trooper was created. Lucas provided the name "Rex," securing the new character's role in Star Wars.

Rex's chin scar was based on the blemish that actor Harrison Ford—who portrayed the smuggler Han Solo in the original trilogy of Star Wars films—made famous in the Indiana Jones saga. Additionally, the Mandalorian Jaig eyes on Rex's armor helmet were derived from concept art for Boba Fett's helmet in the 1980 original trilogy film Star Wars: Episode V The Empire Strikes Back, as later released in The Empire Strikes Back Sketchbook.

During production on the episodes for the fourth season's "Battle of Umbara" story arc, the series' animation crew redesigned Rex's character model, incorporating the new Phase II clone trooper armor that had been gradually introduced for clone trooper characters since the advent of the fourth season. Director Dave Filoni developed the in-universe backstory for his unique "hybrid" armor—Rex kept old parts from his Phase I suit and welded them with the new Phase II gear—as another character trait for him, adding to his distinction and personality.

Several brief scenes featuring Rex in two first season episodes—"Rising Malevolence" and "Storm Over Ryloth"—were cut from the final versions that were broadcast on Cartoon Network, but they were included in their Director's Cut editions in The Complete Season One DVD collection, released in 2009, which integrated them into Star Wars canon.

Rex appears in one of several deleted scenes from the second season episode "Duchess of Mandalore." In the scene, following the Galactic Senate's decision to abstain from occupying Mandalore, Rex seeks out Anakin Skywalker, who has been overseeing preparations for the Mandalore-bound fleet at a Coruscant staging area. After Rex informs him of the Senate vote, Skywalker is pleased to hear the news and has Rex relay the orders to stand down to the rest of the fleet. Although the scene was fully animated, it was cut from the final version of the episode as part of an abandoned story thread featuring Skywalker's military preparations for the Republic occupation of Mandalore.

A deleted scene from the third season episode "ARC Troopers" has Rex lecturing troopers Echo and Fives in the Resolutes hangar bay about their expectations to have already been promoted to Advanced Recon Commandos. While cut from the final version of the episode, it was included in the young-readers book Defenders of the Republics adaptation of the episode, thus canonizing the scene.

In Series Writer Matt Michnovetz's original script for the fourth season episode "Carnage of Krell," Rex was to execute General Pong Krell for his crimes against the Republic, but Filoni decided that such a move would not be appropriate for his character. As a result, the role of Krell's executioner was given to rookie trooper Dogma. A cut storyline from the fourth season episode "The Box," scripted by Brent Friedman, involved Skywalker searching for the bounty hunter Rako Hardeen, whom Obi-Wan Kenobi is posing as for an undercover operation. The Jedi High Council attempts to prevent Skywalker from discovering the real Hardeen, who is in their custody, but when Skywalker finds Rex transporting Hardeen off-world, the Council is forced to reveal the truth. The storyline was abandoned for time and clarity, as well as the unlikelihood of Rex keeping information of that measure of importance from his Jedi General.

In a deleted scene from the fifth season episode "A War on Two Fronts," Rex shows the Onderon rebels how to construct homemade EMP grenades by coiling a wire around a magnet, then adding a remote detonator. He demonstrates the device on a pair of captured B1 battle droids, with Skywalker, Kenobi, and Ahsoka Tano further explaining the advantages of such weaponry to the rebels. Another short deleted scene from a fifth season episode, "To Catch a Jedi," has Rex accompanying Skywalker, Plo Koon, and a Coruscant Guard detail to Coruscant's Level 1313, where Clone Commander Wolffe and his troopers are recovering from a failed attempt to capture a fugitive Tano and Asajj Ventress.

In March 2013, following the fifth season's finale, Lucasfilm announced that the television series would be ending. Since then, Friedman has indicated that there were more plans for Rex in future seasons. In a November 2013 interview with the Rebels Report podcast, Friedman described a story arc that he had scripted featuring Rex and R2-D2 on a major adventure that would have been fun, as well as "dark in its own way." The majority of the story was set on one of the moons of Ryloth. Friedman related the "personal hook" of the arc to the film Terminator 2, since Rex and R2-D2 would have hijacked a super battle droid and would have become attached to it over time. The story arc, comprising four episodes, would have been released as part of an eighth season, though production for those episodes was never completed. Friedman stated that writing those episodes increased his appreciation for Rex as a character.

Rex appeared extensively throughout supplementary material for the television series, including the series' tie-in webcomics; the Slaves of the Republic story arc of the monthly comic series; the first three installments of the graphic novella series; the novel series written by authors Karen Traviss and Karen Miller; and a number of young-reader books. He was also featured in the video games Jedi Alliance and Republic Heroes and was given a role in the non-canonical video game LEGO Star Wars III: The Clone Wars.

Rex was featured in the Clone Wars and Clone Wars Tactics expansions of the Topps Company's Star Wars PocketModel Trading Card Game. From 2008 on, he was designed as an action figure for several sets of Hasbro's The Clone Wars toy line, and he was also made into a LEGO mini-figurine as part of various building sets. His minifigure was given a uniquely designed head piece, a distinction from other clone trooper figures. He was included in packs for the 2008 The Clone Wars and 2009 Galaxy at War expansion sets of Wizards of the Coast's Star Wars Miniatures series. August 2009 saw Gentle Giant Studios release a life-size monument of Rex, standing six feet tall.

In 2010, Rex became the face of Star Wars merchandise packaging as part of the new "Clone and Sky" design. PILOT, the design firm that developed the artwork, was initially reluctant to use Rex because of its original intention to allow the viewer to look into the eyes of the featured character; Rex's helmet limited that emotional connection. To address that void, the background element of the "ominous" blue sky was added to imitate being on the front lines of the Clone Wars. The Rex "Clone and Sky" packaging lasted two years in Star Wars product marketing, with the Sith Lord Darth Maul replacing Rex as the featured face on Star Wars merchandise packaging in 2012. For 2011, Rex became immortalized as part of Sideshow Collectibles' Militaries of Star Wars deluxe figure line.

Rex appeared in the Star Wars: Clone Wars Adventures online video game, in which he was featured in several purchasable sets as well as in the game itself. He encouraged the player-character to play the "Galactic Forces" mini-game—previously for the "Blaster Training" mini-game before Clone Commander Stone replaced him in that role—and to enter combat battle zones, such as Ryloth and the "Battle of Umbara." He was also featured in the tutorial levels for the "Card Assault" mini-game.

Author Jason Fry briefly referenced Rex's role in the 501st Legion in The Essential Guide to Warfare, a third-generation Essential Guide published in April 2012. Fry revealed in an interview that a story more prominently featuring Rex had to be cut from the final version of the book due to length constraints. Fry was later able to rework the omitted material as a short story, Speaking Silently, which was published in Star Wars Insider 139 in January 2013.

In June 2008, initial merchandising material for the television series indicated that Rex was an Advanced Recon Commando, but that rank was not repeated in subsequent material and is therefore assumed to be an error. Furthermore, Rex was listed as a clone commander in Star Wars Insider 103's The Clone Wars: A Who's Who Guide, the Jedi Alliance Prima Official Game Guide, the Wizards of the Coast sourcebook The Clone Wars Campaign Guide, Star Wars: The Clone Wars Activity Annual: Summer Edition 2009, The Official Starships & Vehicles Collection 43, and the StarWars.com Encyclopedia entry for Saleucami, along with numerous issues of The Official Star Wars Fact File. Part 2 of the Fact File remake referred to Rex as a sergeant on one occasion, with the error being repeated in a revised issue. Yet in all other Star Wars material, Rex is portrayed as a clone captain, which this article reflects.

Due to his rank as a captain, Rex's command over the 501st Legion lacks correlation with the Republic Grand Army's Order of Battle, as detailed in Star Wars Legends. Per The Essential Guide to Warfare, a clone captain is in command of a company, while a senior clone commander would command a legion like the 501st. Some source material correctly reflects the system: The 501st Legion's StarWars.com Databank entry stated that Rex led the core group of the 501st, while The Clone Wars novel series established him as the leader of Torrent Company, a 501st unit. Yet other publications—including The Clone Wars: The Visual Guide and his StarWars.com Databank and Encyclopedia entries—simplified his role to the overall leader of the 501st, subordinate only to Anakin Skywalker. To date, no official explanation has been provided to resolve the inconsistency.

There has also been a discrepancy regarding the extent of Rex's mental resistance abilities. The Clone Wars: The Visual Guide suggested that Rex was not able to resist the mind trick that Asajj Ventress performed on him during the Battle of Teth, but the novelization of The Clone Wars film maintained that he was indeed able to avoid succumbing to her mind influence. This article assumes that the latter's interpretation is correct.

The junior novelization of The Clone Wars film stated that Rex had the brown hair customary of clone troopers, which is inconsistent with the majority of other canonical material, in which his hair was depicted as bleached blond. In Slaves of the Republic - Chapter 6: Escape from Kadavo, Obi-Wan Kenobi addresses a clone trooper who is wearing Rex's customized blue-and-white armor as "Cody." The Decoded re-airing of the first season episode "Jedi Crash" mistakenly referred to Commander Bly as Rex on one occasion. Also, the children's activity section of Star Wars: The Clone Wars Comic 6.25 incorrectly identified the Advanced Recon Commando Havoc from the episode "ARC Troopers" as Rex. In addition to erroneously referring to Rex as a commander, Part 51 of The Official Star Wars Fact File mislabels an image of Clone Captain Keeli as Rex.