The Battle of Kaller unfolded as part of the Outer Rim Sieges during the waning days of the Clone Wars, taking place on the planet of Kaller. Following the Confederacy of Independent Systems's successful conquest of Kaller, a Separatist occupation began under the command of General Kleeve. To counter this, the Galactic Republic deployed a battalion from the Grand Army of the Republic, led by Jedi General Depa Billaba, to the planet. This resulted in the temporary liberation of Kaller, as Depa's clone troopers overwhelmed the Droid Army, compelling Kleeve to retreat. Despite this victory, the native Kallerans showed no gratitude, viewing both the Galactic Republic and the Confederacy as invaders.
Despite Kleeve's withdrawal, the Kaller system faced an assault as part of a broader strategy directed by General Grievous after the Battle of Coruscant, forcing Billaba and her troops to engage in combat within a snowy region. While trapped by a droid battalion, Billaba instructed her Padawan, Jedi Commander Caleb Dume, to locate reinforcements. However, these troopers had been rerouted to defend the planet's capital, leading Dume to return with the exceptional clone commandos of Clone Force 99, who swiftly defeated the battle droids.
Before Dume could join Clone Force 99 in fighting the Droid Army, Supreme Chancellor Sheev Palpatine unexpectedly issued Order 66 to the clone army. Influenced by their behavioral modification biochips, Grey and the other clones betrayed Billaba, attacking her as she ordered Dume to flee. With the exception of sniper CT-9904 "Crosshair," Clone Force 99 remained unaffected by the order, and Clone Sergeant "Hunter" and Crosshair pursued the Padawan, with the sniper intending to kill the young Jedi. After being separated from Crosshair, Hunter attempted to reason with Dume, but the Padawan, hearing approaching clones, leaped over a ledge and escaped. Upon Crosshair's return to the sergeant, Hunter falsely claimed he had killed the Padawan. The clone army also liberated Kaller from Separatist control, but the Republic transformed into the Galactic Empire, incorporating Kaller into its dominion.

During the Clone Wars, the world of Kaller, rich in resources and isolated, held little strategic value, although it was located at the convergence of three hyperspace lanes. Nevertheless, it became a target of the Confederacy of Independent Systems, with Count Dooku tasking General Kleeve with overseeing its capture. Following the Third Battle of Mygeeto, Jedi General Depa Billaba's battalion of the 41st Elite Corps was sent to expel the CIS from the Kaller system. However, the Confederacy had already seized control of the planet from the Galactic Republic. With the world under Confederate occupation, the Separatists coerced the native Kallerans, including those from Gamut Key's village, to provide supplies and labor. While the Kallerans were unhappy with the military occupation, the Separatists remained in power and received intelligence indicating Billaba was unstable, leading Kleeve to underestimate the Jedi General.
The Battle of Kaller, fought in 19 BBY near the Clone Wars' conclusion, was also a component of the Outer Rim Sieges, the conflict's final campaign. Billaba and her Padawan, Jedi Commander Caleb Dume, participated in a strategy conference via hologram with other officers involved in the sieges. Although Billaba's battalion was deployed to Kaller after the Third Battle of Mygeeto, the Republic's effort to liberate the Kaller system only commenced in the war's final days.

The battle for Kaller progressed to a point where the Republic was on the verge of victory. Leading their battalion alongside Clone Captains Grey and Styles, Billaba and Dume fought Kleeve's army of B1-series battle droid with their clone troopers in an offensive to liberate a compound being used by Kleeve as his base. As he and the others advanced past the droids, Dume reflected on the Clone Wars and his role in it. Amid the fighting, Billaba instructed him to adopt a defensive stance using the third form of lightsaber combat before issuing orders to her clone trooper officers; she directed Styles to lead his troops in overwhelming the left flank and commanded Grey to lead his men in attacking the right. In their final push to liberate Kaller, she finished her orders by calling for her entire battalion to assault the compound.
As the Jedi and clones fought through the battle droids, Kleeve observed the battle, remarking to his B1 guards that Billaba's leadership was more effective than he had anticipated. With his forces being routed, Kleeve instructed one of his B1s to prepare his Separatist command shuttle for departure before turning to Kalleran Gamut Key. Kleeve stated that the Confederacy needed to abandon their control of Kaller, asserting that the Republic would bring its own form of tyranny. Kleeve then fled aboard his shuttle. Both Dume and Billaba witnessed the starship leaving, interpreting it as Kleeve surrendering Kaller. Standing amidst the remains of B1s and some of her clones, Billaba declared the battle over as one of her troopers killed a surviving B1.
With the Separatist Army having fled, ensuring Kaller's liberation despite Kleeve's threat to return, Billaba spoke with Key, although he and Janus Kasmir explained the Kallerans saw little difference between military generals. Although Dume, Styles, and Grey were angered at Kasmir's lack of respect, Billaba, having been told the planet's climate was currently mild, attempted to calm the Kallerans by informing them her troops would not remain stationed at the compound, instead informing Key they would rest in a field. She then left with Dume, who was surprised at her lack of annoyance.

Traveling to the mountains, Billaba resumed Dume's Jedi training until the suns set, asking him to explain his feelings. Dume confided in her that, even though the galaxy was at war, he had never been happier, but his mentor understood that his joy came from how he had finally found his place in the galaxy. Even so, she told him that the universe would still change and that the conflict and his apprenticeship would one day end, meaning he could not grow too attached to his present. After her lesson, they departed down the mountain to their campsite to join the clones.
While sitting beside their campfire, Dume asked his master why she had not responded to Kasmir's claim that the Confederacy and Republic were the same; she stated that, in part, she believed their actions would speak louder than words before admitting she felt the Jedi made a mistake by becoming generals. Styles and Grey instantly disagreed, feeling the war would have been lost without Jedi leadership, although Billaba clarified her concern came from the Jedi taking on military positions specifically. Dume, meanwhile, was surprised his master was questioning the orders of the Jedi High Council, but Billaba recalled Dume himself was infamous for asking too many questions, which the clone officers found humorous. Nevertheless, Dume explained he had never questioned the decisions themselves, only why the decisions had been made, and his master revealed she had taken him on as her apprentice entirely because of his questioning, giving him a Jedi holocron to aid in his studies. Afterward, Styles continued to tease Dume for being "infamous" at the Jedi Temple.
Despite Kleeve's surrender, Kaller's star system would be besieged following the Battle of Coruscant; General Grievous launched a counterstrategy to offset recent losses by attacking multiple star systems with the remaining Separatist Droid Army. Consequently, the Separatists attacked Kaller and seized control of its capital city. Billaba and her forces moved to engage the Separatists in a snowy area.

Near a cliff, Billaba and a contingent of her battalion, including Grey and other troopers who had served with her for years, found themselves overwhelmed by a battalion of B1 battle droids, supported by three Armored Assault Tank Mk Is. The Jedi General tasked Dume with finding reinforcements, but that force was rerouted to protect the capital. Instead, Dume discovered Clone Force 99, a group of five unconventional clone commandos also known as "the Bad Batch." This elite squad was the only available reinforcement. As the battle against the droids and their tanks continued, more clone troopers and an All Terrain Tactical Enforcer were destroyed. As Grey grew concerned with their lack of progress, Billaba, and other clones hid from tank fire in a trench, Dume returned, sliding down a snowy hill and promising that reinforcements were coming, but Grey was concerned when he revealed only five soldiers would arrive. Nevertheless, Dume promised the team was different from what they would expect and Grey say it was true as realized Clone Force 99 came to the rescue.
Clone Force 99 abruptly entered the battle by rolling a boulder down the hill, drawing the attention of the advancing B1s. However, their blaster fire failed to stop the rock, which crashed into their formation before the Bad Batch charged in. As Billaba and the others watched, the commandos swiftly eliminated every B1 they encountered before turning their attention to the AATs; Clone Sergeant "Hunter" ordered his team sniper, CT-9904 "Crosshair," to fire grappling lines between the tanks, allowing their strongest member, "Wrecker," to push the three vehicles off the cliff. As his fellow commandos took out any remaining B1s, technology specialist "Tech" threw a Electro Magnetic Pulse grenade at an AAT Driver Battle Droid, who had been attempting to order his tank crew to adjust stabilizers. With the tanks defeated, only a few B1 units remained standing, one of which attempted to take command of the Separatist force before being shot by Hunter. The final four B1s standing were taken out by Tech, who placed and detonated a bomb on one of the battle droids, creating an explosion that could be seen from Billaba's position.

Having destroyed every threat in their path, Hunter and his commandos approached Billaba and her troops. During their walk, Wrecker, holding the droid over his arm, took out the last battle droid by decapacitating an OOM command battle droid after the captured automaton ordered them to surrender. Reaching the Jedi and clones, Hunter suggested the battalion launch a counterattack, as another battle droid battalion was approaching their position. Although Grey objected to the plan, as Hunter held no authority over Billaba's forces, she agreed with the idea and ordered Grey to move their troops forward. As the clones moved from their trenches to their new front, the Bad Batch reunited with Dume, who introduced the squad to his master. After she praised their exploits, Hunter informed her of the actual reinforcements' new path to the capital and that his squad was the only additional help she could get.
However, Tech then spoke up, revealing Clone Intelligence had reported Jedi General Obi-Wan Kenobi had engaged General Grievous on Utapau, meaning the war could soon be over. Echo realized that if General Kenobi captured or killed Grievous then the Separatist command structure will collapse along with the droid army since he recently became the new Head of State after Dooku was killed during the Battle of Coruscant. Nevertheless, Billaba recognized that such news did not currently help them, so she allowed her Padawan and the Bad Batch to go on their own to confront the Droid Army.

As Dume and the commandos began to depart, however, Grey received a transmission from Supreme Chancellor Sheev Palpatine, and Billaba sensed something was wrong. As she turned to face her Clone Captain, Palpatine ordered via hologram to follow Clone Protocol 66, branding the Jedi as traitors who needed to be executed. In spite of his loyalty and admiration for his Jedi General, Grey, like all clone troopers, had been implanted with a control chip that forced him to obey the command, so he did not question the order when he turned his DC-15A blaster carbine on Billaba.
Styles also received the order, forcing him to also believe Billaba was a traitor. Overhearing the blaster fire, Dume turned to see his master forced to defend against her own soldiers, cutting Grey's blaster before kicking him down. Nevertheless, Order 66 was repeating throughout the clone communication channels, turning more troopers against their Jedi officer. The execution of Order 66 had been a long planned part of Palpatine's design, as he was truly the Sith Lord Darth Sidious and had engineered the war from the beginning, having wanted to destroy the Jedi and take control of the galaxy.

As Dume ran back to help his master, the Bad Batch took notice of what the regular clones were doing, and Billaba ordered her Padawan to run as she fended off her troops, ultimately succumbing and being killed by their blaster fire as Dume fled. When the Bad Batch approached him, Dume, not realizing they were unaffected by the order, ordered them to stay back before fleeing into the woods. Left to question what Order 66 was, Hunter told Tech and CT-1409 "Echo" to talk to Grey, ordered Crosshair to come with him to find and help Dume, and had Wrecker stay in position to stall anyone who tried to follow them. Using his skill in tracking, Hunter followed Dume, and Crosshair spotted him while he was hiding in a tree. However, unlike his fellow irregular commandos, the sniper's control chip had activated, so he fired upon the young Jedi, making Dume flee. Angered, Hunter ordered the sniper to stand down until they understood what the Jedi had been accused of, but, as a result of his chip, Crosshair remained steadfast in his desire to kill Dume.
After Wrecker failed to stall three troopers from going into the woods, Tech reported to his fellow commandos that the clones had been told the entire Jedi Order had committed treason, which confused Hunter but was accepted by Crosshair. After Tech requested they regroup, Crosshair spotted and again tried to shoot Dume, taking out the tree branch he was standing on. Although the Padawan fell and lost his Jedi cloak, he ignited his lightsaber and rushed at the commando, who ignored Hunter's orders to stand down. After knocking out Crosshair by kicking him into a tree, he turned his attention to Hunter, who tried to talk and threw away his DC-17 hand blaster to prove he was not interested in attacking.

Keeping his lightsaber ignited and running to a ravine, Dume refused to believe the Clone Sergeant and told him to stay back. Although Hunter removed his helmet and said he was also confused as to what had happened, noting he had not taken part in the execution of Billaba, Dume refused to go with the commando and, upon hearing other clones approach, jumped to the other side of the ravine before fleeing into the forest. Having awoken, Crosshair approached his sergeant and asked what had happened; lying to his fellow commando, Hunter claimed to have stunned the Jedi, making the Padawan fall to his death. Nevertheless, Crosshair felt the need to check with his rangefinder, departing as three regular clones arrived to the scene.
The Conquest of Kaller concluded with a Republic victory, marking one of the final battles of the conflict; as Tech had predicted, the war ended after Grievous's death. While Grey and Styles remained stationed on Kaller, the Bad Batch returned to Kamino. Approaching the water world, Crosshair questioned Hunter about Dume's death, noting he had been looking across the ravine instead of down. Hunter, however, claimed he simply had not wanted to witness a death. Crosshair refused to believe his sergeant and filled a counter-report about the Conquest of Kaller, informing the Republic that Dume was alive.

After entering their personal barracks, Crosshair told his squad-mates that Dume had escaped. Looking out their window, Hunter stated he simply did not want to think executing their officers was one of their missions before noticing how loyal Crosshair had suddenly become. When Echo questioned how the troopers could have executed General Billaba after fighting alongside her for years, Tech explained it was a result of the regular troopers' programming; the Bad Batch was, with the exception of Crosshair, too different to be impacted. When Admiral and Governor Wilhuff Tarkin came to Kamino to observe the clones and deliberate on their role in the new Empire, he assigned the Bad Batch to eliminate supposed insurgents on the Inner Rim Territories planet Onderon.
When the group realized the "insurgents" were actually civilians, they returned to Kamino despite Crosshair's protests, resulting in them being detained for their failure. While in the cell, Crosshair argued with Hunter, claiming that every decision he had made since Order 66 had been wrong. Afterward, he was taken away from his squadmates to have his inhibitor chip enhanced. After breaking out of their cell, the rest of the squad, joined by the young clone Omega, escaped Kamino. After failing to prevent their escape, Crosshair remained on-planet, becoming a commander in the Imperial Military.

Meanwhile, on the planet Kaller, Dume, having recovered his cloak, sought refuge in the forest the night after Order 66, eventually fleeing to Plateau City via a transport. Despite being thought to be deceased, Crosshair's report revealed Dume's survival, prompting Grey's clone troopers to scour the city with the intention of eliminating him. Furthermore, the Empire asserted dominance over Kaller, establishing an Imperial Garrison within Plateau City; Gamut Key later recalled that the Republic's control over Kaller was fleeting before the government's transformation into the Empire. Consequently, Dume endured sleepless days, evading his former comrades, unsure of how to fend for himself. One evening, Janus Kasmir discovered him and offered a meiloorun fruit, a safe haven in his ship, the Kasmiri, and a replacement cloak to conceal his Jedi identity.
Upon exiting the Kasmiri, Kasmir was noticed by Styles, compelling him to dissuade the soldier from inspecting his vessel by emphasizing his lack of support for the Jedi. He remembered having disrespected Billaba in Styles' presence following the defeat of Kleeve several days earlier. Abruptly, Dume commandeered the Kasmiri with the intention of reaching Coruscant, believing he had received a legitimate transmission from the Jedi Temple. However, he received another signal from Obi-Wan Kenobi, exposing the previous message as a deception, and he returned to Kaller, anticipating that the clones would not expect him to revisit the site of his Jedi Master's demise. Dume remained with Kasmir, and the pair eventually became partners in smuggling.
Years following the Clone Wars, on the world of Seelos, Kanan, accompanied by Ezra, Sabine, and Zeb, encountered three veteran clones: Rex, Wolffe, and [Gregor]. Inside the Clone's walker, Kanan explained the incident to Ezra to clarify his distrust of clones. Rex responded by stating he never betrayed the Jedi and revealed that they removed their inhibitor chips, asserting that they now had free will.
Grey and Styles persisted in their pursuit of the escaped Padawan. After several smuggling ventures, Dume and Kasmir arrived on the planet Lahn. While Kasmir proceeded to pilfer the necessary supplies, Dume sought out "Jondo," their intended trade partner, only to discover he was actually General Kleeve. Despite being unaware of Dume's true identity, Kleeve declared that their animosity was over and offered a ship for Kasmir in exchange for spice. Upon returning to the Kasmiri, he found Grey pointing a blaster at Kasmir's head, as the clone officer doubted the smuggler's claims of abandoning Dume on Kaller. Abandoning his sole companion, rationalizing that his flight would convince Grey of Kasmir's innocence, Dume returned to Kleeve's establishment.

After Kleeve led Dume to the offered ship, which the former Padawan christened the Escape, Styles and his clones apprehended them. Following Styles' report of Dume's capture, Grey instructed them to rendezvous at their Gozanti-class cruiser, leaving Kasmir behind and informing the smuggler that he was obligated to follow Order 66. Upon entering the cruiser's hold, Grey expressed his displeasure at Dume's continued survival, yet Styles, who had brought him back for Grey to witness the execution, insisted he would relish killing the supposed traitor. Before Styles could fire, Dume reminded them of their shared history with Billaba, informing them that Palpatine had betrayed the Republic. As their ship entered the Kaller system, appearing as though his words had no impact on his former allies, he employed the Force to push them away. After the Kasmiri and the Escape appeared out of hyperspace, he used the Force to activate the airlock. Kasmir rescued him from space, but Styles commanded their pilots to target the two enemy vessels.
Having come to the realization that Dume was correct, Grey attempted to convey to Styles how his actions on Kaller were illogical, as he had blindly followed Order 66, but Styles remained fixated on eliminating Dume. As the Escape and the Kasmiri prepared to launch a coordinated assault, Grey fired upon their cruiser's controls, disabling their ship's shielding, ensuring the success of the two ships' attack. With Grey and Styles perishing in the explosion, the Escape and the Kasmiri returned to Kaller, where Dume severed his ties with Kasmir. Before departing aboard the Escape with the holocron Billaba had entrusted to him and his lightsaber, he informed his former partner and Kleeve that "Caleb Dume" had died on Kaller alongside his master; upon landing on the jungle world of Moraga, he introduced himself as "Kanan Jarrus" to the first person he met.
When the Graf Archive recovered the journal of an artist, potentially Gammit Chond, the section pertaining to the Kallerans mentioned the battle for the planet, further noting that many Kallerans perceived little distinction between Republic and Separatist governance. The artist's observations detailed how every Kalleran he encountered seemed resigned to the perpetual occupation of their world, leading him to question whether the Kallerans even understood which side they were ostensibly on in any conflict they were involved in.

The Battle of Kaller initially appeared in the 2015 comic Kanan 1 and was formally identified in Star Wars Helmet Collection 5. The battle was also depicted in the Star Wars: The Bad Batch premiere episode "Aftermath" in 2021. The animated battle had previously been featured in the opening newsreel of The Clone Wars: Season Seven episode "Old Friends Not Forgotten," although the planet remained unnamed and the footage was mirrored.
However, the portrayal of events on Kaller differs between Star Wars: Kanan and The Bad Batch. In the comic, Grey, identified as a Clone Commander, receives Order 66 at night, and Dume experiences a Force vision of Jedi falling across the galaxy before the attack commences. Following Billaba's death, Grey dispatches the troops, including a unit known as Rostu Squad, into the woods to locate the Padawan. In "Aftermath," Grey, now clad in green armor and identified as a Clone Captain, receives the order during the day, remaining silent as he and his clones assault Billaba. Clone Force 99 is also present, with Hunter and Crosshair pursuing Dume into the woods. During his confrontation with Crosshair, Dume also loses his cloak, which this article assumes he later recovered, given its role in aiding him in evading the Empire in Kanan 2.
When addressing inconsistencies in canon following the divergence in Order 66 between Kanan and The Bad Batch, Pablo Hidalgo of the Lucasfilm Story Group clarified that the core concept of the storyline remained consistent; the same characters performed the same actions in the same location, suggesting that the varying versions of events can be interpreted as storytellers embellishing the narrative. Hidalgo asserted that such discrepancies are inevitable when storylines are adapted across different mediums, reiterating that the overarching storyline remains unchanged. Given that the story group has thus determined that both versions of the story are valid, and that the 2021 Star Wars Encyclopedia "Mace Windu and Other Users of the Force" presented a composite version of events incorporating both the comic and the episode, this article also presents a composite version of events, prioritizing "Aftermath" in instances of contradiction.
The French edition of Mace Windu and Other Users also employs the term "liberation of Kaller" to describe the brief Republic victory, while the English edition uses "victory on Kaller." The 2021 Star Wars Encyclopedia "The Clone Wars" stated that the CIS occupied Kaller for most of the Clone Wars. However, Kanan 9 instead established that the Separatists needed to take control of the planet around the time of the skirmish on Kardoa, and Kanan 6 had established the Separatists needed to capture Kaller from the Republic.