A Venator-class Star Destroyer was in service to the Galactic Republic and its navy during the Clone Wars, and was one of many scuttled on the planet Bracca following the war's end and the formation of the Galactic Empire in 19 BBY. An original Venator-class Star Destroyer, the warship originated from the first batch to be produced. Early in the Imperial Era, the former clone trooper Rex, along with the clone commandos of Clone Force 99, traveled to Bracca, where they used the wrecked Star Destroyer's medical bay to remove the so-called "Bad Batch's" inhibitor chips.
However, while the procedures were underway, the inhibitor chip of clone commando Wrecker activated and turned him against his comrades, as they were in violation of Order 66 and were to be terminated. Despite the activation of the chip, Wrecker was incapacitated after a brief struggle and had his inhibitor chip removed, with the others following afterward. Sometime after, Clone Force 99 was detected by patrolling Scrapper Guild workers, who informed the Empire of the intrusion.
Still aboard the Venator, the Bad Batch saw an opportunity for their squad to acquire much-needed money by salvaging what remained within the cruiser's armory, such as proton torpedoes, explosives, and vital intelligence stored within the central system on the command bridge. However, as the team conducted their salvaging mission, Imperial stormtroopers led by Clone Commander CT-9904 "Crosshair", a former member of the squad, arrived. The Batch snuck out through one of the Star Destroyer's ion engines in an attempt to evade the Imperials, but were nearly incinerated when Crosshair ordered the engine activated. The fugitives were able to escape by using salvaged explosives to blow the engine cone in half, resulting in Crosshair being severely injured by the engine's backblast.
As a Venator-class Star Destroyer, the capital ship was a long, wedge-shaped starship with two indents near the stern. It had two bridges and eight ion engines mounted on its stern. Onboard, it had at least two medical bays, one of which was equipped with a surgical pod. The Venator's command bridge contained databanks with intelligence from the ship's military service, and a proximity sensor to detect nearby vehicles. The Star Destroyer also had hangar bays, an armory, and an artillery deck with several AV-7 Anti-vehicle Artillery Cannons. The armory was stocked with proton torpedos and various types of portable explosives. It was equipped with two hyperwave comm scanners for long-range communications. The starship was powered by an internal power core.
The Venator was part of the very first batch of ships of the class built, late in the Republic Era. By the beginning of the Imperial Era in 19 BBY, the Star Destroyer had been wrecked on the junk planet Bracca in a starship graveyard amidst many other ships, including other Venators, Acclamator-class assault ships, Providence-class Dreadnoughts, and at least one Hammerhead corvette. The starship lay atop a layer of water, which was inhabited by at least one dianoga. The wreckage itself was overrun with scrap rats. The ship's armory still contained numerous weapons, and the ship's memory banks had not been properly erased by whoever had scuttled it. The Venator was largely untouched by workers from Bracca's resident Scrapper Guild, possibly due to the presence of the dianoga.
In that same year, the galaxy-spanning Clone Wars had ended with bloodshed when the Galactic Republic's clone army had been forced to kill their Jedi officers via Order 66, a secret command engineered by the dark side-wielding Sith which activated inhibitor chips implanted in all of the clones. The chips also brainwashed the clones to serve Darth Sidious, publicly the Republic's Supreme Chancellor Palpatine, who reorganized the Republic into the Galactic Empire in response to the alleged treason of the Jedi. Among the very few clones who were immune to the order or who somehow managed to escape the chips' influence were most of the members of Clone Force 99, an irregular clone commando squad whose deviance from the clone standard protected them, and Captain Rex, who had his chip removed with the assistance of the former Padawan Ahsoka Tano.
Some time after Order 66, Rex tracked the so-called Bad Batch down on Ord Mantell after learning of their location from the Martez sisters, who were also friends of Tano. Rex was alarmed to discover the Batch had not removed their chips after learning Wrecker had been suffering from increasingly frequent headaches, as squad member Tech had concluded that their deviant nature meant the chips were not a threat to them. Rex argued otherwise, persuading the squad that it was imperative they get them out as the chips' presence made them a threat to others. Finding out about the wrecked Venators on Bracca, Rex had the Batch meet him on the planet so they could use the medical bay of one of the wrecked ships for the surgery, as he had had his chip removed aboard another such ship.
When the Batch landed their shuttle, the Marauder, in a wrecked hangar amidst one of Bracca's starship graveyards, they met Rex, who led them across another wrecked capital ship to a good vantage point of the Venator's remains, identifying it as their destination. After taking cover from a Scrapper Guild patrol, the clones headed deeper into the wreckage, passing through various areas on their way to the Venator. Rex mentioned the Venator's history as one of the first assembled to the squad, prompting Wrecker to compare the ship to Rex since he was a Generation One clone trooper. Reaching an area with exposed water, Bad Batch leader Hunter sensed movement and warned Tech to stay above the waterline. Rex led the way into the wreckage across a narrow improvised bridge.
Traversing the ship's corridors, Rex told Echo that the last time he had been aboard a Jedi Cruiser, it had not ended well. Noting that Rex had earlier mentioned his lack of control over his actions under the sway of his chip, Echo asked him how exactly he had gotten his out, but Rex only mentioned that he had had help. The group reached a large gap in the wreckage, leading down to the water below, and Rex noted that the medical bay was on the far side. He asked Wrecker to grab a nearby cable, which the clones pulled tight to use to cross the gap. Wrecker was the last one to cross, but his acrophobia made him nervous and he initially refused, before the child clone Omega offered encouragement.
Seizing the cable, Wrecker attempted to cross, but his weight caused the cable to sag and then snap, sending him plummeting. He hit his head against the wreckage on the way down before his leg became caught by the cable, leaving him hanging just below the water. The dianoga living in the depths approached from below, and Hunter ordered Wrecker to climb as the others attempted to pull him up quickly. The creature used one of its tentacles to grab at Wrecker, but he cut it off with his vibro-knife while attempting to climb. However, the creature reached out with more tentacles and dragged him underwater. Wrecker managed to surface after a short time and climbed the cable, Echo firing at the dianoga to force it to retreat while Rex, Hunter and Tech hauled Wrecker up.
Continuing into the wreckage, Rex located a medical bay and he and Tech forced the door open to enter. Tech noted that the room was no longer a sterile environment, but conceded it would do after Rex pointedly asked him if he would prefer the facilities on Kamino. Echo used his scomp link arm to calibrate the surgical pod while Wrecker sat down and Tech retrieved his chip scanner to examine him. Hunter and Omega stowed their equipment by the sides of the room while the girl expressed concern about the dangers of the surgery, but Rex and Hunter both pointed out that leaving the chips in was more dangerous. After Wrecker pulled the chip scanner off, Omega realized that something was not right with him, and Rex said they had to speed things up.
Rex commented to Hunter that his squad had been lucky given how few clones had been immune to Order 66, and as he, Hunter and Echo moved off to the back of the room with Omega to discuss the Batch's experience when the command had been issued, Tech prepared to sedate Wrecker. However, his chip became fully active, and he overpowered Tech before declaring him in violation of Order 66 and choking him before throwing him into the wall. Wrecker retrieved his helmet, and Rex attempted to stun him, but the large clone swatted the pistol out of his hand and into one of the wall lights. Rex, Hunter, Echo and Omega took cover in the corner of the room as the brainwashed clone shouted that they were all traitors and fired at them. Echo noted that Wrecker would destroy the medical equipment if he remained inside the bay. Hunter spotted some gas canisters and formulated a plan, telling Omega to stay with Tech while the others drew Wrecker out. Grabbing a canister, Hunter threw it so it was hit by one of Wrecker's shots, causing a noxious cloud which allowed the other clones to escape into the corridor.
Wrecker followed them into the hallway, firing random shots, but saw no one. He headed down the hall to an intersection, where Rex popped out of cover and attempted to stun him again, but missed and was forced back into cover. Hunter managed to force Wrecker to drop his blaster by throwing a knife at him, and Echo then attacked him with another cylinder. However, Wrecker grabbed him by the head and threw him in Rex's direction, knocking them both out. Hunter attacked Wrecker again, knocking his helmet off with one of the cylinders before being disarmed. He then leapt on the large clone's back and attempted to choke him unconscious, yelling at him to snap out of it, but Wrecker slammed him into the wall and began to choke him, stating that all clones in violation of Order 66 had to be terminated.
Omega, leaving the medical bay, picked up Wrecker's blaster and fired a shot, which caused him to drop Hunter and pursue her. She ran through the hallways and found another medical bay with a mostly-closed door, fleeing through the narrow gap when Wrecker approached. As he forced up the door, the girl found a hiding place deeper in the room. He entered and searched for her, but the first sound he investigated was only a rat. Omega peered out of her hiding place, only to realize Wrecker had found her, and she backed away from him, pleading for him to stop as his actions were due to the inhibitor chip. Wrecker reclaimed his gun and aimed it at her, stating that anyone conspiring with traitors had to be destroyed, but he was struggling against the chip and hesitated for a moment. His hesitation allowed Rex to get the drop on him from behind and stun him, bringing an end to the rampage.
Wrecker was put through surgery to remove his chip, but his vitals were unstable and it took him a while to regain consciousness. Rex suggested to Hunter that he take Omega topside to get some air, but she insisted on staying until her friend woke up. Once he did, the other members of the Batch were relieved, and Rex asked them who was going to go next. Once all of the members of the squad had had their chips removed, with Tech going last, Wrecker apologized to Omega, but she told him it was all right and shared a snack with him, which had become a post-mission tradition for them. Rex went outside, where he spoke to someone over his comlink, telling his contact that he would meet them at the rendezvous by the next rotation. Hunter, arriving at the tail end of the conversation, said he had figured Rex was not yet out of the fight, and Rex said his squad would be an asset. However, Hunter said that his priorities had changed because of Omega, and he was still figuring things out. Rex told Hunter to tell the others he would see them again and to look him up when he had decided what he was going to do. Before he left, Hunter told Rex to contact him if he was ever in a bind, and Rex nodded before vanishing into the fog.
However, Hunter was spotted by a Scrapper Guild patrol as he re-entered the wreckage. One of the scrappers told his comrade that intruders had been confirmed aboard the Jedi Cruiser, and to contact the Empire.