The Battle of Kaller unfolded as part of the Outer Rim Sieges during the final days of the Clone Wars, taking place on the planet of Kaller. This world had previously succumbed to the Confederacy of Independent Systems in the conquest of Kaller, leading to a Separatist occupation under the command of General Kleeve. The Galactic Republic responded by deploying 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, with Depa's clone troopers overwhelming the Droid Army and forcing Kleeve to retreat. However, the native Kallerans showed no gratitude, viewing both the Galactic Republic and the Confederacy as conquerors.
Despite Kleeve's withdrawal, the Kaller system fell under attack as part of a larger strategic move orchestrated by General Grievous following the Battle of Coruscant. This forced Billaba and her troops to engage in combat within a snowy region. Trapped by a droid battalion, Billaba tasked her Padawan, Jedi Commander Caleb Dume, with locating reinforcements. However, these troopers had been redeployed to defend the planet's capital, leading Dume to return instead with the elite clone commandos of Clone Force 99, who efficiently dealt with 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. Due to their behavioral modification biochips, Grey and the other clones turned against Billaba, attacking her as she instructed Dume to flee. Clone Force 99, with the exception of sniper CT-9904 "Crosshair," were unaffected by the order. Clone Sergeant "Hunter" and Crosshair pursued the Padawan, ostensibly to help him, but the sniper intended to eliminate the young Jedi. After separating from Crosshair, Hunter attempted to reason with Dume, but the Padawan, hearing approaching clones, jumped over a ledge and escaped. Upon Crosshair's return, the sergeant Hunter falsely claimed to have killed the Padawan. The clone army also freed Kaller from Separatist control, but the Republic was reorganized into the Galactic Empire, incorporating Kaller into its dominion.

During the time of the Clone Wars, the world of Kaller, rich in resources and isolated, held little strategic value, even though it was situated at the intersection of three hyperspace lanes. Nevertheless, the Confederacy of Independent Systems eventually targeted it, 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 dispatched with orders to remove 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 forced the native Kallerans, including those residing in Gamut Key's village, to provide them with supplies and labor. The Kallerans were understandably unhappy with the military occupation, but the Separatists maintained their control and received intelligence indicating Billaba's instability, causing Kleeve to underestimate the Jedi General.
The Battle of Kaller, fought in 19 BBY near the end of the Clone Wars, is considered part of the Outer Rim Sieges, the final campaign of the conflict. Billaba and her Padawan, Jedi Commander Caleb Dume, participated in a strategic conference via hologram with other officers involved in the sieges. Although Billaba's battalion was sent to Kaller after the Third Battle of Mygeeto, the Republic's campaign 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, with the help of their clone troopers, engaged Kleeve's army of B1-series battle droid in a push to liberate a compound that Kleeve was using as his base. As Dume and the others fought through the droids, he contemplated the Clone Wars and his role within it. Amid the fighting, Billaba instructed him to adopt the defensive stance of 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. She concluded her orders by shouting for her entire battalion to attack the compound, marking their final push to liberate Kaller.
As the Jedi and clones fought past the battle droids, Kleeve observed the battle, remarking to his B1 guards that Billaba's leadership was proving more effective than anticipated. With his forces being routed, Kleeve instructed one of his B1s to prepare his Separatist command shuttle for departure before turning to the Kalleran Gamut Key. Kleeve declared that the Confederacy needed to abandon its control of Kaller, asserting that the Republic would bring its own brand of tyranny. Kleeve then fled aboard his shuttle. Both Dume and Billaba witnessed the starship's departure, interpreting it as Kleeve's surrender of Kaller. Standing amidst the wreckage 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, thus ensuring Kaller's liberation despite Kleeve's threat to return, Billaba spoke with Key, although he and Janus Kasmir expressed that the Kallerans saw little difference between military generals. Although Dume, Styles, and Grey were angered by Kasmir's lack of respect, Billaba, having been informed that the planet's climate was currently mild, attempted to pacify the Kallerans by stating that her troops would not remain stationed at the compound, instead telling Key that they would rest in a field. She then departed with Dume, who was surprised by her lack of annoyance.

Traveling to the mountains, Billaba resumed Dume's Jedi training until the suns set, requesting that he explain his feelings. Dume confided in her that, despite the galaxy being at war, he had never been happier, but his mentor understood that his joy stemmed from finally finding his place in the galaxy. Nevertheless, she informed him that the universe would change and that the conflict and his apprenticeship would one day end, meaning that he could not become too attached to his present circumstances. After her lesson, they descended the mountain to their campsite to rejoin 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 that she felt the Jedi had made a mistake by becoming generals. Styles and Grey immediately disagreed, believing that the war would have been lost without Jedi leadership, although Billaba clarified that her concern stemmed specifically from the Jedi taking on military positions. Dume, meanwhile, was surprised that his master was questioning the orders of the Jedi High Council, but Billaba reminded him that Dume himself was notorious for asking too many questions, which the clone officers found humorous. Nevertheless, Dume explained that he had never questioned the decisions themselves, only the reasons behind them, and his master revealed that she had taken him on as her apprentice precisely 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 forces of the 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 region.

Near a cliff, Billaba and a force from her battalion, including Grey and other troopers who had known 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 retrieving reinforcements, but that force was rerouted to help protect the capital. Instead, Dume encountered Clone Force 99, a group of five unconventional clone commandos also known as "the Bad Batch". This elite squad was the only reinforcement available. As the battle against the droids and their tanks continued, more clone troopers and an All Terrain Tactical Enforcer were eliminated. As Grey, increasingly concerned about their lack of progress, Billaba, and other clones sought cover from tank fire in a trench, Dume returned, sliding down one of the snowy hills and promising that reinforcements were on their way, but Grey was concerned when he learned that only five soldiers would arrive. Nevertheless, Dume assured him that the team was unlike anything they would expect, and Grey realized the truth of this as Clone Force 99 arrived 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 bolts failed to stop the rock, which crashed into their formation before the Bad Batch themselves charged in. As Billaba and the others watched, the commandos quickly eliminated every B1 they encountered before turning their attention to the AATs. Clone Sergeant "Hunter" instructed 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 eliminated any remaining B1s, technology specialist "Tech" threw an Electro Magnetic Pulse grenade at an AAT Driver Battle Droid, who was attempting to order his tank crew to adjust stabilizers. With the tanks destroyed, 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 eliminated by Tech, who placed and detonated a bomb on one of the battle droids, creating an explosion that was visible from Billaba's position.

Having eliminated every threat in their path, Hunter and his commandos approached Billaba and her troops. During their approach, Wrecker, carrying the droid over his arm, eliminated the last battle droid by decapitating an OOM command battle droid after the captured automaton ordered them to surrender. Reaching the Jedi and clones, Hunter suggested that 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 that Clone Intelligence had reported that Jedi General Obi-Wan Kenobi had engaged General Grievous on Utapau, suggesting that the war could soon be over. Echo realized that if General Kenobi captured or killed Grievous, the Separatist command structure would collapse along with the droid army since he had recently become the new Head of State after Dooku was killed during the Battle of Coruscant. Nevertheless, Billaba acknowledged that such news did not currently help them, so she allowed her Padawan and the Bad Batch to proceed on their own to confront the Droid Army.

As Dume and the commandos began to depart, Grey received a transmission from Supreme Chancellor Sheev Palpatine, and Billaba sensed that something was amiss. As she turned to face her Clone Captain, Palpatine ordered via hologram that he follow Clone Protocol 66, branding the Jedi as traitors who needed to be executed. Despite his loyalty and admiration for his Jedi General, Grey, like all clone troopers, had been implanted with a control chip that compelled 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, which forced him to believe that Billaba was a traitor. Overhearing the blaster fire, Dume turned to see his master forced to defend herself 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, with the intention of destroying the Jedi and seizing control of the galaxy.

As Dume ran back to help his master, the Bad Batch noticed what the regular clones were doing, and Billaba ordered her Padawan to flee 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 that 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, instructed 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, causing Dume to 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 that the entire Jedi Order had committed treason, which confused Hunter but was accepted by Crosshair. After Tech requested that 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 demonstrate that 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 that he was also confused as to what had happened, noting that 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, causing the Padawan to fall to his death. Nevertheless, Crosshair felt the need to check with his rangefinder, departing as three regular clones arrived at the scene.
The Conquest of Kaller ended with a Republic victory, becoming one of the battles fought in the conflict's final days. As Tech had predicted, the war reached its end after the death of Grievous. While Grey and Styles remained stationed on Kaller, the Bad Batch returned to Kamino. As they approached the water world, Crosshair questioned Hunter about whether Dume had really died, noting that he had been looking across the ravine instead of down. Hunter, however, claimed that he simply had not wanted to watch a death. Crosshair refused to believe his sergeant and filed 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 that he simply did not want to think that 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 that 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 that the "insurgents" were actually civilians, they returned to Kamino despite Crosshair's protests, resulting in their 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 Kaller, Dume, having recovered his cloak, sought refuge in the forest after Order 66, spending the night there before his escape to Plateau City aboard a transport. Although initially believed deceased, Crosshair's report revealed Dume's survival, prompting Grey's clone troopers to scour the city in a hunt to eliminate him. Simultaneously, the Empire seized control of Kaller, establishing an Imperial Garrison within Plateau City; Gamut Key later reflected that the Republic's reclamation of Kaller was fleeting, preceding the government's transformation into the Empire. Consequently, Dume endured sleepless days, evading his former comrades, lost and uncertain of how to survive independently. One night, Janus Kasmir discovered him, offering a meiloorun fruit, respite on his ship, the Kasmiri, and a replacement cloak to diminish his Jedi appearance.
Upon exiting the Kasmiri, Kasmir was noticed by Styles, compelling him to dissuade the soldier from inspecting his vessel by asserting his lack of support for the Jedi. He remembered disrespecting Billaba in front of Styles after Kleeve's defeat, only days prior. Abruptly, Dume commandeered the Kasmiri with intentions of reaching Coruscant, under the impression that he had received a legitimate transmission from the Jedi Temple. Ultimately, a new signal from Obi-Wan Kenobi exposed the previous message as a fabrication, leading him to return to Kaller, anticipating that the clones would not expect his return to the site of his Jedi Master's demise. Dume remained with Kasmir, and their association evolved into a smuggling partnership.
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 shared the story with Ezra to explain his distrust of clones. Rex responded by saying that he never betrayed the Jedi and revealing that they removed their inhibitor chips, asserting that they were all given a choice.
Grey and Styles pressed on with their pursuit of the fugitive Padawan. Following several smuggling ventures, Dume and Kasmir arrived on the planet Lahn. While Kasmir proceeded to procure their necessities through theft, 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 affirmed that their animosity was over before proposing a ship for Kasmir in exchange for spice. Returning to the Kasmiri, he encountered Grey holding Kasmir at blaster-point, the clone officer skeptical of the smuggler's claims of abandoning Dume on Kaller. Abandoning his sole companion, rationalizing his flight as a means to deceive Grey regarding Kasmir, Dume went back to Kleeve's establishment.

After Kleeve escorted Dume to the offered ship, which the former Padawan christened the Escape, Styles and his clones apprehended them. Upon Styles' report of Dume's capture, Grey instructed them to reconvene at their Gozanti-class cruiser, dismissing Kasmir with the justification of adhering to Order 66. Upon entering the cruiser's hold, Grey expressed displeasure at Dume's continued survival; however, Styles, having brought him back for Grey to witness the execution, insisted on the pleasure of eliminating the supposed traitor himself. Before Styles could fire, Dume reminded them of their shared history with Billaba, revealing Palpatine's betrayal of the Republic. As their ship entered the Kaller system, with his words seemingly ineffective on his former comrades, 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 ships.
Grey, having come to the realization that Dume was correct, attempted to convey to Styles how his actions on Kaller were illogical, as he blindly followed Order 66; however, Styles remained fixated on eliminating Dume. As the Escape and the Kasmiri prepared to launch a coordinated assault, Grey targeted their cruiser's controls to disable their ship's shielding, ensuring the success of the two ships' attack. With Grey and Styles perishing in the resulting 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 with 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, possibly 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 highlighted the apparent resignation of every Kalleran he encountered to the constant occupation of their world, leading him to question whether the Kallerans even understood which side they were technically aligned with in any conflict they were involved in.

The Battle of Kaller initially appeared in the 2015 comic Kanan 1 and was initially identified in Star Wars Helmet Collection 5. The battle also made a later appearance in the Star Wars: The Bad Batch premiere episode, "Aftermath" in 2021. The animated depiction of the battle initially appeared in the opening newsreel of The Clone Wars: Season Seven episode "Old Friends Not Forgotten," although the planet remained unidentified and the footage was mirrored.
However, the depiction of events on Kaller varies between Star Wars: Kanan and The Bad Batch. In the comic, Grey, identified as a Clone Commander, receives Order 66 during the night, and Dume experiences a Force vision of Jedi falling throughout the galaxy before the attack commences. Following Billaba's death, Grey directs 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 daylight, 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 somehow regained later due to its role in helping him avoid the Empire in Kanan 2.
When addressing discrepancies in canon following the difference in Order 66 between Kanan and The Bad Batch, Pablo Hidalgo of the Lucasfilm Story Group noted that the core concept of the storyline remained consistent; the same characters performed the same actions at the same location, asserting that the differing versions of events can be interpreted as storytellers embellishing the narrative. Hidalgo stated that such variations 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 combined version of events between the comic and episode, this article also presents a combined version of events, prioritizing "Aftermath" in instances of contradiction.
The French version of Mace Windu and Other Users also employs the term "liberation of Kaller" for the brief Republic victory, while the English version uses "victory on Kaller." The 2021 Star Wars Encyclopedia "The Clone Wars" indicated that the CIS occupied Kaller for the majority of the Clone Wars. However, Kanan 9 instead established that the Separatists needed to seize 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.