Kaller, located within the Kaller system in the Outer Rim Territories of the galaxy, was a terrestrial planet characterized by its intricate and varied climate. It served as the original homeworld for the Kallerans.
Despite its generally cold nature, Kaller's position within a binary star system resulted in complex seasonal shifts, causing moderate conditions to rapidly transition into extreme weather within a matter of days, allowing Kaller to also possess a temperate environment. This rapid climatic change, a consequence of the binary star system, meant that Kaller could experience drastic temperature swings in short periods. Moreover, it was strategically positioned at the convergence of three distinct hyperspace routes. The majority of Kallerans established their settlements along freshwater rivers, constructing stone structures in smaller settlements and duracrete buildings in urban centers.
During the era of the Galactic Republic, Kaller remained largely isolated due to the Kalleran culture's emphasis on individualism over collective achievements. While Kallerans established local governing bodies and economies, the absence of a unified planetary government made the world vulnerable to colonization and exploitation by galactic corporations and external groups such as the Mandalorians and Pykes. These groups established regional colonies and engaged in mining the planet's mineral resources, forcing many Kallerans to relocate to resource-scarce regions where they were permitted to live peacefully under their own leaders.
Although Kaller was home to diverse groups and species, no external power ever achieved complete dominance over the planet. Kalleran leaders skillfully manipulated rivalries between the offworlders to advance Kalleran political interests. During the Clone Wars, the planet was aligned with the Galactic Republic and became a target for the Confederacy of Independent Systems, with Count Dooku personally tasking General Kleeve with leading the invasion. After departing from Kardoa, the general directed the Separatist occupation of Kaller from the compound belonging to village leader Gamut Key.
In 19 BBY, Jedi Master Depa Billaba and her Padawan Caleb Dume commanded their battalion of clone troopers in opposition to Kleeve's occupation of Kaller. Despite Kleeve's forced retreat, the Kallerans displayed resistance to the Republic's campaign, perceiving little difference between Republic and Separatist control. Following the Battle of Coruscant, Kaller once again became a battleground, with Billaba, Dume, and their clones engaging battle droids alongside the elite squad Clone Force 99, the only reinforcements available due to the ongoing attack on the capital, Coruscant.
The implementation of Order 66 resulted in the betrayal by Clone Captain Grey and Billaba's other clones. After urging her Padawan to flee, Billaba was killed by her own troops, and Dume was pursued into the forests by Clone Sergeant Hunter and sniper Crosshair of Clone Force 99. Crosshair, the only member of his squad affected by Order 66, attempted unsuccessfully to eliminate the Padawan, who managed to escape into the woods. Nevertheless, his mission report revealed Dume's survival, prompting Grey's troops to initiate a search for him in Plateau City.
During the Imperial Era, the Galactic Empire showed minimal interest in Kaller, deeming it insignificant, though some Imperials continued to exert influence on the planet. However, the Empire did not establish a military presence within the Kaller system. Key was appointed as the provincial governor of Kaller with Imperial backing, but he developed a growing resentment towards the regime and the increasing demands placed upon his world by certain Imperials. During the mission to Kaller, Dume, now known as "Kanan Jarrus," made his return to the planet. Jarrus and his fellow rebel crew, the Spectres, engaged in conflict with Imperial stormtroopers who had been alerted to their presence on Kaller.
Kaller's initial appearance was in the Star Wars: Kanan comic book series, authored by Greg Weisman. It subsequently featured in the Star Wars: The Bad Batch series premiere, "Aftermath." The inclusion of Kaller in the show was a reference to the Star Wars: Kanan comic, as the series premiere depicted the same events.
While Order 66's events occur during daylight and involve Clone Force 99 in "Aftermath," its portrayal differs in Kanan 2. On the night after Kleeve's retreat, Grey and Captain "Styles" lead the clone battalion against Dume and Billaba. Following the Jedi General's death, Grey instructs Rostu Squad and all other forces to locate Dume.