Atollon, a planet situated far off in the Outer Rim Territories within the Lothal sector, was a place known to the ancient inhabitants of that region, as evidenced by its presence in their artistic creations. The sole known resident was the Bendu, a mysterious individual who wielded the Force. In the time frame of three years before the Battle of Yavin, the rebel group known as Phoenix Cell established a base there, acting on intelligence provided by the rebel astromech Chopper and AP-5, an inventory droid who had previously served the Empire. Ultimately, the rebels were compelled to evacuate the planet when Grand Admiral Thrawn discovered their base and initiated an attack, resulting in the destruction of Chopper Base and the loss of many rebel lives.
Located in an unmapped area of the Lothal sector within the galaxy's Outer Rim Territories, away from any major hyperspace route, Atollon possessed a breathable atmosphere but experienced a hot climate. Despite the arid conditions on its rocky surface, which was adorned with plated tree corals, the planet had a freshwater source located deep beneath the surface.
The planet's untamed environment was also the territory of a powerful Force being called the Bendu, who considered himself the embodiment of balance between the light and dark sides of the Force. The Bendu resided in a valley situated in the heart of the Coral Mesa. The planet also featured caverns that served as nesting grounds for the krykna.
While Atollon was featured in the artwork of the ancient people of the Lothal sector, it was absent from the star charts of the Empire. Following the near annihilation of Phoenix Cell in various engagements, the burgeoning rebellion against the Empire faced a scarcity of bases for their forces. In 3 BBY, the rebels identified Atollon by cross-referencing rebel data with the Imperial network, a feat made possible by AP-5 and the astromech droid Chopper, and successfully established Chopper Base. After the unexplained disappearance of rebel Lieutenant Dicer, it was discovered that the krykna, a massive spider-like predator, was one of the planet's native species. Eventually, they succeeded in securing the base by deploying sensor markers as a perimeter. Later, the former Jedi Ahsoka Tano journeyed to Atollon to rendezvous with Jedi Knight Kanan Jarrus, his Padawan Ezra Bridger, and Chopper prior to their departure on a mission to Malachor.
Upon their return from the Malachor mission, the blinded Kanan, accompanied by Ezra and Chopper, were greeted by their fellow rebels, Rex, AP-5, and Commander Jun Sato. In 2 BBY, Atollon continued to serve as the location of Chopper Base. While Kanan remained behind to meditate on the Force, Ezra took on a more prominent leadership role within Hera Syndulla's rebel cell and spearheaded a successful mission to rescue Hondo Ohnaka, a Weequay pirate who provided Phoenix Squadron with information regarding the Imperial starfighter reclamation plant known as Reklam Station. While Ezra led a recon mission there, Kanan had an encounter with the Bendu, who guided him in overcoming his fear of the krykna and restoring his connection to the Force. Kanan also entrusted the Sith holocron that Ezra had acquired on Malachor to the care of the Bendu.
Following the abduction of Hera and the other members of the Ghost crew by the former Sith Maul, Kanan and Ezra rode a speeder bike into the Atollon wilderness to locate the Bendu and retrieve the Sith holocron. They informed Bendu that Maul intended to merge the Sith holocron with Kanan's Jedi holocron. The Bendu cautioned Ezra and Kanan that such an action would bring clarity but could also unleash chaos. Nevertheless, he permitted Ezra to retrieve the Sith holocron from a subterranean cave teeming with krykna. With Kanan's assistance, Ezra conquered his fear of the giant spiders, and together they recovered the holocron.
Later, the Spectres, Rex, and Commander Sato convened at Chopper Base for a briefing to discuss a mission aimed at rescuing several cadets from the Imperial Skystrike Academy who wished to defect. The Mandalorian weapons expert Sabine Wren was assigned to lead the mission. After successfully rescuing the cadets, Sabine, accompanied by Wedge Antilles and Derek Klivian, arrived at Chopper Base, where they were welcomed by Commander Sato.
After evacuating rebel dissidents and the rebel cell Iron Squadron from the planet Mykapo, Commander Sato shared an emotional reunion with his nephew Mart Mattin at Chopper Base. Subsequently, Hera, Sabine, Zeb, and Commander Sato remained at Chopper Base while Ezra, Kanan, and Chopper embarked on a mission to infiltrate the Imperial Armory Complex on Lothal with Ryder Azadi's rebel cell. Ezra's team and Ryder maintained communication via hologram throughout the mission. As a result of the mission, the Phoenix rebels discovered that Grand Admiral Thrawn was developing a new starfighter initiative and that Agent Kallus of the Imperial Security Bureau had become a rebel informant.
Utilizing the information gathered by Ezra and Chopper, Hera initiated preparations for a reconnaissance mission as part of Phoenix Squadron's planned assault on Lothal's Imperial factories. Before they could proceed with the mission, Ezra succumbed to a dark side attack orchestrated by Maul. While Hera departed for Lothal, Ezra, Kanan, and Sabine remained behind to confront Maul. Ezra and Kanan encountered Maul in the wilderness after seeking counsel from the Bendu. Ezra agreed to accompany Maul to the planet Dathomir after Maul threatened to activate a homing beacon that would alert the Empire to the existence of Chopper Base.
Later, the E-XD-series infiltrator droid EXD-9 discovered Atollon and Chopper Base. Before it could notify the Empire of Chopper Base's presence, EXD-9 was subdued and deactivated by Zeb, Chopper, and AP-5. The rebels then reprogrammed it into a bomb, which destroyed an Imperial Star Destroyer. Despite this setback for the Empire, Thrawn managed to narrow his search for the Phoenix rebel base to 94 systems.
After a reluctant Sabine agreed to learn how to wield the Darksaber to gain leadership over the Mandalorian people, Kanan and Ezra took her into Atollon's wilderness to train her. Over several days, Sabine managed to overcome her own self-doubt and fears. Her rebel comrades, including Fenn Rau, then vowed to support her mission to rally the Mandalorians over to the rebel cause.
During an undercover mission to rescue the rogue ISB Agent Kallus, Chopper deleted Atollon from Grand Admiral Thrawn's star chart aboard the Star Destroyer Chimaera. Later, several members of Phoenix Squadron witnessed former Imperial Senator and rebel leader Mon Mothma's HoloNet speech announcing the formation of the Alliance to Restore the Republic. Following a rebel mission to Killun Station, Imperial slicers hijacked Chopper in an attempt to find the location of the rebel base on Atollon. Their plot was foiled by Chopper's rebel comrades, who restored Chopper's original programming and transmitted a data surge which destroyed the slicer's Gozanti-class cruiser.
After receiving messages from Kanan's Jedi Holocron and the Malachor Sith Holocron hinting that Jedi Master Obi-Wan Kenobi's life was in danger, Ezra stole an RZ-1T trainer and traveled to Tatooine. He and Chopper returned to Atollon after Kenobi defeated Maul in combat. Thrawn was able to find the base shortly after he and his death troopers exposed and captured Agent Kallus, who was "Fulcrum." With Kallus' transmissions, the course for General Jan Dodonna's forces, and ancient Lothal sector artwork, Thrawn was able to discover the planet. Soon after, a battle ensued on and above the planet between the Galactic Empire and the Rebel Alliance. Towards the end of the battle, after being enraged by Kanan calling him a coward, the Bendu transformed into a storm and attacked the Imperials and Rebels before being subdued when Grand Admiral Thrawn had his AT-ATs shoot the Force-wielder down. The battle ended with an Imperial victory and saw the destruction of Chopper Base and Phoenix Squadron.
Atollon made its debut in the Star Wars Rebels season 2 episode titled "The Forgotten Droid." Its identification was first revealed in the episode's trivia gallery.