Assault on Seelos In 4 BBY , the Galactic Empire launched an assault against rebel and clone forces on the planet Seelos . Prelude . In an attempt to find a planet to host Phoenix Cell ' s new base , Ahsoka Tano suggested the " Ghost ' s " crew to search her fellow during the Clone Wars Captain Rex in whose hands there was a map of useful locations . The Spectres traveled to Seelos , the planet on which the clone had probably retired after the war . There Kanan Jarrus , Ezra Bridger , Sabine Wren and Garazeb Orrelios reached the surface on the " Phantom " , leaving Hera Syndulla on the " Ghost " flying over the planet . The rebels found the clone riding a modified All Terrain Tactical Enforcer , a Clone Wars - era walker , together with two comrades , Commander s Wolffe and Gregor . After some adventures and debates , the group seemed to get along , but Wolffe who was unhappy with the rebels and Ahsoka , alerted the Galactic Empire . Despite realizing his folly , the rebels ' position was now exposed to the Empire . Shortly later , an Imperial probe droid discovered the " Phantom " and inflicted damage on the starship before being destroyed by Rex . Tracking Wolffe ' s signal , the Imperial Security Bureau Agent Kallus reached Seelos aboard the Star Destroyer " Relentless " . Shortly later , Agent Kallus contacted the clones by intercom and demanded that they surrender the rebels . However , Rex rejected Kallus ' demands and he and his fellow clones resolved that they would fight in order to allow the rebels to escape offworld . Before leaving , Rex handed Ezra a list of Old Republic military bases in the Outer Rim Territories and Mandalore . The Battle . Instead of an orbital bombardment , Kallus decided to deploy three AT - AT walkers to destroy enemy forces , represented just by the clones ' AT - TE . To gain an advantage , Wolffe commanded the walker into an approaching sandstorm , causing all the vehicles to be blinded . However , the Force - sensitive rebels Kanan and Ezra were able to use their Force to guide the clone crew through the sandstorm . The AT - ATs and AT - TE attempted to outmaneuver each other until Kallus was able to surround the clone walker with an enveloping maneuver . Rex soon sent Ezra to use the Force to destroy one of the AT - ATs . This took the Imperials by surprise since they not aware that they were so close with the enemies . Kanan pointed Ezra in the right direction , and the young rebel centered one an AT - AT with the AT - TE ' s main gun . Then the clone walker left the sandstorm , pursued by the remaining two walkers . At this point in the battle , Admiral Kassius Konstantine was ordered by Lord Vader to meet with his shuttle , forcing him to abandon the battle . The " Ghost " was finally able to descend to Seelos without having to contend with the Imperial Star Destroyer . Meanwhile the rebels left the AT - TE aboard the " Phantom " to rendezvous with Hera and Chopper on the " Ghost " while Rex and the clones charged the two remaining walkers in a suicide attack . Despite taking several hits , the clones ' AT - TE was able to ram the legs of Kallus ' AT - AT . However , Kallus ' more powerful and taller AT - AT soon gained the advantaged over the vintage AT - TE walker . In spite of the odds against them , Rex and his fellow clones resolved to continue fighting . At the urging of Ezra , Kanan agreed to help the clones . While Sabine flew the " Phantom " , Kanan , Ezra , and Zeb entered the head of the second remaining AT - AT and hijacked the walker . They then used the walker ' s guns to attack Kallus ' walker . Kallus attempted to call for reinforcements but Admiral Konstantine was unable to render any help since he was preoccupied with hosting the Fifth Brother , another Inquisitor . With Kallus ' AT - AT walker weakened , the clones ' AT - TE walker was able to regain power . This allowed Rex to fire the AT - TE ' s laser cannon into the AT - AT walker ' s neck , destroying the Imperial walker . Kallus and two surviving AT - AT pilot s escaped the battlefield in a speeder . Out of gratitude to the rebels , Rex along with Wolffe and Gregor saluted Ezra and Kanan . Aftermath . While Wolffe and Gregor chose to stay behind on Seelos , Rex decided to aid Phoenix Squadron and traveled with the crew of the " Ghost " . The group met with the rebel flotilla , where Ahsoka Tano saw her fellow and had a brief talk with him . Since the events on Seelos , Rex often helped the rebels in their missions , such as in the Blockade of Ibaar , in the rescue on the Imperial Interdictor , the Battle on Garel , an ambush in the Geonosis system , and the establishment of Chopper Base on the planet Atollon . Behind the scenes . The assault on Seelos first appeared in the " Star Wars Rebels " episode " Relics of the Old Republic , " which premiered at the on October 8 , 2015 .