Relics of the Old Republic

"I hope you brought a better class of soldiers than those... Stormtroopers."

- Rex's response to Agent Kallus' threat

"Relics of the Old Republic" is the fourth episode of the Star Wars Rebels animated television series' second season. It is the nineteenth episode of the series overall.

After premiering at New York Comic Con on October 8, 2015, the episode aired on October 21, 2015 on Disney XD.

Official description
''While Kanan continues to struggle with trust issues, the other rebels begin to form friendships with the old clones. And when Agent Kallus arrives, all must join together to battle the Imperials.''

Plot summary
Due to Wolffe's actions, the Galactic Empire was able to track the Spectres to the planet Seelos. Admiral Kassius Konstantine and the Imperial Security Bureau Agent Kallus arrived at the Seelos system to capture or eliminate the rebels once and for all.

Following the attack by the Imperial probe droid, the rebels managed to repair the damage to the Phantom. Before parting company, Rex gave Ezra Bridger a datachip containing a list of former Republic bases in the Outer Rim Territories and Mandalore. Ezra told Rex that the clones should join the rebellion but Rex politely declined, saying that he had seen too many battles. However he, Gregor and Wolffe offered to stay behind in order to delay the Empire so that the Spectres could escape aboard the Phantom and rejoin the Ghost in space. Contacting the clones, Agent Kallus demanded that they hand over the rebels but Rex refused and preferred to fight.

Upon sighting the Imperial Star Destroyer Relentless, Hera Syndulla and Chopper turned off the Ghost systems to avoid detection.

A sandstorm stirred up near their modified AT-TE walker that prevented the rebels from departing. Agent Kallus deployed three AT-AT walkers to destroy the clones and rebels. Wolffe led the AT-TE into the sandstorm, blinding the clones' walker and the AT-ATs, but not Kanan and Ezra. Guided by Kanan, the clones and Ezra attempted to outmaneuver their Imperial pursuers. However, Kallus' walkers were able to surround the AT-TE with an enveloping maneuver. Rex then suggested that Ezra use the Force to destroy one of the AT-ATs. Kanan pointed Ezra in the right direction, and Ezra destroyed one of the AT-ATs with the AT-TE's main gun. They then fled the sandstorm pursued by the Empire.

Back in space, Darth Vader contacted Admiral Konstantine and ordered him to rendezvous with his shuttle in space. Despite Konstantine's protests that this would compromise Kallus' ground mission, Vader ignored the Admiral's concerns and reiterated his orders.

After the sandstorm had settled, the Spectres prepared to depart on the Phantom to rejoin the Ghost in space. Despite Ezra's willingness to stay and fight, Rex commanded Ezra to leave as the clones held off Kallus and his two remaining AT-AT walkers. As the rebels departed on the Phantom, Kallus' AT-AT walker managed to subdue the clones' walker. Before Kallus could destroy the clones, Ezra convinced Kanan and the other rebels to turn back and help the clones; pointing out that they would fight to the death.

Despite his misgivings about the clones, Kanan agreed with Ezra and flew the Phantom back into the fray. While Sabine Wren manned the shuttle, Kanan along with Ezra and Zeb managed to commandeer one of the AT-ATs and turn its weapons on Kallus' AT-AT walker. With his AT-TE no longer trapped under the AT-AT walker's legs, Rex was able to destroy Kallus' walker with a critical hit. Kallus and his remaining men fled the battle on a speeder while the clones saluted Ezra and Kanan. Rex then agreed to join the rebels and returned with them to the Phoenix Squadron.

Meanwhile in space, Admiral Konstantine greeted the shuttle that landed in his Star Destroyer's hangar. Instead of meeting Vader, the Admiral was greeted by the Fifth Brother, a Force-sensitive Inquisitor. When Konstantine told him that his diversion may have compromised Kallus' mission, the Fifth Brother expressed indifference and claimed that he would succeed where Kallus and Konstantine had failed.

Returning to the Phoenix rebel fleet, the Spectres and Rex reunited with Ahsoka Tano. When Rex commented that Ahsoka had grown old, the former Jedi Padawan responded that "it has to happen sometime, Rex" as they embraced. Due to Rex's decision to join the Phoenix rebels, the rebellion gained a valuable new ally.

Continuity
In Rebels Recon #2.06: Inside "Wings of the Master", Lucasfilm Story Group spokesperson Pablo Hidalgo confirmed that Gregor and Wollfe stayed behind on Seelos and made the remaining AT-AT walker their new home.