Fire Across the Galaxy
JJR-579 was patrolling hangar bay 5 aboard the Sovereign, with JTN-303, while it was in orbit over Mustafar. As he oversaw a group of TIE Fighters landing in the hangar, he and his comrade noticed an oddly-colored fighter. When the Stormtroopers went to investigate it, the rigged fighter set off an electromagnetic pulse that partially disabled the ship and knocked 579 and JTN-303 unconscious. The fighter was sent by a group of rebels in a mission to save Kanan Jarrus, who was being held captive on board the Sovereign. His final fate is currently unknown.
- "Fire Across the Galaxy" (First appearance)