KJ-931 represented an early iteration of the assault Skytrooper, a variety of battle droid utilized by the Eternal Empire originating from Zakuul. The droid was stationed on Emperor Arcann's Eternal Flagship in 3630 BBY, when SCORPIO provided the Emperor with the whereabouts of the Anti-Zakuul Alliance's base on Odessen. Consequently, the Emperor, along with the flagship and a substantial segment of the Eternal Fleet, proceeded to Odessen. During the subsequent Battle of Odessen, Alliance forces successfully boarded the flagship. KJ-931 confronted both Lana Beniko and the Alliance Commander in combat, but ultimately suffered defeat and destruction.