The Duel on Stygeon Prime was a confrontation in the Spire, a prison on the planet Stygeon Prime, between the Galactic Empire and a group of Lothal-based rebels who carried out an insurgency against the Empire's rule. The duel, primarily fought between former Padawan Kanan Jarrus and the Jedi hunter known as the Grand Inquisitor, took place in the fifth year before the Battle of Yavin, as part of a mission to rescue Jedi Master Luminara Unduli from Imperial captivity. The rebels learned that Unduli, a former member of the Jedi Council, had survived the Clone Wars and the ensuing Jedi Purge, and was being held prisoner by the Empire. However, Unduli had in reality been executed by the Empire years earlier and the residual Force essence within her bones was being used to lure surviving Jedi