There he preformed Sith expriments on his Massasi warriors turning them into primitive red skinned mutants, and used them as his slaves. Naga Sadow retreated into Yavin IV after his defeat in the Great Hyperspace War by the Galactic Republic. Long before the Galactic Civil War Yavin IV was controlled by the ancient Sith Lord Naga Sadow. However the Empire responded swiftly and sent a massive strike force to Yavin IV, lead by Darth Vader himself the Empire destroyed the rebel base, forcing the Alliance to flee. This marked as one of the greatest victories of the Rebel Alliance. It's destruction was made possible by Luke Skywalker who's piloting skills and use of the force, was able to strike at the Death Star's weak point destroying it. It was here the momentous Battle of Yavin IV took place, a small Rebel strike forces were able to destroy the Galactic Empire's dreaded Death Star. It is the only moon of Yavin that is suitable to live on and served as the Rebel Alliance's secret base during the events of A New Hope.
