Naga Sadow was ruled by ambition: ambition for power, for dominance and for the expansion of the Sith Empire. Marka Ragnos's body was still warm when Naga Sadow clashed with Sith Lord Ludo Kressh over their late ruler's title. The spirit of Marka Ragnos interrupted their duel and told the two Sith Lords of a greater enemy: the Republic and its Jedi defenders.
Naga Sadow saw opportunity in this revelation and launched an attack on Republic space, a move that would see Sadow named the Empire's ruler and spark the Great Hyperspace War. Naga Sadow's ambition and overconfidence soon became his greatest weaknesses. Even with his mastery of Force illusions, the Republic outmatched the Sith. Sadow's invasion failed, and the Republic fleet pursued him back to Sith space. He fled Korriban with his warriors as the Sith Empire crumbled around him.
Sadow sought refuge on the remote moon Yavin Four, where he died after spending years trying to rebuild the Empire he had inadvertently helped to destroy. Naga Sadow's spirit, however, survived to pass on Sith teachings, planting the seed of corruption among his Jedi enemies.