I was there when the Academy on Korriban fell… and the Sith turned on one another, like beasts. Our chance of an empire… destroyed by Revan.
The First Sith Civil War wracked the Sith Empire after the end of the Jedi Civil War. Following Darth Malak's defeat during the final battle of the Jedi Civil War, several of the Sith Lords who had followed Darth Revan and Malak during the war attempted to take what they could from the ruins of the Sith Empire. Confrontation eventually destroyed the Sith in a bloody civil war centered on Korriban's Sith Academy (3,956 BBY-3,955 BBY). The nearby Dreshdae settlement was abandoned.
When Republic forces arrived on Korriban after the Jedi Civil War, they found Korriban barren and lifeless. It was still in this state when the Exile began searching for what was left of the Jedi Council five years later; by that time, much of the Sith Order had been decimated, and a second conflict was to begin.