The War of the Dark Lords, also known as the Stygian War, was the name given to the conflict between the Sith Empire of Darth Revan, and the remnants of the Sith Empire which had survived the Great Hyperspace War, under the control of the Sith Emperor Vitiate. The war lasted for at least five years, during which there were several battles, many of them being both successful and unsuccessful attempts at reconquering captured planets.
The initial phases of the war had two objectives: to conquer the territory of the Sith Remnant, and to discover the coordinates of the Dromund System. The last battle of the war took place on Dromund Kaas, where a small strike team engaged the Emperor in combat, and succeeded in defeating him. Darth Revan and the Sith loyal to him then proceeded to exterminate the Dark Council, which was then followed by Revan's takeover of the remnants of the old Sith Empire.