Darth Revan
this was the self-bestowed title used by the former Jedi Knight Revan, during his campaigns against the Jedi and the Old Republic during the Great Sith War. As Darth Revan, he took his friend and former Jedi Malak as his apprentice, and they quickly began conquering star systems throughout the galaxy. The Jedi Order dispatched a group of agents, led by Bastila Shan, to lay a trap for the Sith Lords, and Darth Revan was believed to have been killed in battle. History clouded the details of the battle, and it was unclear whether Revan was killed by the Jedi or by his own apprentice. In actuality, Revan was simply captured by the Jedi and held for reconditioning. After a complete memory wipe, Darth Revan ceased to exist.