Darth Malak

Stopped by Revan from destroying the Republic, elminating the Council, and all but wiping out the Jedi. Malak had once been Revan's apprentice. With Revan had led an army of Jedi and Republic soldiers against Mandalorian raiders threatening colonies in the Outer Rim. Instead of returning as a hero though he returned as a conqueror The official story was that Revan and himself had been corrupted by the ancient power of the Star Forge. Revan and Malak had bouth sought to destroy the Republic, but Malak had betrayed his Master.

Turned Bastila Shan to the Dark Side(1)