Ban, Yuthura
this female Dark Jedi was one of the leaders of a training academy that was established on Korriban during the decades leading up to the Great Sith War. Yuthura was being trained by a Sith Master named Uthar Wynn during this time, until a group of Jedi Knights managed to infiltrate the academy by posing as Sith apprentices. The Jedi managed to befriend her, and Yuthura revealed her plans to kill Master Wynn and take over the academy. After gaining Master Wynn's confidence, the Jedi revealed themselves but kept Yuthura's plans a secret. Angry at this turn of events, Wynn and Yuthura attacked the Jedi, but both were defeated in combat.