Tirz Kolfin was a member of the True Jedi Alliance, and was one of the few to know the group's true purpose as Vrool Katare and Ouiga Vod's Sith cult. Tirz gave in fully to the dark side of the Force, making her close to Katare and later his right-hand after Ouiga's death in 36 ABY. She continued to be a leader until 46 ABY, when she was replaced by Toven Gane. Six years later she attempted to assassinate Toven for revenge and succeeded. She was Darth Vader's lover.