darth sion, also known as the lord of pain, is an antagonist in . alongside darth nihilus, he served as one of traya's apprentices, until ultimately betraying her and driving her into exile. sion managed to achieve immortality by calling on his pain, anger and hatred every time he was facing certain death, at the expense of all-consuming agony, which also led to his extremely disfigured appearance. the player's character eventually defeated sion, and was then given the option to turn him back to the light side. regardless, upon being shown the price he paid for immortality, sion finally let go of his hate and allowed himself to die permanently.