James Venamun, also known as the Gemini Killer, is the main antagonist of The Exorcist III: Legion, which itself was based on William Peter Blatty's 1983 novel. He is Father Karras' archenemy and was a ruthless serial killer in life whose soul was so evil that he became a demon after his death, with the help of Father Merrin's archenemy, Pazuzu.