Baron Mordo (real name: Karl Amadeus Mordo) is a major villain in the Marvel comics universe. He is a powerful and evil sorcerer whom happened to be Ancient One's former pupil until he attempted to assassinate his mentor but is foiled by the new apprentice Stephen Strange, leading to Baron Mordo being cast out and Dr. Strange eventually becoming "Sorcerer Supreme." Mordo would clash with Dr. Strange on a multitude of occasions, at times with the backing of the demon Dormammu, going so far as successfully impersonating Dr. Strange for a short period of time.