Legion is an Omega-level mutant who has multiple personalities. Fundamentally, he has the ability to alter reality and time on a cosmic scale at will, but due to his multiple personalities, in practice his abilities vary depending on the dominant personality: each alter has different powers enabled by David's subconscious manipulation of reality. The core personality, David Haller himself, generally does not manifest mutant abilities, but must access various personalities to use their power, sometimes losing control of himself to that personality. Some of Legion's personalities physically transform his body (e.g., manifesting a prehensile tongue, becoming a woman, transforming into a werewolf, etc.). The first alter to manifest, Jemail Karami, was telepathic. Other prominent alters include Jack Wayne (telekinetic) and Cyndi (pyrokinetic). Legion has over a thousand different personalities (the exact number is unknown), and his mind can create additional alters in response to external or internal events.