User blog comment:Jamie/Episode 6 - When Light Turns to Dark/@comment-1895174-20140515011111

Has there ever been a face/heel turn that stuck? Villains can reform and stay good (Hawkeye, Wolverine), but when a hero goes bad it always seems like a temporary condition. Some adaptations of Harvey Dent come to mind (namely DCAU Two-Face), but it's otherwise only a matter of time before the character becomes a good guy again.

Except for alternate universe characters whose only purpose is to answer "What if X Character were evil?" like Superboy-Prime.