Charmcaster

Charmcaster is one of the main antagonists of the "Ben 10" franchise. She is the rival of Gwen Tennyson and her current arch-nemesis. While Charmcaster is most a villain, she became a full on anti-hero in "Ben 10: Ultimate Alien", when she decided to team up with Gwen. Charmcaster remained an anti-hero up until the "Ben 10: Omniverse" episode "Charmed, I'm Sure", when she started out as a hero but became a villain again. Charmcaster is now no longer a heroine and it is unknown if she will ever find the good within her again.