Moonstone (real name: Karla Sofen) is a villainess turned anti-heroine of Marvel Universe who is a nemesis of Hulk and once disguised as Captain Marvel (Carol Danvers) for a large amount of time, manipulating her allies. Like many other Marvel villains, she eventually redeemed herself and joined the Thunderbolts. She is the archenemy of Carol Danvers.
Karla Sofen was a psychologist under the tutelage of Doctor Faustus who gained her powers through a mystical moonstone, a strange gem taken from the moon which granted its user great power. She stole the gem from one of her patients, Byron Becton aka Nefarius, via psychological inducement. She absorbed Becton's moonstone armor into her body, giving her ultimate power over the gems.
As the new Moonstone, Sofen gained many powers, including superhuman strength, speed, agility, and durability, flight, control of gravity, photon blast projection from her hands, intangibility, and several other powers.
Moonstone's secret identity was revealed to the public after a battle with the Hulk. Moonstone joined the Masters of Evil as well as at one point teamed up with Baron Zemo. She also battled Graviton, another villain with gravitational powers superior to hers. After Graviton killed one of her childhood friends, and her moonstones were taken from her by the Avengers, Sofen became mentally unstable, and Zemo used this as an opportunity to take the moonstones for himself. She eventually got them back and regained her mental stability.
Moonstone was a member of the Masters of Evil and joined Zemo when he and several other villains went under the guise of a new team of superheroes, the Thunderbolts. She often analyzed and manipulated the other members to study their psychological attributes. Even though she stood up to Zemo alongside the others when he unleashed his real plan for world domination, she never truly reformed and later joined Norman Osborn's version of the Thunderbolts and well as his Dark Avengers as the evil counterpart of Ms. Marvel, with whom she had a bitter rivalry.
- Thunderbolts (formerly)
- Dark Avengers
- Masters of Evil
- Doctor Faustus (former ally)
- Blackout (Marcus Daniels) (former partner)