10 Best Times Supervillains Switched Sides

5. Emma Frost - New X-Men

Now while Emma Frost herself may have struggled to make a permanent switch from evil to good, when she has been on the X-Men, she's added some much needed bite to the X-Men's bark, providing a pragmatic perspective to counteract Professor Xavier's ideological blustering.

Is she liked by her teammates? Not in the slightest (save for Cyclops), but she is an effective hero and has always worked best when operating with the best intentions, even if her approach can sometimes be as chilly as her codename, the White Queen, implies.

Frost became a pivotal member of the team back during New X-Men, and goes on to become headmistress in the wake of Jean Grey's death. This lasts for a while, but Frost ended up being one of the more unfortunate victims of Marvel's decision to wind down their commitments to the X-Men. She was the principle architect of the X-Men's war with the Inhumans, ended up leaving the team, and is now the leader of the Hellfire Club, deeming it the best way to help mutant-kind.