10 Video Game Villains Who Switched Sides (To Fight Something Worse)

The rivalry between Sonic and Dr. Robotnik is on par with that of Mario and Bowser, and yet ever since Sonic Adventure 2, the two characters tend to work together quite often.

This weird enemies-to-occasional-friends transition can be largely attributed to the first instance of Robotnik dropping his plans of world domination in favor of world preservation in Sonic Adventure 2.

Despite the entire game revolving around Eggman being up to no good and even blasting off a chunk of the moon to threaten Earth into submission, in the final act he has a sudden change of heart and decides to help Sonic stop space colony ARK from crashing into the planet, realizing that he won't be able to rule anything if the world turns into ash.

After the day is saved, the old doctor even shows remorse for following in the evil footsteps of his father, although in the later games he goes right back to his villainous ways anyway.

Still, you can see that his one act of good has left some impact on him, as he tends to team up with Sonic from time to time afterward, whenever there are greater threats to deal with.