When has Wario not been a villain. I haven't played any of the Warioware games so maybe he acts differently, but in most of his other games, he just goes around trying to steal other people's stuff. Even in the games where he helps people, he only did it to get something out of it; he didn't care about there well being and wouldn't have done it otherwise. He was also a villain in SSBB.
--
RIP Washington Wizards Franchise
Wizard fan turned heel