For Realzies This Time
I wanted desperately to become a hero, but I found that I could not operate within the laws because there’s simply too much evil in the world to deal with legally
I tried to become a hero, but the nature of my powers inherently set me up to become a villain
Spite
Turns out vigilantism is a slippery slope, and eventually I became the monster I so desperately wanted to eradicate.
I have information the government/other heroes want, and resorted to a life of supervilliany to protect it.
I have a few loved ones I would destroy the world to protect. Looks like I’m going to have to go through with it.
I’m desperately ill with a disease that’s killing my younger siblings. They don’t know I have it as well, and I’m running out of time to find a cure for us. Supervillainy was the only thing I could do.
My powers have skewed my moral code enough that I don’t realize that what I’m doing is wrong