I have such a hard time envisioning Midoriya as a villain. It just... doesn't work in my smooth little brain.
HOWEVER-!
I did have this au from a while back where All Might never saved Bakugou, just watches on and feels like shit because even a quirkless kid is willing to do what he fails to do so how is he supposed to call himself a hero? Despite Midoriya's best effort, Bakugou is suffocated and dies. Izuku hates All Might for just standing there- watching.
All Might is too ashamed to speak to him after and Izuku falls into a deep despair where he begins resenting heroes, seeing the flaws for the first time. He comes to a conclusion that people can't rely on them and have to start standing up for themselves. He starts working on a way to cultivate scenarios where people have to save themselves. (Jigsaw Deku...???? What???) Maybe he starts working with villain's who agree with him and don't actually try to hurt people, just threatens them or something. Idk...
ANYWAY- Bakugou's body is taken by AFO and Ujiko and turned into a nomu. 🤷♀️
(Even still, it just doesn't feel right. I think Deku would still tell himself All Might just ran out of time and it was his fault because he made All Might drop the bottle. He would have more self blame than he would have hate, I think. Also, there are other heroes he would believe are inherently good people. I just don't see him ever really becoming a villain. This was my best attempt at it. Sorry if it sucks, lmao.)