Should I do a Monster AU?
Explanation: In the AU, instead of normal humans, the 80% of the world that has quirks are monsters.
Quirks being Mutations: The "Quirks" are actually called "Mutations" in this AU, the ones with these Mutations are seen as terrifying monsters that can range from furry to skeletal to other-worldly. Izuku was a normal boy that didn't have a Mutation, leaving him as a human. But after getting the One For All Mutation from All Might, he became a monster. Everything else stays the same besides the Quirks.