When does deku become a villain? First Appearance: Villain Deku episode 1: The Villain is Born! Last Appearance: Little Witch Academia episode 25: Goodbye, Cousin!
Why does Deku go evil? After years of constant bullying from Katsuki Bakug? and ostracization from his middle school classmates, Izuku became emotionally and mentally exhausted. That's why he was easily taken over by the evil people in his surroundings.