a villain with a quirk to turn people into brainless humans that are cannibals and it quickly spread as one bite turns people into the brainless humans, thus the zombie outbreak started. people quickly called them zombies and the infection spread rapidly across japan even spreading to separate countries its three years later at theres around 7.5 billion zombies (will you stop it or will you turn into the brainless zombie) btw mineta got sacrificed to the zombies