Junko Enoshima is pretty well known for committing crimes. She turns an entire homeroom class at her school to evil, causing the apocalypse. She then locks her homeroom class into their old school with their memories wiped and forces them to kill one another, with the first victim being her twin sister. When asked why she ruined the world her response amounted to "for the laughs" and she dies with her only regret being that she couldn't inspire more suffering.