Ansatsu Kyōshitsu / Assassination Classroom / anime and manga, 2012–2016

In a world of Quirks and Heroes, one day, when no one expected it, more than half the volume of the moon was blown up, leaving only a crescent. While people are trying to understand the reason of this, an octopus-like villain announces that he was involved in the Moon explosion, and next year he is going to blow up the Earth. Even the All Might himself could not stop him and for this reason the government had to make a questionable deal with him.