The lives of all humans was being threatened and only those given the title of super had a chance of defending their small planet from the entities on the outside. When the race known throughout the galaxies as Rakit show up on Earth's doorstep asking for aid in a war they weren't yet part of but would be dragged into without fail the humans were left with few options. It was kill or be killed and Levi, even though he couldn't die himself, would be damned if he lost his semi peaceful life due to the world ending. He may be a villan in the eyes of humanity but maybe this was his chance to change their perspective, maybe when all this was over he would finally be able to visit his local convent store without someone screaming in his face before running away in terror. Yeah, that would be great.