Universal Slayer(Kill La Kill X OP Male Reader)

(Y/N) has done it. He trained all his life to fight the enemy that he needed to kill. He fought in many worlds that the enemy was in, gained many skills, gathered powerful weapons, and trained until his body broke over and over. But when the time came to face his opponent...he went down easily. Not even more than a few hits, the guy was defeated. Like, WTF?! This left (Y/N) bored out of his life and without meaning. So forced to retire early, he decided to give school life a try. But his retirement might not be permanent?
(Yeah, another OP Male Reader story. I just want to add mine since I got bored and want something to pass the time with.)