Kill Ao

Juuzou Oogami is a skilled middle-aged hitman known for taking dangerous assassination jobs. He has a rule that he only hurts or kills truly evil people. He spent his entire life as an assassin; he regrets never experiencing a normal childhood. Everything changed after a mission when a mysterious wasp stung him with a strange venom, transforming his body into that of a teenager. Soon, Oogami is given a new assignment to go undercover at a private school and investigate it before his boss’s daughter enrolls there. As Oogami investigates the school, he discovers that one of his classmates, Noren Mitsuoka, has ties to the company behind the mysterious wasp; he also wanted to experience the normal life that he never had.