Kill Ao

In the action-packed anime Kill Ao, legendary adult hitman Juuzou Oogami completes an impossible mission, only to be transformed into a 13-year-old boy by a mysterious event. With no time to adjust, his organization gives him a bizarre new assignment: infiltrate a middle school.

Now, the world's deadliest assassin must navigate the chaotic halls of adolescence, dealing with colorful classmates and unexpected school life, all while evading the dangers that stalk his new, younger form. This unique premise blends intense action with comedic and heartfelt moments, exploring themes of identity, second chances, and the stark contrast between a hardened killer's past and the seemingly ordinary world he is forced to inhabit.