Kill Ao follows Juuzou Oogami, a legendary hitman whose perfect career is interrupted when he tears apart a powerful criminal organization and is stung by a mysterious wasp. When he wakes up, the 39-year-old assassin has been transformed into a 13-year-old boy, and his boss hands him an absurd new mission: go undercover in middle school and keep working from the inside.
Forced out of the underworld and into classrooms, uniforms, and the relentless rhythm of teenage life, Juuzou has to hide his true identity while danger keeps closing in on him. Homework, classmates, and the awkward rules of school become just as important as surviving the enemies still hunting him. Kill Ao blends action and comedy around a hardened killer trying to adapt to a second life that is both ridiculous and lethal, where every lesson learned in the classroom can turn into another survival tactic. As his new life unfolds, the contrast between his ruthless skills and the everyday chaos around him drives the story, turning adolescence into another battlefield.
