Kateikyoushi Hitman Reborn! - Let's Ansatsu! Nerawareta 10 Daime! Japan

Reborn!, known in Japan as Katekyou Hitman Reborn!, is a Japanese manga written and illustrated by Akira Amano. The plot revolves around the life of a young boy named Tsunayoshi Sawada, who finds out that he is next in line to become the boss of the most powerful Mafia organization called Vongola, the Vongola Family. As such, the Vongola's most powerful hitman, a gun-toting infant named Reborn, is sent to 'tutor' Tsuna on how to become a respectable boss.