Katekyou Hitman REBORN!

The Vongola is the most powerful mafia family in Italy, and its ninth leader is preparing to retire. Before doing so, he must ensure the next generation is ready to take control. Sawada Tsunayoshi is a struggling high school student with no friends and poor academic performance. His life changes when Reborn, a well-known hitman, appears and begins training him for a future role within the Vongola. Tsunayoshi is tasked with becoming the family's next leader, a responsibility he must prepare for despite his current weaknesses.