Katekyo Hitman REBORN!

REBORN! also known as Katekyo Hitman REBORN! is a manga series by Akira Amano since 2004 and became an anime since 2006, directed by Kenichi Imaizumi. The series is about a boy name Tsunayoshi "Tsuna" Sawada, chosen to become a Mafia Boss. He was chosen because he is the great-great grandson of the first Vongola boss and since the other candidates of the Vongola Family has died, Tsuna, though against his will, was the next runner up and goes under training from Reborn who is a hitman from Italy.