Katekyo Hitman Reborn!
...about the series
Katekyo Hitman Reborn - with Kateyo being an abrevation for Katei Kyoushi (as home tutor) is an ongoing manga in Japan, born from the cracked mind of a great Akira Amano. The main plot is around a boy Sawada Tsunayoshi (Tsuna), who founds out he is the next boss to a powerfull Magia organisation named Vongola, and he get's the family's most powerful hitman as a tutor: infant who is known as Reborn, who has to make from Tsuna a respectable boss.
The manga is serialized in Weekly Shounen Jump, while the volumes are published by Shueisha. It's still an ongoing series. In english language it's serialised under Viz Media, while in Italy by Planeta DeAgostini.
It's one of the best selling Weekly Shounen jump manga, with several volumes becoming top-sellers in Japan. As in the begining it seems a comedy, later on becomes a serious shounen series with violence, and great story line, besides well drawn fights.