Campione!

A Campione – a Godslayer – is a supreme ruler.
Since he can kill a celestial being, he can therefore call on the sacrosanct, divine powers wielded by the gods.
A Campione – a Godslayer – is a lord.
Since the power to kill a deity is in his hands, he therefore looms over all mortals on Earth.
A Campione – a Godslayer – is a devil.
For all mortals who live in the world, none can hope to match their power.
Kusanagi Godou, a 16 year old boy who played in the senior league as catcher and fourth hitter when he was in Junior High. However, an injury put an end to his future in baseball.
During the spring break of his third and last year in Junior High, he got involved in an adventure and ended up slaying one of the Heretic Gods, Verethragna. Thus, he became the youngest and seventh - Campione.
Now that he is a Campione, a godslayer, the young Godou must defeat the troublemaking gods, with the help of his followers!
(Source: Baka-Tsuki)