Jibaku-kun

ジバクくん

Baku, the protagonist of the history, is a normal boy that lives in the first world. He lives with a single and humble ambition: to dominate the world (in the sense of the whole planet). He is very certain, and would certainly die to reach his dream.

One day he meets with Enn, the Great Child of Primas (World One). Enn is known as the strongest Great Child of all the worlds, and he is a successor's search. After finding Baku and talk a little with him, Enn without apparent reason choose Baku his successor. Baku has just become a Great Child and to win the company of Jibaku, the spirit of the first world.

(Source: Wikipedia)