Mashin Hero Wataru: A Story At An Endless Time

魔神英雄伝ワタル　終わりなき時の物語

The story is about a 9-year-old boy named Wataru Ikusabe who is magically transported to a magical realm of the gods called Sokaizan which he is supposed to save. He also befriends many of the Soukaizan natives, and forms some very strong friendship bonds. (Source: Wikipedia)