Mashin Eiyuuden Wataru: Owarinaki Toki no Monogatari
Japanese title: 魔神英雄伝ワタル　終わりなき時の物語
Type: OVA
Episodes: 3
Source: Original
Genres: Fantasy
Studios: Sunrise
Duration: 28 min per ep
Rating: PG-13 - Teens 13 or older

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)