Mashin Eiyuuden Wataru: Owarinaki Toki no Monogatari
Genres: Fantasy
Type: OVA, Episodes: 3
Aired: Oct 1, 1993 to Feb 1, 1994
Studio: Sunrise
Source: Unknown
Synopsis:
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)