Dragon Quest: Dai no Daibouken

After the defeat of the demon lord Hadlar all of the monsters were unleashed from his evil will and moved to the island of Delmurin to live in peace. Dai is the only human living on the island. Having been raised by the kindly monster Brass, Dai's dream is to grow up to be a hero. He gets to become one when Hadlar is resurrected and the previous hero, Avan, comes to train Dai to help in the battle...