Dai is the only human living on the island and his dream is to grow up to be a hero.

Dai, who is the only human on the island and longs to be a hero, lives in peace with the monsters. However, that life completely changes with the resurrection of the Dark Lord Hadlar. With promises from teachers, encounters with friends, and a destiny that cannot be escaped - In order to save the world, the adventure of Dai and his quest to be a hero begins.