The story is set in the galaxy located near the center of the universe. There you can find the Planet Aernia (a planet for Heroes) and Planet Orbs (a planet for robots), governed by Orbiton. Various countries are present in Planet Aernia; they are Volculm (volcanic country of fire), Zylan (oceanic country of water), Elvan (green-rich country of forest), and Aleum (celestial country of clouds).
Antania, is a nucleus of all the present countries. It has an academy that fosters Heroes. Under the reign of the Governor General, Antania upholds a national policy to train Heroes to prevent Planet Aernia to be infringed by the Dark Desire.
Heroes are not only the reliable source of battle.