In this world of warriors and demons, the two seem bound by fate. The warriors, endowed with power by the world, have the sole purpose of slaying the demons; the demons, on the other hand, exist to destroy the warriors. Under the demons' command are twelve legions, each commanded by a powerful and brutal commander, the demons' most trusted servants. However, a warrior who once triumphed over the commanders ultimately fell at the hands of the mysterious "Zero Legion." The commander of the Zero Legion, Demon Arut, is the demon's hidden trump card and most precious "talent." The story unfolds in this world of conflict and mystery.