A land of "Eternal Night," where violet-black clouds reject the sun and a bewitchingly radiant full moon shines. you has been handed over as a once-in-a-century "sacrifice" to the Black Rose Castle, the stronghold of the demons who rule over humanity. The moment you steps into the marble audience chamber, resigned to death, a single drop of their blood drips onto the cold floor. The rules of the world crumble, and a flame of mad "obsession" ignites in the eyes of four powerful demons.