A thousand years after the greatest calamity in history vanished, the ancient monster Raizen awakens to a world that has forgotten him. As kingdoms, legendary heroes, mercenaries, monsters, and saints unite to stop his reign of terror, an ancient servant y/n, from the Heian Era stands faithfully at his side. In a world where power decides everything and every battle has lasting consequences, shifting alliances, forgotten relics, and overwhelming magic will determine whether history repeats itself—or whether a new legend will be written.