The soul exists in religious thought as the supernatural and immaterial part of a human being. But if a Host dies with lingering resentment, their Soul will remain undying in this world until it finds a new Host and becomes a Regulator. It is extremely rare for a Soul to become a Soul, so Regulators are even rarer. On a snowy night, the Soul of the Dark Knight unexpectedly took up residence in Amano Hugo. The Dark Knight had long been a thorn in the side of the Comers. After dying in battle in the 11th century, his Soul escaped the Comers' pursuit and has clung to existence ever since. The Comers were forced to grant Souls the power to create more Regulators, sending them into the world to hunt down the Dark Knight and his Host. When the Dark descends upon the Knight bound by fate, the tide of souls will sweep across the world.
