A Leviathan's Call

Once upon a time, there were two brother gods, The God of Light and God of Darkness, the two brothers always butted heads with each other until they both set a game with the God of Light using a certain silver-haired headmaster and The God of Darkness using a paled skin woman along with creatures of the dark. Next, there's another problem with a red-haired devil king in panic for his younger sister being in an arranged marriage with someone she doesn't want to be with. Running out of ideas to save his sister, a black-haired twin-tailed devil king gave a response that she knew someone who could help the other devil king's sister. While that was happening, the silver-haired Headmaster was worrying about something the Gods told him before, but who knew what they were talking about will come to them.