Eight years ago, monstrous invaders shattered the skies, birthing the Hunter system and the discovery of seven powerful Auras. As the world adapted, an ancient, dying demon fused its essence with a human child. Meanwhile, an old woman's bedtime story hints at the betrayal of the God of Beginning. Years later, we meet Xiyau and Rantaro, siblings surviving in a harsh world, bound by deep love and mysterious strength. Unbeknownst to them, celestial forces — gods and antitheses — descend upon Earth, hunting a power that could reshape everything. On Rantaro's eighteenth birthday, their family mysteriously vanishes, leaving behind a cryptic letter... and setting the siblings on a path entangled with cosmic destiny.