In a world where the lines between the living and the dead blur, a young boy named X witnesses his mother's brutal murder at the hands of his own father. Consumed by a thirst for revenge, X dedicates his life to finding and confronting the man who shattered his world.

This dystopian reality is forever altered by the emergence of magical beings. Governed by the O-7 Council—ancient deities who oversee the delicate balance of life and death—the world is inhabited by reapers and demons enforcing celestial laws.

By day, X is a high school student grappling with his loss and isolation. By night, he transforms into a reaper, navigating a life filled with danger and moral ambiguity. His path is fraught with complications: a rival half-dragon/arcane golem dispatched by the Council to control him, and a mysterious sorceress named Lala whose destiny becomes intertwined with his own.

As X delves deeper into the secrets of his transformation and uncovers the true motives of the O-7 Council, he discovers he is not alone in his quest. His journey will intertwine with others—Ryu, a Black Knight burdened by a mysterious past, and Amari, a boy consumed by vengeance—each with their own battles to fight. Together, their fates may hold the key to the world’s survival, but the price of power could be greater than they ever imagined.