In a timeless struggle between devils and humans, a truce was brokered through the formation of the organization known as Cambion. Comprising members from both sides, Cambion aimed to preserve peace and defend against attacks from cursed humans (banes) and devils.

Rin, abandoned in infancy and raised in an orphanage, found solace in the makeshift family he formed there. At the age of 15, tragedy struck when a devil attacked the orphanage, mercilessly killing everyone but Rin. Helpless in the face of the devil's onslaught, Rin witnessed the death of his loved ones and was subsequently damned by their spirits. This cruel turn of events transformed him into a Bane, a cursed being. Now, as the balance between humans and devils teeters, Rin grapples with his newfound identity and the daunting responsibility to navigate the rising tide of bane and devil attacks, hoping to restore order to an unforgiving world.