Ungar has spent his life hunting monsters. As one of the Holy Relics of the Order of the Light, his purpose is clear: protect humanity, destroy demons, and never compromise. Bellamina is everything he has sworn to oppose. A succubus with her own singular goal: collect his soul. After almost ten years of failure—and mounting pressure by her master to succeed—Bellamina soon discovers her latest prey refuses to fight like any human she has ever encountered. Desperate, she abandons temptation and the blade for something far more dangerous: She asks for his help. When Ungar promises to try and free her from the Pit, he unwittingly binds his soul to an oath that will turn his world upside down. Because while some oaths cannot be broken… Others were destined to change the world.