Thailor is a League demon--they're the bogeymen of demons, working in the shadows to keep the city and its inhabitants safe. Sometimes he wonders why he even bothers helping humans when they couldn't care less about demons, but it's what he's paid to do, and he's good at it.
When Chase stumbles on a demon killing another demon, he knows he'll be the only one to care. He tries to intervene, but he's too late, and no matter what he thinks of Thailor, they seem to gravitate toward each other.
When Thailor is there for Chase when he's assaulted, Chase finally gives in. They're fighting against time to save the city's demons from someone who's kidnapping them and harvesting their organs, and as the body count rises, so does the danger for Chase. Thailor promises himself he'll keep Chase safe, but will he be able to?