Love
Despite not being a classic love story, this novel's underlying theme is love and its contestants are Callie and her incubus which will later take on a physical form as Liam Doyle. It starts with his visitations to her dream and her wondering what he essentially wants from her and it ends with realizing that she is the one who drew him towards her; he is a demon, a creature of darkness and the reason Callie fell for him is that darkness, she was in reality drawn to him because his darkness spoke to her own.
Magic and myth
It appears as though the novel is a jumble of all sorts of popular mythical and magical creatures. You want fairies, demons, vampires or witches? They are all here, presenting themselves with their historical backgrounds. Considering the time of publication of the novel it is no wonder, as the popularity of this theme was at the rise. There are even allusions to the infamous-considered Twilight and the movie adaptations.
