The Reaper - Jackson P. Brown

Amy is an empath, able to sense the auras of the supernatural creatures that stalk London at night. But sorely lacking in knowledge, she spends night after night searching for answers. Gerald is a Reaper - a weapon for hire - on the verge of his Awakening. Of coming into his power and becoming the man his family need him to be. The man they demand he be. When Amy stumbles onto Gerald one night, she notices his strange aura, unlike anything she has seen before. And so, against her better judgement she helps him. In thanks he makes her an offer she can't refuse: become his partner and he will introduce her to a world she has only ever felt the shallow surface of: the underworld. And their first mission together: find a girl who vanished into thin air.