Maddox: Demon of violence 
 Butterfly: upper left shoulder, wrapping around to his back 
 His curse: He is stabbed every night only to be brought back to life the next day and then the next night he has to die again. 
 Ashlyn Darrow: She works for the World Institute of Parapsychology. 
 Supernatural ability: She hears voices about things that they happened in the past. 
 In ancient time, Maddox is the warrior that killed Pandora and then the box that included all the vicious demons disappeared and all the demons possessed the responsible warriors who opened it. The demons have been imprinted on the warriors' bodies with BUTTERRLY tattoos. All of them have been cursed for thousands of years to suffer. 
 Every night death came, slowly, painfully, and every morning Maddox awoke in bed, knowing he'd have to die again later. 
 Ashlyn is a very confused girl. Totally reliant on the World Institute of Parapsychology and totally tired of hearing voices, she is sent to Budapest to meet the "men" who are rumored to have supernatural abilities. She needs help; the Lords think that she is bait from their worst enemies. And maybe she is. Before they come to a conclusion, lonely Maddox already wants her and already protects her. Their age difference does not really matter. Ashlyn is twenty-four years, while Maddox is a few thousands. 
 "Why? What's she to you?" 
 "Mine," was the only answer he had. "She's mine." 
 Lords of the Underworld is one of my favorite PNR series. I have already reread most of the books a few times. The world building is fascinated. Its mythology that tangles mainly ancient Greek myths, myths from other countries, stories from the bible and the writer's imagination is excellent. 
 I also love the dark humor of the novels. 
 The Darkest Night introduces the story of Maddox and Ashlyn which will only grow stronger in the next books as well as some details of the stories of the rest of the Lords who are waiting patiently their own book and their own love story and salvation.