Reyes: Demon of Pain 
 Butterfly: on his chest and neck 
 His curse: Pain, pain and then more pain. He connects cruelty with pain, sex with pain, enjoyment with pain. Any acts of cruelty by him are entirely linked with the gain of just more pain. 
 Danika Ford: Artist 
 Supernatural ability: She has a secret that not even she knows about it (view spoiler)[(She is the All-seeing Eye, one of the four keys needed to find Pandora's box.) (hide spoiler)] 
 Demon Pain and Lord Reyes are Frenemies. Unfortunately they have to share the same body. 
 Luckily Reyes cannot die, because Pain is definitely pushing his limits. Thirsty for hurting, Reyes endures the most excruciating circumstances. 
 He lives for the thrill of pain: 
 ...he jumps from high buildings, 
 ...he cuts his flesh deeply, 
 ...he inflicts self-mutilation, 
 ..he bleeds and bruises and breaks his bones. 
 When he recovers, he starts all over again. No pain is enough pain. 
 Jump, Pain said. Then, more insistently, Jump! Jump! 
 "I told you. Just a few seconds more." Once again Reyes glanced at the ground. Jagged rocks winked in that bleeding moonlight, the clear puddles surrounding them rippling in the wind. Mist rose like ghostly fingers, summoning him closer, wonderfully closer. 
 When Danika is sent as a bait from the Lord of the Underworld's enemies (i.e. the Hunters), the last thing she expects is to be mated to the Lord of Pain and to become one of the Lords' allies. The only thing she wants is to save her family that somehow is tangled in the Lord's war. 
 Reyes will fall in love with Danika with the only way he knows: 
 She clicked her tongue against the roof of her mouth. "Do you want me to hurt you?" 
 She sounded incredulous, yet he realized that's exactly what he'd been pushing her toward. He wanted her to jump from the bed and attack him. He wanted her nails deep in his skin, her teeth deep in his neck again. He wanted pain. From her. Only her. 
 And Reyes and Danika will be smoking hot together! 
 He inhaled deeply, taking every molecule inside his lungs, branding himself with her essence. "This means nothing," she said. "Less than nothing," he lied. "I'll hate myself later." "I hate myself now." She opened her mouth to reply, but he swooped in and swallowed the words. 
 This is definitely the most sensual and passionate book of the series.