Sin is the only female Seminus demon alive who is also master assassin. She has never counted on anyone but herself, including her twin brother Lore. Sin also has a raging libido but can control it because of her tattoo on her right arm called the dermoire. Sin must stay ruthless and show no sign of weakness. But she's been feeling guilty lately because she is responsible for unleashing a virus that's killing wargs, better known as werewolves. If she and her half-brothers, who work at Underground General, a supernatural hospital, can't stop the plague they have named Sin Fever (after her), it will destroy the wargs and may jump to other creatures and perhaps even humans.

Paramedic Conall Dearghul is half-werewolf, half vampire, known as a dhampire. He and Sin acted on their physical attraction once. But as soon as Sin was done with him, she pushed him away. Conall is more than bent out of shape about Sin treating him like dirt, but he can't stop thinking of her. He may just get more than he bargains for when he and Sin team up together to stop the virus.

Not only do they have to stop this deadly virus, but Sin has to stay on her toes since she has been marked for death. And Conall is being forced to take his seat on the Warg Council and fulfill his dhampire duties where he must mate with the females to build up their population. Soon he and Sin are on the run, hiding from those that want to eliminate them both. Sin refuses to become a victim since she has been one before. Conall wants her to lean on him for support and show her that it's alright for her to feel and love.

Sin Undone is the final book in Larissa Ione's Demonica series that fans will not want to miss. Please give me a moment while I mourn because this series is just too good to end. I had joked that Larissa loves to make her heroes suffer (mainly through their physical reaction to sex. The phrase, "blue balls" comes to mind. Larissa is evil like that and I thank her for it)

Sin is haunted by both her past and present, and has no choice but to become cold hearted and sometimes cruel in order to survive. She has killed in the past and will do so again with no remorse. But of course there is more to her than meets the eye. When Conall comes into her life and forces her to reflect on her actions, that's where she begins to forgive herself and those horrendous deeds she was forced to do. She has a true support system from family, friends and even with Conall who wants her as his. Conall doesn't want to own Sin or force her to please him for his own gains. As they come to rely on one another, he sees how special she is, and Sin in turn opens her heart to him. And the passion and sex between is hotter than hot. Larissa Ione writes good sex. Her sex scenes are some of the hottest I've read in a paranormal romance series. You can practically taste the lust and desire Conall and Sin have for one another. These two have great chemistry even as they hurl insults at one another.

Sin Undone doesn't disappoint and makes way for yet a new set of characters and books, in her soon to be released Lord of Deliverance series.

Thank you Larissa for giving us kick ass heroine, alpha, yet protective heroes who make women sigh in lust and a series that has raised the bar for what a paranormal should embody.