Lothaire by Kresley Cole
Lothaire has a plan for assuming the thrones of both vampire races--the Dacian, his mother's people, and the Horde, his father's people--and gaining his revenge for his past torture and neglect and his mother's death. He just needs to get a certain wishing ring in order to remove a human soul from a body that his Bride, Saroya, currently inhabits, and they can rule together after he also makes the body immortal.
As for the human, Elizabeth/Ellie is courageous, smart, funny, and headstrong. She's loyal and family-oriented, and her love for those close to her is her greatest weakness and strongest asset.
And what if Elizabeth is Lothaire's true Bride instead of Saroya? What of the vow he already made to Saroya, who almost makes Lothaire seem like a lapdog by comparison to her own level of evil? And what about the fact that he's slipping closer to complete insanity every time he sleeps?
My favorite part of the book is that the story stays focused on Elizabeth/Ellie, Lothaire, and Saroya without getting caught in outside action and characters, as happens in some other books from this series. I also appreciate that Lothaire is still ruthless, regardless of having found his Bride. This isn't a case of beauty taming the beast and turning him into something domesticated--not even close.
My overall personal rating of Lothaire is an A-.