Death's Mistress — Karen Chance

Dorina Basarab is a dhampir--half-human, half-vampire. Subject to uncontrollable rages, most dhampirs live very short, very violent lives. So far, Dory has managed to maintain her sanity by unleashing her anger on those demons and vampires who deserve killing.

Back home in Brooklyn after the demise of her insane uncle Dracula, Dory's hoping her life is about to calm down. But then she gets some visitors. A friend wants Dory's help in finding a magical Fey relic, and the gorgeous vampire, Louis-Cesare, is desperate to find his former mistress Christine.

Dory and Louis-Cesare quickly discover that the same master vampire Christine is bound to is also rumored to be in possession of the relic. But when the master vampire turns up dead, they realize that there's more at stake than a missing mistress. Someone is killing vampire Senate members, and if Dory and Louis-Cesare can't stop the murderer, they may be next.