Midnight's Daughter

Dorina Basarab is a dhampir, the daughter of a vampire and a human woman. Subject to uncontrollable rages, most dhampirs are born barking mad and live very short, very violent lives. So for five hundred years, Dory has been fighting to maintain her sanity by unleashing her homicidal tendencies on those demons and vampires who deserve killing. But now Dory's vampire father has come back into her life.
Her uncle Dracula, notorious even among vampires for his cruelty and murderous ways, has escaped from prison, and her father wants Dory to work with the gorgeous vampire dueling champion Louis-Cesare to put him back there. Vampires and dhampirs are mortal enemies, and Dory prefers to work alone. But Dracula is the only thing on earth that truly scares her, and when Dory has to go up against him, she'll take all the help she can get.