Darkling

We're the D'Artigo Sisters: Half-human, half-Faerie, we're savvy--and sexy--operatives for the Otherworld Intelligence Agency. But our mixed-blood heritage short-circuits our talents at all the wrong times. My sister Camille is a wicked-good witch whose magic is as unpredictable as the weather. My sister Delilah transforms into a tabby cat when she's under stress. And me? I'm Menolly, acrobat-extraordinaire-turned-vampire. And I'd give my right fang to make my sire pay for killing me. That is, if he doesn't find me first... 

"All over Seattle, humans have been going missing, only to turn up as newborn vampires--the sure sign of a rogue vamp on the loose. It looks like Dredge is to blame. The same sadistic Dredge who gave me my scars, and who may well be in cahoots with the demon Shadow Wing. If so, Otherworld and Earth are screwed. The only way we can hope to defeat Dredge is for me to travel home to Otherworld, where I must face my own demons. Because unless I sever the ties that bind me to Dredge, all hell is going to break loose..."