A Perfect Blood — Kim Harrison

Ritually murdered corpses are appearing across Cincinnati, terrifying amalgams of human and other. Pulled in to help investigate by the I.S. and the FIB, former witch turned day-walking demon Rachel Morgan soon realizes a horrifying truth: a human hate group is trying to create its own demons to destroy all Inderlanders, and to do so, it needs her blood.

She's faced vampires, witches, werewolves, demons, and more, but humanity itself might be her toughest challenge yet.