Bloodbound (Pathfinder Tales)
From the publisher:
Larsa is a dhampir—half vampire, half human. In the gritty streets and haunted peaks of Ustalav, she’s an agent for the royal spymaster, keeping peace between the capital’s secret vampire population and its huddled human masses. Meanwhile, in the cathedral of Maiden’s Choir, Jadain is a young priestess of the death goddess, in trouble with her superiors for being too soft on the living. When a noblewoman’s entire house is massacred by vampiric invaders, the unlikely pair is drawn into a deadly mystery that will reveal far more about both of them than they ever wanted to know.