From the Dark We Came. Pointy Ears & Pointy Teeth, #1

Belar has made lying into an art form. His neighbors know him as a mild mannered music teacher, but to his fellow monster hunters he's a senior agent with one of the best track records in the organization. Werewolves, malignant spirits, and other oddities-you name it, he can find it. And kill it if necessary. But when a vampire shows up in Belar's parlor, his two worlds crash into each other. The vampire is named Cassian, and if he had any sense of decency he would be dead since Belar has already tried to kill him.
Twice. Luckily, Cassian isn't interested in holding a grudge. He wants to hire the hunter. Someone in vampire society wants Cassian dead and they've been using Belar to do their dirty work. Finding the culprit will save them both. Their search for answers takes them through a nighttime world of ancient vampires, demon tailors, and monsters of pure shadow. But Belar hasn't been the only one lying, and enemies and allies are harder to tell apart in the dark.