Breaker of Chains by Jordan L. Hawk

Caught between the worlds of human and drakul, Caleb and Gray must make a fateful choice.

Big changes are afoot at SPECTR. John Starkweather, once a hotshot field agent, is now benched. Instead of chasing down demons during Charleston’s biggest outbreak, he’s stuck interviewing exorcists about a previous case. But what at first seems like a busywork assignment takes a darker turn, as John begins to suspect the increase in possessions might not be coincidence, but part of an unseen conspiracy.

The vampire spirit Gray was made to hunt demons and drink their blood. He and his human host, Caleb Jansen, ought to be at the forefront of SPECTR’s field team. But their new partners refuse to let Gray use any of his abilities, let alone actually hunt and fight.

Fortunately, Caleb and Gray have allies outside of SPECTR: the only other living drakul, Drugoy and his host Yuri Azarov. Yuri and Dru live by no mortal’s rules, and they can show Caleb and Gray how to do the same…depending on how far they’re willing to go.

Because breaking the rules comes with a cost, and the price of Caleb and Gray’s freedom may be the life of the man they love.