In the Twist - The Wild Hunt, #1

Twelve dead children. An ex-priest with the faith to move mountains. A hunter out of the depths of legend. Together, they must find a way to overcome their pasts and become something entirely new if they are to defeat an ancient evil. David Shaughnessy was content in his life as a police detective in Armata, California. It lacked the visceral, sick thrill that came with exorcising demons, but it was better for him, saner.
Until the night he got called out to a vicious murder in the woods, and met Dallan Jaeger. The older man and Interpol agent is much more than he seems to be, and their connection is immediate, powerful. Trust blooms quickly as they learn to work together to pursue the evil fae responsible for the murders. They must learn to do more than trust each other if David is to fulfill his birthright and claim what was so long denied him.
Only then do they have a hope of catching the killer.in the Twist.