Back in the Hunt by K. Sterling

Your soul is his to take. And he takes that very seriously.

After a string of gutting losses, Everly Wells has given up on life. But a near-death experience and an encounter with a cocky paramedic with glowing green eyes, gives Everly a new reason to live…and powerful allies fighting to keep him out of danger.
Bryn Cadwallader and his twin brother might be descended from the hounds of the Wild Hunt, but there are limits to their powers. When Bryn saves Everly’s life, refusing to take the lost mortal’s soul onwards, he realises darker, stranger forces are at work. Rattled but determined to save Everly’s life, Bryn looks to a very different, but uniquely qualified pair of investigators.
FBI Agent Grady Nelson and Professor Nox MacIlwraith.
To track a foe who uses both modern and ancient means, Nelson and Nox must use their knowledge of the occult and experience fighting crime and evil to help Bryn thwart this new, mystical threat. Can they save Everly, or will Bryn be cursed to an eternity hunting for his lost love?
Formerly listed as The Case of the Curious Cadwallader, Back In The Hunt is a hurt-comfort, paranormal mystery romance. It overlaps with the epilogue of Nelson & MacIlwraith: Moon Murder Mysteries #3, and references some events from the Moon Murder Mysteries trilogy, but can be read as a stand alone.