New God Rising by K. Sterling

Their love made him a god. Could it be his undoing?

Professor Lennox MacIlwraith has fought to hang onto his humanity and a life he wasn’t supposed to have. Doomed to be the vessel of an ancient Celtic god, Nox outwitted destiny and death to defeat the Dagda. He found love with his soulmate and has a family again but every day is a battle to suppress his inner deity.
Serve the god, protect the man.
Agent Grady Nelson may have found a higher calling than the FBI but loving a living demigod isn’t for the faint of heart. He’s protected Nox from all manner of evil and now, Nelson faces his greatest challenge. A sadistic and unscrupulous nemesis has discovered that their bond is the source of Nox’s strength… and his greatest weakness.
Gather the hunt.
An unlikely team has formed around Nox and Nelson, ready to settle old scores and prevent a reign of chaos and darkness. What no one can predict or comprehend is the true nature of a god, especially one as capricious as Nox, the new God of Wild Things.
Or what he’d do if anything should happen to Nelson.
Love is powerful enough to create new gods and rewrite legends, but it can turn gods into monsters and inspire unspeakable acts of betrayal. Will Nox and Nelson’s love for each other and their found family of witches, humans, hellhounds, halflings, and demons be enough to save them, or will it be their undoing? Will it be the world’s?