Balefire — Jordan L. Hawk

Whyborne's Endicott relatives have returned to collect on the promise he made to help them take back their ancestral manor from an evil cult. In exchange, they'll give him the key to deciphering the Wisborg Codex, which Whyborne needs to learn how to stop the masters.

To that end, Whyborne, his husband Griffin, and their friends Iskander and Christine travel to a small island off the coast of Cornwall. But when they arrive at Balefire Manor, Whyborne must not only face the evil within the ancient mansion, but the painful truth about his own destiny.