Bloodline — Jordan L. Hawk

Between his bullying father and dissolute brother, Percival Endicott Whyborne has quite enough problematic family members to deal with. So when his sister returns to Widdershins asking for help solving the mystery of a derelict ship, Whyborne is reluctant to get involved. Until, that is, a brutal murderer strikes, leaving Whyborne and his lover Griffin no choice but to take the case. The investigation leads them deep into a conspiracy of blackmail, murder, and darkest sorcery. But worst of all are the secrets held within the family itself, one of which will destroy everything Whyborne believed to be true, not only about his family, but about himself.