Inevitable Darkness by Cassandra Lawson

Mitchell has always known he was more than just a vampire, but he never would have guessed that he is the son of a powerful demon. Since learning of his demon heritage, Mitchell has struggled with his identity and his emerging demon power. When a threat emerges that could destroy those he loves, Mitchell must not only embrace his demon side but also learn to control his dark magic.
Among those fighting by Mitchell’s side is a vampire few would count on to have their back. Ruthless and cunning, Abram has proven time and again that he can’t be trusted. Abram will be the first to admit that Mitchell should avoid him, yet neither seems capable of heeding that warning. As they grow closer, Abram is left wondering if Mitchell will be his salvation, or if he will be Mitchell’s destruction.