War And Darkness (Zombie Apocalypse Series, Book 3‪)‬

Her personal problems are only part of the fight though, Lucifer wants a war and there is no way for anyone to know when the attack will come. They also have a traitor in their midst, a traitor who has been blending in since the beginning. New monsters will be sent to destroy the hotel, demons will ally with them in the fight against the Devil, but even that may not be enough to bring down the King of Hell.