Magesign by Alan Baxter
Three years have passed since Isiah's run-in with Samuel Harrigan and the Devil. He has some time on his hands- a perfect opportunity to track down the Sorcerer, Harrigan's mentor. It should have been a simple enough task, but the Sorcerer has more followers than Isiah ever imagined, and a plan bigger than anyone could have dreamed.
With the help of some powerful new friends, Isiah must track down the Sorcerer and his cult of blood before they change the world forever.
In this long-awaited sequel to the highly acclaimed RealmShift, Baxter once again maintains a breathless pace and blistering intensity, with gods, demons, and humans in the grip of magical conflict. This is dark urban fantasy at its best.