Joseph Delaney 
Brother Wulf: The Last Spook 

Another thrilling and magical adventure from master storyteller Joseph Delaney, set in the multi-million copy bestselling world of The Spook»s Apprentice
We are entering a new age of darkness. Hell has grown in power and neither priest nor Spook can do anything about it. So go home now while you can . . .
Years have passed since Wulf and Tilda vanished from the County. Alice and Tom have given up hope of ever seeing them again — until a terrible enemy from the past forces them to take drastic action, and reach out through time in a bid for help.
Now Wulf faces the greatest and most powerful demon who has ever walked the Dark: the Fiend. He will have to use all his powers — and gather some new ones — to have even a chance of survival . . .