A knight of the word - Terry Brooks

Five years have passed since the cataclysmic events which took place in RUNNING WITH THE DEMON. John Ross, a Knight of the Word, sworn to fight the eternal battle against mankind's demons, has moved on. But his years spent saving mankind from the horror of the Void have taken their toll. He has lost his spirit, his belief and now it seems he has lost his magic. Working in a hostel for homeless children, his life is now spent fighting a battle in which he feels he might make a difference.
But Nest Freemark, whose involvement in those events five years ago shattered her childhood, is about to be drawn once more into the mythic world of the Word and the Void. For she learns that John Ross is in great danger from a demon like no other. And if she doesn't warn him in time - and if he isn't persuaded to take up once more his staff of magic - the battle may be lost for ever.