Read Thicker Than Water by Mike Carey and it does not disappoint. Felix Castor the private-eye ex-exorcist has upped his game and seems to be the guy who specializes in demon control. In this book Castor is implicated the murder of a childhood bully. This leads to a story that really gives Castor much greater dimension. The action liberally interspersed with a plot that spends a great deal of time on Castor's back story.
The more we learn about the nature of the ghosts, zombies, and demons that populate this world the greater the dangers that Fix faces with nothing but his tin whistle.