Firmament

Two girls murdered, two grieving fathers and one stranger who comes to the men offering a method of undetectable revenge.

Mr Raine guides the men through the executions of the perpetrator and his lawyer after a hung jury sees the murderer freed on bail. Others involved in the conspiracy are also dealt with in the same way during the blood letting.
It is only later that the fathers, Chambers and Osolo, discover Mr Raine carries a power older than time and is actually hunting his nemesis by using the grieving men to draw the other into the open.
This is a story encompassing possession, the frailty of mankind, the power which exists beyond that which our puny minds can imagine and the eventual truth.