Night Hunter Series by Robert Faulcon

He had been a quiet family man—devoted to his wife and children, happy in his home, happy in his work. It took just thirty minutes of shattering, obscene violence to transform him into a remorseless, avenging hunter of evil—a savage practitioner and enemy of the occult...Somewhere—somewhere beyond the normal and the good—they had his family. And Dan Brady had to find them. Against him was all the evil of the supernatural—powers he neither knew nor understood... moreHe had been a quiet family man—devoted to his wife and children, happy in his home, happy in his work. It took just thirty minutes of shattering, obscene violence to transform him into a remorseless, avenging hunter of evil—a savage practitioner and enemy of the occult...Somewhere—somewhere beyond the normal and the good—they had his family. And Dan Brady had to find them. Against him was all the evil of the supernatural—powers he neither knew nor understood. Powers he himself would have to learn to use if he were to track down his family in the satanic, preternatural night... less

Determined and remorseless, Night Hunter--a savage avenger of evil--is sworn to destroy the monstrous forces that brutalized and abducted his family. And nothing can stop him . . . not even the guardian of the shrine.

Below London a river flows through the ruins of an ancient temple. A group of children unleashes its unholy secret--and falls prey to the wrath of its guardian. For Dan Brady, their discovery may be a clue to the location of his missing wife and children--and he is prepared to fight to the death.

The sixth book in the Nighthunter series, written by Robert Holdstock under a pen name.