Rogue — Michael Z. Williamson

Kenneth Chinran commanded the elite unit assigned to take out an entire planet in a terrible war. Millions died; billions more perished in the aftermath. One doesn't send a sociopath on such a mission. A sociopath might not stop. Chinran did stop -- but in the process nearly lost his sanity and his soul.

But one of Chinran's men was a sociopath going in. Now he's a trained sociopath with the knowledge and firepower to take out entire tactical teams, evaporate through security cordons and change identity at will. Who do you send after a killer like that? There's only one answer: the man who trained him. The man who made him.