The Obscure by Wesley Azzopardi

A diabolical teenager is on the loose in the heart of Ohio. Over the course of five years, the once paradisaical Holmes County witnesses bloodshed, gore and mass slaughters that will change its history forever.

Guilty of his own wrongdoings and having lived through a traumatic childhood, Orion Pettsburgh becomes the canonical definition of a cold-hearted, ruthless murderer, the worst of his own kind. And nobody can ever collar down the monster he's become.