The Last Mage - The Last Mage, #1

Carter Nash is the Last Mage, a powerful, nearly immortal person that has been drawn to the small Mississippi town of McLain in 1987. AT first, he has no idea why the power residing in him has led him there. After a few months, as he's beginning to settle in, events transpire that not only affect him, but also the entire town. A pact that has been in effect for decades finally nears its culmination leading toward the destruction of not only the town, but eventually the entire world.
Carter, with a handful of allies, takes on the greatest challenge he's yet faced - a demon with a plan.