In The Dark: The Last Mage Book II

In the months since Carter Nash, the Last Mage, stopped the demons from unleashing Hell on Earth, things have changed in the town of McLain, Mississippi. The number of supernatural events has grown and Carter has dealt with them all. He has settled into a relationship with the town's mayor and life is as good as he thinks it can be for an immortal Mage living with a mortal.

Then things changed. A late-night call offering him a large sum of money for a meeting turns into a revelation that vampires actually exist and a quest to aide the vampire nation in its very survival. The situation makes sense to him and he agrees to the offer.

Once he's left town to being that quest, strange things start happening in McLain. Without the presence of the Mage, the few that know the truth about him band together to face this new threat. As they learn more, they discover that something entirely unexpected has come to McLain and only the return of the Mage can keep it from destroying the town and then infecting the world.