Big Easy Witch. The Marshal of Magic Series

You have the right to remain magic. Any spell you use can be used against you. After a disaster of a ritual where the Marshal of Magic accidentally unleased twelve demons into the world, he's been tasked with a mission. Hunt them down and stop the witches who summoned them. Twelve tasks, like Hercules, except he's only got a ghost for company. And trouble. Lot's of trouble. When the first witch pops up in New Orleans, the Marshal is sent on a mission.
Stop her. At any cost. Before she starts the end of the world. Fans of fast paced urban adventure with some comedy tossed in are going to enjoy this series.