The PC's are appalachian witches. Contrary to popular belief magic has nothing to do with pentagrams, sacred geometry, the names of demons, moon goddesses, willpower, or the Force. Witchcraft is just the know how of various things in the unseen side of nature. It's not supernatural, just the less seen natural. It can't be learned so much as absorbed through one's lifetime. It was brought to America by people from the Old World's Old Country and flooded into the States after the Revolution, taking refuge in the mountains.
The witchcraft community isn't insular, but you have to pay attention to notice them - keep your head to the ground. And the mountains are filled with weyres (they don't transform or speak or nothing, but these are cunning, vicious critters with some weird tricks...) and other strange beasts (like the cockatrice, born by a toad hatching a hen's egg). Witchcraft is powerful in it's mundane nature. It's been used all these years to keep cutlerly sharp, heal sick family members, and make sure the pigs don't get gout. It's the know how of what rocks speak and which can be spoken to, and of the languages to do so. It's a combination of common and unseen knowledge of animals, plants, geology, the weather, you name it. It can be subtle and, with the right personality and combination of skills, it can be righteously asskicking.