Ah, thanks so much. In a nutshell, the premise of Motherland: Fort Salem is that a witch in Early America named Sarah Alder saves herself and every other witch in the fledgling country by pledging them to the US military. Magic is channeled through their voices.

Abigail's family, the Bellweathers, are High Atlantic - top of the social heap but their distant ancestors were enslaved Africans and I remember either reading or listening to a piece by the show's creator where he stated that some of the strongest magics that Sarah Alder found were in the seed songs of, you guessed it, slaves. They literally form the backbone of magical canon in the US. That and some other stuff around the Bellweathers formed the basis of this ficlet.