The Zwarte Madam is a supernatural and presumably immortal witch being from Flemish folktales.
The Zwarte Madam is a supernatural and presumably immortal witch being from Flemish folktales. The word zwarte means "black", and madam is a courtesy title, so in strict English translation, the Zwarte Madam is the Black Lady.
Black refers to her deeds and allegiance, not her appearance. No matter how she is described in the various Flemish folktales, she is always an evil being who works in the service of the devil to help collect mortal souls.
But she does not always work actively to corrupt mortals. The Zwarte Madam sometimes appears beside those who are already doomed to hell, presumably as a sort of advance warning.
Fortunately the Zwarte Madam can be warded off with prayer, the utterance of sacred names, or the sign of the cross.
Since good and evil generally balance each other out in folklore, some folk traditions say that there is a direct opposite to the Zwarte Madam, a good figure known as de Witte Madam or the White Lady. The latter character plays only a small role in folktales and does not seem to be an active participant in the saving or protecting of souls.