The Witches' Union is a union of witches.
A seemingly world-spanning organization, the Witches' Union was the result of a number of witches unionizing. The Union issues cards to its members, but, in exchange for unknown, offscreen privileges, imposes regulations upon them, chiefly that they cannot own "mortal money" (a rule whose wording also implies the Union is only open to witches who have mastered immortality).
It is known from the horse's mouth that by 1963, Witch Hazel had been a member of the Union for "two and a half centuries", specifically belonging to its "local 839". On the other hand, it can be inferred that numerous witches did not belong to the Union from the fact that they were observed to seek out and possess mortal money. They include Grimhilde.
Behind the scenesEdit
The Witches' Union is mentioned in the 1963 story TV Trickery.