Theories off the top of my head:
- Black Fairy is Blue’s Sneaky alter ego
- Black Fairy is Maleficent pre-dragon-shape-shifting-witch days
- Black Fairy is a new character
- Black Fairy is an alter ego of the Wicked Witch of the West
- Black Fairy is a buddy/ally of WWW/Maleficent/Regina/Rumple/Cora/Pan/Shadow
I like #2 the best. Or #1, for obvious reasons!
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