It’s a new character, none of the regular guest stars they already have cast, and a character for one episode. Calm down, that’s not Elizabeth Mitchell. And I highly doubt they would add a third sister into the picture of Frozen, that would completely change the sister dynamic between Elsa and Anna. Not to mention: why should such a sister show up this late in the story arc for some fancy ball fairy flashback?
Three sisters going to a fancy ball… maybe the dumb spoiler fairies thought of Cinderella there, aside that they didn’t go the ball together, were only stepsisters and only Cinderella was blonde. Not to mention Anastasia was the younger of the two stepsister, though turned blonde in the Once-ivers, and became Queen in Wonderland… Or, oh, maybe they want to hint she’s coming. I hope not. Whatever.
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