Then again, the writers did tease us for most of a season with a mysterious box that turned out to have a piece of paper in it saying "I know you're Baelfire
Yeah, that was, umm...
I would have even rather it said "I know who your father is..." to make it a little more ominous/mysterious.
But hmmm... "HER"... who major haven't we seen yet? Can't be Maleficent or Evil Queen or Queen of Hearts as we've seen them all... maybe Ursula? Cruella? Madam Mim? Or maybe HER is a princess run amok? Ariel? Tiana? Jasmine? Rapunzel?