the hooded figure

I'm sure it's not going to be Regina in the hood because that would be too obvious and this scheme of her evil half is just a red herring for a more horrifying revelation that Emma didn't see coming. It's hard to imagine who else would be a better shock that isn't part of her family unless it turns out to be an evil twin of one of them the way Regina's dark side separated from her. Who else in her life makes for a fitting adversary to give her impending death a deeper meaning?