TheRightToArmBears said:
Seems to me like it's Lady Stoneheart.
...Which is a shame, because Lady Stoneheart has to be one of my least favourite parts of the books.
I'm not sure about that. Lady Stoneheart even being a character was twist enough. I don't see anything she could possibly do that would be a bigger twist than her own existence. She hasn't done much of anything yet but we're all
expecting her to show up at some point and f*ck around with whatever's going on (for better or worse). If everyone is expecting it, then it's hardly a twist.
My guess is either Mance Rayder or Myrcella - not necessarily something they themselves do or attempt, but more likely something that happens to them.