I'm gonna have to go with Jasnah on this one it immediatey solves one of the bigger mysteries of the last book as well as expands our knowledge of Shademar an equally mysterious place.
Plus you can never go wrong with a Jasnah POV she's such an awesome character and really shows that despite Jasnah being such a intelligent person there are still things that even she underestimates and can't plan for. Hopefully she'll do a better job at taking precautions in the future.