Where to start on responding to all the comments.

This is how Ayra did it. Right as the Night King is looming above Bran, there is brief cutaway to the face of one of his lieutenants. You can see an eye blink, something no White Walker would ever do. Ayra has killed it and using her faceless man skills, was hiding in plain sight. Even then she couldn’t catch the…

The Dragon and the Wolf title refers to Rheagar and Lyanna , not Dany and John. Final will have the big reveal confirmed.