Nós nunca saberemos, ela não está no filme. De Entertainment Weekly (aviso, spoilers para Age of Ultron estão nessa página):
Remember when the second trailer came out and there was a mysterious woman disrobing beside a pool of water inside a cave? Everyone was trying to guess who she might be – Maybe Shuri, Black Panther’s sister, or a member of his personal bodyguard corps, the Dora Milaje? Maybe Jacosta, the “female” mechanism Ultron created in the comics as his bride? I spun a whole theory that this woman could be one of the Eternals, who provide a mystical alternative to the problem of how to defeat an indestructible consciousness like Ultron.
Forget all that. Here’s the answer: She’s no one. That is, she’s not in the movie.
Kevin Feige expande isso um pouco ao conversar com Cinema Blend :
That was just the imagery. That was just interesting imagery as part of a dream sequence… It was part of when Thor was looking around at the oddity and the strangeness happening and it was just an image marketing grabbed.
Agora que o filme está nos cinemas, fica claro que isso se encaixa no enredo do lado de Thor. Felizmente, Joss Whedon (escritor / diretor do filme) tem feito entrevistas discutindo algumas das coisas que foram filmadas, mas cortadas da versão final do filme. No Empire podcast , ele disse:
The original scene was that Thor went to speak to the Norn and how it would work was that he’d go in the pool and the Norn possess him, basically, and Erik Selvig asks all the questions, and the Norn, speaking through Thor, give the answers. So Chris [Hemsworth] got to do something different, and he really threw himself into it, and he did a beautiful job, but it wasn’t well regarded by the test audiences and I feel it’s probably largely because it was a rough cut with no effects, but also because it’s something that in a Thor movie would work brilliantly, but in this movie is just a little too left of centre.
Norns sendo similares a (e na Marvel Comics às vezes literalmente as mesmas pessoas que) as Destinos em Mitos greco-romanos; mulheres que supervisionam o destino das pessoas. Parece muito provável que essa seja a mulher misteriosa, uma das Nornas que revelou o futuro através de Thor.
A versão blu-ray de Age of Ultron tem uma versão mais longa da cena. Thor discute a piscina com Erik e entra na piscina. Um Norn possui Thor, e Erik interroga Norn! Thor sobre como vencer Ultron e o futuro. Aqui o Norn explica 'o Infinito Seis', um novo termo para o Infinity Stones, e toca na história do Infinity War que está chegando. Curiosamente, a mulher do trailer não está nesta versão da cena ...