Board Thread:Questions and Answers/@comment-43328512-20190730013224/@comment-16461120-20190730104527

Previous Valkyrior didn't require the Undrjarn to transform, so it's potentially just an additional part of her ascension and not necessarily the actual catalyst, it's too early to be certain, though I honestly suspect her ascension may be more directly related to her resurrection by the Odin Force during The Death of the Mighty Thor.