Originally Posted by American Maid
Having her turn out to be Hela would be a bit of a strain on continuity, though. For example, there's the story where Sif is in Hel (because some giant made a deal for immortality) and Thor offers his life in exchange for hers. Hela is so impressed by the nobility of the proposed sacrifice that she lets them both go. This was before Sif trained to be a warrior, so it would have taken place at least 900 years before Darcy was born.
I think the movie kind of screwed the pooch by having Thor and Loki apparently be born towards the end of the Viking Age...but then again Thor's Hammer has time travel properties.