Who initially safeguarded what later infects Jane Foster?
Eons ago, Bor, father of Odin, clashes with the Dark Elf Malekith, who seeks to unleash a weapon known as the Aether on the nine realms. After conquering Malekith's forces, including enhanced warriors called the Kursed, on their home world of Svartalfheim, Bor safeguards the Aether within a stone column. Unknown to Bor, Malekith as well as his lieutenant Algrim and a handful of Dark Elves escape into suspended animation.
In present-day Asgard, Loki stands imprisoned for his war crimes on Earth. Meanwhile, Thor, alongside warriors Fandral, Volstagg, and Sif, repel marauders on Vanaheim, home of their comrade Hogun; it is the final battle in a war to pacify the Nine Realms following the reconstruction of the Bifröst, the "Rainbow Bridge" between realms, which had been destroyed two years earlier. The Asgardians soon learn that the Convergence, a rare alignment of the Nine Realms, is imminent; as the event approaches, portals linking the worlds appear at random.
In London, astrophysicist Dr. Jane Foster and her intern Darcy Lewis travel to an abandoned factory where such portals have appeared, disrupting the laws of physics around them. Separating from the group, Foster is teleported to another world, where she is infected by the Aether. Heimdall alerts Thor that Foster has moved beyond his near all-seeing vision, leading Thor to Earth. When Thor finds Foster, she inadvertently releases an unearthly force, and Thor returns with her to Asgard. Odin, recognizing the Aether, warns that the Aether will not only kill Foster but that its return heralds a catastrophic prophecy.
Bor