Mjolnir could be the cause of Jane Foster's cancer in Thor: The Dark World, objecting to Marvel's treatment of her friend director Patty Jenkins. In truth, her character Jane Foster had never really been given much of a chance to shine in the MCU, restricted to the role of primary love interest for the God of Thunder and turned into something of a "Damsel in Distress" in Thor: The Dark World.
The timing couldn't have been more ironic, because in 2014 Jane Foster became more important than ever before to the comics. Jason Aaron launched a shocking arc that saw Thor Odinson become mysteriously unworthy to wield his enchanted hammer Mjolnir, and instead it was hefted by a mystery woman in his stead. This woman was eventually revealed to be Jane Foster, transformed by Mjolnir's power into the Mighty Thor. Although controversial in some corners of the internet, it was a popular arc, handled with skill by one of Marvel's best writers. Given the fractured relationship between Portman and Marvel, it was assumed this was one story the MCU could never duplicate.
And then, at San Diego Comic-Con 2019, Marvel Studios delighted fans by revealing Natalie Portman will indeed be returning to the MCU in Thor: Love & Thunder. Marvel Studios has changed a lot since the production of Thor: The Dark World, pulled out of the wider Marvel Entertainment group and placed under the sole leadership of president Kevin Feige. The Thor franchise too has been revitalized, courtesy of director Taika Waititi, who reinvented it with Jane Foster's cancer plotline.
Jane Foster's Cancer Plotline Explained
In the MCU, Jane Foster is one of Earth's top scientists, even successfully figuring out ways to detect fluctuations in the fabric of reality. In the comics, though, Jane is actually a nurse - and cancer has always been her worst enemy. Cancer runs in Jane's family, and her own mother died of it when Jane was only young, inspiring her medical career. She's frequently worked in cancer wards, treating some of the most vulnerable. And then, heartbreakingly, Jane was diagnosed with breast cancer herself. She began a long and painful course of chemotherapy - and then she learned Thor had lost the ability to wield Mjolnir.
Jane Foster believed there must always be a Thor, and she chose to wield Mjolnir. She did so at a terrible cost, because every time she transformed into Thor, the magic erased all the chemicals in her bloodstream - but did nothing to halt the cancer, which the hammer considered a part of her own natural body. This was actually why Jane was worthy; she was willing to sacrifice herself in order to give the universe the Thor it needed. Her superhero career meant the chemotherapy was worthless, and as the months ed her human form became increasingly frail. Finally, she came to a point where Doctor Strange advised her one final transformation would be fatal - and when Asgard was threatened by the Mangog, she still claimed the power of Thor, even knowing it would be the death of her.
Thor 4 writer and director Taika Waititi was initially unsure whether he'd run with the cancer plot. "That comics run was a big inspiration," he observed in one interview, "and was an influence on the first few drafts. But at Marvel, we always change everything." To remove that would be to pull out the emotional center of Jane Foster's story as the Mighty Thor, and evidently Marvel has recognized that, because Portman has indicated the cancer plot is staying. But that doesn't necessarily mean Marvel will play this straight.
Mjolnir Could Be The Cause Of Jane Foster's Cancer
It's possible Mjolnir itself will be the cause of Jane Foster's cancer in the MCU. According to the hammer's inscription, only one who is deemed worthy - which appears to refer to willingness to sacrifice yourself for others - can wield Mjolnir. To do so is to gain all the power of Avengers: Endgame. But there may well be a cost for any mortal who uses Mjolnir, as hinted in the recently-published book The Wakanda Files. These are a collection of in-universe records compiled by Shuri, and they include several notes on Mjolnir.
According to files taken from the Avengers, "there is a psychic or telekinetic connection through these weapons that magnify his abilities. This might be why Thor has said on more than one occasion that if one of us were to wield Mjolnir, there is a chance that even holding the weapon would crumble our minds into madness. The psychical effects of the weapon on a mere mortal could be catastrophic." There is no reason, however, that any deleterious effects should only be psychological in nature. To gain the power of Thor is to undergo a physical transformation; to become stronger, more resistant to injury, and to channel lightning through your very body. It is true that Steve Rogers suffered no detrimental effects due to his use of Mjolnir; but he is no ordinary man. He has been transformed by the super-soldier serum, and this may well have had the side-effect of granting him resistance to the effects of using Mjolnir. Furthermore, it is important to he only held Mjolnir on a couple of brief occasions.
This would be a smart way of adapting Jane Foster's story for the MCU, and it would actually amplify the themes that ran through Jason Aaron's popular Mighty Thor run. Handled well, it would demonstrate exactly why Jane is worthy; because she is willing to pay the ultimate price to give Earth its champion. And, of course, this is a superhero story; death was not the end for Jane Foster in the comics, and there's no reason it should be in the MCU as well. Such an arc would be poignant and powerful in Thor: Love & Thunder.
