However, where in the comics Mjolnir is specifically targeting her treatment, in Thor: Love and Thunder, each use of Mjolnir drains Jane's mortal energy. It's gotten to a point where doctors are more at a loss over what's happening to her, and they guarantee she will die the next time she uses the hammer.
While Thor had likely believed there was nothing that could be done to the hammer after Hela destroyed it, the broken pieces of Mjolnir came together as soon as Jane neared them, making the hammer whole again and transforming Jane into the Mighty Thor.
In the comics everytime Jane became Thor, Mjolnir purged her body of toxins. In her case those toxins were the chemotherapy drugs that were at the very least keeping her cancer in check. So everytime she became Thor her condition became worse.
However, the film also implies that the hammer only sees Jane as worthy because Thor unintentionally revised the rules of Mjölnir, giving it the power to protect her. Captain America didn't need anything special for the hammer to see him as worthy – he's able to wield it without issue in Avengers: Endgame.
Sadly, Jane isn't around to be part of Thor's new family. In her human form she's dying of cancer, and although Thor's hammer Mjolnir imbued her with the powers of an Asgardian god, this power proved to be too much for her human body.
The Marvel movie doesn't reveal what Jane Foster quietly says to Thor before she dies, as the Avenger is the only person who hears it, and he doesn't disseminate the message – but Natalie Portman has assured us that it a) was a specific line that she delivered into her co-star's ear, and b) that she never plans to ...
But in the movie, we see that the cancer is getting worse by itself, and we learn that using Mjolnir saps Jane's endurance, to the point where lifting the hammer one last time to help defeat Gorr (Christian Bale) would mean her death.
Stormbreaker has the additional power to summon the Bifröst, allowing Thor to teleport anywhere in the Nine Realms. Screen Rant has identified Stormbreaker as the more powerful of the two, based on this ability, as well as it being a much larger and edged weapon.
When Thor and Jane are still dating, Thor asks Mjolnir to always protect Jane no matter what. This oath alone speaks to the deep connection between Thor and Mjolnir, which rarely finds others worthy of wielding it. To keep its promise to Thor, the hammer calls to Jane telepathically, guiding her back to New Asgard.
In 2025, Mjølnir reassembled itself in order to bestow power on to Jane Foster, who began operating as Mighty Thor. However, Mjølnir's power prevented any attempts to treat Foster's cancer. After Foster's death, Thor regained possession of Mjølnir.
In the comics, Jane hesitates at the gates of Valhalla, not wanting her life to be over yet, until Thor and Odin combine forces to revive her. With a second chance at life, Jane makes her cancer treatments a priority, and goes back and heals up while Odinson takes up Mjolnir and becomes Thor again.
As it turns out, Mjolnir is not simply looking for a warrior, no matter how righteous, but rather the first warrior into the fray. As the last man standing against Thanos – and the one who led the charge once reinforcement arrived – the MCU's Steve Rogers rightfully fits the bill.
Although she was a mortal, Jane Foster was able to gain entry into Valhalla after succumbing to her cancer, as she had died in battle against Gorr the God Butcher. Once her spirit entered the realm, she would be greeted by Heimdall who would thank her for looking after his son Axl Heimdallson.
Thanos can't lift Mjolnir… usually. The parameters for “worthiness” in Mjolnir's enchantment are rather vaguely defined, people tend to debate a lot about what exactly constitutes someone as “worthy”.
With his Infinity Formula that had kept him from aging failing him, Fury was severely weakened but able to incapacitate Thor by whispering something in his ear that immediately made him unable to lift Mjolnir; the Odinson rendered unworthy in an instant.
The ruler of the Norse gods, Odin, uses the hammer – called Mjolnir ("Grinder") by Eitri – and eventually passes it to his son Thor, on the condition that he first prove he is worthy to wield the weapon.
In the climax of Death of the Mighty Thor, Jane succumbed to her cancer after becoming Mighty Thor to defeat the Mangog, but Thor and Odin were able to revive her by harnessing the power of the God Tempest, the cosmic thunderstorm that dwells within Mjolnir.
It was eventually revealed that, while Thor's hammer was still on the Moon, it telepathically sought out Jane. She asked Heimdall to take her to the hammer's location, so he transported her to the Moon. When Jane picked up Mjolnir, she instantly transformed and gained Thor's powers.
Indeed, the hammer calls to Jane (Natalie Portman), who is undergoing chemotherapy to treat Stage 4 cancer. The hammer, which can be picked up by those it deems “worthy,” helps her transform into Thor and gives her health and strength—at least for a time.
Many viewers have pointed out that Thanos was able to lift Stormbreaker without a problem, but this is because the ax isn't enchanted as Mjolnir is. Others believe Thanos lifted Mjolnir (although briefly) and have even argued that he would be worthy of doing so.
While no one besides Thor has been able to truly wield the awesome might of Stormbreaker, Groot was the very first being to hold this weapon when one of his arms became the handle for the mighty axe.
Thor is almost immortal. Jane is a very mortal. So senesce would separate them even if cancer didn't. Early versions (silver age?) of Thor comics had a subplot where Odin was willing to make her a goddess.
Across multiple comic continuities, Thor has had several daughters including Brigid Thorsdottir, Thena Thorsdóttir and Torunn Thorsdóttir, the latter recurring in many iterations. In Norse Mythology, Thor had a daughter named Thrud with Sif.
