After Thor becomes unworthy, the hammer choses Jane as its new owner. And that's how Jane becomes the Mighty Thor. And she proves that she is worthy of that title, many times over, with her heroics and sacrifices. Unfortunately becoming Mighty Thor is both a blessing and a curse for Jane.
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.
In a moment of wistful affection for his girlfriend, Thor asked his trusty hammer to always protect Jane, and in doing so unwittingly enchanted Mjolnir to do just that. Just like Thor's father Odin once enchanted the hammer to only be lifted by someone who is worthy, Thor cast a spell that let Jane use its powers.
The chemotherapy is attacking the cancerous cells but Mjolnir doesn't identify the cancer as an illness just as another part of her it needs to protect. Plus chemotherapy really does weaken Jane and make her sick so it's easy to see as an illness on it's own.
In any case, even if the hammer only called to her because of its original oath to the Asgardian prince, Jane proved time and again in Thor: Love and Thunder that she was worthy of Mjölnir as she committed herself to stop Gorr the God Butcher.
Having been adopted by Thor, Gorr's daughter has seemingly become the new owner of the weapon forged to defeat Thanos in Avengers: Infinity War. In Thor: Love and Thunder's ending, Love carried it into battle alongside Thor, who was once again wielding Mjolnir.
Jane does not transform into a god-like being like Thor himself. While she does get to wield his powers while in her Mighty Thor form, she is not permanently altered. Instead, she returns to her weakened human form once she lets go of the hammer.
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.
One possibility is the simplest one available, which would hinge on the rules put on the hammer by Odin's enchantment, which are “Whoever holds this hammer, if he be worthy, shall possess the power of Thor.” Jane was able to take Thor's place in the comics because she became worthy enough to wield Mjolnir, so if the ...
Odin placed several enchantments upon Mjolnir prior to Thor wielding the hammer: This is reflected in the inscription on the side of Mjolnir, which states: Whosoever holds this hammer, if he be worthy, shall possess the power of Thor. For almost the entirety of Marvel continuity, this has exclusively been Thor.
Towards the end of her starring role in Marvel's The Mighty Thor comics, Jane Foster ended her stint as Thor in the storyline Death of the Mighty Thor. In short, Jane's cancer became too severe and, after defeating the villain Mangog, Jane reverted back to her normal self and died in front of her love, Thor Odinson.
The two brothers, clouded by pride and hate, send the Destroyer after Jane, despite the new Thor saving others and fighting for what's right. While she gets thrown around, Thor refuses to back down, which is another reason why Jane is worthy of being Thor.
Like Stormbreaker, Mjolnir also allows Thor to wield thunder and lightning; however, it's not capable of summoning the Bifrost. The magic hammer did develop a power Stormbreaker couldn't, though, and it's able to detach its broken pieces to attack multiple enemies at once, before coming together again.
While Mjolnir felt the need to protect Jane at any cost in Thor: Love and Thunder, the hammer also saw potential in her to do good. Once endowed with the powers of Thor, Jane proved a powerful ally, her kind heart guiding her as she fought alongside Thor and Valkyrie.
Like the MCU version, comic book Jane picked up Mjolnir after she was diagnosed with cancer, and found that every time she turned back into her normal, human self, her cancer was getting worse.
Mysteriously, the broken pieces of Mjolnir, the hammer of the thunder god, transformed her into the Mighty Thor and gifted her the superpowers of Thor, to battle threats internal and external. Wielding Mjolnir herself, she had become a godly protector and a new hero was born!
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.
Most viewers had assumed that enchantment was destroyed when Hela crushed Mjolnir, but it's possible it has endured. If that is the case, the presence of someone who is worthy could have been enough to activate the magic, causing Mjolnir to reform and grant Jane Foster the power of Thor.
In this story, we find three elements of worthiness as far as Mjolnir is concerned: selflessness, sacrifice, and “doing without thinking,” or acting without self-awareness.
In their attempts, Jane tells him, "She won't be alone," signaling the fact that Thor would take the girl under his wing. Finally, before she passes, she tells Thor to keep his heart open, bringing Jane and Thor's story to a heartbreaking close.
History. Torunn is the daughter of Thor and Jane Foster. She's a member of the Next Avengers. When she was a a child she's been looked after by her mother after Thor leaves on an important mission.
Gorr's Daughter Love is Chris Hemsworth's Real-Life Daughter
Jane Foster promises Gorr with her own dying breath that Thor will take care of the child, and Thor, now heartbroken and alone, chooses to adopt the child. But in real life, the actor that plays Love is actually Chris Hemsworth's real daughter.
Conclusion: Thor
Despite Mighty Thor being just as powerful, as she has the powers of Thor, it is Odinson who wins based on fighting experience, hardships, and how, against all odds and even with the loss of Jane, he is still just as strong and eager to keep up the fight against evil.
Jane would later visit Asgard in THOR (1966) #136, as Thor wanted to marry her. Odin granted her immortality, but she doesn't keep it for long. After failing a test created by Odin, she lost her immortality and all her memories of Thor and Asgard.
As Thor's firstborn and strongest child, Magni was a very powerful Norse God, though only regarded as a minor Aesir by Mimir. As such, he is still surpassed by his grandfather Odin, father Thor, uncles Týr, Heimdall and Baldur.