How Jane Foster became the Mighty Thor in Marvel comics

Dr. Jane Foster will make her debut as the Mighty Thor in Thor: Love and Thunder in just a matter of days. And with Natalie Portman's return as the Mjolnir-wielding Jane come many questions about where she's been since she last appeared in the MCU, how she's wielding Mjolnir, and even how Mjolnir was reforged after it was destroyed during the events of Thor: Ragnarok.

Other than a kinda-sorta cameo in 2019's Avengers: Endgame, we haven't seen Jane on-screen in nearly a decade since 2013's Thor: The Dark World. This makes now a perfect time for a reminder of who is Jane Foster really and why she is so important to Thor's history in Marvel Comics. And even more than that, how she became the Mighty Thor in comic books - and what happened to the original Thor - AKA Odinson - when she did.

The answers to those questions lie in Jane's rich and varied Marvel Comics history both before and after her time as the Mighty Thor - which goes back 60 years as of 2022, with Jane having made her debut in the earliest days of the Marvel Universe.

That may seem like an epic tale in the style of classic Viking sagas - and it is - but we at Newsarama are the exact kind of mythical scholars with the knowledge (and time on our hands) to lay out everything you need to know before Jane Foster becomes the Mighty Thor in Love and Thunder.

Who is Jane Foster?

Jane Foster first appears in 1962’s Journey into Mystery #84, created by Jack Kirby, Stan Lee, and Larry Lieber, subsequently appearing in 52 consecutive issues as the love interest of Doctor Donald Blake, the secret identity of Thor. 

These early appearances are heavy on a love triangle dynamic not dissimilar from the one between Lois Lane, Superman, and Clark Kent. Blake and Foster work together. He's infatuated with her, she's infatuated with Thor, and Blake is unable to explain his secret identity to her. 

Eventually, after several run-ins with supervillains ranging from Loki to Lava Man, Blake decides to come clean about his dual identities but he is warned repeatedly by Odin not to do so, with Odin going so far as to strip Thor of his powers to keep the secret of his identity hidden.

Despite not being able to be honest about the connection between him and Thor, Donald Blake makes an impression on Jane Foster and she falls in love with him - leading Thor to defy his father and tell Jane his secret identity.

Odin subsequently offers Jane Foster a test to earn his permission to marry his Asgardian son - but Jane fails, leaving her bereft of her memories of Thor, and the two separate for a time.

Over the years, their romance would be rekindled when Jane was inadvertently merged with Sif, Thor's Asgardian paramour, similar to the way Thor and Donald Blake were each others' Asgardian and mortal counterparts. This arrangement wasn't fated to last, and Jane once again left Thor, this time marrying a mortal doctor while becoming a physician herself, and even having a child.

Still, Jane and Thor's tale wasn't over - though it was about to take a tragic turn.

Jane and her husband, Keith Kincaid, eventually separated when Thor came back into the picture, with Keith taking custody of his and Jane's son Jimmy. Horrifically, not long after, Keith and Jimmy would both die in a car accident, while Jane would be diagnosed with terminal breast cancer.

And though that seems like the ending of Jane Foster's tale, in many ways, it's actually the beginning.

How does Jane Foster become the Mighty Thor?

In the story Original Sin, a bizarre villain known as The Orb steals and releases all the knowledge accumulated by the all-seeing Watcher in his role as the observer of the Marvel Universe - including all the secrets he knows that Marvel's heroes don't want to get out.

As a result of these events, Thor becomes "unworthy" to lift his own hammer Mjolnir in accordance with the enchantment placed on it by his father Odin, leaving it unattended on the moon - unattended, that is, until a mysterious woman's hand picks it up, with its unseen owner turning into Thor.

The new Thor, whose true identity remained a mystery at the beginning of her own relaunched The Mighty Thor title , would quickly begin proving herself as a worthy successor to Thor Odinson (the original Thor) even aiding him in battle against Malekith (you know him from Thor: The Dark World) when the Dark Elf's monster managed to sever the Odinson's arm, later necessitating a magical Dwarf-made prosthetic. 

However, Thor Odinson's approval of his successor's use of Mjolnir and bequeathing of his own name "Thor" and title as God of Thunder to her to did little dissuade his father Odin's anger that an unknown person - apparently not even an Asgardian - had laid claim to the mantle and powers of Thor.

After Thor Odinson (who hereafter becomes known only as 'Odinson' for some time) passes his name and powers onto the new Thor, readers learn that the new God of Thunder is, in fact, Jane Foster - and she's got an even bigger, more dire secret. 

As it turns out, every time she turns into the Mighty Thor and then reverts to her human form, the progress made in treating Jane's cancer is undone, leaving her in an unending state of terminal illness despite her continued heroism. 

All the while, as Jane suffers in her human form, she also serves as the representative of Earth/Midgard on the Asgardian Council of Worlds, creating a situation of intrigue in which she's secretly part of a group that is also looking to expose her secret life as the Mighty Thor.

Jane Foster Thor in the Marvel Universe

In her time as the Mighty Thor, Jane joins the All-New All-Different Avengers alongside characters such as Ms. Marvel Kamala Khan and Sam Wilson Captain America (even briefly becoming romantically involved with Sam), gets embroiled in the death and rebirth of the Marvel Multiverse in Secret Wars, and even helps stand against the evil Red Skull-transformed Steve Rogers when he attempts to conquer America for Hydra in the story Secret Empire.

Eventually, Jane reveals her identity as the Mighty Thor to Odinson and her fellow Avengers, as well as the rest of Asgard, when she is told by Doctor Strange that just one more transformation into Thor will lead to her death, as the strain of constantly treating her cancer and then undoing the progress made has become too much.

Still, Jane decides to take up the hammer one last time in the story 'The Death of the Mighty Thor', when the nigh-unkillable monster known as Mangog threatens Asgard. And though Jane does ultimately defeat Mangog, Mjolnir is destroyed in the process. The prognosis of her death proves accurate, and she dies upon returning to her human form.

But all isn't lost for Jane, who is resurrected by Thor and Odin, becoming the new Valkyrie with a whole new set of powers, including a set of flaming wings and an Asgardian creation known as Undrajarn the All-Weapon - a bracer that can take the form of several different armaments. She subsequently led a now-concluded Valkyrie: Jane Foster ongoing title.

In return for her resurrection and new powers, Jane offers the last shard of Mjolnir (which is later reforged) to Thor Odinson, restoring his name and mantle as the God of Thunder.

Jane is currently active as Valkyrie and has even teamed up with the original Marvel Valkyrie Brunnhilde as well as others (such as a newly introduced Valkyrie who resembles the MCU version) to reignite the entire order of Valkyries in Asgard.

Jane/Valkyrie also recently rejoined the Avengers, and in the current limited series Jane Foster & the Mighty Thor, she's once again taken up Mjolnir just in time to be on comic book spinner racks for the opening of Thor: Love and Thunder.

Jane Foster Thor in the MCU

Jane Foster is well known to MCU fans as Thor's ex, played by Natalie Portman. Though she sat out Thor: Ragnarok, she's back for Thor: Love and Thunder, and will take up Mjolnir just as she once did in Marvel Comics.

Even with all that confirmed, there's still quite a bit we don't know about how Jane/the Mighty Thor will fit into Love and Thunder. As of Ragnarok, Mjolnir was destroyed along with Asgard, and Asgardians established a new homestead in some coastal hamlet with Valkyrie in charge. 

As for Thor himself, he's got a new weapon, the mighty ax Stormbreaker, and he was last seen jetting off to space in the company of the Guardians of the Galaxy. We know he's reuniting with Jane in Love and Thunder, and it seems they'll both simultaneously be Thor - with Jane wielding a remade Mjolnir, as seen in the trailers.

How does Mjolnir get remade, let alone into Jane's hands? That's the big mystery. It may have something to do with the film's villain, Christian Bale's Gorr the God-Butcher, an alien who, in comic books, lives up to his name by slaying countless gods across the entire cosmos.

And even assuming a connection with Gorr still doesn't necessarily account for how or if Thor: Love and Thunder will adapt the other key aspects of Jane's time as the Mighty Thor.

For now, there's more than enough comic book material to look at for inspiration, including a significant body of evidence to suggest Jane Foster could be Thor's long-term successor in the MCU, even likely joining the Avengers sometime in the future.

Jane Foster is just one of the people to wield Mjolnir. Here are the best heroes ever to lift Thor's hammer.