Jane Foster's death in Marvel Comics has always seemed to be inevitable. Writer Jason Aaron's run has revealed that Jane is dying of cancer and worse still, every time she picks up Mjolnir and transforms into Thor, the effect of Jane's chemotherapy is reversed. The cancer is killing her, and Jane's frail human body cannot survive another transformation. Unfortunately, all this is set against the backdrop of the War of the Realms, and Jane has just picked up Mjolnir one last time in order to fight to save Asgard from Mangog.
This has certainly proved to be a tremendous plot, filled with power and emotion. Jane has been Thor for three years now, and the tragedy of her story is building to a head. But, as effective as this story may be, it's also a flawed one. The fundamental problem is that Jane Foster is Marvel's best Thor, and there's no way the Odinson can take her place again.
Jane Foster is Marvel's Best Thor
It's not unusual for Mjolnir to be wielded by someone other than Thor Odinson. The enchanted hammer may not have survived long enough to be held by anyone other than Thor in the movies, but many other characters have picked it up in the comics. In fact, even Captain America's been able to heft Mjolnir on occasion. But only two of these Thors have really made a mark. The first is Beta Ray Bill, and the second is Jane Foster.
Where Beta Ray Bill is a powerful alien, Jane is remarkable precisely because of her humanity. She's an ordinary human being, one who has lived in the realm of gods, and yet now walks among them. Jane has been challenged every step of the way; the gods haven't taken kindly to the female Thor, and she's even wound up dueling Odin himself. Most remarkable of all, Jane's very humanity has allowed her to tap into Mjolnir in a way even the Odinson never has. She alone learned the secret of the God Storm that lies deep within Mjolnir, granting the hammer its incredible power. In Jane's hands, Mjolnir is no mere weapon; it is an ally in its own right.
Of course, the reality is that Jane's very humanity is what makes her worthy. She is worthy precisely because she knows the world needs a Thor, and is willing to pay the price to be one. Jane is well aware that her mortal body is dying. When she picked up Mjolnir that last time, she knew that it would cost her everything. This is what makes her a true hero; she knows the price, and she willingly pays it.
The Death of Female Thor Is Inevitable
The sad truth is that Jason Aaron's story was always going to end in Jane's death. There simply isn't a satisfying way for even a writer of Aaron's caliber to write himself out of this corner. Aaron can draw it out all he wants, but this story needs to come to a head with Jane's death.
And Marvel understands this. That's why they've drawn a deliberate parallel between Jane Foster's death and that of Captain Marvel. In 1982, Jim Starlin wrote a haunting graphic novel in which one of Marvel's heroes, Mar-Vell, died of cancer. It was a powerful and emotional end to the original Captain Marvel's story, and the impact of that event resonated to the present day; Carol Danvers now bears that title in his honor. But, while there are parallels, the reality is that these deaths are very different.
For Captain Marvel, death came as something of a surprise. He was unaware of his cancer until it was far too late to save him, and Marvel's greatest minds labored in vain to cure him. In contrast, for Jane, death has been a constant companion for the last three years. Fundamentally, Jane has had to decide what would define her; the cancer and her mortality, or the hammer and her heroism. As a result, the simple truth is that - unlike Mar-Vell - Jane has actually chosen this. She is the one who decided to wield Mjolnir one last time, knowing what it would mean for her. Not only has Jane chosen this, but she was always going to do so.