WARNING: The following contains spoilers for Valkyrie: Jane Foster #9, by Jason Aaron, Torunn Gronbekk, Ramon Rosanas, Jesus Aburtov and VC's Joe Sabino, on sale now.
Jane Foster is no stranger to wielding some of the Marvel Universe's most powerful weapons. During her time as Thor, she displayed Mjolnir's immense power repeatedly as she came into conflict with Odin, the Phoenix Force, and Mangog. She also managed to show off some new tricks with the trusty old hammer as it showcased new abilities within her hand. After serving a pivotal role in the War of the Realms, Jane Foster became Valkyrie and received the Undrjarn, also known as the All-Weapon.
Jane and Thor teamed up with a multitude of other heroes to fight against a dark infection within Midgard. Then, the pair traveled underground to find the source of this cancerous substance. Surrounded by death, Jane and Thor discovered the source to be the decaying corpse of Øde. As Thor recounts, Øde holds a direct connection to the Rokkva, which was the antithesis to life. Deciding to destroy it with Mjolnir, Thor was instead infected and possessed himself.
In their confrontation, Jane Foster: Valkyrie #9 reveals the true scope of Undrjarn's powers, especially in comparison to Mjolnir.
As Jane battles Thor with the hopes of returning him to his normal self, the All-Weapon is a match for Mjolnir in combat. Although Thor wields the might of Mjolnir, Undrjarn's ability to transform allows Jane to keep her distance and to return his blows. After her attempts to reason fail, Jane unleashes a blast that knocks Thor down, with Jane promising him that the next attack will be fatal. Deciding to attack the source itself, Jane transforms the All-Weapon and destroys the corpse of Øde.
Later, Thor's eldest brother Tyr reveals that the All-Weapon's ability to provide its user with whatever weapon they need is its greatest strength. Since the only substance that could stop the infection was the White Wood of Feierheim, Undrjarn transformed itself into that material and essentially brought it back into existence. It turns out Tyr is responsible for the infection; he takes the weapon from Jane and reveals the true scope of his plan.
The seal that imprisons the Rokkva can only be broken with White Wood, so Tyr started this infection to force Jane to transform her weapon into his needed element. As she lies exhausted from the battle, Tyr takes Undrjarn and a still-infected Thor with him to release this force of death onto the universe. With all of the realms under imminent threat, Jane -- now powerless and in her human form -- is rescued by her flying horse as she races to Asgard to mount a defense against this coming attack.
Valkyrie: Jane Foster #9 reveals the full power of Undrjarn and its implications. Outside of its abilities that allow the Valkyrie to see an individual's coming death, it can transform into any substance at all. Now, it appears that her weapon can meet any match and surpass it. It makes sense why so many Marvel villains, including Bullseye and Mephisto, have taken an interest in this weapon. The All-Weapon is even more powerful than Mjolnir. Thor's hammer always has its own complications in any battle, but Valkyrie's All-Weapon can adapt to any situation, which adds to her power.