Mjolnir's True Master Has Returned for Revenge on Thor: Theory Explained

 The God of Hammers has arrived, but the true identity of Mjolnir's new wielder may lie in an ancient enemy of Odin who existed long before Thor.

Warning: contains spoilers for Thor #20!

The God of Hammers has revealed itself in the pages of Thor #20 - by Donny Cates, Nic Klein, Matt Wilson, and Joe Sabino - and this new, fearsome foe is not who anyone expected, as it's revealed that Mjolnir, Asgard's mightiest weapon, has been hiding one last secret.

In the pages of Thor, the new ruler of Asgard has retrieved Odin from his self-imposed exile. Together, the godly father and son duo are on the tracks of Mjolnir, Thor's former weapon, which has recently forsaken him to find a new owner. The hammer was created by Odin to be the weapon of Asgard's foremost warrior, and once the Thunderer took up the mantle of All-Father, Mjolnir first started behaving erratically and then disappeared completely. When the weapon resurfaced, it left behind a trail of death and destruction that crossed the Ten Realms, for which Thor is being framed. To maintain the fragile peace created after the War of the Realms, the God of Thunder is hunting for his previously inseparable weapon, while at the same time looking for answers for the prophecy of the "God of Hammers," foretelling the King of Asgard's death.

Until now, there have been no clues about the identity of the God of Hammers, because records of the prophecy have recently been destroyed. However, Loki, Thor's brother and current King of Jotunheim, is able to find what little details are left: the God of Hammers will rise, ignite the Ten Realms, take the last King of Asgard, and then, after destroying everything, reshape the world. Shortly after this revelation, Thor learns that Midgard is also under attack, and more specifically his beloved town of Broxton. Enraged, Thor summons Mjolnir, who appears to be finally answering his commands, only to strike the God of Thunder down. When the enemy appears, it is a being made of pure lightning, and her words leave Thor speechless: "I am the God of Hammers. I am Mjolnir."

It appears then that the hammer was not being wielded by a mysterious enemy, but that after centuries of loyal service, Mjolnir is the enemy. The explanation for this could go back in time, long before Thor was even born. The All-Father Odin faced the God Tempest, one of the primordial titans, beings of ancient and immeasurable power. Odin managed to defeat it by trapping the God Tempest inside a piece of the unique metal called Uru, whose origins were also tied to the elder titans. After that, Odin was able to access the God Tempest's power through Mjolnir, and wielded the hammer to protect Earth as one of the Prehistoric Avengers. According to the story told in Mighty Thor #12 by Jason Aaron, Russel Dauterman, Frazer Irving, and Matthew Wilson, the God Tempest perished over the course of the eons she spent trapped inside Uru. However, the powerful cosmic force proved to still have a will of its own, interacting with Jane Foster during her time as Thor, and then cooperating with Thor in reforging Mjolnir at the end of the War of the Realms. Something, however, seems to have changed.

The God Tempest always resented being trapped inside the hammer, and refused to be tamed even by Odin himself, who had to put protective enchantments on Mjolnir after failing to control its power. Apparently, the truce achieved with Thor was short-lived, and it seems likely that the God of Hammers is the God Tempest emerging from the Uru to take a new form. The God of Hammers, then, could be the residual will of this cosmic being, come to new life after the reforging of Mjolnir to become an entirely new creature that promises to upturn Thor's world and the fragile peace he had achieved.