This article contains spoilers for Valkyrie: Jane Foster #10.

Loki's coolest secret was teased in Thor: The Dark World. Tom Hiddleston's Loki is undoubtedly one of Marvel's greatest successes. The Trickster God is a master manipulator and a gifted sorcerer, a master of deception who delights in confusing his brother with illusions. Although Loki died in Avengers: Infinity War, completing his redemptive arc, he's being brought back into the MCU courtesy of the Multiverse. However, one of Loki's most intriguing abilities has yet to be explained in the MCU.

The first Thor film revealed he knew secret ways to traverse between the Nine Realms, hidden even from Heimdall's gaze. Using these mysterious portals, he had traveled to Jotunheim and launched an insane conspiracy to gain Odin's approval. Later, in Thor: The Dark World, Thor was forced to break Loki out of prison in order to access these portals. They were able to escape Asgard without using the Bifrost, allowing Thor to fight for the Nine Realms once again. But just what were these portals?

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Over in the comic side of Marvel, Jason Aaron has finally explained the portals. In Valkyrie: Jane Foster #9, Tyr - another of Thor's siblings in the comics - was sent to Valhalla to serve. There, he eavesdropped on the slain and began to scheme. In the old tales of war and conflict, Tyr learned of forgotten magic, secret places, and powerful objects. He discovered how to use the ancient Urdoors, portals between the Nine Realms that had been established by magic lost in the mists of time. Even the eyes of Heimdall - or his comic book replacement Sif - cannot see these doors. The Urdoors allowed Tyr to fashion a plan against Thor, confident his actions could not be discovered.

Tyr Urdoors Thor

The latest arc in Valkyrie: Jane Foster feels like the spiritual successor of Thor: The Dark World, although frankly much improved. Given that's the case, the Urdoors clearly parallel the portals used by Loki; Aaron has absorbed them into Marvel Comics lore, given them a name, and a hint of an explanation of how they came to be. Of course, it stands to reason the Urdoors must have been forgotten by Asgard; had they been remembered, they would have been guarded. Valkyrie: Jane Foster #10 ends with Tyr defeated, of course, and he is left on the run from All-Father Thor. His story comes to an appropriate conclusion when he is found on Jotunheim by Loki, who promises him sanctuary if he will reveal all the secrets he learned in Valhalla. That means Aaron has now given the comic book version of Loki the same abilities as his MCU iteration.

Of course, in the MCU Loki must have learned of the Urdoors some other way. Curiously, in the MCU only Loki and his adoptive mother Frigga have shown any inclination to use magic; it's possible this is a rarity in the MCU's Asgard, meaning Loki was trained by Frigga but otherwise studied prodigiously to master his talents. If that is the case, he could well have looked through dusty books the Asgardians had forgotten, and thus discovered the secret of the Urdoors.

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