UPDATE: Read Avengers: Infinity War's Soul Stone Location Explained

Where is the Soul Stone? After a decade of Marvel movies, all but one of the Infinity Stones have been brought into play. The Soul Stone, though, remains a riddle, wrapped in a mystery, inside an enigma. The recent Avengers: Infinity War Prelude comic revealed that the Soul Stone's location isn't even known by the Masters of the Mystic Arts, who were actually aware the Power Stone had been secreted away on Morag. Chillingly, they consider the Soul Stone to be the most dangerous of all the Infinity Stones. It's sure to play an important role in Avengers: Infinity War.

Fans were convinced that last year's Thor: Ragnarok would reveal the Soul Stone's location; it didn't. They then suggested it was the secret of Wakanda's mysticism, but Black Panther didn't introduce the Soul Stone either. Marvel knows fans are excited about the Soul Stone, and they're clearly enjoying keeping it in hiding until the right moment. With Thanos aiming to assemble the Infinity Gauntlet, only one thing's for sure; the Soul Stone has to appear in either Infinity War or Avengers 4. With less than a month to go before Infinity War's release, the Internet is buzzing as never before with theories and speculation about the Soul Stone's location. Here are the best fan-theories in circulation!

RELATED: There's A Reason So Many Infinity Stones Have Been Drawn To Earth

This Page: The T.H.A.N.O.S. Theory

The T.H.A.N.O.S. Theory

Thanos wearing the Infinity Gauntlet in Avengers Infinity War

Let's first discuss a common fan-theory; the T.H.A.N.O.S. theory. This idea posits that Marvel has deliberately secreted the Infinity Stones within objects whose first letters spell out the name 'Thanos.' The Space Stone is in the Tesseract, the Reality Stone is the Aether, the Time Stone is contained within Doctor Strange's "necklace," the Power Stone is in an Orb, and the Mind Stone was originally in Loki's Scepter. If this theory is accurate, the Soul Stone is somehow connected to the letter "H." This has led many fans to speculate that the Soul Stone is tied to Heimdall, or to the Heart-Shaped Herb, or even to "Him" (Adam Warlock).

This is likely a case of fans seeing patterns that aren't there. For one thing, the T.H.A.N.O.S. theory only works if you're extremely specific with some of the Stones (the Tesseract and the Orb, for example), and incredibly general in describing the Eye of Agamotto. Meanwhile, it also assumes Marvel always knew certain objects would become Infinity Stones. The Tesseract, for example, was clearly originally intended to be the MCU's equivalent of the so-called "Cosmic Cube," a reality-warping device in the comics. That's why it's energy can be leached to create weapons in Captain America: The First Avenger and The Avengers. It's essentially been retconned into becoming an Infinity Stone.

There's still a chance there could be something to the T.H.A.N.O.S. theory, though. Marvel does like to acknowledge fan-theories, even declaring some of them to be canon; the most recent example was the decision to retcon the young Peter Parker into Iron Man 2. Given the popularity of the T.H.A.N.O.S. theory, Marvel may decide to respect it by linking the Soul Stone to the letter "H." But it seems a stretch. Don't count on this being the case.

The Planet from Avengers Infinity War

The Soul Stone Is The Planet Titan

The Infinity Stones are cosmic items, and they can take many forms and sizes. In the comics, for example, the Power Stone is currently a massive object guarded by the Nova Corps and the Guardians of the Galaxy. Is it possible that the Soul Stone is actually a planet?

The Infinity War trailer opened with a glimpse of a mysterious orange planet, and fans suggested this was the Soul World. That theory has since been disproved; Marvel have confirmed that it's actually Titan, and it seems the film's second act is set on Thanos's homeworld. Thanos would presumably know if his devastated homeworld was actually an Infinity Stone, and he'd surely aim to collect that one first - as Titan is uninhabited, the Soul Stone would be without defenders. This seems pretty unlikely.

Read Theory in Full: Did Infinity War Trailers Already Reveal The Soul Stone?

The Soul Stone Is Lost In The Mists Of Time

It's possible the only way Thanos can retrieve the Soul Stone is by traveling back in time to when it's location was last known. Thus Doctor Strange's Time Stone becomes the key to finding the Soul Stone. The Soul Stone could perhaps be found in the distant past of Thanos's homeworld; if an Infinity Stone was once on Titan, it would certainly explain how Thanos learned about them. Art in the Avengers: Infinity War Prelude hinted that the Soul Stone would be associated with the cosmic in some way - and showed a ringed planet. Titan of course, is a moon of Saturn, so that would fit as the Soul Stone's last location.

This is a fun theory, and it has the advantage of fitting with the overall structure of Infinity War. It also neatly explains why the Soul Stone hasn't been seen to date. After acquiring the Soul Stone, Thanos will presumably return to the present with it, meaning it was essentially outside of time for millennia.

Read Theory In Full: Avengers Theory: Thanos Needs Time Travel To Find The Soul Stone

Tony Stark Is The Soul Stone

This is perhaps the most out-there idea of them all; that the Soul Stone is actually a person, and in fact is Tony Stark! The main piece of evidence is a series of promotional posters, each showing a hero and the Infinity Stone they're most strongly associated with. When it comes to the Soul Stone, it's in the same poster as Iron Man.

RELATED: Avengers Theory: Why Thanos Is Only Attacking NOW

The idea isn't without some sort of precedent, though. Over in the comics, Howard Stark and his wife struggled with childbirth, and it took the help of a rogue Recorder to allow their child to be born. This child was genetically programmed to be the solution to humanity's greatest need, to prepare humanity for the day when powerful alien forces would attempt to conquer the Earth. It's possible Marvel could heavily adapt this plot, with the Soul Stone being given human form, and the Starks bringing up the infant as a defender for Earth. (In the comics, it turned out the "real" Stark child was kept secret, and Tony was adopted as a ruse to hide his brother Arno from the Recorder.)

In reality, the only evidence for this theory is a single marketing poster. Given Robert Downey Jr.'s value to the Avengers franchise, it's hardly a surprise that Marvel would choose to include Iron Man on one of the images. And, unlike all the other Infinity Stones, the Soul Stone isn't associated with any hero. This is probably just a coincidence, even if it has generated some entertaining fan-theories.

Some fans have suggested that the true "soul" of the Avengers is actually Steve Rogers, and that - should the Soul Stone be a person - it should be Rogers. But there's no evidence at all for this theory... yet.

Read Theory in Full: Does This Avengers: Infinity War Art Reveal Who Holds the Soul Stone?

Welcome to Wakanda

Another popular fan-theory is that the Soul Stone is actually in Wakanda. It was contained within the Vibranium meteorite that impacted the African continent 2.5 million years ago, and the Soul Stone's power is what has mutated Wakandan vegetation. This neatly explains why ingesting the Heart-Shaped Herb could give access to the Ancestral Plane - and the Heart-Shaped Herb is orange, after all.

RELATED: Every Major Reveal From The Art Of Black Panther Book

It's true that Black Panther didn't introduce the Soul Stone. "Wakanda already has its thing," director Ryan Coogler explained, "which is Vibranium. For us, that was special enough, so to throw in something like another special thing didn't feel right." But that doesn't mean the secretive African nation couldn't still be hiding the Soul Stone, of course; it could easily be hidden within the Hall of Kings, a sacred object that was never seen in Black Panther. According to this theory, Thanos's invasion of Wakanda is to acquire both the Mind Stone and the Soul Stone. While it seems sensible, the theory does seem a little anticlimatic. The truth is probably rather more dramatic.

Read Theory in Full: Black Panther May Reveal The Final Infinity Stone

Heimdall (Still) Has It

Heimdall frowning in Thor: Ragnarok

One of the oldest fan-theories is that the Soul Stone is the source of Heimdall's powers. After all, his abilities are associated with the color orange, and he claimed to be able to see "every soul" in the Nine Realms; meanwhile, a vision in Avengers: Age of Ultron showed Asgard's watchman blinded. What's more, Heimdall seems to be one of the characters to die when Thanos attacks the Asgardian refugees. Action figures have teased that Thor will wind up in possession of Heimdall's trademark blade, surely an ominous sign. Is it possible that Thanos will acquire not one, but two Infinity Stones when he and the Black Order attack the Asgardians?

As popular as this fan-theory is, it's not particularly persuasive. Thor: Ragnarok reinforced the idea that Asgardians simply have powers because they're gods; it abandoned any attempt to explain Thor's powers away with pseudo-science. The reality is that Heimdall probably has powers simply because he's an Asgardian. Meanwhile, it's worth remembering that Heimdall himself insisted that it was unwise to keep more than one Infinity Stone on a world. It seems unlikely Asgard would have kept the Space Stone had Odin known there was already an Infinity Stone in his Realm. As for Heimdall's likely death in Infinity War's first act? With Thanos and the Black Order attacking, it would be surprising if some of Asgard's defenders didn't die.

The Secret of the Sovereign

Adam Warlock Cocoon in Guardians of the Galaxy Vol 2

Guardians of the Galaxy Vol. 2 introduced viewers to a race known as the Sovereign, who clearly possessed powerful technology. Sovereign are genetically engineered beings, created to "perfect" their race. They're also noted for developing powerful cosmic batteries, which they guard fiercely. These batteries emit an energy that actually draws inter-dimensional creatures to Sovereign territory, and a handful of them were powerful enough to destroy a Celestial.

Both S.H.I.E.L.D. and Hydra were able to draw off Tesseract energy in order to power weapons, so there's no reason the Sovereign couldn't have done something similar with the Soul Stone. That would neatly explain why these "batteries" were so potent. What's more, at the end of Guardians of the Galaxy Vol. 2, the Sovereign's High Priestess Ayesha created a new being - Adam, clearly the MCU version of Adam Warlock. He's strongly associated with the Soul Stone in the comics.

RELATED: Is Adam Warlock the Main Antagonist Of Guardians Of The Galaxy Vol. 3?

This is certainly an entertaining idea, but it seems unlikely. Both Infinity War and Avengers 4 already have a lot of characters and concepts in play, without adding the Sovereign into the mix. Meanwhile, James Gunn has insisted Adam Warlock himself won't appear until Guardians of the Galaxy Vol. 3 at the earliest.

Odin sits with Thor and Loki in a green field in Thor Ragnarok

The Soul Stone Is In Norway

Spinning out of Thor: Ragnarok, some fans theorize that the Soul Stone is in Norway. The evidence is that, when Odin dies, it's in a flare of orange light. He's then able to enter Thor's mind in dreams and visions throughout the film, suggesting he isn't truly dead - his soul has been absorbed by the Soul Stone. This theory would also fit with an Easter Egg back in Iron Man 2, where S.H.I.E.L.D. was monitoring Norway as a "hot spot."

While this is an interesting theory, it just doesn't seem likely. Thor: Ragnarok embraced the supernatural like no other Marvel movie before it (even Doctor Strange explained it away through concepts of quantum mechanics and the like). And orange simply seems to be the color associated with the soul in the MCU. Finally, it's worth remembering Odin was originally going to die in New York. That's why the early trailers showed Mjolnir destroyed by Hela in a back-alley in New York; test screenings made director Taika Waititi reconsider, and he switched locations. "It was such a bummer seeing the great king of Asgard stuck in New York," he explained. "We preferred the idea he'd be in some mystical Norse environment." If the location of Odin's death was important enough to be a hint to an Infinity Stone, Marvel would surely have been wary of switching it up with so little thought.

RELATED: Thor: Ragnarok's Deleted Scenes Hide Odin's Original Death

A Sacrifice Of Love

One fascinating fan theory holds that the Soul Stone can only be obtained through a sacrifice. In the comics, the Soul Stone hungers to consume souls, and it would certainly be fitting if Thanos had to sacrifice someone - say, someone he loved - in order to gain possession of the Soul Stone. The Infinity War trailer included flashback scenes to when Gamora first joined Thanos's Black Order, and showed a surprisingly tender moment between the Mad Titan and his adopted "daughter." Could Gamora be Thanos's sacrifice?

RELATED: Thanos' MCU Origin & Motivations Are Different from the Comics

It's worth noting that this doesn't mean Gamora would actually die, and thus be written out of Guardians of the Galaxy Vol. 3. Souls consumed by the Soul Stone live on inside it, in a realm known as the Soul World. They can even escape - and Gamora is one of the few to have successfully escaped Soul World in the comics.

This theory is a difficult one to evaluate. It certainly seems plausible, and would explain the flashback sequences. What's more, it would also fit neatly with comic book lore, with Gamora believed dead - only to ultimately return, freed from Soul World. This theory has been doing the rounds on 4chan for some months, with claims that it's actually a spoiler, but there's little evidence for this claim.

Thanos Already Has the Soul Stone

In the comics, the Infinity Stones are drawn to one another. To bear one Infinity Stone is to more easily locate another; that may be why Thanos gave a precious Infinity Stone to Loki in The Avengers. If Thanos did possess the Soul Stone, he could use it to track down the other Infinity Stones, making it far less risky to give the Mind Stone to an underling.

It's true that this is the simplest solution. But it's important to note that trailers, TV spots and interviews have given no hint that Thanos already possesses the Soul Stone. It's possible Marvel is concealing this (perhaps using CGI to remove the Soul Stone from the trailer images), but it seems unlikely. After all the buildup, this solution would be pretty anticlimactic.

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So far, every fan-theory has seemed flawed. The Soul Stone's location remains a mystery, but it's one that Infinity War will likely explore. If that's the case, in just a couple of weeks' time, fans will finally have an answer to the question of the decade; where is the Soul Stone?

MORE: Avengers: Craziest Fan Theories About Infinity War

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