Avengers: Infinity War - How Will The Soul Stone Be Introduced?

One of the most popular Infinity Stone-related fan theories is the "T.H.A.N.O.S" theory, which speculates that each letter of Thanos' name is the title of an Infinity Stone container.

So far, we've had "T" (Tesseract/Space Stone), "A" (Aether/Reality Stone), "N" (Necklace/Time Stone), "O" (Orb/Power Stone) and "S" (Scepter/Mind Stone). That just lives the letter "H" for the Soul Stone.

As a result, a lot of fans think that the Stone is hidden with Heimdall.

That would make sense; the first letter of his name, his orange eyes, the orange dot at the centre of his chest, and his line in Thor: The Dark World about peering into souls ("from here I can see nine realms and ten trillion souls") all make him a likely candidate.

In addition, the character is shown with white, milky eyes in Thor's vision during Avengers: Age Of Ultron, where he condemns Thor for leading the Asgardians to hell.

Is this a vision of the future, showing what Heimdall would look like if the Soul Stone was taken from him? The lack of orange eyes seems to indicate as much.

Another possibility is simply that Thanos already has the Soul Stone. The last time we saw him was in Avengers: Age Of Ultron's post-credits scene, where he vowed to hunt the Stones down himself. That was nearly three years ago - isn't it possible he's made some progress?

Finally, the slightly less interesting angle to consider is that the Soul Stone will not be introduced until Avengers 4. While that's not any fun to think about (and it would be frustrating to have to wait so long for answers) the possibility is definitely on the table.

Where do you think the Soul Stone is? Do you agree with our Wakanda theory? Sound off in the comments below!