Have We Seen The Final Infinity Stone In The Marvel Cinematic Universe? [Fan Theory]

In the Marvel cinematic universe, everything is leading to The Avengers: Infinity War. Right now, the Mad Titan known as Thanos doesn't have any of the Infinity Stones in his possession that will lead to this massive conflict, but he'll inevitably collect them, fit them snugly in the Infinity Gauntlet, and wreak havoc on Earth and maybe even the other realms.

However, as of now we've only seen five of the six Infinity Stones. There's the Space Stone, which is inside the Tesseract and now in Odin's vault; the Reality Stone, which is presumed to still be in The Collector's museum after being handed over by Sif and Volstagg; the Mind Stone, which is on Vision's forehead after being removed from Loki's scepter, the Power Stone, which is locked up at Nova Corps headquarters; and the Time Stone, which is contained in the Eye of Agamotto at Kamar Taj.

So where could the Soul Stone be? One fan theory has an an interesting idea of where we might find the final Infinity Stone.

One of the readers over at ComicBook.com proposes that the Soul Stone might be in the hands Heimdall (Idris Elba). The reader proposes a couple pieces of evidence. First, Heimdall is quoted in Thor: The Dark World as saying he can see all the souls in the nine realms. Surely something called the Soul Stone would allow him to do that. Take that into account with the fact that in Thor's vision of the future in Avengers: Age of Ultron, Heimdall is blind. If that future is in a time where Thanos has obtained all the stones, then that could explain his blindness. Finally, though less convincing, is the fact that Heimdall's eyes are about the same color as the Soul Stone, a shade of orange.

The only problem with this theory is that the reason the Reality Stone, formerly The Aether, was brought to The Collector by Volstagg and Sif was that it was deemed unsafe to keep two Infinity Stones in one place. So that means Odin and/or Thor would have to be oblivious to how Heimdall has his powers of sight. But we've been surprised by the presence of an Infinity Stone before when we learned what was inside Loki's scepter, so maybe it's not impossible. Then again, if Thanos already has to take a stone from Vision, having him do the same thing from Heimdall feels repetitive.

We'll find out at some point over the course of the next few Marvel movies before The Avengers: Infinity War. My bet is that Thor: Ragnarok will reveal the Soul Stone, but we'll find out soon enough.

What do you think?