Thanos the Mad Titan plans to destroy Earth in Avengers: Infinity War, but, to do so, he’ll need all six Infinity Stones. That’s kind of a problem right now because no one seems to know where the final Infinity Stone, the Soul Stone, is hanging out. But, wow, do fans of the Marvel Cinematic Universe have some ideas.

The other five Infinity Stones — the Space, Mind, Reality, Power, and Time Stones — are all currently under various powerful beings’ protections and supposedly safe. But, chances are that peace will be shattered soon, since we know there’s going to be an Infinity War. Odds are good that the first battle in the war will involve the still unseen Soul Stone.

That’s why people are so obsessed with the Soul Stone’s location, and why there are so many theories about its location. It’s kind of the key to everything right now, and it’s supposedly just chilling out somewhere in the universe. The question is: where?

Here are crazy 4 theories (and the most likely one) about where the Soul Stone is in the MCU.

4. With Adam Warlock, just like in the comics.

In Marvel’s comics, Adam Warlock, the “Adam” introduced in that after-credit scene in Guardians of the Galaxy Vol. 2, is the one with the Soul Stone (or, rather, Gem), pure and simple.

It was given to Adam by a being known as the High Evolutionary who sort of became a father figure to him. Adam put out the initial rallying cry to bring the Avengers together to stop Thanos from taking all six Infinity Gems for his evil plan to destroy Earth — but it seems unlikely that Adam Warlock will play such a large part in the MCU’s version of Infinity War, especially since Adam’s creation was such an aside.

And that’s not to mention Guardians director James Gunn saying that Adam Warlock will definitely not be involved in Infinity War, making this theory null and void. Sorry, guys.

3. Acting as Heimdall’s eyes.

This theory falls in line with the popular “T.H.A.N.O.S.” theory, which states that the first letter in each of the six Infinity Stones spells out the villain of Infinity War’s name. That part of the theory is a little whacky, since most of the letters line up with the names of the containers the stones are kept in rather than the stones themselves. But we’re here for the Heimdall theory alone, which states that the all-seeing, all-hearing Heimdall (the H in “T.H.A.N.O.S.”) has the Soul Stone.

According to the theory, Heimdall can see across the realms because he has the Soul Stone, which gives his eyes that glowing orange quality reminiscent of Lord of the Rings’s Sauron.

Thor’s Wanda Maximoff-induced vision in Avengers: Age of Ultron depicted his fellow Asgardians, including a blind Heimdall, in Hel. Fans theorize that his vision was foreshadowing that Thanos would tear Heimdall’s eyes out to retrieve the Soul Stone and lay waste to Asgard. Though, it seems Hela will beat him to the whole “laying waste” thing.

2. Behind Odin’s eyepatch.

The Odin theory, specifically from Reddit user RJC2506, suggests that Odin, one of the most powerful beings in the universe, has the powers he does because he has the Soul Stone. Supposedly, Odin is able to imbue that power in the others, which is what charges Thor’s hammer and Heimdall’s visions.

When Thanos takes the Soul Stone away from Odin, bam, Thor loses his hammer — similar to how he does in the trailer for Thor: Ragnarok — and Heimdall loses his eyes, just like in Thor’s vision in Age of Ultron.

1. In Wakanda.

This one’s pretty far-fetched, but some fans theorize that the Soul Stone will make its first appearance in Black Panther, which is set to premiere about three months before Infinity War. As showcased in the Black Panther trailer, Wakanda is one of the most technologically advanced countries in the world but presents itself as a stereotypically low-tech “third world” country. The Black Panther protects Wakanda from the outside world, and some MCU fans think he does so because the country powers its advancements via the Soul Stone.

Sure, an Infinity Stone is probably a great source of clean, natural energy that will most likely never run out, but that doesn’t mean the people of Wakanda are dumb enough to use it that way. In fact, they’re clearly smarter than most residents of the MCU if they’ve elected to stay away from the rest of the world’s problems for as long as they have.

P.S.: There’s a good chance Hela is actually the one in possession of the Soul Stone.

Photos via Tumblr, Giphy, Marvel Entertainment