Avengers: Infinity War - Could Nebula Be The Soul Stone?
At this point, it could probably be ANYTHING.
The Soul Stone and its whereabouts have already been extensively covered across the entire Internet as we all wait the short but agonising period until Avengers: Infinity War is released, with multiple different theories already out there. Even now, more theories are springing up with the latest suggesting Hawkeye might be the Stone or that it might well be one of Thanos' daughters. No prizes for guessing which of those is the more likely.
The daughter in question - for this version of the theory at least - is Nebula, the vengeful former lieutenant of Thanos and Ronan who vowed to take the Titan's head last time we saw her for what he'd done to her. It appeared originally on Reddit and there's certainly something to be said for it, even if it is founded partially on the T.H.A.N.O.S. theory that suggests the vessels holding the Stones spell out Thanos' name (which SURELY cannot be anything more than a part-coincidence).
Anyway, this theory suggests that the original reading of the T.H.A.N.O.S. theory was slightly wrong and the A stands for Amulet (as in the Eye Of Agamotto) rather than the Aether, H stands for Host since the Aether requires a Host to harness its powers and the N doesn't stand for Necklace (which was always a bit questionable) - but rather Nebula.
And as evidence, the Redditor uses this quote:
"My father would have Gamora and me battle one another in training. Every time, my sister prevailed. My father would replace a piece of me with machinery, claiming he wanted me to be her equal. But she won. Again, and again, and again, never once refraining."
So could it be possible that as well as adding bio-tech augmentations to "improve" Nebula, he also used her as a secret vessel for the Soul Stone knowing that it was too dangerous to keep two Stones close together (he already had the Mind Stone, of course) until he had the Gauntlet? The theory goes on to explain how her part will come into play in Infinity War:
"I believe the stone's power can only be harnessed when all the stones are in the vicinity of Nebula, and Thanos will sacrifice her to obtain it once and for all. I also think keeping the Soul Stone in Nebula would be the perfect progression in her character arc, since she has always wanted to be Thanos' favorite child, and when she realises that Thanos has been keeping one of the Infinity Stones in her as a "safe container", it would give her a false sense of comfort and love from her dad, who she has always wanted to impress. I think she will sacrifice herself for Thanos so she can get that recognition, but once she finds out his true motives, she will once again side with the Guardians and Avengers."
There's also a suggestion that Thanos actually bred Gamora and Nebula to play a part in his Infinity Stones plan, with Nebula holding the Soul Stone within her and Gamora set up as a potential Host for the Aether in order for Thanos to extract the actual Stone. He always planned to sacrifice them both, which definitely does sound like him.
Okay, so the whole T.H.A.N.O.S. spelling theory is a little bit silly, but the idea of Nebula being the key has been given something of a boost by the fact that Karen Gillan has recently revealed that Nebula will be absolutely key (and that she had no idea just how much she'd be, as she told ScreenRant recently):
“I had no idea that this was where the character was going. I genuinely signed onto the role thinking it was eight days of filming and then I was going to die in the first Guardians. Three movies later and there’s three more to come out it’s, like, crazy. It’s funny because I read the Infinity Gauntlet, which is what the new Avengers films are based on, as research for my character because it’s her sort of biggest moment within the Marvel comic book world, and then to find out they’re making a double-bill feature based on that, I was just so excited actually because Nebula gets some really cool stuff.”
Could that “really cool stuff” in Infinity War be pointing towards her link to the Soul Stone? It can't simply be a matter of her actually getting her revenge because then Avengers 4 probably wouldn't be continuing the Thanos story. So maybe there's genuinely something in it?