Infinity War's mysterious Soul Stone has inspired many theories over the last several months, each one seeming to get more outlandish than the other. And that's for good reason, since the Russo Brothers and Marvel Studios kept such a tight grip on anything about the film leaking out online. The facts about the rest of the Infinity Stones are all out there, but the Soul Stone continues to be a mystery and according to screenwriters Christopher Markus and Stephen McFeely, a very important part of the Avengers: Infinity War story. This is a SPOILER-free article, so read ahead without fear.

It's no secret that Infinity War is pretty much Thanos' movie. The Russo Brothers have been stating this for months. At one time, there was even an origin story within the movie for the Mad Titan, which was later cut for pacing issues. That being said, the quest to locate all of the Infinity Stones is the guiding thread throughout the story, but screenwriters Christopher Markus and Stephen McFeely didn't want it to feel like Thanos knows where they all are and he's just checking them off of a list. Markus had this to say.

"The Soul Stone was very helpful to us story-wise. When you see the movie you'll see why. We were always worried about Thanos just checking off his shopping list. Right? If I know where everything is, it's pretty predictable."

Infinity War is anything except predictable, which make the allure of the Soul Stone so intriguing for Marvel Cinematic Universe fans. Without giving too much away, the Soul Stone and its whereabouts are a mystery to nearly everybody, which was by design. If Thanos knew where they were all at, that would make for a pretty flimsy storyline. Stephen McFeely explains.

"Also, if he knew where everything is, why is he doing it now? Why didn't he do it during Avengers, if he knew where everything was?"

That's not to say that just because Thanos and the Black Order know where to find most of the Infinity Stones that the movie is predictable, because it's not. Infinity War isn't just about Thanos acquiring those precious stones that make up the universe, it's about his overall mission and the reasoning behind it. The Russo Brothers also recently hinted that viewers will feel empathy for the villain, which is something that actually does come into play for Infinity War. It's not just the superheroes that one feels emotion for.

Depending on what area of the world you live in, Infinity War is either already screening or starting to this evening. MCU devotees have waited a long time for this moment, to see Thanos in all of his glory as well as the location of the Soul Stone, and now is the time. All of the Infinity Stones are important and have their unique place in the story, but the Soul Stone carries the most weight. You can read the rest of the interview with Christopher Markus and Stephen McFeely at CinemaBlend.