With Marvel being as popular as it is, there are bound to be millions and millions of fan theories. Whether you're more into the comics or 100% about the Marvel Cinematic Universe, you know and love the characters. Some fans even get to know the characters so well that they can think of the next storyline the character should go through. We think this is really awesome and that the writers should take note. Good news: sometimes they do. We're not saying that fans give the whole story, but we believe some fan theories and ideas have possibly made their way into a Marvel movie or two.

Extreme fans of the comics are also able to guess plotlines that might happen and are often correct. When you base a whole movie universe on superhero comics, there's always going to be at least one fan who knows what's going on. In this article, we will be discussing the top 25 MCU fan theories we love, and that came true! The MCU and MCU fans are great people. If you want the creative freedom to write or draw about your favorite characters, then the Marvel fandom is the place for you. We know a lot of fans weren't ready for Avengers: Infinity War to come out, and a lot are definitely scared concerning the upcoming Avengers: Endgame. Us too. For now, we will just stick to the 2012 Avengers when they were all having fun in Tony Stark's tower, and no one was dust. Good times.

25 Red Skull Came Back (Yeah, Weird, Right?)

This theory wasn't a huge one to most Marvel fans. We assume a lot forgot about him after he was gone in The First Avenger. Red Skull was a really hated character by many Marvel fans and a lot more Cap fans. There were some people out there with the theory he would come back.

Give those people credit because they were right. When Hugo Weaving reprised his role as Red Skull in Avengers: Infinity War it was a shock. He was only there for a couple minutes but it raises a lot of questions about why he's alive and what for... We'll just have to wait for Avengers: Endgame.

24 Stan Lee Is More Than A Cameo

We lost Stan Lee recently and it's probably the most devastating loss of a loved celebrity in 2018. He was the man who created all our favorite heroes (and villains). One thing we all love about Marvel's movies are the small cameos Stan had in each film.

He would often play a bystander with one line and they were always funny. We'll certainly miss him in the future films. Fans speculated that Stan was more than a cameo, and they were right. Stan was actually a Watcher in the MCU, which are a group of aliens who watch over planets and lives. We hope he continues to watch on wherever he is now!

23 The Green Infinity Stone Was There All Alone

Before we knew Infinity Stones were a thing in the MCU, Marvel was already planting them throughout the movies. Then when some fans started to catch on, it was like playing a game of spot the Infinity Stone.

We might not all have known what they were being used for at that time, but when Doctor Strange was released in 2016 a lot of fans assumed the green Eye of Agamotto the Doctor wears was an infinity stone. They were right, Thanos took it in Infinity War.

22 Thor Rules Asgard

We have been waiting for this to happen since the first Thor movie, Thor (obviously) was released in 2011. If you've seen it recently or been a fan since then, you'll know that Thor was about to be King before Loki started letting the Frost Giants in and everything started to go downhill.

Well, fans of Thor and supporters of Thor ruling Asgard got their shining moment in Thor: Ragnarok. It was literally just a moment, but it still counts. While the third Thor movie was fun, it was also really sad. After Odin kind of just floats away, Thor becomes the ruler of Asgard, his home, before it is destroyed just minutes later.

21 Peter Parker's First Cameo

You might think that Peter Parker first entered the MCU in Civil War but a lot of fans would disagree with you. This one hasn't been specifically agreed to in the MCU, but Kevin Feige and Tom Holland have both accepted it, so it is true. We know Iron Man 2 isn't anyone's favorite Marvel film, but if you feel like watching it again try and spot a young Peter Parker.

We're going to tell you anyway. There's a scene in the movie where a young boy in an Iron Man mask stands up to Whiplash's drones and shoots him with a toy blaster. Tony tells the kid he's doing a good job. It has been accepted by basically everyone that this is young Peter!

20 Vision's Purpose Was The Infinity Stone All Alone

Is it just us who preferred Vision when he was just Jarvis, Tony Stark's AI assistant? Sure he came to life and got a physical form in Avengers: Age of Ultron, but we kind of missed Jarvis. When that happened, many people questioned why he became a thing, and why Tony didn't just pop him back as a bodyless voice.

Well, it wasn't a surprise to many that the glowing rock in Vision's forehead was an Infinity Stone. Obviously, that means Vision had to give up his life if they wanted the stone. That's why it was sad when Wanda had to say goodbye in Infinity War (although there are those of us who think they should have just ripped it out earlier on in T'Challa's lab...).

19 Valykrie's Love Life

This one is a lesser known and less considered fan theory, but it still makes some valid points. MCU fans were introduced to a new character, Valkyrie, in Thor: Ragnarok. She was a strong, confident and awesome warrior who was part of a league of awesome warrior women in Asgard.

According to the comics, Valykrie's real name is Brunhilde and she is a pale white woman with blue eyes and blonde hair. The actress Tessa Thompson doesn't look like this at all, so fans decided that she is a different Valkyrie and Brunhilde is her girlfriend. Tessa Thompson has said herself that Valkyrie is bi, so it's very possible.

18 Ant-Man Adventures In Time And Space

After years of watching Marvel movies, you start to pick up the patterns. We're not saying they get totally predictable because there have been so many twists that have shocked us. You do, however, kind of get the gist of what they're doing.

This is why when Ant-Man came out, fans knew the Quantum Realm, which was sold to audiences as a really bad place, would come up again. They speculated that Hank Pym's wife would come back in the second movie. She did, and confirmed that the Quantum Realm can be used for time travel. The biggest theory now is that it will be used to somehow stop Thanos in Avengers: Endgame.

17 Gamora's Fate

Infinity War was a big storm of emotion. After ten years of introducing characters to the world, Marvel told everyone that not every hero would survive. After briefly mourning and being panicked for their favorite characters, people started to speculate on who would stay and who would go.

Once you start to think of it like that, you notice the characters that don't really have storylines coming up and that's why fans knew Gamora would go. Sacrificed by her father Thanos, Gamora's fate was sad. It's a good thing fans guessed it would happen, so they could prepare themselves.

16 The Name Gave It Away...

This one would've been a spoiler if you're super into the Marvel comics, or if you just love Norse mythology (don't lie, we all had that phase). When it was announced that the third film in the Thor franchise was named Thor: Ragnarok, a lot of fans knew everything was going to break down.

Ragnarok in mythology and the Vikings beliefs was the end of everything. Basically, a big fight where everyone's lives ended. The Marvel comics used this as the end of Asgard. That's what happened in the film, at the hands of Thor and Loki's surprise sister, Hela.

15 Planet Hulk

Seeing as there are so many Marvel comics and so many plot lines, the producers and writers for the movies have a lot to work with. We're sure that when an MCU film is planned, they look a few steps ahead to see if it all ties in. Still, with all the possible ways to go, comic fans haven't gotten a Planet Hulk movie.

Well, they actually might have without realizing. In Thor: Ragnarok, we find out that after The Hulk flew away in the jet in Avengers: Age of Ultron, he must have landed on Sakaar, where Thor meets up with him. If you think about it, it includes the gladiator scenes, so this might as well be the hint of Planet Hulk.

14 The Name Gives It Up Once Again

We understand it's probably difficult to keep the plot of the movie under wraps when you're basing it off of a comic book everyone has read (and when you have Tom Holland in the cast).

When Civil War was revealed as the third film in Cap's franchise, basically everyone knew what was happening. You didn't have to read the comics to understand that the poster of Cap and Iron Man facing each other meant there was going to be a fight.

13 We Know Loki Well

Just like most fans guessed Gamora's fate in Infinity War, a lot of fans speculated about Loki. He's been a loved character since his first appearance in Thor. Even though he was the main villain in The Avengers, he still has one of the biggest followings out of all the characters in the MCU.

So people already thought he would go, but when it was said a main character would perish within the first ten minutes of Infinity War, everyone accepted that it was Loki. It was one of the saddest scenes in the MCU, as Thor was trapped and had to watch his only surviving family member be easily taken out by Thanos. We still don't understand why Loki pulled a knife when he has so many abilities, but there's no use crying over spilled milk.

12 Foreshadowing Strange

All the way back in 2014, The Winter Soldier was released. It is one of the best-loved movies in the MCU, and if you've watched it as many times as we have, you'll already know Doctor Strange is kind of in it. As most of us know, the Doctor Strange movie was released in 2016 and was first announced in 2014 with Benedict Cumberbatch in talks to play Stephen Strange.

Obviously, that all happened and he is a great Strange. Before he was cast and everything mentioned produced, Doctor Strange was spoken of in TWS. At the end of the film, it's mentioned that Hydra has been tracking people and Stephen Strange's name is mentioned.

11 Disloyal Mjolnir

This is one fan theory that had been heavily discussed since the first Thor movie came out in 2011. In that film, Odin banishes Thor to Earth and tells the Mjolnir not to move until someone as worthy as Thor picks it up. Naturally, no one can, not even Thor because he had to learn a lesson. He gets it back a better man, but that's not the end.

Ever since people have been speculating on who could possibly pick up the Mjolnir. They knew someone had to. In Avengers: Age of Ultron, a popular fan theory is that when Steve Rogers tries, it moves a little so he can pick it up, but stops so not to hurt Thor. In the end, it's Vision who is able to pick it up and hand it over. It makes sense considering he's basically entirely pure.

10 Bucky

After The First Avenger, a lot of fans were sad that Cap's best friend fell off the train. Fans of the comics were already aware that Bucky came back as The Winter Soldier - a super life-taker. We don't really need to call that speculation because that was probably going to be the basis for the second Cap movie.

Obviously, they were right and TWS was released three years later. For those who didn't know the comics and didn't speculate, the whole unveiling of Bucky on the street was surprising. The 'Who the [heck] is Bucky?' line gave shivers to many fans. Plus super fans who knew Sebastian Stan's (Bucky) contract was signed for nine movies knew he would have to return. This contract also adds to speculation that Bucky may be the new Cap once Chris Evans leaves.

9 The Allfather

By the third Thor film, when Thor still wasn't ruling Asgard, we figured Odin had to go sooner or later to fit that in. Plus Odin wasn't really much of the storyline anymore and with the title being Thor: Ragnarok, everyone suspected his fate. They were right and the last time we see Odin, he finally acknowledges he loves Loki, which was a sweet moment fans had been waiting for.

After a comical moment of learning Loki had put Odin in an aged care home, and an inspiring speech to Thor, it was time for Odin to join Frigga. It wasn't a normal way to go, but a nice one. Odin kind of just turned into glowing orange light and floated off in the distance.

8 Quake

Although this one takes place in a Marvel show rather than film, we're still counting it because as far as we know, Agents of S.H.I.E.L.D is part of the MCU. Skye is one of the most popular characters on the show so there was bound to be some speculation. We found out she was an orphan and her storyline was to find her biological parents.

In season 2, it's revealed her father was a doctor with anger issues. Comic book fans immediately theorized that he was Calvin Zabo, a villain with a daughter named Daisy Johnson AKA Quake. Fans were right once again when it was revealed Skye was, in fact, Daisy and therefore she is the superhero Quake.

7 Minor Characters Turned To Dust

As we said before once it was revealed that a lot of characters were going to be in Avengers: Infinity War and a lot would be taken out, there was so much speculation. We guess Marvel also wanted to surprise fans with a few shocks when it came to characters turning to dust. Naturally, we assumed (and were right) about lesser characters going. Gamora, Loki, Heimdall, and Vision.

What we didn't expect was so many big names to go either. Bucky, T'Challa, Spider-Man (and wasn't that the saddest scene of all?), and Doctor Strange. We do know most of these will come back as certain characters have more movies announced, and actors still have a few movies in their contract. It doesn't mean it wasn't painful to watch. It just makes Avengers: Endgame worse because we know those who go then will truly be gone...

6 Strange Is Involved With Everything

Doctor Strange having the abilities he has, it makes sense that he is integral to the outcome of Avengers: Endgame. As we know in Infinity War, he saw every possible outcome and told Tony Stark there was only one where they beat Thanos. Sadly it must be at the expense of some favorite characters, but there's a fan theory that has to do with Doctor Strange and Ant-Man.

We were introduced to the Quantum Realm in Ant-Man. It's a place where time and space have no meaning. In Ant-Man, Hank Pym says no one should ever go there. In Doctor Strange we see him go to the Quantum Realm. Fans speculate that Avengers: Endgame involves Doctor Strange using the Quantum Realm to go back in time and stop Thanos' plan. We'll just have to see how this turns out.