MCU Mysteries We're Still Trying To Comprehend

The Marvel Universe has done an amazing job of linking up numerous films and characters in a fairly cohesive world. We can see that the stories are heading towards something really big involving Thanos and the Infinity Stones, even if we're not 100 percent sure what that will entail just yet. But for all the work Marvel has put into making the stories seem real and fully fleshed out, there are still a few things going on that just make no sense.

The introduction of Quicksilver and the Scarlet Witch in Avengers: Age of Ultron introduced a whole bucket of trouble Marvel can't possibly explain. We, as an audience, know that Disney/Marvel owns the core properties of the Marvel Cinematic Universe. They own the Avengers and their constituent members, and now they share Spider-Man with Sony, but they can't use the X-Men — except Quicksilver, evidently, which is strange. He was even in an X-Men movie.

As far as legalities go, the fact that Quicksilver has been both an Avenger and X-Man in the comics is probably what allowed him to appear in two separate film franchises. You'll notice that in the Avengers, he and his sister are never called mutants, and their father Magneto is never mentioned either. Those things are owned by Fox. But does Quicksilver's existence in the MCU mean that the X-Men and the Fantastic Four share a world with the Avengers? Which other mutants have the same crossover ability? A number of X-Men have fought alongside the Avengers over the years, notably Beast and Wolverine. Is there a way they could ever show up in the Avengers universe? Or if not them, then other less prominent X-characters?

Obviously Loki is a pretty crafty dude — we've seen that enough times already — but a lot of his power comes from an Infinity Stone no one even knows he has. On his own with no super-powered alien staff, most of his power seems to be related to casting illusions. So how does he usurp Odin? It's one thing to pull a prank and make people see things that aren't there. It's another to overthrow the throne of Asgard and take out Odin, who seems to be one of the most powerful beings in the universe. Odin can take Thor's powers away just by saying it. He can imbue Mjolnir with powerful magic to ensure only the worthy can wield it, and he has the ability to send Thor to earth even when the bifrost is all busted. What illusion could Loki have possibly cast to counter all that?

As it stands right now, Loki has the Asgardian throne and we don't know if Odin is alive or dead. Either one would be a heck of a feat, and both require some kind of explanation. Here's hoping it gets cleared up soon.

Throughout Captain America: The First Avenger, the Red Skull uses the Tesseract to power his weapons. It's revealed to be a doorway to another world, and in the movie's climax, we get a glimpse of it. While he's fighting with Captain America, the Skull ends up touching the Cube with his bare hands, releasing the Cube's energy, opening the doorway, and getting sucked in. He's never been heard from again. We know from Thor that the doorway actually opened up to the World Tree, which connects each of the nine realms. Loki also gets sucked into the World Tree, and he survives.

Lingering questions: So where did the Skull end up? We know from The Avengers that the Chitauri were waiting on the other end of the Cube's portal. Is Red Skull a prisoner of the Chitauri? Is he working with them? Did he finally get that painful skin condition fixed?

Marvel created a very elaborate backstory for Ivan Vanko in Iron Man 2. Then, the filmmakers decided to cut most of it, leaving audiences with only brief references. All we know for sure is that Ivan Vanko considered the Starks to be monsters. This is one of several hints that maybe Howard Stark isn't really that great of a guy. We know from Agent Carter that he develops dangerously powerful weapons and sometimes let them fall into the wrong hands. That show also takes place before the elder Vanko has his falling out with Stark. Nick Fury makes a brief reference to the incident, but he's also been known to lie to get people to do what he wants them to do.

Lingering questions: Whatever happened between Howard Stark and Anton Vanko was bad enough that it drove Ivan want to murder several people while trying to kill Tony. What exactly happened that forced Howard to have Anton deported? Did they disagree on the feasibility of developing electric energy whips?

There were many twists and turns in Alan Taylor's Thor: The Dark World, but perhaps the most jarring comes at the end of the film, when it's revealed that Loki had somehow survived his encounter with Algrim, returned to Asgard, and usurped Odin from the throne.

After bringing about peace across the Nine Realms and returning to Asgard, Thor tells his father, Odin, of Loki's sacrifice. Instead of taking his rightful place as King of Asgard, Thor rejects the throne, saying he would rather act as a protector. When he leaves, Odin transforms into Loki, who appears to be alive and well. But how did he get there, and what happened to Odin? These are two questions that elude fans of the Marvel Cinematic Universe. When asked about it, Anthony Hopkins, who plays Odin, told MTV he thought Odin was dead. "I've done two [films], that's enough."

Interestingly, though, in Doctor Strange's mid-credits scene, Thor informs the Doctor that he and Loki are in New York searching for their father and that they will return to Asgard when they find him. Therefore, it seems that Odin's whereabouts will be a plot point in Taika Waititi's Thor: Ragnarok. And since Hopkins has appeared in set photos for the film, it seems like Odin is still alive.

In the early 2000s, Marvel launched an alternate, all-encompassing universe known as the Ultimate Universe, which featured re-imagined versions of the publisher's iconic superheroes. Along with these updated versions came new characters and races, such as the Chitauri — an extraterrestrial race of shapeshifters who were meant to replace the mainstream Marvel Universe's Skrulls race.

Casual moviegoers may recognize the Chitauri as the race of aliens who invaded Earth during the Battle of New York in The Avengers movie. In that movie, Iron Man redirects a nuclear bomb through the open portal above New York, toward the Chitauri's mothership in space. When the bomb detonates and destroys the mothership, all of the Chitauri on the ground suddenly drop dead — why?

The Chitauri are a sentient alien race, who do not utilize a hive mind, yet in the movie, they all die as if they were nothing more than drones. It's a stark difference compared to the comics, and something that remains a mystery to this day.

Throughout the first phase of the Marvel Cinematic Universe, audiences are under the impression that if Tony Stark removed his arc reactor, the shrapnel in his chest would reach his heart and he would die. But in the final moments of Iron Man 3, without any explicit reason, the arc reactor suddenly became removable.

In the film's final battle, Aldrich Killian infects Pepper Potts with the Extremis virus, which she, in turn, uses to destroy Killian. After the battle, in order to ensure Potts' safety, Stark finds a way to stabilize the effects of the virus. He says, "As promised, I got Pepper sorted out — took some tinkering. But then I thought to myself, 'Why stop there?' Of course, there are people who say progress is dangerous, but I'll bet none of those idiots had to live with a chest full of shrapnel, and now neither will I."

What changed between the battle and Stark's surgery that allowed him to remove the shrapnel? Did he find some way to utilize the Extremis virus to repair any damage within his chest? Or was there a scientific breakthrough we don't know about? Perhaps it was just a convenient way to end the Iron Man trilogy, but really, it just seems like a mystery we'll never get the answer to.

Speaking of Infinity Stones, the overarching narrative of the Marvel Cinematic Universe has been leading up to an ultimate showdown between Earth's mightiest heroes and the Mad Titan, Thanos, in Anthony and Joe Russo's Avengers: Infinity War. However, thus far, Thanos has yet to recover one Infinity Stone. Instead, he has been recruiting lackeys, like Loki, Ronan, and possibly Ultron, to use and obtain said Infinity Stones for him. Why?

In The Avengers, Thanos gives Loki a scepter housing the Mind Stone so that the Asgardian could mind-control S.H.I.E.L.D. agents to do his bidding. Then, in Guardians of the Galaxy, Thanos promises to destroy Xandar if Ronan the Accuser obtains the Power Stone for him. And, in Avengers: Age of Ultron (though this point is contentious), it appears that Ultron may have been working for Thanos — evident by the fact that Thanos said in the film's mid-credits scene, "Fine, I'll do it myself."

In all three circumstances, both Infinity Stones — the Mind Stone and the Power Stone — have fallen into the hands of the Avengers, and later Asgard. If Thanos wants the Infinity Stones for the Infinity Gauntlet, why doesn't he obtain them himself? He is more than capable of fighting the Avengers without the Infinity Gauntlet, and he can certainly command his own army. Because, after all this time, it appears that using hirelings hasn't worked out in his favor.

In Anthony and Joe Russo's Captain America: Civil War, T'Challa (Black Panther) is from the country of Wakanda, which hosts a special United Nations session to pass the Sokovia Accords — legislation that allows for the international governing body to regulate enhanced individuals, namely the Avengers. He and his family support the initiative, especially after the catastrophic events of Avengers: Age of Ultron. However, the question of the matter is, at the end of the film, does he still support the Accords?

The session is interrupted by an explosion, one that killed the Wakandan leader (and T'Challa's father) T'Chaka. At the time, the primary suspect was Bucky Barnes. And to exact vengeance, Black Panther hunts down Barnes, whom Captain America aids in escaping. After all, Captain Rogers and a handful of other superheroes aren't exactly onboard with the idea of registering themselves (and their abilities) with the United Nations. But, by not signing the Accords and aiding the Winter Soldier, Captain America became a fugitive.

By the end of the film, Black Panther discovers that Barnes was only a scapegoat, and the real villain is Baron Zemo. After that, he offers Captain America and the Winter Soldier asylum in Wakanda, while the Wakandan scientists search for a cure to Barnes' brainwashing. Since T'Challa is now technically harboring fugitives who are strict opponents of the Sokovia Accords, does that mean he no longer supports the new legislation?