Captain Marvel introduced a lot of new ideas and revelations to the MCU, but the most significant -- outside of Carol herself -- might just be the Skrulls. Comic book nerds are hoping that now that the shape-shifting Skrulls are in the picture, it won't be too long before Marvel Studios adapts the Secret Invasion storyline. The comic event featured the Skrulls playing the long game and systematically replacing key super heroes in order to take over the planet.
As to whether the MCU can even do this story is up to debate now that Captain Marvel introduced a more sympathetic version of the Skrulls. However, nothing is ever really off the table with the MCU and so we have to wonder: if Secret Invasion is in the works, what character has secretly been a Skrull this whole time? Someone would have to be a Skrull for the story to have any impact, and it just so happens that we have a few ideas.
Before we begin, here's my rationale for picking my choices:
1. There's no evidence to suggest the Skrulls can also copy superpowers beyond their own natural abilities. Otherwise, they all just would have copied Carol to have an unbeatable army of Captain Marvels. So, only normal humans are options.
2. The character has to make logical sense. If you are trying to take over the world, you're not going to take over a position that has no strategic value.
3. If the Skrulls are taking over Earth, it doesn't make sense to replace a Guardian of the Galaxy or other cosmic characters. That means we're keeping things strictly on Earth.
4. No love interests. It's crossing a very icky line for a Skrull to date anyone while lying about their true identity.
So, who are we looking at?
Thaddeus "Thunderbolt" Ross
This is one of the more obvious and popular candidates, but there's a good reason for that. Thaddeus Ross is the Secretary of State, which means he's in one of the highest seats our government has to offer. The Skrull would be able to lay the ground work and use some political influence to prepare the planet for invasion, like, oh, I don't know...trying to control the Earth's superheroes and influence what they can and can't do. That's where the Sokovia Accords come into play and it could have been "Ross'" attempt to take some big pieces off of the chess board. Plus, there's a big gap in Ross' story. How does he go from being a washed up general getting wasted in the middle of the day to the Secretary of State? Maybe the Skrulls replaced the drunk Ross with their own man and got him a seat in Washington?
The Skrulls are going after all of the Ross'. It makes sense that the Skrulls would want a man inside of the CIA to keep tabs on everything and further advance the invasion. Everett Ross seems to be in a high enough position to hold some sway. Of course, the real reason to go for Ross above all other agents is because of his close relationship to Wakanda, the most powerful country in the world. Controlling Wakanda would be a top tier item for the Skrulls, and Ross has already got the trust of Black Panther and the royal family. It'd be pretty lucky if a Skrull became Ross and THEN got swept up into the Wakanda business, so I think Ross would be replaced after the events of Black Panther.
Erik Selvig has been around since Phase One and his big brain has helped to save the day on more than one occasion. However, he just might be a little too smart. Not only was Selvig able to build a portal machine from the Tessaract but he was also able to nullify the effects of the Aether in Thor: The Dark World. It's possible for a human to be that smart, but it would make sense if he was actually a brilliant Skrull science guy. If he were a Skrull then that means that he was able to study the Tesseract for an unknown amount of time, getting vital data on a potential resource. He also worked closely with the Avengers, putting him in the position of a mole.
This one is admittedly a long shot, but it would certainly be an impactful reveal. For starters, Hank Pym is one of the smartest men on the planet and he keeps a portal to another dimension in the back of a van. He's definitely a worthwhile target to replace. If Hank were a Skrull, that would hit fans right where they live. He's obviously a big character in the Ant-Man franchise and people have grown attached to him. I'm kind of breaking my no love interest rule here because 90% of Hank's motivations are to be reunited with his wife, Janet, but that doesn't stop him from getting replaced after Janet is rescued. The Skrull Hank can then avoid getting too friendly with her. Plus, Hank Pym was a Skrull in the comic book as well.
Maria Hill is a perfect candidate to be a Skrull. She's not had a lot of spotlight but she's recognizable to fans. Hill is also a small enough character where it doesn't break continuity if she was a Skrull the whole time. Iron Man can't be a Skrull because then we've been following a fraud for 11 years, but Hill doesn't have that problem. She's also Fury's right-hand woman and is privy to a lot of information. It's a no-brainer for a Skrull to assume her position to gain intel and influence to prepare for the invasion. The only drawback is that Hill might be too obvious a suspect to be a secret Skrull.
Wakanda is the most powerful country in the world and pretty much dominates in all categories. They have the best technology, the best weapons, the best defenses, and the best warriors. Wakanda already proved it's capable of matching an alien invasion, so of course it would be the number one obstacle to remove for the Skrulls. The best way to do that is to get someone in a powerful position on the inside, and there aren't too many more powerful than the queen. Queen Ramonda has the ear of the king and is privy to all the goings-on of Wakanda. Plus, it would be a major blow to Black Panther to find out his mom was replaced by an alien.
Again, it looks like I am breaking my love interest rule, but I don't think sharing one kiss really counts. Cap moves slow, people! While Sharon Carter's position as a CIA agent probably makes her a suitable target, it's really her proximity to Captain America that makes her valuable to the Skrull. By replacing one of Cap's friends, the Skrulls would be easily able to measure Cap's movements and gain access to his inner circle. Of course, all of this is assuming that Cap makes it out of Avengers: Endgame alive, which seems...unlikely at this point.
War Machine as a Skrull makes a shocking amount of sense when you really think about it. If you were a Skrull, you would probably try to assimilate into the U.S. military. Maybe you also decide to befriend a notable arms dealer and covertly gain access to his cache of advanced weapons. Then maybe you get lucky enough to actually get one of his battle suits all to your own. And if you're going to be a superhero, then you might as well hang out with all of them and join their ranks, collecting intel and weaknesses all the while. It could be that Rhodey was just playing us all this time and rolling with the punches as they come. It would certainly be a gut punch to both fans and Iron Man if this beloved supporting character has been a villain the entire time.
I'm still a little skeptical on whether Marvel should make a Secret Invasion movie after learning more about the Skrulls and their situation, but the people at Marvel are also much smarter than me. Maybe they already know how it would work! If that's the case, this list features some prime choices for secret Skrulls that can make us doubt everything we know. We're still a long way off from a Secret Invasion movie, but the long game is Marvel's specialty.