The Marvel Cinematic Universe has seen some monumental events already by pulling elements from the source material. We've seen a few of Marvel's landmark stories influence its films, including Civil War, Planet Hulk and Infinity Gauntlet. It's always nice to see elements of classic stories in the MCU, from interwoven plot threads to small Easter eggs for beloved characters like Beta Ray Bill. However, what if one story's threads have been lurking in the MCU the whole time? We know that Infinity War left the Avengers in upheaval, and with their numbers and humanity itself reduced by Thanos' snap, there comes a certain vulnerability. If anyone was to strike against the Avengers or even Earth itself, now would be the perfect time. In Captain America: Winter Soldier, it was revealed that Hydra had infiltrated S.H.I.E.L.D. and it threatened to cripple the entire planet.
What if Hydra's infiltration was just the beginning? What if their blueprint was adopted by a far more capable and deceptive enemy? Like the martians from H.G. Wells' timeless War of the Worlds, there are aliens in the Marvel Universe who regard our world with envious eyes. Those aliens are the Skrulls: shapeshifters capable of infiltration on a level previously unseen in the MCU. The Secret Invasion book saw several super-teams and indeed the whole planet deceived, with major players captured and replaced, allowing them to almost seize control of Earth. While there are currently just rumors about Secret Invasion coming to the MCU, what if it has actually already begun? With that sobering thought in mind, let's look at those who may be in our midst already...
15 CAPTAIN AMERICA
Steve Rogers uncovered a dastardly plot by Hydra to enforce their own image of what the world should be in Captain America: Winter Soldier. The star-spangled Avenger found the corruption ran deep and undetected for years within S.H.I.E.L.D. Given his experience dealing with rooting out an unseen enemy, he couldn't possibly be party to an infiltration himself. Or perhaps he is precisely the perfect candidate to be replaced by a Skrull.
We aren't sure what Steve and his Secret Avengers were doing between Civil War and Infinity War, so their intrepid leader may not be Cap at all. He may have been replaced in the time between the two events. In the original Secret Invasion, the Skrulls implanted memories into their sleeper agents, so his bond with Bucky may also have been a fabrication and the events of Civil War an early attempt by the Skrulls to divide and conquer.
14 IRON MAN
In Secret Invasion, Tony was definitely not a Skrull, although he was almost convinced at one point. Their leader, Queen Veranke, managed to infect his suit with a virus that attacked his immune system. While he struggled with the attack on his body, she tried convincing him he was one of the Skrull sleeper agents. Mind games aside, Marvel could have Tony be one of the Skrulls lurking among the heroes.
It's likely the Tony we saw all the way up to his confrontation with Thanos in Infinity War is the real Tony, However, all the way out in space with a reduced number of allies thanks to the snap, MCU's favorite inventor could be captured and replaced on his way home.
Though a newer hero in the MCU landscape, our friendly neighbourhood Spider-Man may not be who he says he is. One of the heroes claimed by Thanos' actions in the culmination of Infinity War, Peter could return as a changed hero. Alternatively, he may not return at all and a Skrull agent could take his place.
Once things calm down after Thanos is defeated, Peter will need formal training. The Avengers opening up their facilities and information to who they believe is their newest member may prove catastrophic. Posing as an unassuming teenager would be great cover for a sleeper Skrull. If they think Peter's green now, wait until he reveals his true nature...
12 BRUCE BANNER
Bruce has been through a lot over the movies he's appeared in for the MCU. During the events on Infinity War, Bruce finds he can no longer call upon the Hulk. Originally, fans speculated it was because he was afraid of Thanos, but in a recent interview the Russo brothers confirmed this not to be the case.
Bruce returning seemingly powerless is very suspicious when we examine it through the lens of a potential Skrull infiltration. He was seen battling the Hulk internally, physically turning green and shouting at himself. However, Skrulls' various abilities would allow them to put on this sort of pantomime as it's easier to replicate the absence of a Hulk than to mimic his raw power.
Another hero who was claimed by Thanos' snap, Drax could come back altered or replaced. With Dave Bautista threatening to quit recently over script issues relating to James Gunn, if things suddenly get to the point where he does leave, having him as a Skrull could be an easy way to execute his departure.
Guardians of the Galaxy Vol. 1 and 2 featured Skrull language on computers throughout, so Drax already exists within an environment to be left open to the aliens. Drax traditionally is far more destroyer-orientated than his lighthearted movie counterpart. This may be because the MCU Drax was replaced a while ago and the Skrull agent portraying him has a better sense of humor.
Scott had the unfortunate luck to become trapped in the quantum realm after the events of Ant-Man and The Wasp. Though he's gotten out before, it may take him quite some time to do so now. In that time, another Scott could show up to aid the Avengers, a Scott with nefarious hidden motives.
Having Ant-Man off the table leaves a very appetizing opportunity to the Skrulls. It also helps that, though he did join Cap in Civil War, the Avengers don't know too much about Scott. Ant-Man being a bit of an unknown would make posing as him quite easy to keep hidden.
9 NICK FURY
Nick Fury's very nature is to deal in secrecy, so having him be a shapeshifter would be quite the reveal. As the MCU's resident spymaster, we'd expect Fury to detect a Skrull rather than be one, which makes the idea even more jarring to the Avengers.
The ideal counter to an infiltration is someone who understands the intricacies of espionage; without Fury, who would the Avengers turn to? Not only would this reveal provide an unexpected foil for the heroes, it would allow Nick's mantle of the authority on spy work to be passed to someone like Maria Hill or even Black Widow.
8 CAPTAIN MARVEL
There has been a lot of talk that the seeds for a Secret Invasion replicating in the MCU could be sewn in Captain Marvel. With Carol's link to the Kree and the importance of the Kree-Skrull War in the Avengers history in the comics, it would make sense to bring them in initially in her film.
This could also explain her absence, as she may be captured and her replacement has been being trained all this time. In the comic, not all of the Skrull Agents were as competent as others; some didn't know everything about who they replaced. In Carol's case, we can imagine that a Skrull that's been training since the '90s (where Captain Marvel is to be set) will be near undetectable.
M'Baku made himself a firm fan favourite during Black Panther, his subplot transitioning him from antagonist to ally was a real treat. It would be heartbreaking to have him revealed as a Skrull but both he and the Jabari are positioned quite well to be used as an avenue for infiltration.
Though part of Wakanda, M'Baku lives separate from the other tribes, remotely in the mountains. The Skrulls could effectively use this to their advantage and cripple Wakanda from within by assuming the identities of the Jabari. Due to their distance from the rest of Wakanda, others may not notice the changes until it is too late.
Though he has returned from life-ending predicaments in the past, Loki's demise in Infinity War had a feeling of finality to it. Thought Loki himself may not return, it's very possible he might come back in the form of a Skrull. Fans like to see Loki, so bringing him back in some capacity may be on the cards, even in this medium.
Not only would this confuse the Avengers, but it may cause Thor a lot of emotional turmoil. This would be a rather manipulative but effective way to take one of the more powerful Avengers off the board. The trickster God is deceptive by nature, a Skrull agent may find the guise fits like a glove.
While Rhodey wasn't taken out of commission following his accident in Civil War, he was shown as having a more reduced role in Infinity War. Though he showed up for the battle of Wakanda, with the initial approach of the Black Order, he was stationed at the Avengers facility, liaising with the government.
This eludes to Rhodey having a lot of downtime, possibly alone in the facility for extended periods. This solitary role makes him a prime target to be exchanged with a Skrull operative. Given his duties and contacts as a colonel, the effects a silver-tongued Skrull could have on the US as a whole is frightening.
Wong, being the companion of Dr. Strange, has access to lots of magical artifacts and arcane knowledge. If the Skrulls want to fully infiltrate our planet, they have to be ready to fight on the magical battlefield too. Wong would be a perfect choice to replace with a sleeper agent given his role isn't always in the limelight.
Though Twitter had a lot of fun making memes about how he peaced-out in Infinity War before things got too hairy, there may be a sinister reason for this. Citing protecting the Sanctum as his reason for leaving, he didn't reappear. This is quite suspicious, as the most precious thing they were to protect (the Time Stone) was with Strange.
3 IRON FIST
Danny Rand provides an entry for Skrulls to the Defenders, as they characteristically infiltrate all super-teams in Secret Invasion. Given that we know Iron Fist season two will take place in K'un Lun, and that traditionally the mystical city only links to the earth every so often, if Danny remains there and cannot return for a while, a Skrull could take his place.
The change may have already happened, however, as in season two of Luke Cage, he is acting differently. Luke himself even comments on it, telling Danny he seems different. Perhaps Danny simply has a new lease on life, or maybe the Secret Invasion is already underway...
Elektra has had a rough time. Her most recent outing saw her used an an agent of The Hand. She could return yet again, but what if it isn't Elektra? In the original Secret Invasion, the opening dialogue about the Skrulls comes with Hank Pym, Reed Richards and Tony Stark being confronted with a deceased Skrull, posing as Elektra.
In order to keep in line with the original story, having Elektra be discovered as a Skrull would not only be a nod to the source material, it would provide a major link to the MCU at large. It would give an idea of the scale of the invasion, reaching street-level characters as well as major players.
Cloak and Dagger saw both of the titular heroes' destinies combined to save New Orleans. In all cases where the chosen two united to save New Orleans throughout history, one of the chosen had to lose their life.
In Cloak and Daggers' case, neither of the two were claimed by the act. However, Cloak seems to retain the weight of losing his brother whereas Dagger seems a lot more at peace with her baggage. This may simply be that she has the resolution she sought, or it may be that the real Dagger was claimed by her destiny and that the reinvigorated Dagger is a Skrull agent...