Warning: massive SPOILERS ahead for Avengers: Infinity War! Read ahead at your own risk!
If you have seen Avengers: Infinity War, then you already know the devastation that occurs. Thanos snaps his fingers, unleashes the full power of the Infinity Stones and wipes out half of all life in the universe. The Avengers and Guardians of the Galaxy ranks have been depleted, which means there's room for other characters to enter the equation.
We already know that characters like Hawkeye and Ant-Man are expected to show up, but that raises other questions about the side characters that we may see. On that note, and with less than a year to go until Avengers 4's May 3, 2019 release date rolls around, we're diving into the extended Marvel Cinematic Universe roster to figure out which MCU characters could make surprise appearances in the final Phase Three movie. We have pulled out 12 of the most likely candidates, so let's get started with one of the MCUs most beloved personalities.
One of the men who started it all, Phil Coulson has been a fundamental element of the MCU ever since his first appearance in Iron Man. The character was seemingly killed in The Avengers, but as any fan of Marvel TV will tell you, he lives on as an Agent of S.H.I.E.L.D. We already know that Coulson will return to the silver screen side of the Marvel Cinematic Universe next year when the 1990s-set Captain Marvel debuts in March, and with so many different plot threads coming to a head two months later when Avengers 4 debuts, it would seem to make perfect sense to give him a scene in the final Phase Three movie. After all, with Nick Fury and Maria Hill gone, Coulson is all we have left.
This one seems like a long shot, but stay with me. Earth's Mightiest Heroes took a serious beating during the events of Avengers: Infinity War, and a major attack took place in New York City. Even if the film side of the Marvel Cinematic Universe never acknowledges the existence of The Defenders heroes, the fact of the matter is that they still exist in this world. Given how desperate our heroes look at the end of Avengers: Infinity War, it's hard to imagine that characters with the fighting skill of Daredevil and Iron Fist or the raw power of Jessica Jones and Luke Cage wouldn't be welcomed into the fold. If ever there was a time to bridge the gap between film and TV, it's right now.
Valkyrie was one of the coolest standout players during the events of Thor: Ragnarok, but she was nowhere to be found when Thanos attacked the Asgardian refugee vessel in Avengers: Infinity War (the implication being that he let the hard-drinking warrior live). Thor Odinson was able to bring her out of hiding during their last adventure, which saw her re-adopt her old mantle as one of Asgard's greatest warriors. With the single greatest threat ever to face the universe looming, it seems logical to assume that Thor could once again bring her back to pad the ranks of The Avengers and add another power player to the roster. Beyond that, maybe she will finally be able to coax Hulk out of Banner?
Peggy Carter is an interesting character to examine because there are several different ways for the Marvel Cinematic Universe to bring her back in Avengers 4. One way would be for us to see yet another hallucination, not unlike the one seen in Avengers: Age of Ultron. However, another viable option would be for us to see Steve Rogers actually go back in time to be with Peggy Carter in World War II and get that dance that they talked about before he crashed Red Skull's plane into the Atlantic Ocean. With the Time Stone in play, pretty much anything is possible, which means death is not enough to stop Peggy from making her way back to the Marvel Cinematic Universe.
There's a reason why Hawkeye didn't battle alongside The Avengers in Avengers: Infinity War. He became a full-blown family man and was retired with his wife and kids. Alas, we already know that Avengers 4 is going to see Hawkeye return to battle (possibly under the name Ronin this time around), which means something will likely have to happen to his family in order for him to pick up his trusty bow once more. We don't necessarily know if this means Laura Barton or one of his kids will die, but we generally expect to see something heartbreaking happen on the Barton family homestead, which will ultimately pave the way for Clint to come back.
The Ant-Man corner of the Marvel Cinematic Universe will definitely receive more exploration now that Avengers: Infinity War is in the rearview. Scott Lang and Hope Van Dyne will finally team up in Ant-Man and The Wasp later this summer, and the assumption is that they will then go on to join The Avengers in Avengers 4. However, if Hank Pym survives the events of Ant-Man and The Wasp, it would seem reasonable to assume that he may show up to lend a hand as well. Remember, Hank isn't just a former hero in his own right; he's also a brilliant scientist with access to the Quantum Realm. He could be an invaluable partner in the coming battle.
Despite the fact that so much of Avengers: Infinity War takes place on Black Panther's home turf, there are a few key Wakandan members of the Black Panther cast missing. Chief among these absent characters is Nakia, who is nowhere to be found when the Black Order and the Outriders show up to lay siege to the African nation -- which makes a certain degree of sense, as she's a globetrotting spy. That said, despite the logic behind her absence, Nakia is a fundamental element of the Black Panther lore in the Marvel Cinematic Universe, and it only seems logical for Avengers 4 to potentially find a way to include her and deal with the fallout of T'Challa's untimely demise.
Another Phase One mainstay, Happy Hogan has featured prominently in every stage of the Marvel Cinematic Universe thus far, albeit with a reduced role as the years have gone by, as Jon Favreau has become increasingly busy elsewhere. Happy's most recent appearance in the MCU came last year when he took on the role of Peter Parker's "internship" advisor in Spider-Man: Homecoming, and it's clear that he has continued to work closely with Tony and Pepper for years, with their friendship dating as far back as the 1990s. Avengers 4 represents the culmination of a lot of different storylines, and it would only seem fitting for the MCU to bring back Happy for another outing to round out his arc.
The Asgardian ranks have been seriously depleted over the course of the last few years, with Lady Sif standing out as one of the clear causalities of war. The character was nowhere to be seen during the events of Thor: Ragnarok (despite the deaths of the rest of Thor's friends) and the Russos recently came out and stated that she was one of the beings erased from existence at the end of Avengers: Infinity War. That said, it's generally expected that some of the people killed by Thanos at the end of Avengers: Infinity War will return, and Lady Sif seems like a character who could be incredibly helpful (not to mention popular with fans) if resurrected for the coming fight.
Like many of the characters on this list, we still have no idea if Everett Ross survived the finger snap that evaporated half of all life in the known universe. Nevertheless, if he did survive the events of Avengers: Infinity War, then it stands to reason that he has officially gotten to work on cleaning up Thanos' mess and figuring out what happened. In many ways, Ross has arguably taken on the role previously held by Phil Coulson in the earlier years of the Marvel Cinematic Universe, and the Black Panther character could be a principal government liaison in the mission to rally the remaining Avengers and Guardians of the Galaxy in preparation for the coming counterassault.
Helen Cho only has one notable MCU appearance under her belt, but her importance to the overarching Marvel Cinematic Universe landscape cannot be overstated. Her appearance in Avengers: Age of Ultron saw her actually create Vision while under Ultron's control, and the film ends with her survival after being freed from the mind control. Helen is a brilliant scientist and one of Earth's most gifted minds, which could make her a key ally as the Phase Three story builds to a climax. Beyond that, if there's any chance that Vision could come back, she's probably one of the few people that Earth's Mightiest Heroes could turn to in order to make that a reality.
Lastly, we round out our list of MCU characters who could appear in Avengers 4 with one of the most heartbreaking of the bunch: May Parker. Peter Parker's loving aunt only recently found out about his status as the friendly neighborhood Spider-Man at the end of Spider-Man: Homecoming, and if she survived Thanos' finger snap at the end of Avengers: Infinity War, then she's going to wonder why Peter didn't come home from school once people started to fade away. She already has plenty of excuses to distrust and dislike Tony Stark (enabling a teenage superhero that you're trying to protect will do that), so something tells us that there's plenty of drama for Marvel to mine by exploring how May will react to Peter's "death."