The Fan Theories Swirling Around ‘Avengers: Doomsday’ Range from Brilliant to Absolutely Wild
With its December 18, 2026 release date now well inside the horizon, hype around ‘Avengers: Doomsday‘ has reached a fever pitch. The Marvel Cinematic Universe has already captivated audiences with major announcements, including the return of Chris Evans as Steve Rogers and a forgotten Thor character spotted in early teasers, giving fans more than enough fuel to run wild with speculation. And run wild they absolutely have.
The film brings back the Russo Brothers to direct and reunites two of the MCU’s most beloved alumni, with Robert Downey Jr. taking on the role of Doctor Doom and Evans returning as Steve Rogers for the first time since ‘Avengers: Endgame.’ That combination alone was enough to send the internet into overdrive, but now Marvel Studios Canada has added even more to the conversation by sharing a collection of fan theories on their social media, shining a spotlight on some of the most creative and provocative predictions floating around the fandom.
One of the theories spotlighted suggests that Steve Rogers will be captured by Doctor Doom and transformed into a sinister Captain Hydra by the film’s end. That concept actually has serious traction among MCU observers. There are longstanding theories that Doom could be leading a team of dark Avengers, with a HYDRA-controlled Captain America potentially among them, an idea that has real precedent in Marvel Comics from the 2016 ‘Captain America: Steve Rogers’ storyline. Adding weight to this, the Russo Brothers themselves told Empire Magazine that Steve Rogers is at the center of their story, saying they have a “special affinity” for the character and “can’t see this narrative without his central role in it.”
Another fan prediction highlighted by Marvel Studios Canada calls for the return of Natasha Romanoff, and there is genuine reason to believe the MCU is at least teasing that possibility. Descriptions of an exclusive trailer screened at CinemaCon 2026 reportedly hint at the return of Scarlett Johansson’s Black Widow through a clever shape-shifting narrative device involving Rebecca Romijn’s Mystique. That said, Johansson herself has been publicly firm about moving on, stating plainly that fans need to “let it go” and that Natasha “saved the world” and deserves to keep her hero moment. Whether that is a genuine goodbye or the world’s most convincing misdirect remains deliciously unclear.
The theory about ‘Ms. Marvel’ potentially crossing paths with the X-Men in ‘Doomsday’ is one that has picked up real momentum beyond social media speculation. Actor Andy Serkis appeared to accidentally confirm Iman Vellani’s involvement during a press interview for an upcoming animated film, telling Vellani directly “I’m excited to see you in Doomsday” before she immediately told him he could not say that. The mutant angle is particularly compelling given that the MCU revealed Kamala Khan to be a mutant at the end of her Disney+ series, which could tie her directly into the film’s major X-Men crossover storyline.
As for the claim that Doctor Doom will stand as the greatest MCU villain by a wide margin, the creative team is clearly aiming for exactly that. At CinemaCon, the Russo Brothers described Doom as “not simply a villain” but rather “one of the most complex Marvel characters” who is “always three moves ahead.” Joe Russo has also shared that Downey is deeply immersed in the role, actively writing backstory and pitching costume ideas, calling him “so dialed in” to the process. If even half of these fan theories come true, ‘Avengers: Doomsday’ could genuinely deliver on that promise.
Which of these theories do you think is most likely to actually happen, and is a Captain Hydra turn for Steve Rogers the twist the MCU has been quietly building toward all along?
