No franchise in entertainment history has been studied and scrutinized on the level of the MCU, with fans putting every last detail under a magnifying glass to try and see how it all connects. With that being the case, the storied franchise is still too vast for everyone to know everything, meaning some facts about the movies and now shows are known only to a select few.
For some die-hard fans, the fun of MCU fandom goes beyond Easter eggs and deciphering potential speculative elements. It includes behind-the-scenes details and some in-universe facts that are on their own level of enjoyment, and sometimes offer an intriguing glimpse into what might have been and possibly even what could be.
Captain Marvel Was Originally In Age Of Ultron
There are many powerful versions of Captain Marvel in the comics. There were very nearly two in the MCU. Captain Marvel was actually intended to appear in Avengers: Age Of Ultron, and a scene was filmed with a stand-in with her appearing with the new Avengers team at the very end of the movie.
Marvel Studios ultimately decided to wait to introduce a major character like Carol Danvers in her own movie, leaving knowledge of the existence of the almost-Captain Marvel to die-hard fans who enjoy learning about the productions.
Fury's Big Week
Most MCU fans know that the franchise is pretty intricately linked between its many movies and shows. Only a few may realize how closely some of them are. "Fury's Big Week" is the name of a comic book tie-in that makes clear that three movies, including Iron Man 2, Thor, and The Incredible Hulk all take place during the same week in the MCU.
This fact is capitalized on in an episode of What If..?, where Hank Pym takes down the nascent Avengers before they form. The episode also contains a shocking revelation about the MCU - Nick Fury had reached out to The Wasp to join S.H.I.E.L.D.
Fandral Is Played By Different Actors
Some fans may have noticed, but it's likely that only die-hards realized that Fandral, one of the Warriors Three who fight alongside Thor in his movies, has been played by three different actors in the MCU. Fandral was played by Josh Dallas in Thor and by Zachary Levi in Thor: The Dark World and Thor: Ragnarok.
Levi has actually been cast for the first movie but had to drop out. Stuart Townsend replaced him, but that didn't work out, either. Dallas finally played the role but for the second movie, he had to bow out due to scheduling conflicts and Levi was back in.
Gemma Chan Was In Captain Marvel As Another Character
Most comic book fans know that Sersi is the character Gemma Chan is playing in the upcoming Eternals movie. Only the most devoted fans may realize that Gemma Chan has already appeared in the MCU, but not as Sersi. She played Minn-Erva, a ruthlessly efficient member of the Kree Starforce in 2019's Captain Marvel.
It was a relatively small role that ended with the Kree sharpshooter dying in the climactic battle, but it's not the end for Gemma Chan. She is unlikely to die as Sersi since she is one of the immortal Eternals living on Earth.
Mighty Thor: Battle Royale
MCU fandom is a global phenomenon, but still, only some die-hard fans may know that Thor: Ragnarok had a completely different title in Japan. In that country, the movie was retitled Mighty Thor: Battle Royale, a nod it seems to a popular aspect of Japanese entertainment. Battle Royale is a 2000 Japanese movie about students fighting each other to the death.
This title may have been more sensible in Japan, where the term Ragnarok, a major component of Norse mythology, is not generally known. The arena battle made more sense in the context of the tournament fighting of Battle Royale.
The Photon Nickname
A minor detail MCU die-hards likely caught in Captain Marvel provides a lot of potential meaning. In the 2019 movie, Maria Rambeau's Air Force callsign is 'Photon.' This is referenced again in her memorial plaque at SWORD in WandaVision. Comic book fans know that Monica Rambeau, Maria's daughter, uses Photon as one of her many aliases in the Marvel Universe.
This use of the name Photon is unlikely to be arbitrary and could well become Monica's official superhero moniker as she continues on her journey into future MCU projects.
The Milano Is Named After Alyssa Milano
MCU fans know that Guardians Of The Galaxy is full of '80s references, thanks to Peter Quill being a child of the era. His love is reflected in the manifestation of Pac-Man and David Hasselhoff, but the biggest emblem is his ship, the Milano. The name of his spaceship is a tribute to Alyssa Milano, the actress famous for her role in Who's The Boss? back in the '80s.
Though the etymology of the name isn't given in the movie, writer and director James Gunn revealed that Milano is named after the actress in a 2014 tweet answering a fan's question.
Madripoor Is An Important Location
Most fans probably didn't spend too much time thinking about Madripoor, a location visited in The Falcon And The Winter Soldier. Major fans of the MCU and the comics know this obscure island nation is actually one of the most important fictional countries in Marvel Comics and has strong ties to the X-Men.
Madripoor is really the first significant element of mutant lore to appear in the MCU. The country is the site of many solo Wolverine adventures, especially in comics from the 80s.
The Significance Of August 23rd
August 23rd is a very obscure element that only die-hards are likely to know. The date is marked on a calendar in WandaVision, leading to some speculation that was then reinforced when the first trailer for Spider-Man: No Way Home appeared on that date. While that may have been pure coincidence, fans also see a greater meaning.
It's possible that August 23rd is a reference to Avengers #238, a comic book with some bearing on the story of WandaVision. The story features The Vision losing his memory, as he does in the series, and facing off against his friends, including Monica Rambeau.
Spider-Man License Plates
8/23 isn't the only super obscure fact connected to Spider-Man in the MCU. Only die-hard fans will know that specific issues of Spider-Man comics are also referenced in the MCU Spidey movies, most often in license plates. These references occur throughout the first two movies, and most often appear with the prefix 'ASM,' referring to The Amazing Spider-Man.
These include ASM 2865, for Amazing Spider-Man #28, the first appearance of Molten Man, as well as ASM 212, a license plate that pays homage to the first appearance of Hydro-Man in Amazing Spider-Man #212.