The comic book movies of theMCU, theDCU, and beyond often leave unexplained mysteries, and sometimes answers come outside of the movies. Across the respectivemovie timelines of the DCEU, the MCU, and other comic book film franchises, numerous interconnected narratives have played out across their own shared movie universes. These movies often tease future developments or deliberately leave questions unanswered, usually as a means of enriching the overall experience of the shared universe.
However, in many cases, themovies of the MCU, the DCEU, and others leave these plot threads hanging for one reason or another, or simply neglect to offer answers to burning questions. Thankfully, answers are sometimes offered in the most unexpected of places, including in media outside of the movie universe in question. On more than one occasion, tie-in materials, interviews, and other methods have been used to clear up unsolved comic book movie mysteries.

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10How Trevor Slattery Escaped Prison After Iron Man 3
Iron Man 3 (2013)
After the events ofIron Man 3, Trevor Slattery, the actor who had assumed the role of the Mandarin, was imprisoned for his role in Aldrich Killian’s schemes. Within themovie timeline of the MCU, Slattery goes from incarceration afterIron Man 3to being in the Mandarin’s clutches inShang-Chi and the Legend of the Ten Rings. For those only following the movies of the MCU, this raised the question of how exactly Trevor Slattery escaped from prison.
The Marvel one-shotAll Hail the Kinghad already answered that question, however. It shows Trevor Slattery’s life in prison, beforehe is interviewed and then abducted by an agent of the Mandarin, who breaks him out. Somehow, the events ofAll Hail the Kingslipped by some MCU fans, though it had already offered an explanation to how Trevor Slattery could appear in Shang-Chi after his arrest.

9How Joker’s Goons Got To The Cathedral
Batman (1989)
Tim Burton’sBatmanis widely hailed as a landmark title in superhero cinema, but that isn’t to say that it didn’t leave one or two unanswered questions. The film’s climax sees Batman chase Joker to the roof of Gotham Cathedral, only for three of the villain’s henchmen to appear and attack the Dark Knight. As the film doesn’t show or explain why the three goons were there, it was commonly considered a baffling plot hole.
The movie’s novelization actually offered a clear and logical explanation to the mystery, though. The story explains that the thugs told Joker they had fled to the Cathedral roof during the villain’s fight with Batman in the Batwing, in order to get a better view of proceedings.The novelization simply and effectively rationalizes the goons’ presence in the cathedral by explaining that they had simply climbed up there before the Joker or Batman.

8The MCU Earth’s Official Designation
Spider-Man: Across the Spider-Verse (2023)
Even before the MCU had officially begun to explore the Multiverse, the franchise had hinted at the existence of other realities and alternate timelines. In the comics, the main Marvel Universe is dubbed Earth-616, andSpider-Man: Far From Homesignaled that this would also be the official designation of the MCU’s own universe. However,Spider-Man: Across the Spider-Verseasserted that the MCU was in fact Earth-19999, referencing the events ofSpider-Man: No Way Home.
The confusion over the official designation of the MCU’s main continuity was cleared up outside of the movies.Marvel’s official MCU Timeline book revealedthatthe franchise’s central reality is, in fact, Earth-616, giving a definitive answer to the question raised by inconsistencies within Marvel movies. This marked another example of Marvel resolving an issue outside of the movies themselves.

7What Happened To The DCEU’s Robin
Batman v Superman: Dawn of Justice (2016)
Themovies of the DCEUfeatured many iconic DC characters, but one who was conspicuous in his absence was Robin, Batman’s traditional sidekick. The franchise’s use of an older and battle-hardened Batman saw its references to Robin made only sparingly, with only one major piece of evidence that he existed within the DCEU’s continuity at all. At one point, Robin’s defaced armor is shown on display in the Batcave, heavily implying that Batman’s sidekick was murdered by the Joker.
The DCEU never goes as far as to explicitly explain what happened to Robin, though. It seems clear from his costume that the Joker killed him, but details are not explored within the franchise. DirectorZack Snyder later confirmed that the identity of Robin was not Jason Todd, as per the Death in the Family story from the comics, but that the Joker had instead killedDick Grayson in the DCEU, clearing up part of the mystery surrounding his death.

6Why Spider-Man Homecoming Said 8 Years Later
Spider-Man: Homecoming (2017)
As the MCU’s timeline has grown increasingly complex, so too have the continuities of its individual heroes.Spider-Man’s movie timelinein the MCU was an especially confusing one, as the original release of his first solo movie,Spider-Man: Homecoming, indicated that it was set in 2020, eight years after the events ofThe Avengers. This created a major mystery around how exactly the MCU timeline would work, particularly in howHomecomingfit in with the franchise’sAvengersmovies.
The MCU’s official timeline book revealed thatthe “Eight years later” title card was in fact a mistake, and that it should have read “Four years later”. The book firmly placed the events ofSpider-Man: Homecomingin 2016, clearing up one of the MCU’s worst timeline issues. As such, the movie mystery was resolved outside of the franchise itself.

5How Ma-Ma’s Death Could Actually Make Things Worse
Dredd (2012)
Though comic book movies outside of the MCU and the DC Universe typically haven’t achieved the same levels of success as those from major franchises, 2012’sDreddearned itself cult status. The comic book adaptation saw Karl Urban’s Judge Dredd take on Ma-Ma, an urban warlord with an army of violent crooks at her disposal. The movie ends with Ma-Ma’s death, but it’s clear that the resulting power vacuum will be something of a problem for the residents of Mega-City One.
Dredd: Underbellywas the comic book sequel to the movie, exploring the fallout of Ma-Ma’s death. The movie explored the implied issues that arose as the result of the antagonist’s demise, including the economic repercussions of Dredd taking Ma-Ma’s Slo-Mo drugs out of circulation.Underbelly ties up multiple loose ends left by the 2012 movie, giving answers to many questions left unanswered after Ma-Ma’s death.

4Why Tony Stark Was Recruiting Avengers When He Was A Rejected Candidate
The Incredible Hulk (2008)
2008’sThe Incredible Hulkends with a scene in which Tony Stark approaches General Thaddeus “Thunderbolt” Ross about putting a team together. The next entry into the MCU, 2010’sIron Man 2, was set shortly before the events of The Incredible Hulk, and reveals that Stark was rejected from the Avengers. This created an apparent plot hole regarding why Stark would be recruiting for a team he had been rejected from.
The Marvel one-shotThe Consultantresolved the plot hole by explaining Stark was sent by SHIELD on purpose.The reasoning behind this was that Stark’s personality would dissuade Ross from pushing for Abomination to become an Avenger, which it explains is exactly what happened in-universe. As convoluted as the retcon may seem, it fixed an MCU plot hole without dropping needless exposition in one of the franchise’s movies.

3How The Kryptonian Ship Ended Up On Earth In Man Of Steel
Man of Steel (2013)
The very first entry into the DCEU’s short-lived timeline was 2013’sMan of Steel, which introduced Henry Cavill’s Superman in an origin story that saw him face off against General Zod. Despite resolving its central conflict, the movie left one or two questions unanswered that were not explored in subsequent DCEU movies. Perhaps the most glaring of these was regarding the crashed Kryptonian scout ship discovered by Clark Kent and how it came to be on Earth.
The story of exactly how it crashed is chronicled in theMan of Steelprequel comic, an official tie-in for the movie. It follows Kara Zor-El as she travels toward Earth in the scout ship, only for damage to its controls to force a crash landing. The comic ends by showing exactly how the ship figured intoMan of Steel’s story, neatly tying off the movie mystery.

2Why Wanda & Pietro Didn’t Die In Hydra’s Experiments
Avengers: Age of Ultron (2015)
After the Maximoff twins were briefly introduced in one of theMCU’s post-credits scenes, they made their full debut inAvengers: Age of Ultron. Starting the film as agents of Hydra and the result of Baron Strucker’s experiments with the Mind Stone, Wanda and Pietro turn heroic ahead of the Battle of Sokovia. However, exactly why Pietro and Wanda were able to survive the devastating experiments had not been explained, only that they were considered “miracles”.
WandaVisionconfirmed that Wanda’s magical powers had been latent since birth, but that the Mind Stone enhanced them. However, before that,the MCU tie-in bookThe Wakanda Filesexplained that the Maximoff twins had already possessed genetic abilities, which is why the Mind Stone experiments didn’t kill them. Though it was later explained in one of theMCU’s TV shows, the mystery was first resolved by an MCU tie-in book.

1How Billy Dee Williams’ Harvey Dent Became Two-Face
It’s no secret that Tim Burton’s time making Batman movies was cut short. Burton had more movies following the Caped Crusader planned, meaning that he was unable to fulfill some of the unresolved mysteries of his two Batman movies. One of these was how exactly Billy Dee Williams’ Harvey Dent would become Two-Face, as he was only briefly shown in the movies prior to his transformation.
The tie-in sequel comic series,Batman ‘89, explored Harvey Dent’s story in detail. Following on from his brief appearance in the 1989 movie,the comics show his transformation into the villain Two-Face, finally clearing up the mystery left unresolved after Burton’s exit from the franchise. In doing so, it marked yet another example of comic book movie mysteries from theMCU, theDCU, and beyond being resolved outside of the movies themselves.