What to Watch Before 'Avengers: Doomsday': The Essential Marvel Films
By Elliot Lines - September 29, 2026
With Avengers: Doomsday bringing together the Avengers, the Fantastic Four, the original X-Men and a host of other Marvel characters from across the MCU and beyond, preparing for the next chapter is no small task.
Directed by Anthony and Joe Russo, Avengers: Doomsday is shaping up to be one of the MCU's biggest crossover events yet. Alongside established MCU heroes, the film will bring back several actors from the original X-Men films, while The Fantastic Four: First Steps introduced the new Fantastic Four directly into a story that will continue into Doomsday. Marvel Studios president Kevin Feige has described the film as one involving "worlds literally colliding", making the Multiverse Saga more important than ever.
But with over two decades of Marvel films behind Doomsday, where should you actually start? From the original X-Men to Loki and Deadpool & Wolverine, here are the films — and one essential Disney+ series — to watch before Avengers: Doomsday.
X-Men (2000)
If you're preparing for the return of the original X-Men, there's no better place to start than where it all began. Bryan Singer's X-Men introduced audiences to Patrick Stewart's Professor Charles Xavier, Ian McKellen's Magneto, James Marsden's Cyclops and Rebecca Romijn's Mystique — four of the legacy X-Men characters now returning for Avengers: Doomsday.
The importance of revisiting X-Men goes beyond simply remembering who these characters are. The film establishes the relationship between Xavier and Magneto, their opposing approaches to mutantkind and the foundations of the original cinematic X-Men universe. With Doomsday bringing these versions of the characters into the MCU's increasingly complicated multiverse, understanding where they came from makes their return considerably more meaningful.
X2: X-Men United (2003)
While the first X-Men establishes the core team, X2: X-Men United expands the world considerably — and introduces another returning character in Alan Cumming's Nightcrawler.
Nightcrawler's inclusion is particularly notable because Cumming's Kurt Wagner has not appeared in a live-action X-Men film since X2. His return therefore reaches further back into the Fox X-Men era than most of the other confirmed legacy characters. Revisiting X2 also provides another look at Xavier, Magneto and the wider mutant world that Doomsday is now bringing back into the fold.
Captain America: The First Avenger (2011)
Before Avengers: Doomsday brings together characters from across different corners of Marvel, it is worth returning to the beginning of Steve Rogers' story.
Captain America: The First Avenger establishes Steve's relationship with Peggy Carter, a relationship that becomes increasingly important as the MCU develops. Their story ultimately becomes intertwined with Steve's decision at the end of Avengers: Endgame, while the Multiverse Saga has also introduced alternate versions of familiar Marvel characters, including Peggy's Captain Carter.
With Chris Evans returning to the MCU for Doomsday, revisiting this film gives Steve Rogers' history and his connection to Peggy a useful emotional foundation before the next Avengers event.
Avengers Assemble (2012)
The film that started the MCU's original Avengers era remains essential viewing before Doomsday.
Joss Whedon's Avengers Assemble is where Iron Man, Captain America, Thor, Hulk, Black Widow and Hawkeye first properly come together as a team. It establishes the dynamic between Earth's mightiest heroes and demonstrates why putting a group of wildly different personalities together can be just as important as the threat they are facing.
That is particularly relevant to Doomsday. The new film is expected to put multiple generations and versions of Marvel characters in the same story, including the Avengers, Fantastic Four and X-Men. Looking back at the first time Marvel's heroes had to learn how to work together provides a useful reminder of how far the MCU has travelled.
Avengers: Infinity War (2018)
The MCU's Multiverse Saga may have moved beyond Thanos, but Avengers: Infinity War remains crucial, alongside Endgame, because it establishes the scale of threat required to bring Marvel's heroes together.
The film brings together virtually every corner of the MCU at the time, while Thanos' quest for the Infinity Stones demonstrates what happens when one individual attempts to reshape existence on an unimaginable scale. It also sets up the devastating events that follow in Endgame.
Most importantly, Infinity War forms half of the story that fundamentally changes the Avengers and leaves the MCU's heroes scattered. Understanding that fractured state makes the subsequent evolution of the team — and the prospect of another enormous threat in Doomsday — easier to appreciate.
Avengers: Endgame (2019)
If Infinity War establishes the fall of the Avengers, Avengers: Endgame establishes the consequences.
The film closes the Infinity Saga, completes Steve Rogers' original MCU journey and dramatically reshapes the Avengers going forward. It also introduces the time-travel mechanics that become increasingly relevant to the MCU's later exploration of alternate timelines and realities.
For Doomsday, Endgame is especially useful because it establishes the emotional history behind many of the returning characters. It also provides the foundation for the MCU's post Endgame era, where questions surrounding time, branching realities and alternate versions of characters become central to the overarching story.
Loki (Season 1 & 2)
Now I know what you're thinking, strictly speaking, Loki isn't a film — but it is arguably one of the most useful pieces of MCU viewing before Doomsday.
The series takes the Loki who escapes with the Tesseract during the events of Endgame and throws him into the world of the TVA, introducing a much deeper understanding of timelines, variants and the structure of the multiverse. By the end of Season 2, Loki has taken on a completely different role within that multiverse, making the series particularly relevant to the increasingly interconnected story surrounding Doomsday.
Marvel's own material describes the series as taking place after Endgame, while the TVA and its relationship with branching timelines become fundamental parts of Loki's story. If Doomsday is going to deal with worlds colliding, Loki provides some of the clearest context for understanding why there are different realities in the first place.
Shang-Chi and the Legend of the Ten Rings (2021)
Shang-Chi has been largely absent from the MCU since his debut, making his return in Avengers: Doomsday a natural reason to revisit his first film.
Shang-Chi and the Legend of the Ten Rings introduces Simu Liu's hero while establishing the mysterious Ten Rings themselves. The film's post-credits sequence leaves one particularly significant question unanswered: exactly where did the Ten Rings come from, and what were they communicating with? That mystery has never been fully resolved on screen. The Ten Rings' unusual origins could therefore become relevant when Shang-Chi finally returns, although Marvel has not confirmed that their mysterious signal will be connected directly to Doomsday. The fact that the MCU has deliberately left their origins unexplained makes the film's ending worth remembering.
Spider-Man: No Way Home (2021)
Few films demonstrate the MCU's ability to bring characters from completely separate continuities together better than Spider-Man: No Way Home.
Tom Holland's Spider-Man is joined by Tobey Maguire and Andrew Garfield's versions of the character, while villains from their respective universes cross into the MCU. The result is the MCU's first major demonstration of just how dramatically the multiverse can alter the boundaries between previously separate franchises.
That makes No Way Home valuable prep for Doomsday, particularly given the return of characters originating outside the MCU's main continuity. It establishes that different versions of familiar characters can coexist — a concept that becomes increasingly important as Marvel prepares to put the MCU's heroes alongside the original X-Men.
Black Panther: Wakanda Forever (2022)
Black Panther: Wakanda Forever is important for establishing the next generation of Wakanda's leadership, particularly Shuri's journey towards becoming the new Black Panther.
Following the death of T'Challa, Shuri ultimately takes on the mantle herself, becoming one of the MCU's key heroes. Her position within the wider Marvel universe makes the film useful preparation for seeing how the newer generation of heroes fits into the enormous ensemble being assembled for Doomsday.
It is also an important reminder that the MCU's post-Endgame Avengers landscape is very different from the one established by the original team.
Doctor Strange in the Multiverse of Madness (2022)
If Loki explains the multiverse from a broader perspective, Doctor Strange in the Multiverse of Madness shows what happens when characters actually begin travelling between realities.
Doctor Strange and America Chavez encounter alternate universes, including a reality containing the Illuminati, while Wanda Maximoff's pursuit of her children demonstrates just how dangerous multiversal interference can become. The film also establishes Doctor Strange's increasingly important role in navigating supernatural and multiversal threats. With Doomsday expected to bring multiple realities and characters together, Multiverse of Madness provides some of the clearest cinematic groundwork for the concept.
Deadpool & Wolverine (2024)
Deadpool & Wolverine is arguably the most direct bridge between the old Fox Marvel films and the modern MCU.
The film embraces the existence of multiple universes while bringing Ryan Reynolds' Deadpool together with Hugh Jackman's Wolverine. More importantly for Doomsday, it demonstrates that characters from the former Fox Marvel universe can now cross directly into the MCU's wider multiverse.
The film also introduces Channing Tatum's Gambit to the big screen in a role that had been in development for years. With Tatum now part of the Doomsday cast, Deadpool & Wolverine provides the most recent context for one of the returning Marvel characters — while its multiversal story establishes the rules that make the larger crossover possible.
The New Avengers / Thunderbolts* (2025)
The team formerly marketed as the Thunderbolts is now the New Avengers, making this film important for understanding the MCU's current Avengers landscape.
Yelena Belova, Bucky Barnes, John Walker, Ghost, Red Guardian and Bob come together under Valentina Allegra de Fontaine, eventually establishing themselves as a new superhero team. Marvel's official synopsis describes the group as an unconventional collection of antiheroes who ultimately find a reason to unite.
That matters because Doomsday isn't simply picking up where the original Avengers left off. The MCU now has a new generation of heroes operating under the Avengers name, alongside established characters and returning legacy heroes. Understanding where this team comes from helps explain the superhero landscape heading into the next crossover.
The Fantastic Four: First Steps (2025)
There is one film that should probably be considered essential viewing immediately before
Avengers: Doomsday — The Fantastic Four: First Steps.
Marvel's First Family are entering the MCU from Earth-828, a separate retro-futuristic reality inspired by the 1960s. Reed Richards, Sue Storm, Johnny Storm and Ben Grimm are introduced as established superheroes in their own universe before being drawn into the larger Multiverse Saga. Marvel has confirmed that the Fantastic Four will return in Doomsday, where they will interact with the Avengers and X-Men as worlds begin to collide.
The film's credits sequence makes the connection even more direct, introducing Doctor Doom into the Fantastic Four's world and ending with the promise that the team will return in Avengers: Doomsday. The exact nature of Doom's relationship to Earth-828 and his connection to Robert Downey Jr.'s version of the character are questions for the upcoming Avengers film to explore, but First Steps is clearly designed as a major piece of the road to Doomsday.
So, What Should You Actually Watch?
If you want the full experience, the films above provide a broad tour through the characters,
universes and relationships that could feed into Avengers: Doomsday.
However, if you're short on time, the most useful core rewatch would be:
1. X-Men
2. X2: X-Men United
3. Avengers Assemble
4. Avengers: Infinity War
5. Avengers: Endgame
6. Loki — Seasons 1 & 2
7. Spider-Man: No Way Home
8. Doctor Strange in the Multiverse of Madness
9. Deadpool & Wolverine
10. The New Avengers
11. The Fantastic Four: First Steps
Together, these provide the clearest route through the MCU's original Avengers, the Fox X-Men, the multiverse, the new Avengers and the Fantastic Four — the major pieces currently known to be coming together when Avengers: Doomsday arrives.
Avengers: Doomsday releases in cinemas December 18, 2026.
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Elliot Lines
Founder/Lead Editor
Elliot loves to surround himself with all things movies. Whether that be his movie related LEGO collection or enough Blu-rays to restart blockbuster.
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