What to Watch Before Avengers: Doomsday: The 7 Essential MCU Picks

Doom Is Coming, and Nobody Has Time for 30 Movies

🎬 This guide is part of our MCU Hub — the full timeline, the post-credit scene guide, and the Tony Stark and Thanos character arcs.

Avengers: Doomsday lands in theaters on December 18, 2026, with the biggest cast Marvel has ever put in one film: the Fantastic Four, the original X-Men, half the current Avengers roster, and Robert Downey Jr. as the villain, Victor Von Doom. It’s genuinely the payoff for 18 years and 30-plus films of setup — which is exactly the problem if you’re a dad with maybe four or five free evenings between now and opening weekend.

You don’t need all 30. Most of the MCU’s back catalogue is either self-contained or irrelevant to what Doomsday is actually building toward. What you need is the small handful of titles that directly explain why this specific cast is in this specific movie — and a realistic sense of which ones are safe to watch with your kids and which ones need a solo slot after bedtime.

That’s what this list is. Seven titles, in the order we’d actually watch them, each with the reason it matters for Doomsday and an honest Kid Co-Watching Rating based on the age guidance in our own full reviews — not a generic MPAA number pulled off a poster.

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Avengers: Endgame (4K Ultra HD) (opens in a new tab)

The last time this many heroes shared one screen — Doomsday is explicitly trying to top this, so it's the required rewatch.

1. Avengers: Endgame (2019) — The Bar Doomsday Has to Clear

Start here, even though it’s the oldest title on this list. Avengers: Endgame is the last time the MCU assembled a cast at anything close to Doomsday’s scale, and Marvel’s own marketing has been openly comparing the two — Endgame’s home-media listing is explicitly being pitched as “essential rewatch homework” ahead of December. If your kids (or you) have forgotten how genuinely huge that final battle felt, this is the reset button.

It also reintroduces the two characters whose absence and return define the current era: this is the last time we see the original Avengers team intact before the torch passes, which is the exact framing Doomsday is playing with by bringing Robert Downey Jr. back — not as Tony Stark, but as the villain. (Our full Endgame review has the complete breakdown if it’s been a while.)

Why it matters for Doomsday: it’s the scale reference point. Every trailer beat and every “biggest crossover since—” comparison assumes you remember what Endgame actually delivered. Kid Co-Watching Rating: 12+. Real emotional weight in the finale; plan for a few pointed questions afterward.

2. Spider-Man: No Way Home (2021) — The Multiverse Template

Spider-Man: No Way Home is where the MCU first proved a “everyone’s variant shows up in one movie” crossover could actually work, pulling in Tobey Maguire’s and Andrew Garfield’s Spider-Men from entirely different film franchises. That’s the exact trick Doomsday is running at a much bigger scale with the original Fox X-Men cast — so if you want to understand how Marvel handles a multiverse guest star before Doomsday drops a dozen of them in one trailer, this is the reference film.

It’s also just a genuinely great watch for the whole family, and one most households have probably already seen — which makes it an easy, low-effort rewatch to slot in early.

Why it matters for Doomsday: establishes the “variant from another universe” mechanic Doomsday leans on hard. Kid Co-Watching Rating: 12+. Emotional stakes, comic-book action, nothing that should catch a family audience off guard.

3. Doctor Strange in the Multiverse of Madness (2022) — Meet the Illuminati

Where No Way Home shows the multiverse working, Doctor Strange in the Multiverse of Madness shows it going wrong — alternate universes, darker variants, and the Illuminati as a glimpse of what “other Earths” actually look like when they’re not friendly. It’s a genuinely different tone from most MCU entries (closer to horror in places), and it’s the film that made “which universe is this” a question every subsequent Marvel project has had to answer.

Doomsday’s ensemble is explicitly a collection of heroes from different corners of the multiverse converging in one place. This is the film that first made that idea feel dangerous instead of just fun.

Why it matters for Doomsday: sets up the stakes of multiversal incursions — the actual mechanism Doomsday’s marketing keeps hinting at. Kid Co-Watching Rating: 12+, and check in with more sensitive kids — a few sequences push into genuine horror-movie territory.

4. Loki, Seasons 1 & 2 (2021–2023) — How Variants and Timelines Actually Work

If Doctor Strange shows you the multiverse is dangerous, Loki Season 1 is where you learn the rules. Variants, branching timelines, the idea that one bad decision spins off an entire new universe — all of it gets explained here more clearly than anywhere else in the MCU, largely because the show has the runtime to actually walk through it instead of rushing past it in a single action sequence.

Two seasons is a bigger ask than a single film, and Season 2 in particular leans into some genuinely dense, philosophical territory that can lose a casual viewer. If you’re truly pressed for time, Season 1 alone gets you the core concept — the branching-timeline mechanics — without the deeper Season 2 detour into the TVA’s origins.

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The Fantastic Four: First Steps (4K Ultra HD) (opens in a new tab)

Reed, Sue, Johnny and Ben's MCU debut — the newest team in the Doomsday cast, and the freshest required viewing on this list.

Why it matters for Doomsday: without this, “variant” is just a word the trailer uses. With it, you understand exactly what kind of crossover Doomsday is attempting. Kid Co-Watching Rating: 12+. Talky and occasionally slow for younger viewers, but nothing objectionable content-wise.

5. Deadpool & Wolverine (2024) — Why the Original X-Men Are Even Here

This is the single most important entry on this list for understanding Doomsday’s cast list specifically. Deadpool & Wolverine is the film that pulled the entire 2000–2019 Fox X-Men universe — Patrick Stewart’s Professor X, Ian McKellen’s Magneto, the works — into the MCU’s multiverse as a parallel Earth. Every one of those legacy actors returning in Doomsday’s trailer is only possible because this film opened that door first.

It’s also, worth saying plainly, an R-rated, foul-mouthed, extremely violent movie — the tonal opposite of most of this list. Watch it yourself first and decide if or how much of it is right for your household; this is the one entry here we’d default to a solo, after-bedtime viewing for most families.

Why it matters for Doomsday: it’s the direct mechanism by which the original Fox X-Men cast becomes available to appear in an Avengers film at all. Kid Co-Watching Rating: 16+ (R-rated violence and language). Not a family movie night pick.

6. The Fantastic Four: First Steps (2025) — The Newest Team in the Cast

Marvel’s first family finally got their MCU introduction in The Fantastic Four: First Steps, a stylish period-set reboot that stands on its own as a good film regardless of what comes next. But it also exists specifically to seed Reed, Sue, Johnny and Ben’s role in the wider Sacred Timeline before Doomsday puts them in a frame with the Avengers and the X-Men.

Given that Victor Von Doom is the Fantastic Four’s signature villain in the comics — and now the villain of the movie carrying their name in its subtitle — this is required viewing for understanding what the Fantastic Four bring to Doomsday’s fight, and why Marvel chose this team to headline the connective tissue between the current MCU and its villain.

Why it matters for Doomsday: it’s the freshest, most direct setup — the film literally exists to put this team on the board before December. Kid Co-Watching Rating: 10+. Family-friendly retro styling, lighter in tone than most of this list.

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Prime Video (30-Day Free Trial) (opens in a new tab)

Most of these seven rent individually on Amazon, official Fox X-Men films included — no second subscription needed to work through this list.

7. Spider-Man: Brand New Day (2026) — The One That Actually Matters Most

If you watch only one movie on this entire list, make it this one. Spider-Man: Brand New Day quietly did something no MCU project had done in six years of X-Men-adjacent cameos: it introduced Sadie Sink’s Jean Grey as a mutant who was always part of the main Sacred Timeline, not a multiverse variant visiting from somewhere else. That’s a fundamentally different thing from every earlier X-Men tease, and it’s the plot thread Doomsday’s marketing keeps circling without fully explaining.

Here’s the genuinely interesting wrinkle: Doomsday’s own trailer confirms the original Fox X-Men actors are returning too — as multiverse variants, per the mechanic Deadpool & Wolverine established. So the film now has to reconcile a brand-new, native X-Man with a cast of legacy variants playing a version of the same lineage. Nobody in Marvel’s marketing has addressed how that gets resolved, which makes this the single loudest open question heading into December. We go deep on exactly this collision in our X-Men Earth-616 explainer, including what Jean Grey’s arrival sets up for the wider “Mutant Saga.”

It also happens to be, in our own reviewer’s assessment, the best Marvel film made yet — so this isn’t homework you’re doing reluctantly.

Why it matters for Doomsday: it’s the most direct, most recent connective tissue to the film’s central X-Men/Avengers collision — arguably more relevant than anything else on this list. Kid Co-Watching Rating: PG-13. Real action and some intense moments (The Punisher is on screen) — worth a heads-up conversation with younger viewers beforehand.

One More Thing: Why RDJ as the Villain Hits Different for Dads

None of the seven titles above cover this directly, so it’s worth saying separately: watching Robert Downey Jr. show up in December as Victor Von Doom — not as Tony Stark — is going to land very differently for anyone who watched Iron Man in a theater back in 2008 than it will for a kid who’s only ever known RDJ as the hero. If you’re in the first group, that’s worth sitting with before you walk in.

Eleven years and eight films built Tony Stark into the emotional center of the entire Infinity Saga, right up through the sacrifice at the end of Endgame — the film at the top of this list. Doomsday is deliberately trading on that history rather than ignoring it: the marketing has been explicit that this is the same actor, not a new face in old makeup, and that’s a genuinely different kind of stunt casting than Marvel usually pulls. It’s part legacy-actor nostalgia, part “here’s how deep the rabbit hole goes” flex, and part a real acting swing for RDJ himself.

For your kids, this is also a good, low-stakes moment to explain how comic-book storytelling works — the same actor playing a hero in one story and a villain in another isn’t a contradiction, it’s how “variants” and alternate versions of a character work across a multiverse. If Endgame is on your list anyway, watching Tony Stark’s ending right before you see Victor Von Doom’s introduction is the most efficient way to make that generational hand-off land for everyone in the room, not just the parent who remembers 2008.

The 7, Side by Side

If You Genuinely Only Have Three Nights

Real talk for the truly time-crunched: if seven movies and two show seasons is still too much before December, cut it down further.

Watch Spider-Man: Brand New Day, Deadpool & Wolverine, and The Fantastic Four: First Steps. In that order or reversed, those three cover the newest and most Doomsday-specific setup — why the X-Men are back, why the Fantastic Four matter, and what the marketing is actually building toward. You’ll be missing the broader multiverse context from Loki and Doctor Strange, but you won’t be lost in the theater, and you can always watch the rest of this list after the credits roll and you inevitably want more.

One thing to skip entirely, if you’re pressed for time: don’t feel obligated to rewatch the Fox X-Men trilogy (2000-2006) itself before Doomsday. It’s genuinely fun homework if you have the hours, but nothing on this list requires it — Deadpool & Wolverine explains everything you structurally need to know about why those actors are back, without assuming you remember the plots of films from two decades ago. And if you do want to fill any of these seven in fast, most of them rent individually on Amazon — no second subscription required just to catch up.

Common Mistakes Dads Make Prepping for a Crossover Like This

Trying to watch the whole MCU in release order. Thirty-plus films in four months isn’t a movie-night plan, it’s a part-time job. If completionism is genuinely your thing, our full MCU Watch Order is the reference — but that’s a different project from “get ready for one specific film,” which is what this list solves.

Assuming every entry is family viewing because it says “Marvel” on the poster. Deadpool & Wolverine is R-rated for a reason, and Doomsday’s own PG-13 rating still means real action violence at a scale most of this list doesn’t reach. Screen your own list against your kids’ ages, not the studio’s brand.

Skipping the newest releases because they feel like “extra credit.” The Fantastic Four: First Steps and Spider-Man: Brand New Day are the two most recent entries on this list, and they’re doing more direct Doomsday setup than anything from the Infinity Saga. Recency matters more than usual here.

FAQ

When does Avengers: Doomsday release?

December 18, 2026, in theaters.

Do I need to watch all 30-plus MCU movies before Avengers: Doomsday?

No. The full watch order rewards completionists, but if you’re catching up on a deadline, seven titles cover the storylines Doomsday is actually pulling from: the last Avengers-scale team-up, the multiverse mechanics, why the original Fox X-Men cast is back, and the Fantastic Four’s MCU debut.

Is Avengers: Doomsday appropriate for kids?

It’s expected to be PG-13, in line with every other Avengers film. With this many storylines converging, it also rewards prior knowledge more than a typical MCU entry — not the easiest one to walk into cold with a younger viewer.

Why is the original X-Men cast back in Doomsday if those films aren't MCU canon?

Deadpool & Wolverine pulled the entire 2000-2019 Fox X-Men universe into the multiverse as a parallel Earth, which is how Patrick Stewart, Ian McKellen and the rest can appear as multiverse variants. Separately, Spider-Man: Brand New Day introduced Jean Grey as a native mutant already living in the main MCU timeline — a different thing entirely, and the collision between the two is one of Doomsday’s biggest open questions.

If I only have time for one movie before Doomsday, which one?

Spider-Man: Brand New Day. It’s the most recent, it’s a genuine 5-star watch on its own, and it sets up the exact plot thread — Jean Grey and the X-Men’s arrival in the main timeline — that Doomsday’s marketing keeps teasing.