Avengers: Doomsday Has Two Essential Prep Watches, Not 27

This article discusses post-credit scenes from Thunderbolts* and The Fantastic Four: First Steps. The opening section is spoiler-safe; specific details begin after the warning below.

Marvel announced much of the Avengers: Doomsday ensemble through a long presentation built around actors’ chairs, a format that rewarded recognition while saying almost nothing about narrative weight. A chair could mean a lead role, one scene, a visitor from another continuity or an efficient way to keep several branches of Marvel fandom occupied during production.

That distinction matters because the cast spans characters from recent Marvel Cinematic Universe films and veterans of the earlier X-Men movies. Treating every name as required preparation turns one theatrical release into a survey course covering years of uneven continuity, much of which may contribute no more than a familiar entrance.

The useful anchor is smaller: the final scene of Thunderbolts*, in which the newly branded Avengers detect a vessel bearing the Fantastic Four insignia entering their universe. It is the clearest released bridge into Doomsday, connecting two active teams without requiring viewers to infer importance from an actor’s place in a marketing presentation.

This belongs to cinema coverage. The preparation happens mostly at home, but the decision concerns what viewers need before a major theatrical sequel and, later, whether its scale justifies a premium-format ticket. At present, Marvel has supplied enough information to build a short watch list, not enough to recommend paying extra for the eventual presentation.

The cast reveal answers the wrong question

Casting announcements tell audiences who has reported for work. They do not explain whose unresolved story drives the film, how long anyone appears or whether an actor returns as the same version of a character last seen elsewhere.

That uncertainty is particularly acute around Robert Downey Jr. as Doctor Doom. Marvel has publicly identified the role, but Downey’s history as Tony Stark does not establish that Doomsday will connect Doom to Stark within the story. Rewatching the Iron Man films on the assumption that the casting itself creates a plot link would confuse an audience-facing surprise with evidence from the narrative.

The same restraint should apply to the returning X-Men performers. Their presence makes the older films relevant to the marketing campaign, and viewers who remember those characterizations will recognize more of the intended effect. It does not yet make the complete Fox-era series required viewing. Those movies contain multiple timelines, recast roles and continuity revisions; without an official trailer showing which history Doomsday uses, a full rewatch could consume many evenings to prepare for what may amount to compressed introductions.

Marvel benefits when each announced name sends viewers back through a streaming catalog. The reader does not receive a prize for complying early.

Spoilers begin here: watch Thunderbolts* first

Thunderbolts* is the strongest preparation title because its ending does two pieces of practical work. The film forms the group later labeled the New Avengers, then its post-credit scene places that team inside the institutional dispute surrounding the Avengers name before interrupting the argument with a larger problem: a craft associated with the Fantastic Four has appeared from another universe.

That scene establishes the working status of Yelena Belova, Bucky Barnes, John Walker, Ghost and Red Guardian more efficiently than their separate earlier appearances would. Those projects explain individual histories, but Thunderbolts* shows the group’s current chemistry, its public identity and the fragile conditions under which it operates. For Doomsday preparation, current position matters more than complete biography.

The movie also introduces the Watchtower as the team’s base and leaves Bob’s unstable power hanging over its future. A viewer coming directly from older Avengers films would otherwise have to absorb the new headquarters, the disputed branding and the altered team roster while Doomsday is handling its main conflict. Thunderbolts* moves that setup out of the next film’s opening stretch.

Watch the entire movie rather than skipping to the coda. The Fantastic Four vessel is the concrete bridge, but the preceding story explains who is standing in the room when the alert arrives and why this version of the Avengers cannot be treated as a settled replacement for the original team. The film is ensemble preparation, not a scavenger hunt for a logo.

Nothing in that recommendation makes Black Widow, The Falcon and the Winter Soldier or Ant-Man and the Wasp mandatory. They add background for individual members. They are optional if one character’s history has faded, and a recap will usually cover the missing mechanics without turning the assignment into several more features plus a series.

The

Fantastic Four supplies the other side of the bridge

The Fantastic Four: First Steps is the second essential watch because Doomsday draws in its central family, while the film’s own coda places Doctor Doom near Franklin Richards. The scene does not explain Doom’s full plan, but it establishes a direct point of interest between the announced antagonist and a child whose unusual abilities shape the Fantastic Four’s story.

First Steps also introduces the team in a separate, retro-styled universe rather than quietly folding it into the MCU’s main setting. That structural choice makes the Thunderbolts* signal more than a cameo alarm: the incoming vessel represents contact between worlds. Watching both films supplies the departure point and the arrival point, even though Marvel has not yet shown the journey between them.

Again, the whole film earns its place. The team’s public role, Reed and Sue’s family dynamic and Franklin’s importance are likely to matter more than memorizing every earlier screen version of the characters. The older Fantastic Four adaptations are not prerequisites; First Steps establishes a new continuity with its own cast and design language.

The order should therefore be Thunderbolts followed by The Fantastic Four: First Steps. Release chronology supports that sequence, and the repeated spacecraft image works cleanly: first as an unexplained arrival seen by the New Avengers, then as part of a fuller story about the family crossing into Doomsday’s orbit. Reversing the two would not cause confusion, but it would turn the Thunderbolts coda into confirmation rather than the intended interruption.

Keep Loki and the X-Men in the waiting room

Loki remains the most plausible addition to the list, particularly because its second season gives Loki a central role in maintaining branching timelines. A branch is an alternate version of events, and the series spends substantial time clarifying how those branches can coexist or collapse. That makes it useful vocabulary for Marvel’s multiverse stories.

Useful is not the same as confirmed. Tom Hiddleston’s announced return raises the probability that Loki’s current position matters, but the public story evidence does not yet show whether Doomsday will rely on the Time Variance Authority, revisit the series’ exact rules or use Loki in a more limited capacity. Two seasons are a large attention cost to assign on probability alone. Leave them off the core list until a trailer or synopsis makes the mechanism visible.

The earlier X-Men films belong in the same conditional category. If official footage establishes that Doomsday continues a particular film’s timeline, that title can be added rather than importing the entire series. X-Men and X2 might eventually provide the cleanest character baseline, while Days of Future Past could matter if the story explicitly invokes its altered history. For now, choosing among them would be editorial guesswork dressed as certainty.

Nor does Downey’s casting make Avengers: Infinity War and Avengers: Endgame compulsory refreshers. Those films remain the foundation for the MCU’s previous Avengers configuration, but Marvel has not publicly established that Doom inherits Tony Stark’s memories, face or personal relationships within the fiction. The resemblance may become the point. It may also be a casting choice that the characters never interpret as viewers do.

What would make the list expand

The threshold is straightforward: an official trailer, synopsis or released scene must connect a previous story’s unresolved event to Doomsday’s conflict. A character merely appearing does not clear it. Footage of Loki controlling a timeline problem would add Loki; dialogue locating the returning mutants within a named X-Men continuity would add the relevant film; a plot connection between Doom and Tony Stark would justify an Avengers refresher.

Until then, the two-film order saves a considerable block of time and preserves context that is demonstrably useful. It also avoids a common franchise-marketing trap, in which the possibility of a callback becomes an obligation to revisit everything that could be called back.

The premium-ticket question must wait even longer. Cast scale does not establish visual scale, and a large ensemble can produce a film dominated by rooms, close-ups and digitally combined cameos as easily as one designed around expansive action. Format advice should follow footage, aspect-ratio information and exhibition plans, not a row of chairs.

For now, the spacecraft at the end of Thunderbolts* remains the test. It links a formed team to an arriving one, while the First Steps coda places Doom inside the latter’s unfinished story. Everything beyond those two links is provisional homework, and provisional homework is still homework.

Questions people ask

What should I watch before Avengers: Doomsday?

Watch Thunderbolts* first, then The Fantastic Four: First Steps. Together they establish the New Avengers, the Fantastic Four’s separate universe, the vessel connecting those groups and Doctor Doom’s interest in Franklin Richards. No other released title has the same combination of direct setup and confirmed returning characters.

Do

I need to watch every X-Men movie before Avengers: Doomsday?

No. Returning actors confirm that X-Men characters appear, but Marvel’s public materials have not established which earlier timeline or events the film expects viewers to remember. Wait for a trailer or synopsis to identify the relevant continuity, then add the specific movie rather than restarting the full series.

Is

Loki required viewing for Avengers: Doomsday?

Not yet. Loki explains branching timelines and ends with its title character occupying a position that could matter to a multiverse conflict, but no released story material has confirmed how much of that machinery Doomsday uses. It is the first likely addition if official footage supplies the link.

Should

I rewatch Avengers: Endgame because Robert Downey Jr. plays Doctor Doom?

Only as an optional refresher. Marvel has announced Downey as Doom, but casting the former Iron Man actor does not by itself create a story connection between Doom and Tony Stark. Endgame becomes required preparation only if official material shows that Doomsday turns that resemblance or Stark’s history into part of its plot.