WHAT YOU NEED BEFORE DOOMSDAY

Earth-616 is the main reality, and there are infinite others; a version of the same person in another one is a variant. Two of those realities matter in December, and both used to be legal problems rather than plot points: the Fox X-Men films are Earth-10005, and the Fantastic Four live in a separate retro-futurist universe of their own.

The Infinity Stones are finished. Six singularities that predate the universe, and the engine of the first twenty-three films. Thanos used them a second time to destroy them; the survivors then borrowed the past versions in 2023 for the two snaps that undid him, and returned each one to the exact instant it was taken so that no branch would form. The Stones are not this saga's object. The multiverse is.

The Sacred Timeline and the TVA. For eleven years of films the multiverse did not visibly exist, because the Time Variance Authority was actively pruning any timeline that deviated from a single approved one. Every TVA agent is an abducted, memory-wiped variant living a manufactured life and believing it completely. Loki Season 1 reveals this, and it retroactively explains the silence.

The Blip. Thanos erased half of all life in 2018 and the survivors reversed it in 2023. The vanished returned the same age, having experienced no time at all, to a world that had aged five years without them — causing housing crises, refugee organisations, identity fraud, grief and resentment that later films actually deal with. It affected the entire universe, but only that universe, which is why the Peters from other realities in No Way Home have no Blip in their histories.

Two sagas. The Infinity Saga is Phases 1–3 — villain Thanos, object the Stones. The Multiverse Saga is Phases 4–6 — villain originally Kang, now Doctor Doom, object the multiverse itself.

The switch was a mid-course correction and it shows in the seams: several Phase 4 and 5 setups now point at nothing in particular. If parts of the middle feel unresolved, that is because they are.

He Who Remains — a 31st-century scientist who discovered the multiverse, watched his own variants wage a war that destroyed nearly everything, and won by isolating one timeline and pruning all others — built the TVA, wrote its mythology, and then offered Loki and Sylvie a choice: take over from him, or kill him and let the branches run freely.

Sylvie kills him. Loki disagrees and argues they should stop and think, because the alternative is a multiversal war; she kisses him, pushes him through a time door, and does it alone. The multiverse opens. That is the inciting incident of the entire saga.

The TVA's Temporal Loom was engineered to weave one timeline and cannot weave infinite ones, so after Sylvie's kill it moves toward a detonation that would destroy everything. In Season 2 Loki works out that the machine exists to limit the multiverse rather than sustain it, destroys it, walks out into the raw timelines, gathers the dying branches in his hands and holds them together himself — alone on a throne at the end of time.

He is currently the thing preventing the multiverse from collapsing, and he is confirmed in the Doomsday cast. That combination makes this the single most likely piece of setup for the film.

Two other breaches matter. Strange's botched memory spell in No Way Home reached into other universes for anyone who knew that Peter Parker is Spider-Man, and was closed only by making everyone in every universe forget he existed. And Multiverse of Madness named the mechanism worth watching for: incursions, where two universes physically collide and one or both are destroyed.

Incursions are the most likely mechanism for whatever Doom does.

If you carry nothing else forward, carry these.

1. There are two Lokis. The one who took the Tesseract in Ragnarok is dead — Thanos killed him in Infinity War. The one who is alive today is a 2012 variant who branched off during Endgame's time heist and never lived through any of it.
2. Wanda has no sister. Pietro is her twin brother, and he died in Age of Ultron. The Pietro in WandaVision is a fake.
3. Isaiah Bradley was already a super-soldier. John Walker is a different man entirely with no serum, which is why he takes one.
4. Thor did kill Thanos — the 2018 one, in the first ten minutes of Endgame. The one in the final battle is a 2014 version pulled forward in time, who has never snapped and never held the Stones.
5. Gamora is not resurrected. The one who died on Vormir is permanently dead. The one who is alive is a 2014 version stranded in the present with no memory of anyone.
6. The Multiverse Saga changed villains mid-run. Kang was the plan until 2023; Doom is the plan now. Several Phase 4 and 5 setups therefore point at nothing.

There are two Avengers-shaped organisations, and they are in a trademark dispute. The first is Sam Wilson's — Sam as Captain America, Joaquín Torres as the new Falcon — small, and being rebuilt since Brave New World.

Isaiah Bradley stands with it as an ally rather than an operative.

The second is the New Avengers: Yelena Belova, Bucky Barnes, John Walker, Ghost, Alexei Shostakov and Bob Reynolds, operating from the rebranded Avengers Tower — "the Watchtower" — with Valentina Allegra de Fontaine nominally in charge and actually under their control.

Sam is not a member of the second group, and the tension is explicit: the Thunderbolts* post-credits has him arguing that they do not get to call themselves the Avengers at all.

Whether they reconcile is presumably a Doomsday plot point — both Sam and the entire Thunderbolts roster are in the cast, so they end up in the same room.

Staying dead. Tony Stark, who took the Stones, erased Thanos and his entire army, and died doing it. Natasha Romanoff, on Vormir, for the Soul Stone. Vision — though his rebuilt body, White Vision, flew off with the original's memories and is the subject of VisionQuest. Pietro Maximoff, in 2015. T'Challa, of an undisclosed illness between films. Ramonda, killed by Talokan forces. Jane Foster, of cancer, having chosen to fight anyway. Odin, Frigga, Heimdall and Hela. Aunt May, killed by the Green Goblin. Maria Hill, in Secret Invasion. Foggy Nelson, killed by Bullseye on Vanessa Fisk's instruction. And Thanos, erased from existence — both versions.

Kang is finished as well. Jonathan Majors was fired by Disney in December 2023, Avengers: The Kang Dynasty was cancelled, Doctor Doom replaced him as the saga's antagonist, and there is no announced plan to recast.

Alive and load-bearing. Steve Rogers, who lived a full life in the past and returned as an old man to hand the shield over. Thor, raising Gorr's daughter Love. Sam Wilson, Captain America with no enhancement whatsoever, which is precisely the point. Bucky Barnes, a congressman, with his HYDRA conditioning confirmed gone on screen. Loki, the 2012 variant, at the end of time. Shuri, the current Black Panther. Namor and Namora, in an uneasy truce. Scott and Cassie Lang. Shang-Chi, holding the ten rings, with Xialing running the Ten Rings organisation. Bruce Banner as Smart Hulk, with a son, Skaar, on Sakaar. Stephen Strange, with a third eye from the Darkhold. Wong, Sorcerer Supreme. Clint Barton, retired to the farm and mentoring Kate Bishop. Carol Danvers, mostly in deep space. Valkyrie, King of New Asgard.

Alive, but somewhere strange. Peter Parker has been erased from everyone's memory — no family, no friends who know him, a rented apartment and a homemade suit — and Brand New Day's post-credits scene has Ned's tracking app pinpointing Spider-Man somewhere in deep space. Monica Rambeau is stranded in another universe, the one with Beast and Charles Xavier in it. Matt Murdock is publicly unmasked and under arrest for vigilantism, after a public trial that ended with Wilson Fisk forced out of the mayoralty.

Wanda Maximoff is presumed dead under Mount Wundagore, having destroyed every copy of the Darkhold across every universe first.

No body is shown, and a scream is audible from the rubble, so Marvel deliberately left it ambiguous — and Elizabeth Olsen is not listed for Doomsday.

The Fantastic Four: First Steps is set in a separate universe with a retro-futurist 1960s aesthetic, not on Earth-616. Galactus offers to spare their Earth in exchange for Franklin Richards, whose cosmic potential could take on his hunger permanently. They refuse. Sue expends everything she has to push Galactus into a portal and dies — and Franklin, days or weeks old, reaches out, touches her, and she revives. No explanation is offered, which is the point: he is an infant with power nobody understands, including his parents.

Then the mid-credits, four years later. Sue leaves Franklin alone for a moment and returns to find a man in a green cloak holding a metal mask standing over him. That is Victor von Doom's first on-screen MCU appearance, and it is silent.

How the Four reach Earth-616 is never shown.

The Thunderbolts* post-credits — an extradimensional craft marked with a 4 arriving on Earth-616 — is the arrival, and Doomsday presumably covers the mechanism.

Franklin's own reality-altering ability is the most-cited fan explanation.

Marvel has said this film flows directly into Doomsday.

Fox held the film rights to the X-Men and the Fantastic Four for decades and made thirteen X-Men films in their own continuity, entirely separate from the MCU. Disney bought Fox in 2019. Rather than erase those films, Marvel designated that continuity Earth-10005 and had Deadpool & Wolverine formally fold it into the multiverse.

That film also saves it. Logan was Earth-10005's anchor being — an individual so central to a reality that when they die, the universe unravels around them — and rescuing that universe from deletion is precisely why Patrick Stewart, Ian McKellen, Kelsey Grammer, Alan Cumming, Rebecca Romijn and James Marsden can appear in Doomsday as those exact characters, decades later.

Whether they are the exact individuals from the original trilogy or variants of them is not confirmed; the trailer suggests the former, and Marvel has not said.

The groundwork was laid a film earlier, in The Marvels: Monica wakes on the far side of a rift she closed from the wrong side, in a white medical facility, beside a Maria Rambeau who never had a daughter, and her doctor is Kelsey Grammer's Beast, mentioning that "Charles asked for an update." The scene uses John Ottman's score from X2 and Days of Future Past, which is the signal that this is the Fox universe.

One further piece of groundwork sits in the physical geography. The half-emerged Celestial corpse in the Indian Ocean — now "Celestial Island" — is made of adamantium, the metal bonded to Wolverine's skeleton and claws in the Fox films.

Putting a giant deposit of it into Earth-616 is deliberate groundwork for a Wolverine who originates here rather than being imported.

Released 18 December 2026, directed by Joe and Anthony Russo. Marvel's own synopsis describes heroes from three distinct universes set on a collision course against an existential threat.

The three are Earth-616, the Fantastic Four's retro universe, and the Fox X-Men's Earth-10005.

From the trailer: Doom on a throne; Sue Storm narrating that Victor was once different, that he was always the smartest person in the room, that everything he loved was taken from him; the Fantastic Four having a prior history with him; a destroyed New York.

The confirmed cast, by faction. The New Avengers: Yelena, Bucky, John Walker, Ghost, Red Guardian, Sentry. The Fantastic Four: Reed, Sue, Johnny, Ben. The Fox X-Men: Xavier, Magneto, Beast, Nightcrawler, Mystique, Cyclops, and Channing Tatum as Gambit. Wakanda and Talokan: Shuri, M'Baku, Namor, Namora. Returning from Earth-616: Thor, Steve Rogers, Sam Wilson, Scott Lang, Cassie Lang, Shang-Chi, Loki and Joaquín Torres. The antagonist: Robert Downey Jr. as Victor von Doom. Charlie Cox's Daredevil has been reported as involved, though he does not appear on the headline listing.

Notably absent: Tom Holland, and neither is Mark Ruffalo. Also absent are Elizabeth Olsen and Idris Elba, both consistent with those characters being dead.

The reporting consensus is that Spider-Man's absence is deliberate, and that Brand New Day's post-credits sets up Secret Wars (2027) rather than Doomsday.

Marvel routinely omits cameos from cast lists, so absence is not proof either way.

Avengers: Secret Wars follows on 17 December 2027 and concludes the Multiverse Saga. Kevin Feige has ruled out splitting it into two films.

Whether Doom is a variant of Tony Stark. It is the most-repeated fan theory, it rests on the casting, Marvel has not confirmed it, and it may be a red herring.

How the universes are brought together. Incursions are the likeliest mechanism, and Loki holding the multiverse together at the end of time is likely to matter, but neither has been stated.

How Steve Rogers stayed in the past. The directors and the screenwriters have publicly given contradictory answers, and Marvel has never picked one.

With Chris Evans confirmed in the cast, whichever answer Doomsday picks will probably become canon retroactively — so do not over-invest in explaining it before December.

Two further holes are Marvel's rather than this document's. Howard Stark's vibranium: Klaue's theft from Wakanda is dated 1992, decades after the shield was made, and the earlier supply chain has never been explained. Returning the Soul Stone: Rogers goes back to Vormir, Natasha does not come back, and how you return a Stone that cost a life is never addressed.

Finally, the dead ends, so you do not sit waiting for them: the Council of Kangs, Victor Timely, and He Who Remains's warnings about his variants now lead nowhere.

And several characters have simply stopped being mentioned rather than being resolved — Mordo, the Grandmaster, Arishem, Skaar, Adam Warlock, and the Eternals taken for judgment.

The fifteen load-bearing titles run about 33 hours in this order: The Avengers, Age of Ultron, Civil War, Infinity War, Endgame, Loki Season 1, Shang-Chi, No Way Home, Multiverse of Madness, Wakanda Forever, Loki Season 2, Deadpool & Wolverine, Brave New World, Thunderbolts*, and The Fantastic Four: First Steps.

Three traps if you are catching up rather than rewatching. Do not watch Loki Seasons 1 and 2 back to back — they are separated by two years and by Quantumania, and Victor Timely reads differently after it. Watch Hawkeye episodes 1–5, then No Way Home, then the finale, because the finale aired five days after the film opened. And skip Black Widow's post-credits scene until you reach Hawkeye, since it takes place years after the rest of that film.

And the one thing most worth carrying into December: Doom is not a villain-of-the-week. In the comics he is the Fantastic Four's antagonist first, and the fact that First Steps ends with him standing silently over Franklin Richards is the actual load-bearing setup — more than anything in Quantumania or Loki. Watch that mid-credits scene twice.