Avengers: Endgame Was Just the Opening Move: Every Secret Wars Setup You Missed

Say what you will about Endgame's headache-inducing time rules, but the movie quietly laid a ton of track for where Marvel wants to take Avengers: Secret Wars. Back in 2019, the plan clearly pointed to Kang as the next big problem. Even with the villain conversation shifting over the last year, the groundwork Endgame put down still fits whether we land on Kang or, if the current chatter pans out, a Doctor Doom played by Robert Downey Jr. (very much a rumor, but a loud one).

How Endgame quietly set the table for Secret Wars

• The Quantum Realm is basically a transit hub — The whole Time Heist runs on Pym Particles and the Quantum Realm, which Endgame positions as a space outside normal space-time. Later projects make it clear that it is not just for time-hopping; it can bridge dimensions too. Translation: the Avengers (or a Doom-level schemer) can use the Quantum Realm as a doorway between timelines and realities.
• Branching timelines become the rulebook — Endgame tosses out the 'change the past, change the future' idea and replaces it with branches. If you alter an event, you spin off a new reality instead of overwriting the main one (aka the Sacred Timeline). The movie takes us through eight different branches during the heist; six of those are temporary and get cleaned up by Steve returning the Stones at the end. Some of the branches, though, leave behind messy, useful hooks the MCU can revisit.
• The Ancient One quietly tees up incursions — When Bruce visits 2012, the Ancient One lays out the stakes of yanking a Stone from her timeline. She draws the classic glowing string diagram and warns about what happens if you remove a lynchpin from reality.

  'Take a Stone out, and you expose your reality to dark forces.'

  That is basically the first on-screen nudge toward incursions — universes colliding and destroying each other — which becomes a plot engine in Doctor Strange in the Multiverse of Madness and is a direct runway to Battleworld territory in Secret Wars.
• Variants are not just a Loki thing — Thanks to synced Nebulas, 2014 Thanos learns he wins, then dies, then the Avengers time-rob him. He pivots, jumps forward, and invades Earth-616's Sacred Timeline as a past-version variant. The movie demonstrates that an alternate-timeline version of a character can cross into the main reality and cause real damage. If Doom ends up being the endgame villain, expect the 'multiple variants in play' angle to matter.
• Loki's Tesseract detour lights up the TVA — In 2012, the Tesseract skitters to Loki, he zaps out, and the TVA snatches him because that was not supposed to happen. That intervention kicks off the broader multiversal crisis we see in Loki. By the end of Season 2, Loki is literally the God of Stories, holding the tree of timelines together. That positioning screams 'pivotal piece on the board' once universes start smashing into each other.
• Steve's happy ending adds instability — Cap returns the six Infinity Stones to their exact points of origin to stitch up those temporary branches. Then he chooses the life he never got with Peggy, which creates another branch where two Steves exist: one on ice and one growing old with her. That kind of duplication is textbook multiversal instability — exactly the sort of fracture that can snowball into incursions. If Doom is the final boss, this is the kind of crack he would love to pry open.

Why this matters if Kang changes, Doom arrives, or both

Endgame's rules — Quantum Realm transit, branches, variants, and the first whispers of incursions — are flexible enough to support either a Kang-centric path or a Doom takeover. Even the Thanos detour proves the MCU will pull in alternate versions of big characters when it serves the story. If the rumor mill is right about Robert Downey Jr. showing up as a Doom variant (again: rumor), Endgame still maps to that outcome.

Quick Endgame refresher

Directed by Joe and Anthony Russo, Avengers: Endgame stars Chris Evans, Robert Downey Jr., and Scarlett Johansson, hit theaters on April 26, 2019, pulled in a worldwide $2.7 billion, sits at 8.4/10 on IMDb and 94% on Rotten Tomatoes, and was produced by Marvel Studios. It is streaming on Disney+ if you want to rewatch the Time Heist with all this in mind.

Clock check

Avengers: Secret Wars is currently slated for December 17, 2027 in the U.S.