A brutalMCUfan theory predictsAvengers: Doomsdaywill bring back Josh Brolin’s Thanos only for Robert Downey Jr.’s Doctor Doom to kill him in the opening scene.Avengers: Doomsday’s cast announcementconfirmed the return of over two dozen Marvel characters, including the Thunderbolts, the Avengers, and Fox’s multiversal X-Men. Other MCU characters may also return, either in major roles that haven’t been announced yet or in cameo appearances that make the most out ofAvengers: Doomsday’s multiversal premise. Some of these supporting characters may include TVA agents, minor MCU heroes, and assorted mutants from different X-Men timelines.
The concept of the multiverse opens up countless possibilities forAvengers: DoomsdayandAvengers: Secret Wars.Avengers: Infinity WarandAvengers: Endgameexceeded all expectations regarding cameos, going as far as featuring cameos such as Red Skull, Howard Stark and Jarvis, Frigga, the Ancient One, Alexander Pierce, Crossbones, and Harley Keener.Avengers: DoomsdayandAvengers: Secret Warscan up the ante with new cameos by characters from all over the Marvel multiverse. Aside from characters fromFox’s multipleX-Mentimelines,Fantastic Fouruniverses, and possibly Sony’s Spider-Man universes, Phase 6’s crossover movies could introduce new variants of established MCU characters.

Doctor Doom Kills Thanos In Marvel Comics’ 2015 Secret Wars
One Of Doctor Doom’s Greatest Feats Of Power Is Killing Thanos With His Bare Hands
The MCU’sAvengers: DoomsdayandAvengers: Secret Warswill likely draw a lot of inspiration from Marvel Comics' severalSecret Warsstorylines, including 2015’s highly popularSecret Wars. Prior to this comic book run, Thanos joins forces with villains like Terrax, Maximus, Proxima Midnight, and Namor to destroy universes that are on course to collide with Earth-616. Betrayed by Namor, Thanos and the rest of his team — the Cabal — meet the Ultimate Universe Reed Richards, better known as “The Maker”, and survive Earth-616’s collision with Earth-1610, which leads to the creation of Battleworld and the rise of God Emperor Doom.
After Avengers: Doomsday’s Cast List Reveal, I’m Convinced That Avengers: Doomsday Is Going To Make Doctor Doom Stronger Than Thanos
New details for Avengers: Doomsday suggest that Doctor Doom could actually be the most terrifying force that the Avengers have yet had to face.
God Emperor Doom’s right-hand man, Doctor Strange, sends Thanos to a Battleworld realm inhabited by zombie versions of Marvel characters. Thanos survives the zombies' attack and escapes, helps create an insurrection against God Emperor Doom’s reign, and decides to confront Doom all by himself. Unimpressed,Doom acknowledges the fact that Thanos isn’t wielding the Infinity Stones in his gauntlet, ignores Thanos' threats, and punches a hole through his chest. God Emperor Doom then mocks Thanos as he rips the Mad Titan’s spine from his body. While Thanos eventually resurrects, hisSecret Warsdeath continues to be his most humiliating defeat.

Avengers: Doomsday Has The Chance To Replicate Secret Wars’ Most Brutal Doctor Doom Moment
Thanos' Death Could Be Doctor Doom’s Best Way To Show Off His Power
AlthoughAvengers: DoomsdayandAvengers: Secret Warsare very likely to be based on Marvel Comics’Time Runs OutandSecret Warsstorylines, the MCU won’t adapt the comic books panel-for-panel, as the Multiverse Saga would have needed to follow a significantly different story beforehand. Nevertheless,Marvel Studios could easily adapt God Emperor Doom’s most brutal moment from 2015’sSecret Warsby openingAvengers: Doomsdaywith a powerful variant who meets his end at the hands of Robert Downey Jr.’s Doctor Doom in an alternate timeline. This timeline could be Doctor Doom’s original universe or a distant reality he invades.
Avengers: Doomsday’s opening scene could be the best moment to establish the true extent of Doom’s power and ambition

The on-screen death of a live-action Thanos variant played by Josh Brolin would be an appropriate cameo for a movie the scope ofAvengers: Doomsday.Avengers: Doomsdaymight also be one of the few places where Doctor Doom’s most brutal feats of power could fit, asthe Multiverse Saga’s conclusionmight take with it the possibility of seeing a live-action Thanos on the big screen again. And while Doctor Doom’s murder of Thanos could also take place inAvengers: Secret Wars,Avengers: Doomsday’s opening scene could be the best moment to establish the true extent of Doom’s power and ambition.
Thanos’ Death In Avengers: Doomsday Would Repeat A Great Infinity War Trick
Avengers: Doomsday’s Opening Scene Has The Chance To Flip Loki’s Infinity War Death
Avengers: Infinity War’s opening sequence saw Thanos decimate the Asgardian survivors fleeing Asgard’s destruction. Thanos' attack claimed the lives of Heimdall and countless other Asgardians. Most notably, Loki failed to trick Thanos and hide the Tesseract, leading Thanos to break Loki’s neck and bring a definitive end to the original God of Mischief’s life.Loki’s death inAvengers: Infinity Warfollows a very similar structure to Thanos' death in 2015’sSecret Wars, including the victim’s threatening final words and the murderer’s brutal killing method.InAvengers: Doomsday, Doctor Doom could give an alternate-universe Thanos a taste of his own medicine.
Loki’s Death And The Destruction Of All Universes Will Be Avengers: Doomsday’s Version Of Thanos' Snap In Infinity War According To Devastating Marvel Theory
A bleak Avengers: Doomsday theory showcases how Tom Hiddleston’s Loki could die and lead to an Infinity War-level dark ending for the MCU movie.
Similarly to howAvengers: Infinity Warbrought backThe Avengers' main villain just to kill him off during the opening sequence,Avengers: Doomsdaycould bring backAvengers: Infinity War’s main villain and kill him off during its opening scene in order to prove just how powerful Doctor Doom is in comparison. This is exactly what Marvel Comics' 2015Secret Warsdid with Thanos' brutal death, and it could have an even clearer effect on the big screen considering that Thanos was the Infinity Saga’s overarching villain and the one who led many key MCU characters to their death, including Loki.

Marvel Has Already Proved Thanos’ Best Future Is Propping Up Other Villains
Thanos Might Only Return In One-Off Appearances That Kill Him Off Immediately
Ever since Iron Man performed the third snap to kill Thanos and his forces inAvengers: Endgame,the MCU has brought Thanos back multiple timesjust to kill him off immediately afterward.Ronan, Killmonger, Infinity Ultron, and an alternate-universe horde of zombies have been some of the characters who killed alternate Thanos variants inWhat If…?, and Earth-838’s Illuminati apparently stabbed the Mad Titan with his own sword on Titan years before the events ofDoctor Strange in the Multiverse of Madness. Robert Downey Jr.’s Doctor Doom could join the growing list of Thanos killers inAvengers: Doomsday’s opening scene.
The only way Marvel Studios might be able to bring the Mad Titan back without undoingAvengers: Endgamemight be by killing off his multiversal variants

While Thanos is a villain with enough potential for multiple new appearances, the only way Marvel Studios might be able to bring the Mad Titan back without undoingAvengers: Endgamemight be by killing off his multiversal variants. If Thanos came back as a genuine threat, the dramatic weight of the original Thanos' defeat inAvengers: Endgamecould be diminished, as the original variant would no longer seem unique. Killing off too many Thanos variants also risks turning the villain into a joke character. Therefore, Marvel could retire the Mad Titan for good with a final send-off inAvengers: Doomsday.
X Alternate-universe Thanos variants made cameos dying inWhat If…?andDoctor Strange in the Multiverse of Madness. This might be the only way to bring back Thanos effectively, as depicting him as an actual threat would undoAvengers: Endgame’s ending.



