There are many majorMCUmysteries that Marvel Studios can solve after confirming the first actors cast inAvengers: Doomsday. The Russo brothers' upcoming crossover movies are two of Marvel’s most highly-anticipated projects ever, and this excitement has become more prominent after Marvel confirmed the first27 actors set to reappear in Phase 6’sAvengers:Doomsday. The 2026 movie will bring back many notable Marvel movie stars, including members of the Avengers, the Thunderbolts, the Fantastic Four and the X-Men, which means many loose ends can be wrapped up.
Sincethe likes of Anthony Mackie, Winston Duke, Simu Liu and Channing Tatum will be returning inAvengers: Doomsday, mysteries from these actors' last appearances in the MCU can easily be addressed. Marvel Studios will also need to explain how theclassic X-Men team can returnfrom 20th Century Fox’sX-Menfranchise, and, indeed, how Robert Downey Jr. can portray Doctor Doom after playing Iron Man. WhileDoomsdaywill surely address many unanswered mysteries, these eight might be the most crucial stories the MCU can explore.
8Who Will Be In The MCU’s Official New Avengers Team?
Captain America: Brave New World Teased The MCU’s New Avengers
At long last, seven years after the team was last seen on-screen,Doomsdaywill be bringing together anew version of the Avengers.The team’s rebuilding was recently teased in 2025’sCaptain America: Brave New World, as Sam Wilson was urged to bring them back together, and while this didn’t come to fruition in the Phase 5 movie, it will inAvengers:Doomsday. Sam Wilson and Joaquín Torres have been teased as the first two official members, Captain America and the Falcon, and Marvel may have just confirmed even more.
I Can’t Believe I Forgot That 1 Missing Avengers: Doomsday Actor Has Already Confirmed They’ll Be In It
After Avengers: Doomsday’s cast announcement left some fan-favorite heroes out, it’s good to remember that one major character was already confirmed.
It’s possible thatDoomsday’snew Avengers team could comprise Anthony Mackie’s Captain America, Danny Ramirez’s Falcon, Chris Hemsworth’s Thor, Letitia Wright’s Shuri, Tenoch Huerta Mejía’s Namor, Simu Liu’s Shang-Chi, Winston Duke’s M’Baku and Paul Rudd’s Ant-Man. There are manymissing potential Avengers memberswe’d love to see still confirmed forAvengers: Doomsday, including the likes of Captain Marvel, the Hulk, She-Hulk, Spider-Man and more.It’s been so long since we’ve seen the Avengers in live-action, it will be very exciting to see a new version of the team form inDoomsday.
7How Will Monica Rambeau Get Back To Earth-616?
Monica Rambeau Was Trapped In An Alternate Universe In The Marvels
The ending of 2023’sThe Marvelssaw Teyonah Parris' Monica Rambeau use her powers to mend a hole in the fabric of reality, but become trapped on the other side. While Parris hasn’t been confirmed to be returning inAvengers: Doomsday, there has still been a huge hint that this cliffhanger ending will be resolved, asKelsey Grammer will be returning as Beast inDoomsday.Grammer reprised his role from 2006’sX-Men: The Last StandinThe Marvels, appearing as the Beast ofThe Marvels’alternate universe, so his return suggests this reality will be revisited.
Some have theorized thatThe Marvels’alternate world could be that of Fox’sX-Menfranchise, designated Earth-10005, but it’s unclear whether this is the case. It’s possible Marvel Studios may have introduced a new variation of the X-Men, one that even includesLashana Lynch’s Maria Rambeau as Binary, an enhanced version of Captain Marvel.Grammer could be returning as Beast fromX-Men: Days of Future Past’srevised timeline, but it would be fantastic to seeThe Marvels’cliffhanger ending get addressed, so hopefully Teyonah Parris and Lashana Lynch also get cast inDoomsday.
6Is M’Baku The New King Of Wakanda?
M’Baku Challenged For The Throne In Black Panther: Wakanda Forever
Winston Duke’s confirmation forAvengers: Doomsdaysuggests Wakanda will play a key role in the Phase 6 movie, especially since both Letitia Wright and Tenoch Huerta Mejía have also been announced.Duke’s M’Baku, the leader of Wakanda’s Jabbari tribe, has gone from minor villain to steadfast hero and confidant to Shuriover the duration of theBlack Pantherfranchise. 2022’sBlack Panther: Wakanda Forever, however, ended withM’Baku being teased for a much larger role, as he was seemingly the sole challenger for the throne of Wakanda.
M’Baku would make the fifth ruler of Wakanda on-screen in the MCU, following in the footsteps of Bashenga, T’Chaka, T’Challa and Ramonda.
Avengers: Doomsdaycould easily bring Winston Duke back to the MCU as King of Wakanda, granting him even more power and influence, and perhaps changing Wakanda significantly beforeRyan Coogler’sBlack Panther 3explores this in more detail.M’Baku in the MCU would make a fine King, much stronger and more heroic than his Marvel Comics counterpart, and he would be a fantastic asset to the Wakanda-set stories inAvengers: Doomsday. While M’Baku may be Wakanda’s King, Shuri will still be the Black Panther, at least for the time being anyway.
5What Happened To Gambit After Leaving The Void In Deadpool & Wolverine?
Gambit Left The Void In Deadpool & Wolverine’s Deleted Scene
After almost two decades of lobbying for the role, first auditioning forX-Men: The Last Standand later being promised a solo movie that never came to fruition, Channing Tatum finally debuted asRemy LeBeau’s Gambit in 2024’sDeadpool & Wolverine. Tatum’s performance garnered a huge amount of praise, which spurred speculation of his return in the MCU’s officialX-Menprojects or in a finally-realized solo movie. However,Tatum’s next MCU appearance will, in fact, be inAvengers: Doomsday, which will see him team-up with the X-Men team for the first time ever.
“It Was Just My Name, It Wasn’t Exactly Gambit:” Channing Tatum Addresses Casting In Avengers: Doomsday, Hints He May Not Play Gambit
Channing Tatum addresses his return as Gambit in Avengers: Doomsday, joking that he may not be playing the same character from Deadpool & Wolverine.
It could be assumed that Channing Tatum’s version of Gambit inAvengers: Doomsdaywill be the same that Deadpool and Wolverine partnered with in the Void at the End of Time in their eponymous 2024 movie. Adeleted scene fromDeadpool & Wolverinerevealed thatGambit was set to leave the Void through a “Marvel Sparkle Circle,” a portal created by the Master of the Mystic Arts.Avengers: Doomsdaycan confirm whether this is still the case, and, if so, who saved Gambit from the Void, explaining Channing Tatum’s long-anticipated return perfectly.
4Who Is Shang-Chi’s Ten Rings Beacon Signaling Across The Cosmos?
Wong Revealed The Ten Rings Sending A Beacon In Shang-Chi & The Legend Of The Ten Rings
While Phase 4 was altogether rather divisive, there were several projects that have received universal acclaim among MCU audiences. One of these was 2021’sShang-Chi and the Legend of the Ten Rings, which introducedSimu Liu’s titular Shang-Chi to the MCUand answered mysteries concerning the Ten Rings organization that has been in the MCU since the very beginning. However,Shang-Chi and the Legend of the Ten Ringsalso created mysteries of its own, particularly in apost-credits scene that saw Wong, Bruce Banner, Carol Danvers, Katy and Shang-Chi examine a beacon in the latter’s mystical bangles.
Initially, theories suggested this mysterious beacon could have been signaling a variant of Kang the Conqueror, but Marvel Studios' reshuffling of the MCU and altering ofAvengers: The Kang DynastyintoDoomsdaysuggest something different. Instead, it’s possibleShang-Chi’s beacon could point directly to Doctor Doomor another universe.It will be fantastic to finally see Simu Liu back in action inAvengers: Doomsday, and even more exciting to get the rings' unanswered beacon mystery explored, as this alone could kick-start the events of the Phase 6 crossover.
3What Happened When Professor X Killed The X-Men Before Logan?
Avengers: Doomsday May Take Place Before The Events Of Logan
2017’sLogan, which was, at the time, Hugh Jackman and Patrick Stewart’s final movie as Wolverine and Professor X, respectively, was set in 2029, the future of Fox’sX-Menfranchise. A year prior,Charles Xavier’s seizure had caused the death of the X-Men and many others, and this timeline could correlate with the continuity ofAvengers: Doomsday. With several members ofFox’s X-Men team set to return inDoomsday, including Stewart himself, the Phase 6 movie might be the last opportunity for Marvel to explore this intense and dramatic storyline.
Deadpool & Wolverine(2024)
It would be thrilling to seeProfessor X accidentally cause the deaths of the classic X-Men teaminAvengers: Doomsday, setting the stage for the events ofLogan, and kick-starting a new chapter for the X-Men in the MCU’s main continuity. This event has never been depicted on-screen, but now is the time, asthis might be the last time that the likes of Patrick Stewart, James Marsden and Alan Cumming reprise their roles. It would also be great to see Hugh Jackman confirmed to return as Wolverine, perhaps alongside the likes of Halle Berry and Famke Janssen, among others.
2How Did Earth-838’s Other Heroes React To The Scarlet Witch’s Attack?
Avengers: Doomsday Is The Perfect Place For Earth-838 To Be Revisited
2022’sDoctor Strange in the Multiverse of Madnesswas the first MCU project to explore alternate realities in any kind of detail, asBenedict Cumberbatch’s Doctor Strange and Xochitl Gomez’s America Chavez journeyed to Earth-838 to escape the Scarlet Witch. However, Elizabeth Olsen’s hero-turned-villain followed them andmassacred Earth-838’s Illuminati, killing that reality’s Mister Fantastic, Black Bolt, Captain Marvel, Professor X and Captain Carter. The deaths of these heroes must have caught the attention of the world’s other characters, which could come to a head inAvengers: Doomsday.
Earth 838’s Illuminati comprised Patrick Stewart’s Professor X, John Krasinski’s Mister Fantastic, Anson Mount’s Black Bolt, Hayley Atwell’s Captain Carter, Chiwetel Ejiofor’s Baron Mordo, the Sorcerer Supreme and Lashana Lynch’s Captain Marvel.
It’s possible that Earth-838’s variants of the Invisible Woman and the Fantastic Four, Carol Danvers, Magneto and the X-Men, the Inhumans and even the Avengers could appear inDoomsday. This could explain many ofDoomsday’sreturning actors, while it would be great to see others also be confirmed, such as Chris Evans, Brie Larson and more.It would be great to see the aftermath of the Scarlet Witch’s attack on Earth-838 explored inDoomsday, and this reality could be expanded by debuting some returning actors as comic-accurate variants, perhaps as a new Illuminati team.
1Why Does Doctor Doom Look Like Tony Stark?
Robert Downey Jr. Will Play Doctor Doom In Phase 6, Not Iron Man
Perhaps the biggest mystery that Marvel Studios needs to address inAvengers: Doomsdayis exactly howRobert Downey Jr. can debut as Victor Von Doom, a.k.a. the supervillain known as Doctor Doom.Downey Jr. played Tony Stark’s Iron Man for eleven years in the MCU between 2008’sIron Manand 2019’sAvengers: Endgame, in which Stark sacrificed himself to defeat Thanos and save the universe. Since then, Downey Jr. has taken home an Academy Award, so it’s no wonder Marvel Studios wanted to snap him up for another iconic Marvel role, but this has caused some confusion.
How Robert Downey Jr.’s Doctor Doom Can Still Be A Tony Stark Variant Explained In Shocking MCU Theory
A shocking new MCU theory could explain how Robert Downey Jr.’s Doctor Doom can be both Victor Von Doom and a Tony Stark variant in Phase 6.
It hasn’t yet been revealed what the connection betweenTony Stark and Victor Von Doomwill be inAvengers: DoomsdayandSecret Wars, though the Russo brothers have teased that Stark’s legacy will be significant somehow.Theories have suggested that Doom and Stark could be variants of each other, or Doom could have somehow claimed Stark’s face. This will present some key challenges for the MCU’s heroes who knew Iron Man, but will also need some explaining inAvengers: Doomsday, as while Downey Jr.’s casting is exciting, it can’t simply be overlooked and unexplained.
