There are many major MCU mysteries that Marvel Studios can solve after confirming the first actors cast in Avengers: 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 first 27 actors set to reappear in Phase 6’s Avengers: 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.

Since the likes of Anthony Mackie, Winston Duke, Simu Liu and Channing Tatum will be returning in Avengers: Doomsday, mysteries from these actors’ last appearances in the MCU can easily be addressed. Marvel Studios will also need to explain how the classic X-Men team can return from 20th Century Fox’s X-Men franchise, and, indeed, how Robert Downey Jr. can portray Doctor Doom after playing Iron Man. While Doomsday will surely address many unanswered mysteries, these eight might be the most crucial stories the MCU can explore.

8

Who 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, Doomsday will be bringing together a new version of the Avengers. The team’s rebuilding was recently teased in 2025’s Captain 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 in Avengers: 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.

It’s possible that Doomsday’s new Avengers team could comprise Anthony Mackie’s Captain America, Danny Ramirez’s Falcon, Chris Hemsworth’s Thor, Leтιтia 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 many missing potential Avengers members we’d love to see still confirmed for Avengers: 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 in Doomsday.

7

How Will Monica Rambeau Get Back To Earth-616?

Monica Rambeau Was Trapped In An Alternate Universe In The Marvels

The ending of 2023’s The Marvels saw 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 in Avengers: Doomsday, there has still been a huge hint that this cliffhanger ending will be resolved, as Kelsey Grammer will be returning as Beast in Doomsday. Grammer reprised his role from 2006’s X-Men: The Last Stand in The Marvels, appearing as the Beast of The Marvels’ alternate universe, so his return suggests this reality will be revisited.

Some have theorized that The Marvels‘ alternate world could be that of Fox’s X-Men franchise, 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 includes Lashana Lynch’s Maria Rambeau as Binary, an enhanced version of Captain Marvel. Grammer could be returning as Beast from X-Men: Days of Future Past’s revised timeline, but it would be fantastic to see The Marvels’ cliffhanger ending get addressed, so hopefully Teyonah Parris and Lashana Lynch also get cast in Doomsday.

6

Is M’Baku The New King Of Wakanda?

M’Baku Challenged For The Throne In Black Panther: Wakanda Forever

Winston Duke’s confirmation for Avengers: Doomsday suggests Wakanda will play a key role in the Phase 6 movie, especially since both Leтιтia 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 Shuri over the duration of the Black Panther franchise. 2022’s Black Panther: Wakanda Forever, however, ended with M’Baku being teased for a much larger role, as he was seemingly the sole challenger for the throne of Wakanda.

Avengers: Doomsday could easily bring Winston Duke back to the MCU as King of Wakanda, granting him even more power and influence, and perhaps changing Wakanda significantly before Ryan Coogler’s Black Panther 3 explores 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 ᴀsset to the Wakanda-set stories in Avengers: Doomsday. While M’Baku may be Wakanda’s King, Shuri will still be the Black Panther, at least for the time being anyway.

5

What Happened To Gambit After Leaving The Void In ᴅᴇᴀᴅpool & Wolverine?

Gambit Left The Void In ᴅᴇᴀᴅpool & Wolverine’s Deleted Scene

After almost two decades of lobbying for the role, first auditioning for X-Men: The Last Stand and later being promised a solo movie that never came to fruition, Channing Tatum finally debuted as Remy LeBeau’s Gambit in 2024’s ᴅᴇᴀᴅpool & Wolverine. Tatum’s performance garnered a huge amount of praise, which spurred speculation of his return in the MCU’s official X-Men projects or in a finally-realized solo movie. However, Tatum’s next MCU appearance will, in fact, be in Avengers: Doomsday, which will see him team-up with the X-Men team for the first time ever.

It could be ᴀssumed that Channing Tatum’s version of Gambit in Avengers: Doomsday will be the same that ᴅᴇᴀᴅpool and Wolverine partnered with in the Void at the End of Time in their eponymous 2024 movie. A deleted scene from ᴅᴇᴀᴅpool & Wolverine revealed that Gambit was set to leave the Void through a “Marvel Sparkle Circle,” a portal created by the Master of the Mystic Arts. Avengers: Doomsday can confirm whether this is still the case, and, if so, who saved Gambit from the Void, explaining Channing Tatum’s long-anticipated return perfectly.

4

Who 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’s Shang-Chi and the Legend of the Ten Rings, which introduced Simu Liu’s тιтular Shang-Chi to the MCU and 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 Rings also created mysteries of its own, particularly in a post-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 of Avengers: The Kang Dynasty into Doomsday suggest something different. Instead, it’s possible Shang-Chi’s beacon could point directly to Doctor Doom or another universe. It will be fantastic to finally see Simu Liu back in action in Avengers: 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.

3

What Happened When Professor X Killed The X-Men Before Logan?

Avengers: Doomsday May Take Place Before The Events Of Logan

2017’s Logan, 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’s X-Men franchise. 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 of Avengers: Doomsday. With several members of Fox’s X-Men team set to return in Doomsday, including Stewart himself, the Phase 6 movie might be the last opportunity for Marvel to explore this intense and dramatic storyline.

It would be thrilling to see Professor X accidentally cause the deaths of the classic X-Men team in Avengers: Doomsday, setting the stage for the events of Logan, 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, as this 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.

2

How 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’s Doctor Strange in the Multiverse of Madness was the first MCU project to explore alternate realities in any kind of detail, as Benedict 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 and mᴀssacred 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 in Avengers: Doomsday.

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 in Doomsday. This could explain many of Doomsday’s returning 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 in Doomsday, and this reality could be expanded by debuting some returning actors as comic-accurate variants, perhaps as a new Illuminati team.

1

Why 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 in Avengers: Doomsday is exactly how Robert 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’s Iron Man and 2019’s Avengers: 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.

It hasn’t yet been revealed what the connection between Tony Stark and Victor Von Doom will be in Avengers: Doomsday and Secret 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 in Avengers: Doomsday, as while Downey Jr.’s casting is exciting, it can’t simply be overlooked and unexplained.

Upcoming MCU Movies

• 
  

  
  

  Thunderbolts*

  Release Date

  
  May 2, 2025
  

  
  
  
  

  
  

  Powered by

  
  

  
  Expand
  Collapse
  

• 
  

  
  

  The Fantastic Four: First Steps

  Release Date

  
  July 25, 2025
  

  
  
  
  

  
  

  Powered by

  
  

  
  Expand
  Collapse
  

• 
  

  
  

  Avengers: Doomsday (2026)

  
  
  
  
  

  
  

  Powered by

  
  

  
  Expand
  Collapse
  

• 
  

  
  

  Spider-Man: Brand New Day

  Release Date

  
  July 31, 2026
  

  
  
  
  

  
  

  Powered by

  
  

  
  Expand
  Collapse
  

• 
  

  
  

  Avengers: Secret Wars

  Release Date

  
  May 7, 2027
  

  
  
  
  

  
  

  Powered by

  
  

  
  Expand
  Collapse