Marvel still has not said who defeats Doctor Doom in Avengers: Doomsday. Two recent clues give fans different answers: Shang-Chi, whose Ten Rings are singled out in a Marvel Legends description, and Franklin Richards, who appears in a strange trailer shot with Johnny Storm. Both ideas have real material behind them. Neither is a confirmed spoiler.
Theory one: Shang-Chi’s Ten Rings
Hasbro’s Avengers: Doomsday Marvel Legends wave includes Doctor Doom, Thor, Sam Wilson’s Captain America, the Fantastic Four, Magneto, Cyclops, Gambit, and Shang-Chi. The Shang-Chi figure comes with two Ten Rings effects, but the product copy is what got fans talking: “With the powerful Ten Rings around his arms, Shang-Chi may be the only hero powerful enough to stop the threat the Avengers face.”
That sounds like a plot clue until you look at the wording. It says “may,” and it says “the threat,” not “Doctor Doom.” Toy descriptions are written to make a figure sound important. This one can point toward Shang-Chi without promising that he wins the final fight or even faces Doom alone.
The idea is still believable. The Ten Rings have an unexplained signal attached to them after Shang-Chi and the Legend of the Ten Rings, when Wong, Carol Danvers, and Bruce Banner tried to work out what the artifacts were contacting. If Doomsday connects that mystery to the multiverse or to Doom’s mix of science and magic, Shang-Chi could have a way to disrupt the plan. That is a useful theory, not an announcement.
Theory two: Franklin Richards may be the real key
The more story-focused clue may be in the trailers. Both Avengers: Doomsday trailers show Johnny Storm holding his nephew Franklin Richards as a bright white light surrounds them. The shot looks like a disaster, which is why fans have connected it to an incursion and assumed the pair may be facing their final moments. The footage itself does not identify the light, the location, or when the scene happens.
Franklin is already tied to the movie’s biggest mystery. The post-credits scene of The Fantastic Four: First Steps puts Doctor Doom near the Richards family and Franklin, giving Victor a direct reason to care about the child. In Marvel Comics, Franklin can reshape reality on a massive scale. That makes him a logical target if Doom wants to survive, control, or rebuild a collapsing multiverse.
Franklin also gives Marvel a way to connect the Fantastic Four’s family stakes to the larger multiverse plot. Saving his family could matter more than landing the final hit on Doom.
That does not mean Franklin will defeat Doom with a single blast. If the theory is right, his role could be more important than a normal fight: he may restore a damaged reality, reverse an incursion, or give the other heroes a way to undo Doom’s plan. The white flash could be the start of that choice, or it could be a trailer fake-out designed to make the scene look worse than it is.
The two theories could fit the same story
Shang-Chi and Franklin do not have to be competing answers. The Ten Rings could help identify or contain the multiverse problem, while Franklin’s power could repair the damage. A team that includes Thor, Sam Wilson, the Fantastic Four, the returning X-Men, and Shang-Chi would have room for both characters to matter without turning either one into the only person who saves everyone.
That also fits the scale of the film better than a clean one-on-one victory. Our earlier Avengers: Doomsday trailer coverage looks at what Marvel has actually shown about Doom so far, and none of the official footage names the hero who will win.
What Marvel has actually confirmed
Marvel has confirmed Robert Downey Jr. as Doctor Doom, Simu Liu’s return as Shang-Chi, a large Avengers and Fantastic Four ensemble, and a December 18, 2026 theatrical release. It has not confirmed that Shang-Chi defeats Doom, that Franklin survives an incursion, or that either character is the final answer.
The safest reading is that Marvel has left two doors open. Shang-Chi has a weapon with an unresolved cosmic history. Franklin has the kind of reality-changing potential that could reshape the ending. Until the studio explains the trailer shot or releases a real plot detail, both remain strong possibilities—not confirmed spoilers. For another announced Doomsday storyline, see our coverage of Chris Evans’ brutal Steve Rogers test.
