Avengers: Doomsday - Robert Downey Jr's MCU Return As Doctor Doom, Explained

Well, the biggest news just dropped at San Diego Comic-Con. "Iron Man" star and Oscar winner Robert Downey Jr. is returning to the Marvel Cinematic Universe. The actor's iconic run as Tony Stark ended with 2019's "Avengers: Endgame," when his character sacrifices himself to finally put down the ultimate big bad, Thanos (Josh Brolin).

However, fans (like we here at Looper were) will be shocked to learn that Downey doesn't seem to be gearing up for another go as Iron Man. No, he's coming back as none other than Victor von Doom.

The full live reveal of Robert Downey Jr. announced as Doctor Doom during the Marvel Studios Hall H panel at San Diego Comic-Con 2024. #SDCC pic.twitter.com/OlOJOQf0C4

— Rob Keyes (@rob_keyes) July 28, 2024

As shown in the clip above from Rob Keyes of ScreenRant, during Marvel Studios' Hall H panel to promote "Avengers: Doomsday," the Russo brothers, along with Kevin Feige, stood in front of a group of masked and robed Doctor Dooms. After the directors mentioned they'd need "the greatest actor in the world" to properly bring one of Marvel's strongest villains to the silver screen ... there was a pregnant pause. Then, one of the Dooms unmasked themselves to reveal none other than Downey himself. How? What? Why? Let's try and break this down.

In 2010's "What If? Iron Man: Demon in Armor," fans are taken to Earth-11029. In this world, a young Tony Stark is more or less the stand in for Reed Richards (aka Mister Fantastic). Roommates with none other than Victor von Doom, Stark earns the cunning villain's contempt and envy. Early in the story, Doom tricks Stark into helping build a high-tech machine that swaps their minds. Stark, now trapped in Victor's body, desolate and removed from his immense Stark wealth, is forced to "return" to Latveria, while Doom enjoys the spoils of being Tony Stark.

A high-stakes "Face/Off" type of plot ensues, with Stark having to overcome depression, addiction, and, of course, Doom himself. While Kevin Feige has remained adamant that the character of Tony Stark should be left alone after his iconic death in "Endgame," with Robert Downey Jr. set to return to the MCU, and with the franchise digging deeper and deeper into the Multiverse well, drawing from this particular "What If?" story sounds like a no brainer. It could be a terrific way to introduce just how despicable of a villain Doom truly is, all while giving Downey the chance to dive in a role that offers incredible duality. Portraying a Tony Stark whose mind has been hijacked by one of Marvel's nastiest villains? That could be one hell of a ride. 

Breaking down his decision to take up the Doom mantle, Downey was simple in his reasoning. "New mask, same task," he told the Comic-Con audience (per Disney). "What can I say? I like playing complicated character[s]."

"Avengers: Doomsday" is set to release in theaters in May 2026. Whether Downey is playing some type of variant that combines the characters of Stark and Doom, or whether he's playing the villain himself, remains up in the air. Interestingly, the actor was only introduced at Comic-Con as "Victor von Doom." Whichever route Disney and Marvel decides to go, it's clear both Doom and Downey are the type of names needed to fill the void after Marvel Studios dropped Jonathan Majors, who was supposed to carry the franchise as the next big bad.

With Kang the Conqueror seemingly no longer lined up to be the MCU's ultimate evildoer, Doctor Doom is the perfect candidate to fill those villainous shoes. Admittedly, it is a bit odd seeing the character's name attached more to the "Avengers" and not the "Fantastic Four," his traditional archenemies. However, Doom has long been an enemy for all Marvel heroes. Seriously, the green-cloaked ruler of Latveria is always down for all the smoke. So, let's see what Feige and the Russo brothers can cook up now with Downey back aboard the MCU train.