Russo Brothers Say “We’re Back to Phase Zero” With ‘Avengers: Doomsday’ and Robert Downey Jr.

At SXSW London, the Russo brothers spoke openly about their return to the Marvel world. They said they are treating their next film, Avengers: Doomsday, as a kind of fresh start. Joe Russo explained it in simple terms, saying, “This is starting over from scratch.” He also added, “We want to make sure everybody feels like this isn’t leaning on anything from the past.”

The event took place on a rainy afternoon and had a wide focus on how modern film worlds are built. The Russo brothers were joined by Donald Mustard, who works with them at their company AGBO. They also talked about how storytelling is changing because of younger audiences and new creators coming from digital platforms.

Before talking about Marvel, they mentioned how impressed they are with new low-budget filmmakers who are getting attention online and in theaters. Anthony Russo said that these small films show how quickly things are changing in the industry. He talked about how younger creators are now shaping what audiences watch and how successful films can come from very small budgets.

The main focus of the talk was their return to the Marvel Cinematic Universe. After the huge success of Avengers: Infinity War and Avengers: Endgame, the directors said they had stepped away from the franchise because they felt exhausted. But later, a new idea from writer Stephen McFeely brought them back. Anthony Russo said that this idea “reignited” their interest and opened new creative possibilities for them.

Joe Russo explained that Avengers: Doomsday will not continue the story in a simple way. Instead, he said the goal is to reset the feeling of the franchise. He said they are working with a “phase zero” mindset, meaning they want to rebuild the experience from the ground up. He described it like this, “That serial shifting and changing and surprising you and then reinventing itself and then shifting and changing and then surprising you — that’s exciting and I think you’re going to see some shifting and changing [with Doomsday].”

One of the biggest surprises from the talk was the confirmation that Robert Downey Jr. will return to the Marvel universe, but this time as a villain. The Russos said they had already spoken with him about the idea, and they are excited about what it could bring to the story. Joe Russo said, “We are back to phase zero. This is starting over from scratch.”

The directors also spoke about working with large casts. They explained that each character matters deeply to fans, so they have to be very careful with how they handle every role. Joe Russo said they treat it like managing many perspectives at once, where each moment has to be balanced so no character feels ignored.

They also talked about how people watch films today. Joe Russo said that audiences should be free to watch stories on any platform they want, whether in theaters, on phones, or at home. He also said that storytelling should not be limited by format or strict rules.

The SXSW London 2026 session showed that the Russo brothers are thinking about change in a big way. With Avengers: Doomsday, they are not just continuing a franchise, but trying to reset how it feels and how it connects with audiences again.

Have something to add? Let us know in the comments!