The Marvel Cinematic Universe is “back to phase zero” with the release of Avengers: Doomsday, co-director Joe Russo has said.

Speaking at SXSW, attended by The Hollywood Reporter, Russo told fans to expect “some shifting and changing” with Doomsday, starring former Iron Man actor Robert Downey Jr. playing antagonist Dr. Doom.

“So, get ready for it. Look, we were with Rob [Downey Jr.] earlier today. We were both talking about this concept that we are back to phase zero. This is starting over from scratch. We want to make sure everybody feels like this isn’t leaning on anything from the past.”

The MCU is divided up into six phases: the first three made up The Infinity Saga, and the second three are dubbed The Multiverse Saga. It’s a categorization that began in 2008 and is planned out up to 2027. Phase Six began with the release of The Fantastic Four: First Steps last year. It was thought that this December’s Avengers: Doomsday and next year’s Avengers: Secret Wars, as well as this summer’s Spider-Man: Brand New Day, would be included in Phase Six. But Russo’s comment suggests the end of phases altogether for something of a reboot with Doomsday.

And while Russo insists Doomsday “isn’t leaning on anything from the past,” it features a number of fan favorite characters and actors from the original Avengers team, including Chris Evans as Steve Rogers and Chris Hemsworth as Thor. The question is, what will this Phase Zero mean for the ongoing MCU?

Perhaps we'll need to brace ourselves for a bunch of new young actors playing The Avengers and other Marvel heroes, as the MCU ditches the old in favor of the new. Last year, Marvel Studios chief Kevin Feige said the studio planned to recast the X-Men characters when the superhero team gets its own MCU movie, pointing to the Secret Wars comics from 2015 as the studio’s inspiration for a “reset” of the MCU.

“We’re utilizing that [story] not just to round out the stories we’ve been telling post-Endgame, just as importantly — and you can look at the Secret Wars comics for where that takes you — it very, very much sets us up for the future,” Feige said.

“Endgame, literally, was about endings. Secret Wars is about is about beginnings.”

And Marvel is reportedly focusing on making an X-Men movie with a younger cast "to keep the cost down," as well as Black Panther 3, while it's apparently in no rush to get Blade or Deadpool 4 out the door.

Wesley is Director, News at IGN. Find him on Twitter at @wyp100. You can reach Wesley at wesley_yinpoole@ign.com or confidentially at wyp100@proton.me.