One wasted MCU Phase 2 villain has been rumored to be returning for some time, and a new theory could provide the perfect explanation as to how.

A new MCU theory suggests how a wasted villain from Marvel Studios’ Avengers: Age of Ultron in Phase 2 could return to pose an even greater threat in the MCU’s future. The MCU’s Phase 2 primarily focused on expanding the stories of the “Big Three” founding Avengers members: Tony Stark’s Iron Man, Steve Rogers’ Captain America and Thor. These stories culminated in the Avengers banding together once again in 2015’s Avengers: Age of Ultron, as the team’s mission to dismantle HYDRA strongholds around the world saw them acquire Loki’s scepter, which housed the Mind Stone, and give life to Ultron.

Ultron, a powerful artificial intelligence housed inside the Mind Stone, wreaked havoc on the Avengers and the fictional Eastern European nation of Sokovia in an effort to render humanity extinct and establish a metal society. Despite being a formidable adversary, the Avengers thwarted Ultron’s plan and destroyed the villain with the help of the Scarlet Witch, Quicksilver, and the synthetic being Vision. This caused a stir, as Ultron is one of the Avengers’ longest-running villains in Marvel Comics, but was relegated to a one-off foe in live-action, though there has been speculation that Ultron could return in the MCU’s future.

Infinity War Suggests Ultron May Still Be Alive Inside Vision

According to a theory posed by Reddit user minor_correction, Marvel Studios has already revealed how Ultron can return to the MCU, despite his demise almost a decade ago. Back in Avengers: Age of Ultron, Ultron began to create a vibranium body for himself, fit with the Mind Stone as a powerful weapon, but this body was acquired by the Avengers and integrated with the JARVIS artificial intelligence to create the Vision. Vision’s origins were referenced during Avengers: Infinity War, as Bruce Banner noted that Vision isn’t just the Mind Stone, but is an amalgamation of everyone who helped create him.

The fact that Bruce Banner notes that some aspect of Ultron still exists inside Vision informs the theory that Vision’s body could be used to revive Avengers: Age of Ultron’s villain. Vision was killed by Thanos at the end of Avengers: Infinity War, so that the Mad Titan could acquire the Mind Stone for his quest, but the Vision’s body was rebuilt by SWORD during Phase 4’s WandaVision. If the new White Vision still has the same make-up as the original Vision, it’s possible that the mysterious new character provides the perfect way for Ultron to return to the MCU.

When Could Ultron Return To The MCU?

Since the theory suggests that Ultron’s return to the MCU is tied directly to the Vision, the villain likely won’t return in a project that Paul Bettany isn’t involved in. Currently, Bettany has only been confirmed to be reprising the role of White Vision in Marvel Studios’ upcoming Vision Quest series, the second spinoff from WandaVision after Agatha: Darkhold Diaries, so it’s possible that Ultron could pose a threat during the series. A version of Ultron has already returned to the MCU, as the successful Ultron robots protected the Illuminati of Earth-838 in Doctor Strange in the Multiverse of Madness.

Perhaps the most likely place for Ultron’s return in the MCU’s future is in Marvel Studios’ Armor Wars project, a movie that is set to mark the return of Don Cheadle’s Rhodey, a.k.a. War Machine. Marvel Comics’ Armor Wars storyline saw Tony Stark investigate stolen Stark technology that had been acquired by villains around the world, and since both Ultron and Vision were technically created by Tony Stark, both of these artificial intelligences would be clear additions to the MCU’s Armor Wars. Paul Bettany hasn’t been confirmed to reappear in Armor Wars, but this casting wouldn’t come as a shock.

MCU Theory Also Means Tony Stark Could Return In Ironheart

If the theory that Ultron could be revived from the copy of the villain residing inside Vision turns out to be true, then it’s possible that other aspects of Vision’s personality could also be resurrected. This includes Robert Downey Jr.’s Tony Stark, who has been rumored to return to the MCU since his departure in Avengers: Endgame. In Marvel Comics, Stark creates an AI copy of himself to mentor Ironheart, so perhaps an artificial version of Tony Stark from Avengers: Age of Ultron could be uploaded to have the same relationship with Dominique Thorne’s Riri Williams in her Ironheart series.