Marvel Resurrected Ultron In A New Avengers Film - But You Likely Never Saw It
Despite him being an enduring threat on the pages of Marvel Comics, Ultron (James Spader) doesn't boast an impressive Marvel Cinematic Universe track record. The villain notably battles the Avengers in the aptly-titled "Avengers: Age of Ultron," but comes up short. He then disappears from the main franchise timeline, with an alternate version going on to become the ultimate villain of the "What If...?" animated series — for good reason. As it turns out, the big screen Ultron has been resurrected, in a new Avengers-centric film no less, but few have actually seen it.
On the Disney Cruise Line, Disney Wish, Marvel fans can visit Worlds of Marvel: a cinematic dining experience featuring a live-action short film, "Avengers: Quantum Encounter." As Ant-Man (Paul Rudd) and Wasp (Evangeline Lilly) give a presentation about Pym Tech to passengers, Captain America (Anthony Mackie, who has strangely been absent from the MCU for some time), Ms. Marvel (Iman Vellani), and later Captain Marvel (Brie Larson) arrive to stop an incoming threat. The threat in question is Ultron (Ross Marquand) himself, along with hordes of his mechanical minions. Thankfully, the heroes are able to stop him from taking and using the experimental Quantum Core.
Though it's cool to see Ultron return to the MCU forefront, not only is this an incredibly niche way to bring him back that isn't very accessible for most fans, but "Quantum Encounter" isn't even technically MCU canon.
Unfortunately, Ultron's return in Quantum Encounter isn't MCU canon
The biggest question one is likely to have after watching "Avengers: Quantum Encounter" is how is Ultron alive once again? It's heavily implied that he's destroyed by Vision (Paul Bettany) at the end of "Avengers: Age of Ultron," thus ending his reign of terror before it could properly begin. While it's not impossible that, as an artificially intelligent being born from technology and an Infinity Stone, he rebuilt his army and a body for himself in secret, the real reason he was able to return is that "Quantum Encounter" doesn't take place in the main MCU timeline.
Even though it seems to focus on MCU versions of characters, "Quantum Encounter" is in its own lane entirely. It's not explicitly stated to be MCU canon, much like the Disney Parks attractions found within Avengers Campus. After all, on neither the big or small screen have the events of the short been addressed. No MCU project has mentioned Ultron's return, which should be a major point for the franchise to follow up on considering he threatened to destroy the entire world, and Ms. Marvel hasn't joined up with the Avengers in any form outside of the short. In fact, "The Marvels" sets her up to form a completely different version of the team.
Thus, the wait continues for Ultron's return to the main MCU spotlight. Time will tell if he'll return to give the new incarnation of the Avengers a run for their money, or if his tenure in the central timeline is well and truly over.