Even now in 2025, years after the Multiverse Saga began laying the groundwork for their arrival, it's still hard to believe that the X-Men are on their way to the Marvel Cinematic Universe. Some of the previous X-Men cast members have made cameo appearances (Patrick Stewart, Evan Peters, and Kelsey Grammer) while others have found a more full-time role in the MCU (Hugh Jackman's Wolverine comeback will likely lead to more); and it's all leading to the arrival of a brand new cast of mutants in the Marvel Studios franchise's X-Men movie.
Before we get there, however, a multitude of cast members from that original Fox movie series is going to be involved in Avengers: Doomsday (and potentially Avengers: Secret Wars too) and that could very much entail much bigger roles. Will they face off against the Avengers? Will their universe be destroyed at the hands of Doctor Doom? Who knows.
What we do know is that they will seemingly be going up against some very familiar enemies, who are about to make their long-awaited MCU debut.
Sentinels debut in Avengers: Doomsday set photos
Photos from the set of Avengers: Doomsday have unveiled the first look at the MCU's iteration of The Sentinels. The photos (which can be viewed here in a tweet) showcase the foot and sole of the robotic beasts and they come from social media user UnBoxPHD (who also unveiled the first look at Milly Alcock's Supergirl suit). Needless to say that these photos have sent the internet into meltdown as they feature the official debut of the longtime X-Men villains.
The Sentinels have hunted the X-Men for years and have remained one of the biggest threats to the existence of mutants since their debut in Marvel Comics all the way back in 1965. Large, robotic behemoths, they are designed for the sole purpose of taking down mutants. Not only are they insanely large, they are incredibly durable and remain resistant to almost all types of attacks - meaning that even mutants with enhanced abilities have a hard time keeping them down. That's especially true for the ones who can reassemble themselves.
Although most of the Sentinels are just programmed to follow the commands of whoever is controlling them, they often answer to one larger sentient robot known as Master Mold. And their hive-mind-like communication networks allow them to gang up on any mutant in their crosshairs. Like The Terminator, they can't be bargained with or reasoned with; they simply exist to either capture or destroy mutants. And, as the last line of defence between them and mutants, the X-Men are always in their crosshairs.
Knowing that they will be involved in Avengers: Doomsday has just increased the levels of hype. While it won't be the Sentinels' first live-action appearance (they played quite a large role in 2014's X-Men: Days of Future Past), fans are excited about the prospect of seeing them sport a more comic-accurate look this time around. Although they certainly looked intimidating in Days of Future Past, the sleek redesign didn't sit too well with audiences, particularly as the X-Men franchise was well-known for changing the characters' appearances, suits, and overall comic-accuracy. That isn't a recurring thing in the MCU, so there are hopes that they will have their signature purple and green color scheme (which can be seen in animated series X-Men '97).
With Ian McKellen, Patrick Stewart, Kelsey Grammer, Alan Cumming, Rebecca Romijin, James Marsden, and Deadpool and Wolverine's Channing Tatum as Gambit, there will be plenty of things about Avengers: Doomsday to enjoy for X-Men fans. And seeing the team of mutants going up against Sentinels (potentially even in comic-accurate suits) is right at the top of that list.
Avengers: Doomsday arrives in movie theaters on December 18, 2026.