Tony Stark, who sacrificed himself through the use of the powerful Infinity Gauntlet, tragically died after saving the world for the last time.
This action may have an unexpected side effect, however, it will continue the legacy of Iron Man. The power of Infinity Stones may bring the next villain of MCU or its greatest hero back in some capacity.
One possibility is that the convergence of the Infinity Stone energy might have somehow triggered the Iron Man armour that Tony wore. This is enhanced by the fact that the armour used in the Infinity War / Endgame is based on the comic book of Iron Man’s “Bleeding Edge” armour. In the comics, this armour gave Iron Man superpowers, bonding somewhat with him and allowing him to gather it into his bone structure.
The film version did not emphasize this point, but the comparison to the look of the original material cant be denied. This advanced level of technology can be manipulated with the power of stone, bringing life to the dormant machinery even after Tony’s death.
The Ultron II can be made from the remains of Stark’s Mark 47 armour and can be kept as a gentle gesture of gratitude for Tony’s ultimate sacrifice. From there, it would remember faint glimpses of Tony’s past, namely his most evil creation, and rebuild itself into a new Ultron. Many also believe that the MCU will begin to take a more cosmic trajectory, especially with the introduction of the Eternals.
IRON MAN 2.0(20)
The irony of this situation is that even the original and final hero of the MCU, Iron Man, will essentially become its next biggest villain. This could be true if armour gets the sentence not a new version of Ultron. One possible way to do this is to make the same armour version of the Iron Man 2020 character.
This villain is the amoral cousin of Tony Stark, though with a little more Victorian-looking armour. Appropriately, he’s come back as the biggest villain of the Iron Man in the comics this year, so his inclusion in the movie universe makes a little more sense than usual.
Once again, the empowering technological logic with the last memories and moments of Tony’s life can be used to describe this new Iron Man, who acts and sounds like a warped version of the original. Featuring the voice of Robert Downey Jr., this literal ghost can also work in the machine.
The actor is done with Tony Stark’s version of Iron Man, but voicing an Iron Man who is explicitly not Tony Stark, or at least the real one, could be done to work around this logic. From there, the face of the MCU would be warped into its next great nemesis, adding a new armour to the Iron Man legacy, at the same time destroying that legacy.