Ultron

There’s no way of knowing for sure if Ultron is gone for good in the Marvel Cinematic Universe. In fact, he probably isn’t, as the nature of his character means there are a number of ways in which he could return, despite his apparent death in Avengers: Age of Ultron.

With that in mind, there’s every chance he could join the MCU Masters of Evil, should they emerge – particularly as he has led his own version of the team in the comic books.

He would provide another in-built Avengers villain for the team and, given that he’s a robot, something entirely different to the other members. He provides brains, brawn and the potential for more of his drones to aid the team’s cause. And James Spader’s return would definitely be welcome to the big screen.