AVENGERS: AGE OF ULTRON has been in theaters for several weeks and has already surpassed the $1 billion worldwide box office mark. While the movie is starting to slow down in theaters — although there should be a good bump in domestic numbers during the Memorial Day holiday weekend — let's look at all of Ultron's forms in the movie.
First of all, if you still haven't seen the movie yet... shame on you. Go and see it already, then come back to read this post.
In the movie, Ultron is an amalgam of several things: Alien technology, Baron Strucker's Hydra research and Tony Stark's technical brilliance. When these are combined by Stark to create his global Iron Legion police force, Ultron develops a conscience and overpowers the firewalls set in place by both Stark and JARVIS.
Ultron's first form is that of a beaten Iron Legion body, called Ultron Mark I per Marvel Studios.
After Ultron reveals himself to the Avengers he sends his Ultron drones, who have taken over Stark's Iron Legion robots, to attack the team. When defeated, Ultron downloads himself to a new body located in Baron Struker's castle headquarters from the beginning of the movie.
This is when Ultron takes control of an advanced Hydra robot body and this is his ultimate version for the majority of the movie. This version might be referred to as 'Ultimate Ultron' or 'Ultron Mark II.'
Ultron then begins to build bodies for his drone army while in his new castle headquarters using Hydra tech left behind after the Avengers raided it in the beginning of the movie (weird they left all that stuff, right?). Each are called an Ultron Sentry per Marvel Studios.
You might think this was all the forms that Ultron took on in the film but he also has the ability to move himself into any Ultron Sentry body as well. The blue glow of an Ultron Sentry would turn red when Ultron took control. This was briefly seen in the movie but is also documented in several of the movie's toy lines. This was the cause of some confusion with some fans because when Ultron takes control of one of his Sentries, he is then called 'Ultron Prime.' You can see a great example of this in the following image from the Hot Toys line.
And that brings us to the end of Ultron's forms in AVENGERS: AGE OF ULTRON. Even though Marvel Studios never showed Vision killing Ultron, they can easily retcon him back for a future Marvel Cinematic Universe movie. And let's be honest in agreeing that seeing an angrier and more mature psychotic killer robot is something fans should want to see once again down the road.