So, I started to predict how each character was going to be like in the film and their fate by the end of it. So in no particular order, here are the cast.
(Remember, this is just my opinion. This stuff would not happen all in one film. Sorry if I make any continuity mistakes throughout).
Quicksilver (Pietro Maximoff)
He is very protective about sister (Scarlet Witch). He starts off along with Wanda as an ally of Ultron after he rescues them from Baron Von Strucker’s bases. He dies during the fight, to protect Scarlet Witch from Ultron. The so called ‘Age of Miracles’ sparks the idea that superheroes should give in their identities to the government, which starts the Civil War.
[Black Widow](movie:1070824) (Natasha Romanoff)
Throughout the film, she builds a relationship with Bruce Banner, which is hard as he can turn into the Hulk at any time unexpectedly. With this bond, she is the only person who can calm him down during the fight with the Hulkbuster by holding hands. By the end of the film, she hands herself into the government along with Iron Man as the Avengers split up at the end.
After being created by Iron Man with help from the Korean scientist that Claudia Kim portrays, he was meant to help the Avengers in defeating all the HYDRA bases, including Baron Von Strucker’s. However, with his own intelligence he evolves himself, transferring his mind to different Iron Man robots, until he creates a version of himself made of Vibranium, the strongest metal in the universe, which causes all of the Avengers a problem. He helps rescue Quicksilver and Scarlet Witch at the start of the film, but later goes his own way to protect the Earth, by defining all humans as a plague to it. This could then change Captain America and Iron Man’s morals, thus setting up the Civil War. He also creates Vision, a concept created by Howard Stark (and built on by Tony) when Edwin Jarvis dies.
Scarlet Witch (Wanda Maximoff)
A character that is rescued by Ultron from Baron Von Strucker’s clasp. However, she and her brother Quicksilver later turn to the Avengers and fight against Ultron. She watches her brother die at the hands of Ultron, in which he did to protect her. Like I said before, The so called ‘Age of Miracles’ sparks the idea that superheroes should give in their identities to the government, which starts the Civil War.
Iron Man (Tony Stark)
He creates Ultron to help the Avengers take out all of the HYDRA bases. However, after Ultron rebels, conflict happens between the Avengers and he is blamed. This is the birth of the ‘Civil War’ storyline, where Iron Man and Captain America split sides due to a disagreement about the identity of superheroes. He gets onto bad terms with the Hulk, forcing him to use his Hulkbuster armour to make sure New York isn’t in any more trouble. He also give Ultron the A.I. for Jarvis, so he can create Vision. By the end of the film, his fights with Hulk end up in Bruce being transported into a safe cosmic planet.
Thor (Thor Odinson)
Thor breaks up with Jane Foster, because of how he has to keep returning to Asgard for his duties. He now lives on Earth and is still worthy of wielding Mjolnir. He leaves at the end of the film to return to Asgard. He has no role in Civil War as he has other issues to tend to in Asgard.
Captain America (Steve Rogers)
At the start of the film, him and the Avengers are going around the world destroying HYDRA’s bases, much like the SSR after WW2. The leader of the Avengers then starts feuding with Iron Man which causes a division and people have to pick sides. This does not help that Ultron is also tearing up the city at the same time. During this time, Captain America travels back in time to have his dance with Peggy, but also uncovers information about Howard Stark’s plans when Edwin Jarvis dies (Vision). He then arrives back in present day Earth, where Ultron breaks his shield. He then goes to Wakanda and talks to Ulysses Klaw about fixing it. He is currently in preparation for war against the government and whoever takes their side to protect the privacy of superheroes.
A secondary character in the film, she spends time with the Avengers now that her work with S.H.I.E.L.D. is finished for the time being.
She appears when Steve travels back in time, to dance. It is also mentioned that she had passed away.
Hawkeye (Clint Barton)
Despite being one of the original Avengers, he is sidelined and doesn’t get the fight scenes he deserves. However, there is one scene where he sees the [Agents of S.H.I.E.L.D.](series:722469) on the news and points out that Mockingbird is hot, which is humourous.
Hulk (Bruce Banner)
Bruce Banner throughout the film is losing the ability to control his anger and pits fights against fellow Avengers. Iron Man steps in to help control him with brute force, but Black Widow’s relationship with him is more effective in calming him down. However, his lack of control gets too much and he is sent to a cosmic planet in a pod by Iron Man and the government, which does not go down too well with Avengers like Black Widow. However, Bruce is alive and safe.
An enemy of the Black Panther, who Captain America consults about fixing the shield with Vibranium.
After travelling around the world in an attempt to wipe out HYDRA for good, he returns to briefly give support to Iron Man, who is a bit shocked by the outcome of his invention.
Created by Ultron using J.A.R.V.I.S.’ A.I., he awakens in the last part of the film when all hope seems lost of patching up the mess that Ultron caused.
Baron Von Strucker (Wolfgang)
After keeping Quicksilver and Scarlet Witch captive, he is slain by Ultron when the Avengers arrive at that HYDRA base.
War Machine (James Rhodes)
War Machine is shown during the party scene, but is not utilised from then onwards.
Keep in mind that this is just speculation and what would be ideal in my eyes for Avengers: Age of Ultron.