An idea I had after seeing Age of Ultron. Please give me some feedback on what you think of this.
Former Lance Corporal James Hudson was volunteering in Sakovia using his much preferred skills as a cook until one night he was abducted by Strucker's men and forced to undergo experimentation. He resisted and fought, during one of his 'sessions' he was able to break free almost making it outside of the camp before a sniper put a bullet through his head. And for a time he was believed to be dead. Until the Avengers attacked Strucker's castle. A stray lighting bolt of Thor's hit the ground striking Jimmy's half dead body in the chest. After digging himself free, and screaming at the top of his lungs, Jimmy slowly made his way into the city 'borrowing' clothes he found on the way whilst his body healed itself.
Subconsciously following Wanda's perfume, which his instincts told him was familiar, he stumbled into Maximoff's meeting with Ultron in the church. Joining the trio as the twins apparently knew him and the metallic stranger offering to help fix his broken mind. He also turned on Ultron after finding out his end game siding with the Avengers and fighting along side them in the final battle. Again 'borrowing' some clothes he found in the tower before hand.
He sided with Cap during the events of Civil War stating "that it starts with registration and ends with millions of you slaughtered"
Update 8th May 2018: Infinity War hiding/on the run appearance
Jimmy hudson @ Marvel Credit to all who it belongs too.
whoops thought I had made the bio lol. Anyways no I had something as these lines in mind;
like the Maximoffs he was a test subject for Strucker's experiments (unwillingly) during which he tried to escape which caused his body to start to reject what they were doing to it and the guards using lethal force to stop him from getting out of the castle leading to his death and being buried in a mass grave with the rest of the dead.
Basically the first micro is him during experimentation then crawling out the grave back to life, which leads onto the second micro as his body starts healing