The Avengers: Age of Ultron is set to start filming soon with a release date of, May 1st 2015. Ultron being set as the villain with no Hank Pym in sight, many people have speculated that Tony creates him with further solidification seen in the announcement trailer shown at comic con. A lot of people also speculate that Ultron or maybe even Vision is Jarvis corrupted or in a form of evolution. Well, personally I found the Jarvis idea a bit silly and have done some thinking about how they can have Ultron be the villain, the creation of Ultron and how The Avengers could be the cause of Ultron's creation. I have an idea that could be solid in some cases and I hope that my fellow users can see this being a good, solid idea. Without further ado. I will have it in sections with how the four main Avengers have a part in creating arguably the deadliest and most formidable Avengers foe.
Tony Stark/Iron Man
As everyone knows, Tony blows up all of his suits at the end of Iron Man 3. So, I believe that he and Pepper are living happily and Tony doesn't have much association with anyone from Shield or The Avengers outside of Bruce Banner. I believe that Tony at some point gets kidnapped by Quicksilver, Scarlet Witch and Baron Von Strucker, with me so far? They kidnap him because Baron Von Strucker created a more evil looking Iron Man armor but he wants it to be its own being, they kidnap Tony for his brain patterns and use them for Ultron to be a smart and deadly foe with a mind of his own. Similar to Hank Pym using his own brain patterns for Ultron in the comics but, movie being for more nefarious reasons.
From here, the descriptions will be shorter due to less of a direct involvement in Ultron's origin.
Steve Rogers/Captain America
From here on out, this is where it's indirectly the cause of Ultron's origins. Von Strucker is the leader for Hydra, carrying out what Red Skull started in The First Avenger. Ultron's creation involves Cap emotional and indirectly due to the fact that it's Hyrda (more less) who creates Ultron.
Hulk and Thor
Even more indirect, Ultron will be created to be capable of also taking on the likes of Hulk and Thor. Seeing what they did in the battle of New York, Von Strucker ensures that no one will be able to take out Ultron thus, making Ultron a formidable foe BUT, not without the help of...
Scarlet Witch
I believe Scarlet Witch will hex Ultron which in turn activates him and as a replacement for Wasp, he falls for her (which wouldn't be much of a change from the comics). I also believe her and Quicksilver will join The Avengers to stop Ultron due to him killing Von Strucker as he sees him as his "father" and the only way they can stop him is to join, The Avengers.
Side notes: I believe they'll kill off Hawkeye and Black Widow in the final battle, Rhodey will get killed in the rescue mission to save Tony thus giving a messed up Tony even more reason to suit back up AND I believe Scarlet Witch will try to hex Vision but instead of killing him, it causes him to change and he'll turn on Ultron because of the effects her hexes had on him.
That's all I got. What do you guys think? I know it won't entirely be plausible but, some of it I can see happening. Comment below with your thoughts.