First, you need to understand Tony Stark's character really well. Read the comics, watch the movies. Then, create an interesting original character (OC). Give your OC a unique backstory, personality traits that can interact well with Tony Stark's. Also, come up with a good plot. It could be something like your OC helping Tony Stark in a new technological project or facing a common enemy together.
You can start by looking on fanfiction websites like Archive of Our Own (AO3). There are tons of Iron Man Tony Stark OC fanfictions there. Just use the search function and type in 'Iron Man Tony Stark OC' and you'll get a whole list. Another option is Fanfiction.net, which also has a large collection of fan - made stories.
Tony Stark became Iron Man after being kidnapped by terrorists. While captive, he was forced to build a weapon. Instead, he created a suit of armor to escape. This was the first version of the Iron Man suit.
Tony Stark became Iron Man when he was captured by terrorists. He was forced to build a weapon for them but instead, using his brilliant mind and the limited resources available in the cave where he was held, he built a suit of armor to escape. This was the first prototype of the Iron Man suit.
Well, it all started when Tony was kidnapped and forced to build weapons. He then built a suit to escape and decided to use his tech for good, becoming Iron Man.
Maybe he realizes that the cost of being Iron Man is too high. His suits are constantly damaged, and he has to deal with numerous enemies. This could lead to him quitting in the fanfiction to avoid further harm to himself and those around him. For example, his suits might put Pepper Potts in danger, so he decides to stop.
The Avengers would also have to adjust. They've come to rely on Iron Man's technology and his combat skills. His departure could create a power vacuum within the team. For instance, they might struggle to come up with new strategies in battles without his innovative thinking. And his friends like Rhodey and Happy would be worried about him, wondering if he's made the right decision.
It would be amazing. You'd get to be in the thick of all the high - tech action. You could help Tony with his suit upgrades, maybe even suggest some cool new features. And when it comes to battles, you'd be right there by his side, using your own skills and the gadgets he provides to take on the bad guys.
Iron Man and Howard Stark would likely start with a bit of shock. Howard might be amazed at the technology Tony has created, and Tony would be in awe of seeing his father alive (if it's that kind of scenario). They'd probably exchange some witty remarks, with Howard being a bit more old - fashioned in his speech. Then they'd start discussing technology, with Howard offering some of his classic insights and Tony showing off his modern advancements.