In a fanfiction, an OC could be a young protege who is being trained by both Spider - Man and Iron Man. The OC has to learn how to balance the street - level heroics of Spider - Man with the high - tech world of Iron Man. Along the way, they face challenges like dealing with their own insecurities and the jealousy of other superheroes, all while trying to prove themselves in the superhero community.
The OC could be a new hero from a different part of the world. For example, if they come from a small, technologically advanced country, they could bring a fresh perspective to the Marvel universe. Their skills and abilities could complement Spider - Man and Iron Man. They might start by helping out in local problems in their home country and then get noticed by the two heroes, eventually joining them in bigger battles.
Sure, Spiderman has received mentorship from Iron Man in the comic universe. This has included giving him advice, providing tech support, and guiding him in his superhero endeavors.
One popular trope is the 'fish - out - of - water' story. Your OC, coming from a normal life, suddenly finds themselves in the middle of the superhero world. Another is the 'power - up' trope, where your OC discovers new powers or abilities during the course of the story. And the 'team - up' trope is also common, where your OC teams up with Spiderman and the Avengers to fight a common enemy.
When writing this kind of fanfiction, start by researching the existing Spiderman and Avengers universes thoroughly. Know the powers, personalities, and story arcs of the main characters. For your OC, decide on their powers carefully. If they have super strength, think about how it compares to the Hulk's. Then, plot out a story that has a clear beginning, middle, and end. In the beginning, introduce your OC and their situation. In the middle, build up the conflict, whether it's against a new villain or an internal struggle within the group. At the end, resolve the conflict in a satisfying way.
Another possible antagonist could be Doctor Octopus. His brilliant mind and powerful mechanical arms would give Iron Man and Spider - Man a tough fight. He might be after some technology that Iron Man has or be trying to prove his superiority in the scientific and criminal world, which would bring him into direct conflict with our heroes.
In such fanfiction, one interesting aspect could be how Iron Man mentors Spider - Man in the ways of being a superhero. Maybe he teaches him about advanced tech - based combat strategies that are unique to Iron Man's style.
You can try fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfictions, including those with different relationship pairings like Spiderman and Iron Man in a gay relationship.
One great 'Iron Man OC Fanfiction' is 'The Techno Titan's Apprentice'. It has an interesting original character who teams up with Iron Man to face a new threat from an AI gone rogue. The story is full of action and the OC's unique skills add a fresh twist to the Iron Man universe.