It might start with a small incident where Steve dismisses Peter's ideas or concerns. This initial rift then grows as more events unfold. For example, Steve might take credit for something Peter did, which makes Peter angry and less likely to forgive.
In the fanfiction, the conflict could be developed through a series of misunderstandings. Maybe Steve's actions are misinterpreted by Peter as being self - serving when in fact they were meant to be for the greater good. But by the time the truth is revealed, the damage is done and Peter's feelings of unforgiveness have already taken root. The author could also show how other characters' reactions to the situation between Peter and Steve either fuel the conflict or try to resolve it, but ultimately Peter remains unforgiving for the time being.
The fanfiction could develop the conflict by showing how their different backgrounds and experiences shape their responses to situations. Steve, with his military background, may act more rigidly, while Peter, as a young and independent hero, may rebel against Steve's authority. This clash of styles and attitudes would gradually intensify the conflict between them until Peter is firmly set in his unforgiveness.
Perhaps Steve in the fanfiction was involved in a cover - up of some sort that affected Peter. Say, Steve knew about a threat coming towards Peter but didn't tell him in time because he thought Peter couldn't handle it. When Peter found out, he felt betrayed and thus couldn't forgive Steve. Also, if Steve accidentally caused harm to one of Peter's friends or allies while on a mission, that could be a major factor in Peter's unforgiveness.
Maybe Peter Parker has his own distinct view of Steve. He might feel that fanfiction often distorts Steve's real character or the relationships in the original story, so he doesn't like it.
The story could develop with Steve Rogers being very shocked and then trying to reason with Peter. He might hold back from fighting back because he understands Peter is young and could be acting out of emotion. For example, he could start a conversation to clear the air and find out what's really wrong.
It would likely be very strained. Naruto would probably avoid Kushina as much as possible. He might not even look at her when they're in the same room.
In many fanfictions, their friendship develops over shared interests. They both have a sense of justice and a desire to protect the innocent. This common goal brings them together. They could start training together, with Bucky teaching Peter some hand - to - hand combat and Peter showing Bucky some of his web - slinging tricks. As they spend more time together, they start to understand each other's quirks and fears, deepening their friendship.
At first, it's a bit rocky. Peter is used to being on his own, and Tony has his own way of doing things. But as they spend more time together, they find common ground. Tony helps Peter with his schoolwork, especially in science - related subjects. Peter, in turn, shows Tony the importance of having a pure heart in the superhero world. They go through challenges together, like fighting villains side by side, which deepens their bond.
The relationship can start out a bit rocky in some fanfictions. Tony may be initially dismissive of Peter as just a kid. But as Peter shows his capabilities, Tony starts to take him more seriously. They then start to bond over their love for science and technology. Peter is eager to learn from Tony, and Tony enjoys teaching Peter new things. This mutual exchange helps their relationship grow from a mentor - mentee one to a true friendship.
Maybe Peter doesn't like the way Steve is portrayed in fanfiction. Some fanfictions might deviate too much from the original character, and Peter prefers the official version of Steve.
Peter might not be a fan of the genre of fanfiction in general. He could prefer original works and find fanfiction, especially about Steve, to be unoriginal or too derivative. Also, it could be that he has had some bad experiences reading poorly - written Steve fanfiction in the past that has put him off completely.
The fanfiction could develop the conflict by showing how their different beliefs affect their relationships with other characters. If James is friends with a group that Harry doesn't trust, it can intensify the disagreement between them. As they interact more with these different groups, the conflict grows.