There could be some S.H.I.E.L.D. agents. Even though Peter is used to working with the Avengers, S.H.I.E.L.D. might keep an eye on him while he's patrolling alone. Agents like Coulson (if he's still alive in the fanfiction's universe) or new agents could interact with Peter, either to offer assistance or to give him some tasks to complete for the greater good.
Maybe the Vulture could make a comeback. In this fanfiction, he might be out of prison and looking for revenge on Peter. Or it could be a new villain that has heard about the young Spider - Man patrolling alone and sees it as an opportunity to take him down. And of course, there's always the possibility of Aunt May finding out more about his solo patrols and getting worried.
Perhaps in this fanfiction, Peter is patrolling alone when he stumbles upon a mysterious artifact. This leads him on a quest to figure out what it is and who it belongs to, all while keeping it safe from those who would use it for evil. He has to use his Spidey - sense and his intelligence to solve the mystery.
The main characters are definitely the two Peters. However, other supporting characters are likely to include Pepper Potts who could offer some non - combat help to the Peters, like providing resources or shelter. And then there's Spider - Man's friends from his own universe like Ned Leeds or MJ. In the Avengers side, Thor could be involved in some way, perhaps using his Asgardian knowledge to help the Peters understand the multiverse concept better.
Obviously, Peter Parker, also known as Spider - Man, is a main character. Then there are the Avengers like Tony Stark, Captain America, Thor, Black Widow, and Hulk. They often play important roles in the fanfiction, either as Peter's mentors, teammates, or sometimes even as antagonists in certain plotlines where there are misunderstandings or conflicts.
Other Avengers might interact with Peter too. For example, Rhodey could befriend Peter and train with him. Or Natasha could teach Peter some spy skills, which could be useful for his superhero activities.
Obviously, Peter is the main character. There could also be his neighbors who might play a role. For example, an old lady next door who gives him advice or a young boy who is curious about Peter's solitary life.
Peter, of course, is the main character. His classmates could also be important characters. Maybe there's a nerdy kid who helps Peter solve problems during the trip. The teacher in charge of the field trip is also likely to be a character. There could be a local guide at the field trip destination who has some interesting stories to tell.
Peter is surely the central character. In addition to the well - known Avengers, there might be other characters too. For instance, Doctor Strange could be involved as he has knowledge about the Stones. Also, villains who are after the Stones might also be considered main characters in a sense as they drive the plot forward. It's all about how Peter and the Avengers interact with these characters in the context of the Stones.
Peter is young and idealistic, while Natasha is more world - weary. In fanfiction, this can create an interesting dynamic. Peter's enthusiasm can sometimes rub off on Natasha, making her remember the reasons she became an Avenger in the first place. For example, Peter might be excited about a new technology they are using on a mission, and his excitement can make Natasha see things in a new light.
One way is by getting involved in Peter's school life in a more official capacity. Maybe they could arrange for some anti - bullying seminars at the school. Natasha could also train Peter in stealth and evasion techniques so that he can avoid the bullies more easily. Thor could even offer to be Peter's bodyguard for a while, at least until the bullying situation is resolved.
One character could be Dobby. Even though Harry is living alone, Dobby might still find a way to visit him and offer his help. Another could be the Hogwarts ghosts. They can pass through walls and might visit Harry in his solitary abode.