On a more emotional level, the memory of Peter would be a driving force for many characters. His death could inspire some to become better heroes or lead to new heroes emerging. His sacrifice could also be a symbol that unites the community against the forces of evil in the fanfiction world.
Well, it could be due to a number of reasons. Maybe he sacrifices himself to save the city from a powerful villain. In some fanfictions, he might die in a fight against an overwhelming enemy that he just couldn't defeat on his own.
Doctor Octopus is also a likely candidate. His mechanical arms and high intelligence could give him an edge. He could manipulate a situation where Peter is caught off - guard and unable to defend himself, resulting in his death.
In some versions, Peter's reaction could be one of extreme anger. He could go on a rampage to seek revenge on whoever or whatever caused Tinkerbell's death. His anger could fuel him to take on powerful enemies he might not have dared to face before.
Peter Pan is likely to be deeply affected. Tinkerbell has always been by his side, so her death might make him feel a great sense of loss. He could become more withdrawn or reckless, as he has lost his faithful companion.
In some fanfictions, Peter might die heroically while saving the city from a powerful villain like Venom. He could sacrifice himself to protect his loved ones and the innocent.
It would deeply affect Tony Stark. Tony has been like a mentor to Peter, so his death would be a huge blow. Tony might blame himself for not being able to protect Peter.
Peter might initially be in a state of shock. He could isolate himself from his friends and the world around him, constantly replaying memories of Aunt May in his head. He may also feel a great sense of guilt, thinking that he could have done more to protect her.
Peter would likely feel betrayed. He looks up to the Avengers, and for them to hurt him would shatter his trust. He might start to question his own judgment in idolizing them and could become more withdrawn.
Well, one possibility is that a new hero could emerge in his place. Maybe one of his friends or a previously unknown character with powers would step up to protect the city. For example, Miles Morales could become even more prominent earlier than in the regular storyline. The city would be in chaos without Spider - Man, so the police might have to step up their efforts in a new way.
Maybe she sacrifices herself to save Peter Pan from a great danger, like a powerful enemy in Neverland.