Spider - Man, being the youngest of the group, would be really excited. He would love seeing all the different versions of the Avengers' story. He might even get some inspiration from the fanfiction for his own heroic deeds. He could exclaim 'This is so cool! There are so many ways our story can be told!'
When it comes to reading Endgame fanfiction, the Avengers' reactions are diverse. Thor, with his jovial nature, would likely enjoy the creative liberties taken in the fanfiction. He may even be inspired by some of the new storylines. Steve, being the more traditional and values - oriented one, may have a hard time accepting fanfiction that goes against the moral code he adheres to. Tony would approach it with a mix of amusement and scrutiny. He would be entertained by the creativity but also quick to point out any flaws in the logic or characterization. Natasha would be on the lookout for how her character is developed in the fanfiction, hoping for accurate and strong portrayals, while Bruce would be intrigued by the scientific concepts, whether accurate or not, that are explored in the fanfiction.
The characters could have mixed feelings. They might appreciate the creativity of the fans in some cases. For instance, if a fanfiction delves deeper into a relationship between two characters in a way that makes sense, they could be happy about it. But if the fanfiction goes against their values or misrepresents them, they would be unhappy. Take the Goblin Slayer, he values his mission above all, if a fanfiction makes it seem like he doesn't, he would be displeased.
Some characters might be amused. For example, Iron Man could be like 'Well, this is an interesting take on our story.' He might find the creative interpretations of his character in the fanfiction either entertaining or a bit off - mark.
Some characters would likely be entertained. For instance, Loki might enjoy seeing the various ways fans write him as a more complex anti - hero. He'd probably find the creativity in the fanfiction quite appealing.
The characters are often filled with grief. They see their friends and comrades die in Endgame, and this can bring out deep sadness. For example, Thor might be even more broken - hearted seeing his brother Loki's death again. Captain America could feel a sense of guilt, thinking he could have done more to prevent some of the deaths.
They react differently. Stark might immediately start thinking about how to improve the tech in the movies. Cap is likely to be more focused on the story and the characters' motives.
Some would be intrigued. Captain America, being an open - minded person, might be interested in seeing different interpretations of their team dynamics. He could even gain new insights about his relationships with his fellow Avengers through the fanfiction.
Some characters might be in awe. For instance, Thor could be excited to see different versions of himself and his friends. He might see a version of himself that is even more powerful or a version of Loki that is actually good, and it would be a shock but also a source of amusement for him.
Characters might also be a bit critical. They know their world and themselves better than the fanfiction writers. So they could be nitpicking at inaccuracies or things that don't quite fit with their personalities. But at the same time, they may also be impressed by the creativity and passion that goes into creating these fanfictions.
There could be characters who are outraged. If the fanfiction distorts their personality or makes them do things completely against their nature, they may be very angry. For example, a noble character made to act like a coward in the fanfiction would likely not take it well.