For heroic - centric fanfictions, they would likely be disdainful. Since they oppose heroes, seeing stories that glorify heroes would annoy them. They might scoff at the idealized versions of heroes in those fanfictions.
Regarding shipping fanfictions involving them, it depends on the pairings. If it's a pairing that they think makes sense for their characters, like Toga and Twice having a close bond in a fanfiction, they might be okay with it. But if it's a really strange or out - of - character pairing, they would probably be confused or disgusted.
They might be amused. They could find some fanfictions that depict them in ways they never thought of, which might make them chuckle at the creativity of the fans.
The more philosophical fanfiction would intrigue the Jedi Masters. Yoda, for instance, would probably nod his head and say 'Much to think about, there is in these words.' They would see it as an opportunity to further explore the concepts of the Force, good and evil, and the nature of the Star Wars universe. However, the average stormtrooper might not understand it at all and just shrug it off as some strange mumbo - jumbo.
The cynical characters might be critical. They could pick apart the plot holes or the unrealistic elements in the fanfiction. They might say things like 'This doesn't make any sense compared to the real Grinch story.'
The Bnha universe's reaction would be mixed. Those who are into complex stories, like Todoroki, might study the relationships in Hamilton fanfiction. But others, like Mineta, might not be interested at all because it doesn't have much to do with his usual interests. Overall, it would depend on the individual characters' personalities and interests.
Hero characters might analyze it from a moral perspective. They could either approve or disapprove of the way the story is told in the fanfiction depending on whether it aligns with their sense of right and wrong. Villain characters, on the other hand, might look for ways to use the ideas in the fanfiction to their advantage, like new ways to create chaos.
Izuku would probably be terrified at first. After all, he's been kidnapped by villains. But then, his hero - like determination would kick in. He might start looking for ways to escape or at least resist their plans.
A villain like Shigaraki would likely be interested in the power levels in the MCU fanfiction. He's always looking for ways to increase his own power, and seeing the various powerful artifacts and abilities in the MCU might give him some ideas. He could think about how he could use similar things in his own plans to take over the MHA world.
In a horror - themed fanfic, villains like Adam Taurus could be intrigued. Horror often plays on fear and power dynamics, which are things he is familiar with. He might be interested in seeing how the fanfic writers use elements of horror to create a new and terrifying RWBY world, and he might even get some inspiration for his own actions from the scarier aspects of the fanfic.
The Justice League as a whole would have a diverse range of reactions. Some members like the Flash would be all for it, seeing it as a fun exploration of Batman. Others like Wonder Woman might use it as a way to understand how the public perceives Batman's role in the League. And then there are those like Aquaman who might just shrug it off unless it directly affects his interests. The fanfiction could also potentially create some internal discussions within the League about how they are all portrayed in the public's imagination.
Some of them might laugh. They would see the creative and sometimes out - there ideas that fans come up with in the fanfiction. For example, if there's a fanfic where Oliver Queen teams up with a really strange character from the Arrowverse, it could be quite humorous to them.