The Capitol citizens would likely be entertained. They live in a world of excess and novelty, so reading fanfiction about the Hunger Games characters would be just another form of amusement for them. However, the tributes from the districts might have a more complex reaction. For those from the poorer districts, it could be a source of hope or a cruel reminder of their situation, depending on how the fanfiction is written. For example, if a fanfic shows a district winning in a way that seems impossible in reality, it could give them hope, but if it's a cruel or inaccurate portrayal, it could be disheartening.
Katniss could start to question her own identity. If the fanfiction presented her in ways she didn't expect, she might wonder if there were parts of herself she hadn't fully explored. For instance, if a fanfic made her out to be more emotional than she thought she was.
Some characters might be shocked. For example, Katniss might find it strange to see alternate versions of her story. She could be angry if the fanfiction misrepresents her motives or actions. Peeta, on the other hand, might be more intrigued and try to understand the different perspectives presented in the fanfiction.
Some MHA characters might be flattered. For example, Midoriya would probably be really excited and take it as a sign of how much he's inspired people. He might even look for positive lessons in the fanfiction to improve himself.
The Flash would likely find it really entertaining. He might enjoy reading about his super - speed being used in all sorts of crazy ways in the fanfiction. And he could also use it as a way to pass the time when he's not out saving the day. He might even start to wonder if some of the ideas in the fanfiction could actually work in real - life superhero situations.
Yang would likely have a big reaction. If the fanfiction shows her in a cool fight scene, she'd be all for it and might even show it off to her friends. But if it portrays her in a negative or weak way, she'd be really annoyed.
Some characters might be flattered. If they are depicted as heroes in the fanfiction, it would boost their egos. For instance, Oliver Queen might enjoy reading about himself as an even greater hero than he already is.
Percy would probably find it hilarious. He has a good sense of humor and would likely enjoy the wild and crazy scenarios fans come up with. He might even share the funnier ones with his friends at Camp Half - Blood.
Naruto would be thrilled. He loves attention and the idea that people are writing stories about him would make him feel really special. He might even try to find the authors and befriend them.
It's hard to say exactly how the Capitol would react. They are a complex and often cruel entity. They could see the fanfiction as a form of rebellion, even if it's just a creative exploration. They might start to investigate the authors of the fanfiction to see if they are part of any real - life resistance groups. Or they could simply laugh it off as the silly musings of the oppressed districts, not realizing that these stories could potentially have a greater impact on public perception than they think.
There are also those who would be intrigued. Clary, being the curious one, would probably read fanfiction with great interest. She might be amazed at the different ways fans have imagined the story continuing or the relationships evolving. She could even get some inspiration from it for her own adventures, thinking about how the fans' ideas could be incorporated into her real - life challenges in the Shadowhunter world.