They could be angry. If the fanfiction portrays them in a negative or untrue light, like making them do something completely against their moral code, they would likely be furious. For instance, a noble knight character reading a fanfiction where he is a cowardly thief would not be happy at all.
They could be shocked. Some might not expect the wild ideas that fans come up with in fanfiction.
Kiba and Akamaru might find it really funny. They have a more light - hearted nature. They would enjoy reading about the different battles and situations the characters are put in, in the fanfiction. They might even get some inspiration for their own training or adventures from the wild ideas in the fanfiction.
Some characters like Jack Crawford might be dismissive. He is a no - nonsense FBI agent and might think fanfiction is just a waste of time and not in line with the real investigation and profiling work he does. So he would probably just roll his eyes and move on.
Draco Malfoy would probably be outraged at first if he read fanfiction that showed him in a positive light towards Harry and his friends. He's so used to being on the opposite side, but then he might secretly be a bit flattered by some of the more complex characterizations of him.
Ruby would be all wide - eyed and full of enthusiasm. She'd be like a kid in a candy store, eager to share any cool ideas she found in the fanfiction with her team. For example, if there was a super - cool ninja weapon in the story, she'd start thinking about how Crescent Rose could be modified to have some of those features.
Some characters would be shocked. Allison, for instance, might be taken aback by how some fanfictions explore her power in different ways. She could be both fascinated and a little bit worried about how fans perceive her use of the 'I heard a rumor' ability.
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 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.