Hermione would probably approach it with a very critical eye. She'd analyze the writing style, the consistency with the original lore, and might even be a bit miffed if there were inaccuracies. She'd likely write notes in the margins if she had a physical copy, pointing out all the wrong spells or misinformation about Hogwarts.
Some characters might be amused. For example, Harry Potter himself could find it quite interesting to see different interpretations of his adventures. He might chuckle at some of the more out - there ideas in the fanfiction.
Voldemort, on the other hand, would likely be enraged. He'd see any fanfiction about him as a form of disrespect or a misrepresentation of his power. He might seek out the authors of the fanfiction in his own dark and menacing way if he could.
Some characters might be amused. For example, Katniss could find it strange to see different interpretations of her own story. She might be a bit irritated at first if the fanfiction misrepresents her motives or actions, but then she could also see the creativity in it.
Some characters might be amused. For example, Denki Kaminari could find the wild and creative ideas in fanfictions really funny. He might share the funniest parts with his friends like Kirishima.
The Cullens might be quite intrigued. They could compare the magical elements in the Harry Potter fanfiction to their own vampire - related 'magic'. For example, they might find the different spells and potions in the fanfiction fascinating and draw parallels to their own abilities, like Edward's mind - reading which could be seen as a form of magic in its own way.
Katniss might be shocked and a bit angry at some of the out - of - character portrayals in the fanfiction. She's used to being in control of her own story, and seeing others twist it could be irritating.
They might be really surprised. Harry could find it strange to see different versions of his own story. Hermione would probably be critical at first, analyzing the plot holes or inaccuracies compared to the real events. Ron, on the other hand, might find some of the more comical fanfictions quite hilarious.
They might be amused. After all, seeing different interpretations of their own story could be quite entertaining for them.
Some MHA characters might be really intrigued by Disney fanfiction. For example, Izuku Midoriya would probably be super excited. He loves stories and analyzing different characters' motives, just like he does with heroes. He'd be all about exploring the new worlds and character relationships in the Disney fanfics.
Some might be horrified. The violence and destruction in WW2 were on a large scale. RWBY characters are more used to one - on - one or small - scale battles against Grimm. They would likely find the mass casualties and the destruction of entire cities very difficult to comprehend at first.
Some characters might be amused. For example, Wei Wuxian would probably find the creative interpretations of his story quite interesting. He has a carefree nature and would likely enjoy seeing different takes on his adventures and relationships.
The Hetalia characters' reactions to America fanfiction would depend on their personalities. Germany, being the strict and no - nonsense type, might be a bit critical of inaccuracies in the fanfiction. He could be like, 'This is not how it should be!' On the other hand, Japan might be very polite about it, even if he doesn't quite understand all the concepts. He might simply say it's an interesting take on the American character. Canada might be happy that the fanfiction gives more attention to his neighbor, as he often gets overlooked in comparison.