In Naruto future reaction fanfiction, characters might react to various things. For example, they could react to new jutsu developed in the future. They might be amazed at the power and creativity behind it. Maybe Naruto himself would be excited to see how the next generation has advanced the art of ninjutsu.
Naruto would be devastated. He has always idolized his father, so being betrayed by him would shatter his world. At first, he might be in denial, not wanting to believe that Minato could do such a thing.
He might be really surprised. Some fanfictions could show him in situations he never thought of, like different kinds of friendships or battles. He'd probably be curious about how fans see him and his world.
Naruto could find some similarities between his own values and Batman's. Both are determined to protect their respective worlds. However, the storytelling style in Batman fanfiction might be a new concept for Naruto. He may enjoy the complex characters and the dark, gritty atmosphere often found in Batman stories, or he could be put off by it as it's so different from the more straightforward good - vs - evil in his own world.
Naruto is devastated. He feels a huge void in his heart. Jiraiya was the one who believed in him from the start, and his death makes Naruto question a lot of things. He might even start to doubt his own strength for a while.
There would likely be a lot of negative reactions. Fans of the Naruto series who love the original themes of friendship, heroism, and ninja values would be appalled. The Naruto fandom is quite large and protective of the original spirit of the show, so this kind of fanfic would be seen as a desecration of the characters and the world that has been created.
Naruto would probably be deeply hurt. He values his relationship with Sasuke so much that such a betrayal would shatter him. He might become withdrawn or angry.
Well, Boruto might have a range of reactions. If the fanfiction shows Naruto as a really powerful and cool hero, which he is, Boruto would probably feel proud. But if it's something that twists Naruto's character in a negative way, he would likely be angry or defensive. He respects his father a great deal, so any false portrayal could upset him. He may also find some of the more out - there or creative fanfictions amusing, like ones that put Naruto in a completely fictional adventure that's way different from what actually happened.
A frequent theme is the exploration of character relationships in the future. For instance, how do Naruto and Sasuke's relationship evolve further? And how do other characters react to this? Also, the theme of facing new, more powerful threats together often appears. Characters' reactions to these threats can vary from determination to fear.
He might be really surprised. He would see all kinds of new interpretations of his world, his friends, and his adventures. Some fanfics could show him achieving even greater things in the future, which would make him feel proud. And if there are fanfics that explore his relationships in new ways, he'd be quite intrigued.