Sasuke could be intrigued. If he comes across a well - written fanfic that really captures the essence of his relationship with Naruto or offers a new perspective on his goals and journey, he might get drawn into it. He might start to think about how these different ideas could fit into his own understanding of his life and the world around him. For instance, if a fanfic shows him a different path he could have taken, it might make him reflect on his choices.
He might be surprised. Fanfics can be full of wild ideas that he never thought of, like strange pairings or new jutsu concepts.
Naruto would probably be angry at first. He's always been a free - spirited person, and being kidnapped by Sasuke, his friend - turned - rival, would surely make him mad. He'd likely try to fight back immediately, using his ninja skills and his never - give - up attitude.
Naruto might react with a sense of responsibility. If he saw a future where Konoha was in danger, he would feel it was his duty to do something about it. He could start by gathering information from the future vision, like the weaknesses of the enemy. Then, he would share this knowledge with his comrades and come up with a plan to protect the village.
Naruto would be devastated. Sasuke is his closest friend and rival. He would likely go into a state of deep mourning at first. He might isolate himself for a while, just trying to come to terms with the loss.
Naruto's reaction would be complex. He would be devastated because his bond with Sasuke is so deep. However, he also trusts Sasuke to an extent. So, he would be torn between his immediate emotional response of anger and his long - standing faith in Sasuke. He might start to look for clues and evidence, and in the process, he could end up uncovering Kabuto's devious plan while also reaffirming his friendship with Sasuke. He would probably be more determined than ever to set things right and prove Sasuke's innocence if he is indeed innocent.
He would probably be shocked. The fanfic might have some very different takes on combat and characters that he's not used to.
Naruto himself would likely be outraged. He has his own goals and reasons for his relationship with Sasuke, and being labeled as a 'fan' by Ino would be offensive to his pride. He'd probably try to set the record straight right away.
Sasuke would be furious. He's always been protective of Naruto in his own way. He would immediately start looking for her, using all his skills and resources. He might even go on a rampage if he thought Naruto was in serious danger.
They may find it funny. There are often humorous fanfictions that could make them laugh.
He might be entertained. The abridged versions often have humor and can make light of serious situations in the original Naruto story.