He'd probably be very intrigued. Percy has a penchant for adventure and new things, and this fanfiction would be something completely different from what he's used to.
I think young Sasuke would have a very intense reaction. He was so consumed by his hatred for Itachi at that young age. A Sasuke vs Itachi fanfiction would be like a trigger for him. He would be eager to see how the fictional fight is portrayed. If Sasuke in the fanfiction is shown as strong, it might fuel his own ego and make him strive even harder to become powerful. However, if the fanfiction shows Itachi as superior, it could enrage him. He might feel that it undermines his own goal of defeating Itachi and he might even want to find the writer to correct their 'wrong' view.
I like Naruto in these fanfics because he always stays true to his beliefs. He is constantly trying to bring Sasuke back to the village and is willing to fight for their friendship.
One of the best moments is when they have a rematch that showcases their growth. Naruto has become stronger with his new jutsu, and Sasuke has further mastered his Sharingan powers. The intense battle of ideologies during the fight is captivating.
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.
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. His positive attitude and never - give - up spirit often inspire Sasuke. Also, his ability to connect with people gives them an advantage. He can rally support from unexpected places and his chakra is always a big boost in tough battles.
It really depends on the writer's preference. Some fanfictions might have Naruto winning because of his unwavering belief in friendship and his ability to draw on the power of the nine - tails. Others might have Sasuke winning due to his strategic mind and mastery of the sharingan.
It's not clearly stated in the original Naruto series that Konoha as a whole watches Naruto vs Sasuke fanfiction. Fanfiction is a creation of the fans outside the official story. However, it would be an interesting concept to think about. Some characters might be amused or even inspired if they were to read such fan - created stories, but there's no in - canon evidence for it.
In some cases, Sasuke could be angry. He might see Naruto's request as a sign of weakness or as Naruto giving up too easily. He could lash out at Naruto, telling him to fight instead of asking for death. However, he would still be deeply troubled by the request and would probably struggle with it for a long time, constantly thinking about whether or not he should consider it.