Naruto would likely be devastated. His old team was an important part of his early life in the ninja world. He might initially go into a state of shock, unable to believe that they are gone. Then, his grief could turn into anger, vowing to find out who was responsible and make them pay.
The older characters such as Kakashi would be cautious. They would recognize Naruto but also be worried about the implications of someone from the future being in the present. They would want to know if his presence could change the future in a negative way. For example, they might fear that his actions could lead to the earlier awakening of a powerful enemy. As for the villains, they might see future Naruto as a threat and try to eliminate him as soon as possible. Orochimaru, for instance, would be very interested in Naruto's future powers and might try to capture him to study. And the new generation of ninja in the past would look up to future Naruto, seeing him as a symbol of what they could become.
Minato and Kushina would likely have a complex reaction. They would be proud of Naruto's heroic deeds in fanfiction. But if they saw him being in danger or having a hard time, they would be worried. Also, if there are parts where Naruto's values seem different from what they taught him, they might be a bit confused.
Peter will probably be very confused at first. He's used to being part of the team, and suddenly being hunted by them is a huge shock. He might try to talk to them to clear up any misunderstandings.
At first, Naruto would likely be shocked. He has always been so loyal to his team, and this sudden betrayal would be a huge blow. He might stand there in disbelief, unable to process what's happening.
Sasuke would likely be devastated. Despite their past differences, Naruto was his rival and in a way, his closest friend. He might go into a deep state of regret and isolation. Sakura would be heart - broken. She loved Naruto, and his death would be a huge blow to her. She might become more withdrawn and focus all her energy on her medical ninjutsu. Kakashi would be filled with a sense of failure. He was Naruto's teacher, and he would feel responsible for not being able to protect him.
Issei could be a bit nervous at first. He might worry about what his classmates will think. But if they show positive reactions, he could become more confident and start sharing more about his writing. However, if they react negatively, he may feel a bit down and might even regret that they saw it.
On the other hand, their fight could also be a turning point for the team. It might make the team realize that they need to communicate better. Their fight can act as a wake - up call for the whole team to address any underlying issues and improve their overall team spirit. For instance, the coach could use their fight as an example to teach about the importance of respect and cooperation among teammates.