Sasuke might be initially cautious. He would observe Cell carefully to assess his threat level. He could offer his Sharingan - enhanced perception to help Naruto in the fight. Sakura, she would be worried about Naruto but also ready to jump in and heal any wounds. Shikamaru might be thinking of strategies in the background, trying to come up with a way to outwit Cell using his intelligence.
His friends' reactions would be diverse. Naruto's more hot - headed friends like Kiba might be excited about the new firepower the modern army brings. They might want to jump right into using the guns and other weapons. But Naruto's calmer friends like Neji (if he were still alive in the fanfiction) would be more cautious. They would worry about the long - term effects on the ninja world, such as the potential for mass destruction and how it would change the balance of power. And Ino might be interested in how the modern army's communication systems could be used to improve their own ninja intelligence networks.
At first, Naruto might be in shock. He has always trusted his friends, so the sudden betrayal would be a huge blow. He could be silent, unable to process what has just happened.
Sakura might be a bit surprised at first. But she would probably be happy for Naruto as long as he is happy. She might also be curious about the elf and want to learn more about her. Sasuke would likely be more reserved in his reaction. He might not show much emotion on the surface but deep down he would be glad that Naruto has found someone. Kakashi would probably give Naruto some sage advice about making a relationship work, especially since it's with someone from a different species.
There could also be friends who are so loyal to Naruto that they would consider following his request if they truly believe it's for the greater good. However, they would be deeply pained by it. Kakashi, for instance, might understand Naruto's selfless nature but would also struggle with the moral and emotional implications of taking his life.
Sakura might be a bit surprised at first. She would probably tease Naruto a little about it, but then she'd also be curious to see what's in those fanfics. She might even start reading some herself to see how the fans portray her relationship with Naruto.
Sakura, being the kind - hearted and practical one, would immediately start giving Naruto advice on how to keep his braces clean. She might also tell him about the foods he should avoid so that the braces don't get damaged. Sasuke, on the other hand, would be his usual aloof self. However, if any other village kids were to make fun of Naruto because of the braces, Sasuke might subtly step in and intimidate them. Shikamaru would likely grumble about Naruto's new look adding to the chaos in their group. But deep down, he would understand that it's just another thing that makes Naruto unique. Kiba and Akamaru would initially find it funny. Kiba might even joke that Naruto's braces look like some strange ninja weapon. But as time goes on, they would all get used to it and it would just become a normal part of Naruto.
Sakura would likely be shocked at first. She might feel a bit of jealousy or disappointment as she had some feelings for Naruto in the original story. But being a medical ninja, she would probably also offer her help to Blackfire during the pregnancy. Kakashi would be more composed. He would probably give Naruto some advice on responsibility and how to handle the situation with all the political and social implications. Sasuke might be indifferent on the surface but secretly be a bit worried about how this would affect Naruto's standing in the ninja world.
Naruto might initially be in shock. He has always believed in his friends, so the betrayal would be a huge blow. He could try to reason with them at first.