If Naruto joined the Akatsuki, his relationship with the other Akatsuki members would be diverse. Some, like Hidan, might see him as an enemy no matter what. But others, like Konan, might be more open to him. She has a more complex view of things compared to some of the more blood - thirsty members. Naruto would also have to deal with the Akatsuki's leader, Pein. Their relationship could range from mutual respect to outright hostility depending on Naruto's actions and goals within the organization.
Naruto joining the Akatsuki in fanfiction would completely turn his relationships upside down. His friends in Konoha would feel betrayed, thinking he's turned his back on them. At the same time, he would be forming new relationships within the Akatsuki. He might start to see the members as individuals with their own stories rather than just villains. This could lead to some really interesting character development, both for Naruto and for the Akatsuki members he interacts with. For example, he could form an unlikely friendship with Kisame, who has his own sense of loyalty and honor, albeit in a different way than Naruto's.
His relationships would be completely turned upside down. His friends in the Leaf Village would be confused and hurt. Meanwhile, in Akatsuki, he'd have to build new relationships. Some members might be hostile at first, but others could potentially become comrades. For example, he might form an unlikely bond with Hidan, who is very different from Naruto in beliefs but they could learn from each other in a strange way.
His personality might become more guarded. He'd be surrounded by people who are mostly out for themselves or have very different values from him. So, he'd need to be more cautious in showing his true self.
If Naruto was trained by the Akatsuki in fanfiction, his relationships would be completely transformed. For starters, his relationship with Kakashi would be strained. Kakashi has always been Naruto's mentor in a way, and seeing Naruto side with the Akatsuki would be a shock. His friends like Sakura and Shikamaru would also be confused and probably try to bring him back to the 'right side'. And his relationship with the villagers of Konoha would turn sour as they would fear his new - found Akatsuki - related powers.
Regarding Kisame, Naruto's positive and energetic attitude could be a shock to him. Kisame might start to question his own loyalty to the Akatsuki as Naruto tries to bring a different perspective. Their relationship could be one of constant friction and yet also a bit of mutual respect as Naruto doesn't shy away from Kisame's power.
His relationship with his friends in Konoha would be severely strained. They would likely feel hurt and confused by his sudden departure. On the other hand, in Kiri, he would have to build new relationships from scratch. He might initially be an outcast but gradually earn the respect of some Kiri ninjas.
His relationship with Sasuke would become even more complex. Sasuke might see Naruto's joining of Akatsuki as a betrayal or a sign that Naruto has finally given up on Konoha. Naruto's old friends in Konoha, like Sakura and Kakashi, would be very confused and hurt. They might try to bring him back, but also be wary of his new Akatsuki ties. And within Akatsuki, Naruto would have to navigate relationships with members who have different motives and personalities, some of whom might not trust him at all.
Naruto's relationship with Kisame might become an interesting one. At first, Kisame would likely be very suspicious of Naruto. But as time goes on, Naruto's determination and strength could earn Kisame's respect. With Itachi there, he might be more open - minded towards Naruto. As for Kakuzu, Naruto would probably constantly clash with him due to Kakuzu's money - loving nature. Naruto would try to convince him that there are more important things than wealth. And with Sasori, Naruto would be horrified by Sasori's use of human puppets and would try to make him see the value of human life.
Naruto's relationship with his sensei, Kakashi, would be severely strained. Kakashi has always been a guiding figure for Naruto, and Naruto joining the Akatsuki would seem like a betrayal. However, Kakashi might also suspect that Naruto has an ulterior motive. As for his relationships with the other Konoha ninjas, they would be filled with suspicion and mistrust. But Naruto could also form new relationships within the Akatsuki. He might befriend some of the members who have a bit of good in them, like Konan perhaps, and together they could work towards a new future for the Akatsuki.
Naruto's character would change significantly. Firstly, he would be more secretive. In Konoha, he was an open book, but in the Akatsuki, he'd have to keep his true intentions hidden. His sense of loyalty would be tested as he'd be in a group that opposes his former home. He may also become more calculating. For example, he'd need to figure out how to use the Akatsuki's resources to his advantage while also trying to protect Konoha in the long run. He would no longer be the naive boy who always rushed into battle; instead, he'd have to think several steps ahead.
If Naruto is trained by Akatsuki in fanfiction, his skills would be transformed in multiple ways. His chakra control could be refined to a much higher level. Akatsuki members are experienced in dealing with large amounts of chakra, and they could teach Naruto how to better manage his own vast reserves. His combat strategy would shift from the more straightforward and honorable style of Konoha to a more cunning and adaptable approach. He might also gain knowledge about sealing techniques that the Akatsuki has used to capture tailed beasts. This new knowledge could not only enhance his fighting abilities but also give him an edge in dealing with other threats in the ninja world. His ability to sense and counter opponents would be sharpened as well, as the Akatsuki often deals with dangerous and powerful foes.