His friends from Team 7 might initially be very skeptical of Zabuza's training. They could worry that Naruto is being led astray. This would cause a rift in their relationships as Naruto would be defending his choice to train with Zabuza, believing it's the best way to get stronger and protect them all in the long run.
With Sakura, Naruto's attitude could shift. Instead of being the goofy, love - stricken Naruto she's used to, he could become more distant. He might be so focused on his training with Zabuza that he doesn't have time for Sakura's attempts to get his attention. This could make Sakura feel rejected and lead to some tension between them.
Naruto's friends might be initially suspicious of the new skills and attitude he gets from Slade's training. For example, Sasuke could see Naruto's new combat style as too ruthless and this could create tension between them. Sakura might worry that Naruto is getting too influenced by a dangerous figure. However, if Naruto can show that he's still the same person at heart, they could gradually accept his new abilities.
Naruto might also develop a more ruthless edge to his fighting. Zabuza was a cold - blooded killer in a way. While Naruto wouldn't become evil, he could be more decisive in combat, not hesitating as much when it comes to taking down opponents. He may also learn some of Zabuza's sword - fighting skills, adding a new dimension to his fighting style if he combines it with his kunai and shuriken use.
On the other hand, Naruto's training could bring him closer to some of his friends. If he has to train with someone like Shikamaru, they could develop a better understanding of each other. They might share strategies and learn from one another, strengthening their bond in the process.
In this fanfic, Naruto's relationships would be in flux. Regarding his friends, they would look up to him as he gains knowledge and power from the Sannin. His relationship with Sakura could change as he becomes more capable of handling Sasuke - related issues. With the village elders, Naruto might gain more respect as they see his potential growing under the Sannin's tutelage. His connection with the Nine - Tails would also be different. As he learns from the Sannin, he could use the Nine - Tails' power in new ways, which might change how he is perceived by the fox and how he interacts with it. All in all, his relationships would be reshaped by the new experiences and skills he acquires from the three Sannin.
His relationship with Sasuke might be affected. Naruto might approach Sasuke differently, with new strategies learned from Zetsu. He could be more secretive about his intentions towards Sasuke, which might either make Sasuke more curious or more distrustful. With his friends in Konoha, they might be a bit wary of Naruto at first because of his new training source. But once they see that Naruto is still on their side, they would support him.
Naruto's relationship with his sensei, like Kakashi, would change. Kakashi would be both proud and cautious. Proud because Naruto is getting stronger, but cautious as the Shinigami - related training is uncharted territory. His bond with the other villagers would also shift. Some might see him as a protector with new, otherworldly powers, while others might be suspicious of the Shinigami's influence on him. Overall, his relationships would be in a state of flux as he adapts to his new self after the training.
His friends might be initially shocked. But Naruto being Naruto, they would soon accept it. Sasuke might see Naruto's alien heritage as a new way to gain power and become more interested in working with him again. Sakura would be worried about the potential dangers it could bring to Naruto, and be more protective. Shikamaru might find it all too troublesome at first, but then start to strategize on how to use Naruto's newfound abilities for the village's benefit.
His relationship with Sasuke might be different. With Kurenai's influence, Naruto could be more understanding and patient, which might help him better deal with Sasuke's issues. His bond with Sakura could also change as he may approach her in a more mature way, having learned from Kurenai about relationships.
His relationship with his friends would likely change. He might become more distant at first as he focuses on his training with the female shinigami. But in the long run, his new powers and insights could make him a better protector of his friends. For example, he could use his newfound skills to rescue them from more dangerous situations.
His relationship with Sasuke might change. Sasuke might initially be confused or even critical of Naruto without his headband. But as Naruto shows his determination without it, Sasuke could gain a new respect for him. With his friends like Sakura, they might be more protective of Naruto, fearing that others will target him without the symbol of his ninja status.