If trained by Kami as a kid, Naruto's abilities would transform. Firstly, his ninjutsu would be more powerful. He could infuse his Rasengan with some sort of divine energy, making it even more destructive. His ability to sense danger and his intuition would be sharpened. He'd be able to predict his opponents' moves more accurately. Also, he might gain the ability to fly or at least jump extremely high distances, which would give him an edge in battles. His healing ability could also be improved as Kami might teach him some special techniques related to self - recovery.
Naruto's abilities would change in multiple ways. His chakra would likely be of a different quality. It could have a divine essence that makes his jutsu more effective. For example, his shadow clone jutsu could create clones that are not just physical replicas but also have some sort of spiritual power. His taijutsu could be infused with a divine grace, making his punches and kicks more powerful and precise. He could also gain the ability to manipulate natural elements in a more extreme way. For instance, he could turn a small stream into a raging river or create a tornado out of thin air. His connection with the nine - tailed fox might also be affected. Maybe he could gain better control over the fox's power, or even use the fox's power in a new and unexpected way.
His abilities would be enhanced greatly. He could have better chakra control. For instance, he could use chakra more efficiently and might be able to perform jutsu with less effort. His physical abilities like strength, speed and agility would also improve. He could run faster than normal ninjas and jump higher.
His combat abilities would become more diverse. Madara could teach him new forms of taijutsu and ninjutsu. For example, Naruto might learn some of Madara's signature space - time ninjutsu, which would give him an edge in battles. His chakra control would also improve as Madara is very proficient in chakra manipulation.
In such a fanfic, Naruto might gain some really unique powers. Maybe he could learn to control nature in a more divine way. For example, he could make plants grow instantly to use as cover in battles, like creating a forest out of thin air. His physical strength could also be enhanced in a special way that is different from normal training. And his understanding of the ninja world might be deeper as Kami could give him insights into the origin and purpose of ninjas.
If Naruto was trained by Danzo and joined Team 7 in a fanfic, his abilities would change significantly. Danzo's training would probably give him a more strategic mindset. He could be more proficient in using weapons and stealth. In Team 7, he'd learn to coordinate with Sasuke and Sakura. His chakra control might improve in different ways, and he could develop new jutsu that are a combination of what he learned from Danzo and what he discovers while on missions with Team 7.
Naruto's abilities would change significantly. Ichigo has unique spiritual powers, and through his training, Naruto might develop a form of 'spiritual chakra'. His ninjutsu could become more powerful as he combines the new understanding of energy with his existing chakra control. Also, Naruto's combat strategy would shift as he learns from Ichigo's more direct and aggressive fighting style.
If trained by Sanji, Naruto's sensory abilities could get better. Sanji has a good sense of smell which he uses in various situations. Naruto could learn to use his senses more effectively, not just relying on his chakra senses. Also, Naruto's ability to endure pain might increase. Sanji has endured a lot in his life, and he could pass on some of that mental toughness to Naruto, allowing him to push through tougher battles and train harder without getting worn out as easily.
His character would likely become more mature. Kami's influence could make him more patient and less impulsive.
Naruto would probably develop a more diverse set of combat skills. With Edward's training, he could incorporate more acrobatic maneuvers into his fighting style, similar to how Edward moves on ships and during battles. His perception skills would also be sharpened as he learns to read the intentions of his opponents in different ways. For example, instead of relying solely on his ninja senses, he could learn to read body language like a pirate. His ability to adapt to new environments would be enhanced as well, since Edward has experience in various terrains and situations.
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.
He might become more cautious. Tsunade is a more calculating ninja compared to some of Naruto's previous mentors. So Naruto could start to think before he leaps, rather than just charging into battle head - first all the time.