Well, if Naruto was trained by Danzo, he might be more ruthless at first. But joining Team 7 could soften him up. He'd probably bring some of Danzo's combat techniques and secrecy to the team. It could make for an interesting dynamic, with Naruto being a bit more of an enigma compared to his canon self.
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.
In this fanfic, perhaps Naruto's godlike powers would be a result of Danzo's unorthodox training methods. Danzo could push Naruto to his limits, making him a force to be reckoned with. Naruto might also have to deal with the distrust of his friends at first, as they are suspicious of his association with Danzo.
It could be the other Hidden Villages. Since Naruto is becoming so powerful under Danzo's training, they might see him as a threat and try to stop him. Maybe they would send their best ninjas to take him down.
In such a fanfiction, Naruto might become a more shadowy and ruthless ninja. Danzo's training methods are often extreme and focused on loyalty to the village above all else. Naruto could lose some of his idealism and become more of a tool for Danzo's political games.
Well, if Naruto was trained by Danzo in fanfiction, it would be a huge departure from his normal growth. Naruto is all about hope and friendship. But under Danzo's tutelage, he could be molded into a more cynical shinobi. His jutsu might develop in different directions. For example, he could be pushed to learn more dangerous and morally ambiguous ninjutsu. Also, his relationships with his friends might change as he becomes more secretive and less open - hearted due to Danzo's influence.
One possible plot twist could be that Danzo, despite being 'good', has a hidden agenda related to Naruto's power. Maybe he wants to use Naruto to gain political influence in the Hidden Leaf. Another twist could be that Naruto discovers Danzo's past misdeeds while being trained, which creates a moral dilemma for him. He has to decide whether to continue training under someone with a dark history or break away.
Naruto might become more calculating. Since Danzo is known for his strategic thinking, Naruto could pick up on that. He may not be as impulsive as in the original story.
One possible interesting plot could be that Team 7 is trained by a new sensei who has a very different style from Kakashi. This new sensei focuses more on survival skills in extreme terrains. So, Naruto, Sasuke, and Sakura have to learn how to build shelters in deserts, jungles, and snowy mountains. They also learn to hunt for food and purify water in the wild. This new training makes them stronger both physically and mentally, and they develop new jutsu based on their experiences in these extreme conditions.
If Naruto joined Team Avatar, there would be a lot of chaos at first. Naruto's boisterous and head - strong personality might clash with some of the more reserved members of Team Avatar like Katara. However, his determination and never - give - up attitude would inspire the team. His unique jutsu, like the Rasengan, could be used in creative ways against their enemies. He could also learn a great deal from the bending arts, perhaps even finding a way to combine his chakra - based techniques with bending.