He would become more introspective. The Rinnegan has a lot of history and power, and Naruto would have to understand its origin and how to use it properly. This could lead to him maturing faster, as he now has a greater power to protect those he loves. He might also become more of an enigma to his friends as he delves into the secrets of the Rinnegan.
Perhaps in the fanfic, Pein gives Naruto the Rinnegan to create a balance of power. With the Rinnegan, Naruto might face new enemies who are after this powerful dojutsu. He would then have to use his newfound power, along with his existing skills like Sage Mode and Rasengan, to protect his friends and the village. The story could also explore how Naruto's view of the world changes with this new power.
Naruto's character would develop in multiple ways if he got the Rinnegan. Firstly, he would become more cautious. The Rinnegan is a powerful and dangerous ability, and one wrong move could have disastrous consequences. So he would think twice before acting. Secondly, he would gain a new sense of purpose. He might see himself as a guardian of a greater balance in the ninja world, not just the Hidden Leaf. His leadership skills would also be enhanced. He could use the Rinnegan to analyze battle situations more accurately and lead his comrades more effectively. Additionally, his view of the ninja world's history would expand, as the Rinnegan has connections to ancient powers and events. This would make him more of a sage - like figure, guiding the younger generation with his new - found wisdom and power.
Naruto's character would experience a significant shift. He has always been known for his raw power and determination. With the Sharingan, he would gain a new level of perception. This could make him more cautious in battle as he now has the ability to see things in more detail. Emotionally, he might become more reserved as he tries to understand the Uchiha's history and the significance of the Sharingan. His growth would not only be in terms of power but also in his understanding of different ninja clans. He would strive to use the Sharingan in a way that unites the ninja world rather than divides it, showing his growth as a character who values peace and unity above all else.
His relationships would change too. Some of his friends might be a bit intimidated by his new power at first. But Naruto would work hard to show them that he's still the same person. He could also form new alliances with those who are interested in the Rinnegan's power, either for good or bad reasons. Overall, he would grow into a more complex and powerful version of himself, with a greater sense of responsibility for the ninja world.
Naruto's character might become more conflicted. His usual positive and straightforward view of the world could be challenged. He might start to question his own ninja way more often, as Pein's extreme methods would force him to re - evaluate his beliefs about how to achieve peace.
His understanding of pain and suffering could deepen. Pein has a complex relationship with pain, and through his training, Naruto could gain a new perspective on it. This might make him more empathetic towards his enemies, or it could fuel his determination to end the cycle of hatred in a different way.
The story would change drastically. Naruto's combat abilities would be enhanced. He could use the Rinnegan's powers like the Six Paths techniques, which would give him an edge in battles. For example, he could use the Preta Path to absorb chakra attacks from opponents.
Naruto's character would likely become more complex. With the Rinnegan, he may start to question his previous beliefs. He might become more cautious as he realizes the great power he now holds. For instance, he may be more hesitant to jump into battles without thinking first.
His character would become more complex. With these new powers, he might face new moral dilemmas. For example, the power of the Rinnegan could tempt him to use it in ways that might not be in line with his usual values.
If Danzo mentored Naruto in a fanfic, Naruto would likely develop a more complex understanding of the ninja world. He'd see the political intrigue and the need for tough decisions. His character could become more self - reliant as Danzo's methods are often about individual strength and cunning. However, he'd also have to fight against the more negative aspects of Danzo's teachings, like the disregard for some lives in the name of the greater good. This internal struggle would shape him into a more nuanced character.