Naruto's personality could also become more solemn. The responsibility that comes with the Rinnegan is huge. He now has the power to potentially reshape the ninja world, for better or for worse. This knowledge could weigh heavily on him, making him seem more serious and less likely to crack jokes all the time. He still has his core values of friendship and protecting the village, but the Rinnegan makes him more aware of the greater implications of his actions.
He could become more confident, bordering on overconfident at times. With the Rinnegan, he has access to incredible powers, and this newfound strength might make him believe that he can handle any situation alone. However, his friends would surely keep him in check. For example, he might initially rush into a battle thinking his Rinnegan - enhanced abilities will ensure victory without fully considering the risks, but then realize his mistake when his friends point it out.
If Naruto got the Rinnegan, he might become more cautious. The power of the Rinnegan is so great that he would realize he needs to be more careful with it. He wouldn't be as brash as before.
Well, the character might become more confident, or perhaps overconfident. The power of the Rinnegan can be overwhelming, and they might start to think they're invincible. For example, they could become more reckless in battles, taking on stronger opponents without proper planning.
Well, typically after awakening the Rinnegan, Naruto might become more powerful and his perspective on the ninja world could shift. He might see the underlying connections between different ninja powers and villages more clearly. His confidence would likely soar as the Rinnegan is a very powerful dojutsu. This new power could also make him a target, forcing him to be more cautious and strategic, which is a big change from his sometimes impulsive nature.
Another possibility is that it's a result of some strange chakra experiment gone wrong (or right). Scientists in the Naruto universe are always dabbling in chakra research. Maybe an experiment meant to enhance her natural abilities instead gives her the Rinnegan, and she then has to learn to control it quickly to avoid being consumed by its power.
Yes, Naruto acquires the Rinnegan in the manga.
Yes, Naruto does obtain the Rinnegan in the manga.
If Naruto got the Rinnegan in fanfiction, it could completely change the power dynamics. For one, his combat abilities would skyrocket. He could use all the Rinnegan - related jutsus like the Six Paths techniques. This would likely make him even more of a force to be reckoned with against foes like Sasuke or any new threats. It might also change his relationships. For example, his standing among the shinobi villages could become even more dominant, as the Rinnegan is seen as a very powerful and rare dojutsu.
The Sage of Six Paths himself could be the key character. Since the Rinnegan was originally his power, he could appear in the fanfic in some form, like a spirit or a time - traveling version of himself. He could then directly bestow the Rinnegan upon Naruto, seeing Naruto's potential and the need for such power to maintain the balance in the ninja world.
His character would have a darker edge. The vampire nature could bring out a more primal and possessive side. And the Rinnegan would give him new levels of power and knowledge. He might start to question his old values as he realizes the potential of his new powers. He could become more solitary, training alone to master his combined abilities rather than relying on his friends like he used to.
He might become much more powerful. With the Rinnegan, he could gain new abilities like the Six Paths powers, which would make him a force to be reckoned with in battles.