It could be that he was in a life - or - death battle against a powerful enemy. Maybe he was pushed to his limits, and in that moment of extreme stress and desperation, his latent power awakened in the form of the Rinnegan.
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.
In some fanfictions, Naruto might awaken his Rinnegan through a powerful and ancient jutsu. For example, he could come across a hidden scroll that contains the knowledge and power to unlock this dojutsu. Maybe a mysterious sage or an old shinobi reveals the secret to him, guiding him through a series of trials that eventually lead to the awakening of the Rinnegan.
Sasuke's reaction could be complex. At first, he would be enraged. After all, the Rinnegan is a symbol of his power and his journey to gain strength. However, he might also have some mixed feelings. He and Naruto have a deep bond, and he might wonder if Naruto had a good reason for taking it. But overall, his initial reaction would likely be one of fury and a desire to get his power back.
In one possibility, Naruto could be in a life - or - death battle against an extremely powerful enemy. This intense situation could trigger some latent power within him, leading to the awakening of the Rinnegan. Maybe he has a connection to an ancient power or a special bloodline that was previously unknown, which surfaces during this crucial moment.
One possible consequence is that he gains new and extremely powerful abilities. With the Rinnegan, he could have enhanced perception, be able to use all six paths techniques more effectively, and perhaps even have the power to manipulate time and space to a certain extent. This would make him an even more formidable opponent.
It could be a new character, a rogue ninja from a long - lost clan. This antagonist might have a vendetta against Naruto because they see his potential to awaken the Rinnegan as a threat to their own plans for power. They could be trying to stop Naruto from achieving this new level of power so that they can carry out their evil deeds unopposed.
The awakened bloodline might also change Naruto's appearance in some way. This could be a factor in how the harem members view him. If he becomes more physically striking, it could intensify their feelings. Also, depending on the nature of the bloodline, it could give Naruto access to new forms of chakra or skills that the harem members would be eager to learn from him, strengthening their bonds.
One implication is that he becomes much more powerful. The Rinnegan gives him access to powerful abilities like the Six Paths techniques, which would change the power dynamics in battles in the fanfiction. He could now face stronger enemies more easily.
In Naruto fanfiction, the Rinnegan in Naruto is often portrayed in really cool and powerful ways. Some fanfics might give Naruto the ability to use all the Rinnegan powers to their fullest extent right away, like being able to effortlessly summon the Gedo Statue or use the Deva Path powers without any drawbacks. It's a way for writers to explore new storylines and make Naruto even more of a badass than he already was in the original series.