Yes, there are likely to be such fanfictions out there. The world of fanfiction is vast and diverse, with fans often combining elements from different fictional universes like 'Harry Potter' and the concept of the Rinne Sharingan from 'Naruto'. You can try searching on popular fanfiction websites to find them.
Well, it depends on the specific fanfiction. There are countless Naruto fanfictions out there. Some authors might decide to give Naruto the Rinne Sharingan to make him even more powerful or to introduce new plot twists. For example, it could be a result of some special training or a mysterious power transfer in the fictional world of the fanfic.
There are quite a few. A lot of fanfiction authors like to explore the concept of Naruto having the Rinne Sharingan. It often leads to some really interesting plotlines. For example, some stories might have Naruto use the Rinne Sharingan to rewrite the history of the ninja world, or he could use it to gain new jutsu that were previously unavailable to him. It's a really cool concept that many authors have fun with.
It can also change Naruto's relationships. His friends might be in awe or even a bit scared of his new power. Enemies would surely target him more. Also, it could mean new story arcs. For example, he might have to deal with the dark side of the Rinne Sharingan's power, like being tempted by its overwhelming abilities. And he may need to find a way to use it for good without succumbing to its potential negative influences.
A possible fanfiction could be about the origin of the Rinne Sharingan having some connection to the world of RWBY. Maybe there was an ancient civilization in RWBY's past that had a similar power, and through some sort of dimensional rift, it influenced the development of the Rinne Sharingan in Naruto's world. This would involve a lot of world - building and exploration of both universes' histories.
I'm not sure which ones are the most popular exactly, but ones that have a unique take on how Naruto got the Rinne Sharingan tend to be well - liked. For example, if it's a result of some ancient prophecy or a hidden power within Naruto that awakens as the Rinne Sharingan, it can draw in readers. Also, stories that show Naruto using the Rinne Sharingan to do something extraordinary like saving the entire ninja world in a new and unexpected way are likely to be popular.
Well, in the 'Naruto awakens the Rinne Sharingan fanfiction', it's possible that Naruto's character arc takes a whole new turn. With the Rinne Sharingan, he might be able to see the chakra flow in a much more detailed and different way. Maybe he could even communicate with the tailed beasts on a deeper level, using the unique abilities of the Rinne Sharingan. This could lead to new forms of cooperation between them and Naruto, which would be really exciting for the story.
It could be a rogue ninja who has also obtained a corrupted form of the Rinne Sharingan. This antagonist would use the power for his own gain, causing chaos in the Naruto world. He might be seeking to overthrow all the existing shinobi villages and establish his own rule, using the unique abilities of the Rinne Sharingan like the ability to create powerful illusions that can affect entire villages at once.
Perhaps the OC's Rinne Sharingan gives them the ability to travel between different dimensions. This leads to an adventure where they accidentally bring a great evil from another dimension to their own world. They then have to use their powers in creative ways to send the evil back.
Naruto himself is often a common character. Since it's related to the Naruto universe, he might be a part of the story, either as a friend or a rival to the character with the Rinne Sharingan. Sakura could also be a common character, perhaps as one of the members of the harem.