As for his friends like Shikamaru and Choji, they might be in awe of Naruto's new power. However, they could also be a bit worried that this new Sharingan might change Naruto too much. Naruto would have to work hard to assure them that he's still the same old Naruto, just with a new power, and this could lead to some really interesting character - development - driven storylines.
With Kakashi, Naruto might have a different kind of mentorship. Kakashi, being familiar with the Sharingan, could help Naruto in ways he didn't before. But at the same time, Naruto's new Sharingan might also surprise Kakashi and make him re - evaluate Naruto's potential. This could strengthen their bond as they explore the new abilities together.
His relationship with Sasuke would be very different. Since the Sharingan is an Uchiha - related thing, Sasuke might be both jealous and intrigued. They could end up being rivals in a whole new sense, competing to see who can master their respective powers better.
His relationship with Sasuke would be really interesting. Instead of Sasuke being the only one with the Sharingan, Naruto now has it too. Sasuke might feel a mix of envy and camaraderie. Envy because Naruto has something that was so much a part of his identity, and camaraderie because they now share a powerful ability.
Well, it could have the ability to time - travel. Imagine Naruto using it to go back in time to prevent some of the great tragedies in the Naruto world, like the Uchiha massacre. This would change the whole storyline in a very interesting way.
Naruto's relationships with his friends in Konoha would also shift. They might look up to him more, but at the same time, they could be a bit intimidated by this new power. For example, Shikamaru might be more cautious around Naruto as he tries to figure out how this new power affects Naruto's decision - making. And with his new abilities, Naruto might have to keep some secrets from his friends to protect them, which could strain their relationships a bit.
His relationship with Sasuke would be very different. Sasuke might be both jealous and intrigued that Naruto now has an Uchiha power. They could become more equal in terms of power, which might lead to a more competitive but also more collaborative friendship. Naruto could also use the Sharingan to understand Sasuke's pain better, seeing the memories of the Uchiha massacre through Sasuke's eyes.
For Kakashi, if he were to gain an enhanced Mangekyo Sharingan in this crossover, his relationship with his students would shift. He would be even more of a figure of power and mystery to them. His interactions with Naruto might become more about teaching him how to counter the Sharingan's powers, as Naruto would be facing more powerful Sharingan - users. And his relationship with Sasuke could become more strained, as Sasuke might see Kakashi's new power as something he wants to surpass even more urgently.
If Naruto had both powers, his relationship with Sasuke would be affected. Sasuke might see Naruto as an even greater rival or, on the other hand, might be more willing to work with him. They could train together to better understand and control these new combined powers. Sakura might be in awe of Naruto's new abilities and try to support him in a different way, perhaps by researching more about the Sharingan and Rinnegan to help him. Kakashi, having knowledge of the Sharingan, could mentor Naruto in using it in combination with the Rinnegan.
Naruto's growth as a ninja would take a different path. He would need to train differently to master the Sharingan. This could involve more mental discipline compared to his usual physical - intensive training. His fighting style would also evolve. Instead of relying solely on his shadow clones and Rasengan, he'd incorporate Sharingan - based techniques. This would make him a more versatile and unpredictable opponent, and his journey to becoming Hokage would have new challenges and opportunities related to this new power.
His relationship with Sasuke would be very different. With the Sharingan, Naruto would have a new connection to Sasuke's clan. Sasuke might see Naruto in a new light, perhaps as a rival in a different sense. They could have more complex interactions as Naruto tries to understand the Uchiha side of things.
Well, relationships in Naruto Mangekyou Sharingan and Rinnegan fanfiction are often re - defined. When a character unlocks the power of these eyes, their friends may feel a sense of duty to protect them from those who would seek to harm them for their power. However, enemies may target the character's loved ones to get to them. Also, in some fanfictions, characters with these eyes may form a special bond with others who have a similar power or a connection to the origin of these eyes. This can create new alliances and rivalries within the Naruto universe.
His character development would likely be more centered around the power and mystery of the Sharingan. He might become more brooding and introspective like Sasuke at times, as he tries to understand the power he has been given.