The story might progress as Naruto struggles to control the Sharingan at first. He may have some internal conflict as he tries to incorporate this new power into his existing set of skills. As he gets better at using it, he could start to change the power structure in the ninja world. His relationships with his friends and allies could also be affected. For instance, Sakura might be more worried about him as the Sharingan could put a strain on his body. Naruto could also use the Sharingan to uncover secrets about his parents or the history of the ninja clans that were previously unknown.
In a fanfiction where Naruto has Kakashi's Sharingan, the story could progress in many ways. Firstly, Naruto would need to train to fully master the Sharingan. This training could lead him to different places and introduce him to new characters who could help or hinder his progress. He might also use the Sharingan to form new alliances. For example, he could use it to prove his worth to some clans that were previously skeptical of him. His use of the Sharingan could also lead to a rift between him and some of his friends who are jealous or worried about the power it gives him. As the story unfolds, Naruto could face a great enemy who has a deep understanding of the Sharingan and uses that knowledge to try and defeat him.
One possible storyline could be that Naruto receives Kakashi's Sharingan through some sort of magical or experimental transfer. This new power could make Naruto even more formidable in battle. He might start to see the world in a different way, with the Sharingan's abilities to copy jutsu and predict movements. This could lead to new training regimens as he tries to master the Sharingan's full potential while still relying on his own Uzumaki powers like the Nine - Tails chakra.
In some fanfictions, it could be due to a special jutsu gone wrong. Maybe a jutsu that Kakashi was using to transfer some of his chakra to Naruto for a mission accidentally transferred his Sharingan power as well.
One great fanfiction could be about Kakashi using his Sharingan to train Naruto in a special jutsu. Maybe he shows Naruto how to better perceive an opponent's moves by using the Sharingan's ability to analyze. This could lead to Naruto developing a new and powerful technique that combines his own chakra control with the insights from the Sharingan.
Well, if Naruto had the Sharingan and Byakugan, his combat abilities would skyrocket. The Sharingan could help him copy enemy jutsus more effectively, and the Byakugan would give him near - 360 - degree vision. This would make him even more of a force to be reckoned with in battles against the Akatsuki. He could anticipate attacks better and counter with his own powerful jutsus. It would also change his relationships, as his new powers might make some characters jealous or more eager to team up with him.
Naruto with Shisui's Sharingan would have some amazing new abilities. The Sharingan's visual prowess would let Naruto see chakra flow more clearly. This means he could detect hidden enemies or traps more easily. In terms of his existing skills, his Rasengan could be enhanced. He might be able to infuse the Sharingan's power into it, making it even more destructive. Also, his teamwork with his friends would be different. He could use the Sharingan to better coordinate with them during joint missions. For instance, he could quickly assess the situation and direct his friends to the best positions in a battle.
One possibility is a genetic anomaly. Maybe there was some long - forgotten connection between the Uzumaki and Uchiha clans in the past that resurfaces in Naruto. Another could be that a powerful enemy or ally uses a special jutsu on Naruto that implants the True Sharingan into him. It could also be a result of Naruto's own experimentation with chakra manipulation in his quest to become stronger.
In fanfiction, Naruto could get the Sharingan through a blood - related connection that is revealed later. For example, it could be discovered that he has some distant Uchiha ancestry that gets activated somehow. Maybe a powerful enemy's attack awakens this dormant Uchiha blood in him, and as a result, he develops the Sharingan. It could also be that a powerful sage or a new character uses their own unique powers to bestow the Sharingan upon Naruto for a specific purpose.
If Naruto had the Sharingan in fanfiction, it would likely lead to some interesting power - up scenarios. He could combine the power of the Sharingan with his own massive chakra reserves. This might make him an even more formidable opponent. His training would also take a new turn as he'd have to learn to control and master the Sharingan's abilities, like the different levels of the Sharingan and their unique powers.
One possible reason could be that Kakashi is in a life - threatening situation and realizes that Naruto is the best candidate to inherit his Sharingan. He knows Naruto's potential and his desire to protect the village. Another reason could be that Kakashi wants to see how Naruto would use the Sharingan in combination with his own unique abilities. He's curious about the new powers and techniques that Naruto could create with it. Also, it could be a way for Kakashi to show his complete trust in Naruto, as the Sharingan is a very precious and powerful gift.
One implication is that it changes his combat style. He can now use the Sharingan's abilities to predict enemy moves and copy jutsu more effectively. Another is that it might affect his relationships. For example, Sasuke might see him differently. Also, it could lead to new power - up scenarios and different training regimens in the fanfiction.