It could have completely changed the dynamics of his battles and his relationships with others. The Sharingan would have given him an extra edge and new abilities.
If Naruto had the Sharingan in fanfic, he'd likely become even more powerful. His combat skills would improve as he could use the Sharingan to predict his opponents' moves more accurately. He might also be able to use some of the unique jutsus associated with the Sharingan. For example, he could potentially learn to use Amaterasu if the fanfic writer allows for that kind of power combination.
Well, he'd probably be extremely powerful. The Sharingan already gives some great abilities like enhanced perception and the ability to copy jutsu. If Naruto had a blue Sharingan, he might be able to combine those with his own massive chakra reserves. Maybe he could use the Sharingan to better understand and counter his opponents' moves while using his Rasengan or other jutsu more effectively.
In a fanfic, Naruto with the Rinnegan and Sharingan would have a whole new set of challenges. He would have to deal with the jealousy and fear of other ninja villages. His own village might also be divided on how to handle his new powers. On the positive side, he could use these eyes to better understand the history of the ninja world. For example, the Rinnegan might give him insights into the Sage of Six Paths' true intentions, and the Sharingan could help him uncover secrets about his own family. He would also have to train hard to fully utilize the combined potential of these two powerful eyes, which could lead to some interesting training arcs in the fanfic.
I recommend Shurunyan in the Entertainment Circle to you. This book is about Xuan's second transmigration to Earth's parallel world. He relied on Shurunyan to become a mighty mudslide. He didn't want to get involved in the infighting of the entertainment industry. He just wanted to be a relaxed and happy plagiarist. However, he accidentally entered the entertainment industry, so he could handle it with ease and was very interesting. I hope you like my recommendation.😗
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.
Naruto might adapt by first trying to understand the basic functions of the Sharingan. He could start with the simple ability to see chakra flow more clearly. Since he has always been perceptive about people's emotions, he could use the Sharingan to read the emotions of his enemies through their chakra, which would help him in battles.
The Sharingan in a Naruto fanfic can be a really interesting element. It often adds depth to the story. Writers can explore different aspects of it, like the unique powers of different levels of Sharingan, such as the Sharingan's ability to copy jutsus. It can also be used to show the character's growth. For example, a character might start with a single - tomoe Sharingan and progress to the Mangekyo Sharingan, which could be a significant plot point in the fanfic.
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 drawback could be the strain on his body. The Sharingan is a powerful dojutsu, and Naruto's body, which is used to his own chakra system, might not be able to handle it well at first. This could lead to fatigue and over - exertion during battles.