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.
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.
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.
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 red hair, it would likely have been a significant visual change. It might have influenced his personality traits ascribed by others or the way his skills and abilities were perceived. Maybe it would have added an extra layer of mystery or charm to him.
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.
One reason could be some sort of experiment. Maybe Orochimaru or another villain was trying to create a super - ninja and combined the genetic material of the Uchiha with Naruto's. Another possibility is that it's a gift from a powerful being. For example, a god - like entity could have bestowed the Sharingan on Naruto to help him in his quest to bring peace to the ninja world.
He might have increased visual abilities. For example, he could see chakra flow more clearly, which would be a great advantage in battle.
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 presence of the Sharingan could also change the character's relationships. Other characters might be in awe of this new power, or they could be suspicious and fear it. The character with the Sharingan would have to deal with these new attitudes. They might be seen as an outcast or a powerful ally depending on how they use their power. It could also attract the attention of the gods or more powerful beings in the Percy Jackson universe, who might want to either control or destroy this new and unknown power.
Well, in 'naruto sharingan fanfiction', the theme of rivalry is quite common. Characters with sharingan often have rivalries with other powerful characters. Another theme is the mystery surrounding the sharingan. Writers like to create stories that uncover secrets about the sharingan that were not known in the original Naruto series. Also, friendship is a theme, as characters with sharingan form bonds with others while dealing with the power and responsibilities that come with it.