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.
The consequences could be far - reaching in the fanfiction. Naruto's relationship with Kakashi might change. There could be a deeper sense of respect and a new kind of bond formed because of this transfer. In terms of power, Naruto could unlock new jutsus or abilities that are related to the Sharingan. He might be able to combine his existing Rasengan techniques with the Sharingan - enhanced perception. This could make him an even more formidable opponent. However, it could also put a strain on his body. The Sharingan is known to consume a lot of chakra, and Naruto's body might need to adapt to this new power drain. If he overuses it, it could lead to exhaustion or even long - term damage.
One great 'Naruto Kakashi's Sharingan' fanfic could be 'The Legacy of the Sharingan'. It delves deep into how Kakashi's Sharingan not only affects his combat abilities but also his relationships with other characters like Naruto. It might show how he passes on some of his knowledge related to the Sharingan to Naruto.
They're popular because Kakashi is a very popular character. His Sharingan gives him a unique and cool look. Fanfics about it allow fans to explore more about his powers, which were not fully shown in the original series. For example, fans can create scenarios where Kakashi uses his Sharingan in ways we haven't seen before.
One idea is that an enemy targets Kakashi's Sharingan and Naruto has to protect it. Along the way, Naruto learns more about the Sharingan's capabilities and how to use it against the enemy. This would be a great opportunity for Naruto to grow as a ninja and for their friendship to deepen.
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.
If Naruto had a Sharingan in fanfiction, it would drastically change the story. He could quickly copy enemy jutsus like Sasuke. His combat ability would skyrocket as he could predict movements better. Also, his relationships might change. For example, his bond with Sasuke could be different as they'd both have the Sharingan. It would also make his training with Kakashi more interesting as Kakashi could teach him unique Sharingan - related techniques.
A new character could be created as the main character. This character could be an orphan who discovers they have a single Sharingan eye, and they don't know where it came from. They then embark on a journey to find out about their heritage and the origin of their eye. Along the way, they meet various Naruto characters and learn about the power and responsibility that comes with the Sharingan. They might face challenges from both those who want to steal their eye and those who fear its power.
Well, Naruto already has his own powerful abilities like the Nine - Tails chakra. But getting Kakashi's Sharingan could enhance his perception skills. He'd be able to see attacks better and react faster. Maybe he could even copy some jutsu more easily, just like Kakashi used the Sharingan to copy many jutsu in the original series.