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.
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 '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.
In a fanfic, Naruto getting Sasuke's Sharingan could be part of a plot where Sasuke sacrifices himself to save Naruto. Before dying, he gives Naruto his Sharingan. Naruto then has to deal with the new power as well as the emotional weight of carrying a part of Sasuke. He could use the Sharingan to see through illusions more easily and even gain some of Sasuke's memories related to the Sharingan's usage.
Well, Kakashi's adoption would likely bring more stability to their lives. He could train them more intensively and offer better guidance. Naruto might finally feel like he has a proper family, which could boost his self - confidence. Sasuke, on the other hand, could find a new sense of belonging and might be less likely to go down the dark path he did in the original story.
Kakashi may also get angry. Angry at the people or things that caused Naruto to get those scars. This anger could fuel his determination to make Naruto stronger, so that he can better defend himself in the future. He might then intensify Naruto's training, all while having a new - found sense of protectiveness towards Naruto.
Kakashi would be deeply concerned. Given his relationship with Sasuke, he'd feel a strong sense of duty to save him. He'd use his extensive network of contacts within the ninja world to try and find out where Sasuke has been taken. He might also reflect on his past training with Sasuke and how he can use that knowledge to anticipate the kidnappers' moves. He'd be ready to face any danger or obstacle in his path to rescue Sasuke. And he'd be constantly thinking about Sasuke's safety and well - being during the whole process.
The fanfic could be centered around Sasuke's best friends, Naruto and Sakura, and how they interact with Sasuke's Sharingan. For instance, Naruto might be curious about the Sharingan's abilities and constantly ask Sasuke to show him new tricks. Sakura, being a medical ninja, could study the Sharingan's effects on Sasuke's body to ensure he doesn't overuse it and harm himself.
There could potentially be some really creative and out - of - the - box fanfictions with this concept. But finding one might be a challenge. You could try searching on specialized fanfiction websites and use specific search terms like 'Kakashi Sasuke non - traditional relationship fanfiction' and then look through the results to see if there are any that involve the idea of Sasuke being pregnant. But remember, this is a very unusual concept even for fanfiction.