It could be that there is a prophecy in the fanfiction which states that Naruto's death at the hands of Kakashi is necessary to prevent an even greater evil. Kakashi, being a selfless shinobi, decides to fulfill this prophecy against his will. He secretly battles Naruto and kills him. This action, though, has far - reaching consequences. The Akatsuki might take advantage of the situation, and the other villages could see Konoha as a threat now that Naruto is dead.
Perhaps in the fanfiction, there is a misunderstanding. Kakashi mistakes Naruto for an enemy who has somehow disguised as him. In the heat of the moment, Kakashi uses a powerful jutsu on Naruto without realizing it's him until it's too late. This would create a great deal of guilt for Kakashi and a huge shift in the relationships within the ninja village. Konoha would be in chaos as they lose Naruto, who was seen as a symbol of hope.
One possible plot could be a dark turn in the story. Maybe Kakashi is under some kind of mind - control. He could be forced to fight Naruto by a powerful enemy who has taken over his mind. Naruto, being unprepared for such an attack from his mentor, gets killed. This would then lead to a series of events like Sasuke going on a rampage to find out the truth and avenge Naruto, and the whole ninja world being in shock as one of their most promising heroes is gone.
If Naruto was raised by Kakashi in fanfiction, their relationship would be very different from the original. Kakashi could teach Naruto more about the Sharingan and its secrets since he has one. Naruto might also inherit some of Kakashi's reading habits and love for Icha - Icha Paradise, which could lead to some really funny moments.
The other villages might react with a mix of shock and suspicion. They knew Naruto was a powerful force for good in the ninja world. His death could be seen as a sign that something was amiss in Konoha. Some villages might even fear that Konoha was becoming unstable and could pose a threat. Characters like Gaara, who had a special bond with Naruto, would be deeply saddened and might try to find out the real reason behind Naruto's death.
Yes, there might be such fanfictions out there in the vast world of fan - created content. However, this goes against the general storyline of the Naruto series where they are comrades.
In such a fanfiction, one possible plot could be that Naruto faces an extremely powerful enemy who is about to kill Kakashi. Naruto, being the selfless hero he is, steps in and uses a powerful jutsu that requires sacrificing his own life to save Kakashi. This could lead to a great deal of mourning among the other characters, especially those close to Naruto like Sasuke and Sakura. They might then vow to carry on Naruto's will and protect the village even more fiercely in his memory.
One possible plot could be that Naruto and Kakashi are in a fierce battle against a powerful enemy. Kakashi is about to be fatally attacked when Naruto jumps in front of him and takes the hit. As Naruto is dying, he might have some final words for Kakashi, perhaps about the importance of protecting the village and their friendship.
Well, Naruto might gain new abilities. He could potentially use the Sharingan's powers like predicting movements better in combat. It would be a huge boost to his already formidable skills.
One possible scenario could be a power imbalance. Maybe Sasuke discovers some new, extremely powerful jutsu that Naruto has no defense against. For example, a jutsu that can nullify Naruto's chakra or attack his spirit directly. Another possibility is a miscommunication or a breakdown in their relationship. If Sasuke believes Naruto has betrayed him in some way, his anger could lead him to kill Naruto. However, this goes against the core of their bond in the original series.
One possible plot could be an alternate universe where time and events are distorted. Maybe some time - travel or magic is involved that leads to Naruto being in a situation where he could get Kushina pregnant. It would be a very strange and complex plot, considering Kushina is Naruto's mother in the original story.
Well, it could lead to chaos in the Hidden Leaf. His friends like Sasuke might go on a vengeful rampage. They would be filled with rage and guilt, thinking they could have prevented it. The village would also be in turmoil, as Naruto was their hero and a symbol of hope.
The villagers of Konoha would be divided. Some would trust Kakashi and believe there was a good reason for Naruto's death, while others would be furious. The older generation, like Tsunade if she was still around, would demand an investigation. And for Hinata, she would be the most affected. She might feel like she lost her purpose in life with Naruto gone, but then find new strength in seeking justice for him.