If Sasuke kills Naruto and regrets it, it would completely shatter the hope that Naruto represents in the story. The ninja world, which was slowly moving towards unity because of Naruto, would plunge into chaos. Characters like Sakura would be deeply affected, and Sasuke himself would probably isolate himself even more. His regret might lead him on a new journey of redemption, but the damage to the world would be hard to undo.
Well, if Naruto was born in Iwa, the whole story would be flipped on its head. For one, he'd grow up with different values and training methods from Iwa. His relationships would be completely different. Instead of having friends like Sasuke and Sakura from Konoha, he'd have Iwa comrades. His ninja way might be more in line with Iwa's harsh and competitive environment. Maybe he'd be more aggressive in his fighting style. Also, the relationship between Iwa and Konoha would be more complex as Naruto could potentially be a bridge or a source of conflict between the two villages.
Sasuke's development would be complex. He might start to question his entire ideology that led him to kill Naruto. He could become more empathetic towards others as a result of his regret, realizing the value of life that Naruto always represented. He might also try to make amends in the ninja world, but it would be a long and difficult journey as he has to deal with his own guilt.
In a fanfiction where Naruto kills Sasuke and obtains the Sharingan, it would be a game - changer for the story. Naruto would gain new abilities like enhanced visual perception and the potential to use some of the Uchiha's signature jutsu. However, this would also create a lot of internal conflict within Naruto. His ninja way has always been about saving his friends, not killing them. So, this act would make him question his own identity and values. Moreover, the political situation in the ninja world would be in chaos. The Uchiha clan's power being transferred to Naruto, an outsider in terms of the Uchiha, would be a controversial matter that could spark new rivalries and alliances.
In a fanfiction where Naruto kills Sasuke at the Uchiha compound, it's a very dark turn. Naruto's character would be severely damaged in the eyes of many. His journey was about saving Sasuke, not killing him. This could also lead to a power vacuum as Sasuke was a powerful shinobi. The Uchiha clan's already tragic story would become even more so. It might also cause Naruto to lose his way, as Sasuke was a sort of mirror to him, and without Sasuke, he might lose his motivation to keep getting stronger.
If Naruto gives up on Sasuke in fanfiction, the storyline could take a very different turn. For one, the whole dynamic of their relationship, which has been a central part of the original Naruto story, would be completely disrupted. Naruto has always been determined to bring Sasuke back to the village. Without that drive from Naruto, Sasuke might become even more isolated and perhaps fall deeper into the darkness. This could also lead to different power alignments in the ninja world. Allies of Naruto might question his change of heart, and enemies could take advantage of the rift between the two former friends.
This fanfiction changes the power balance within Konoha. Sakura was growing to be a capable kunoichi. Her death would mean a loss of potential power and knowledge for Konoha. Also, it could lead to a rift between Sasuke and the village. Instead of being a potential ally or a wayward ninja, he becomes a murderer, and Konoha would have to deal with him differently.
It alters the theme of the original Naruto story. The original story often emphasized forgiveness and the power of friendship. In this fanfiction, if Naruto kills Haku, it might shift towards a darker theme of sacrifice and the harshness of the ninja world. This could also change how the other characters develop. For instance, Sakura might view Naruto differently, either fearing him or seeing him as a more decisive and perhaps colder hero. And Naruto himself might struggle with guilt or a new - found sense of power that comes from taking a life, which would be a huge departure from his usual self in the original storyline.
Yes, there are likely some fanfics out there with such a plot. Fanfiction is a creative space where authors explore different scenarios. However, it goes against the general narrative of the Naruto series where Naruto is more about saving Sasuke.
Well, it completely shatters it. Their relationship which was built on rivalry, friendship, and a sense of mutual understanding is now gone. It's a tragic end to what could have been a great story of redemption and friendship.
In the original Naruto storyline, Naruto is a character full of hope and determination. He would never give up easily, especially not to the point of taking his own life. So in this fanfic, it's a huge deviation as it goes against his core trait of perseverance. He has faced countless difficulties and setbacks in the original story but always found a way to keep going.