One possible storyline could be that Naruto's sister is being targeted by a powerful and vengeful enemy. Naruto, being the selfless hero he is, throws himself in front of a deadly attack meant for her. His death could then inspire his sister to take up his ideals and become a great ninja in her own right. Another idea is that there is a dangerous mission to protect a secret related to their family that only his sister can safeguard in the future. Naruto sacrifices himself to ensure she can complete this important task. And perhaps in his last moments, he passes on his most powerful jutsu or some important knowledge to his sister to help her in her future battles.
In this type of fanfiction, it could be that Naruto's sister is kidnapped by a group of rogue ninjas. Naruto tracks them down and in the ensuing battle, he realizes that the only way to save his sister is to take on a powerful and cursed jutsu himself. The jutsu is too much for him to handle and he dies in the process of nullifying the threat to his sister. His sister, witnessing this, may then start on a journey to find a way to bring Naruto back to life, exploring ancient ninja arts and making alliances with powerful allies along the way.
One possible storyline could be that Hanabi is captured by a group of rogue ninjas. Naruto, being the hero he is, hears about it and immediately sets out to rescue her. He uses his signature jutsus like the Rasengan to fight off the captors and finally saves Hanabi.
A common scenario in such fanfictions is that Hinata sacrifices herself in a war - torn situation. For instance, in a great ninja war, Naruto is the key to victory but is targeted by the enemy's most powerful forces. Hinata, with her unwavering love for Naruto, jumps in front of a massive attack aimed at Naruto, knowing full well that it will cost her life. This selfless act then serves as a major turning point in the story, inspiring Naruto and his comrades to fight even harder.
Another storyline could involve Naruto's sister being trained more rigorously by the village elders because they see more potential in her. Naruto, feeling neglected, then goes on a self - discovery journey to find his own strength outside the village's traditional training methods. As he grows stronger, his sister realizes the mistake of the elders and tries to make it up to Naruto.
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.
His death would be a huge shock to the ninja world. Naruto is a well - known and respected figure. His sacrifice for his sister would be seen as an ultimate act of heroism. It could inspire a new generation of ninjas to be more selfless and protective of their loved ones. Also, the villages that Naruto had strong relationships with, like Konoha, would likely hold memorials for him and his story would be passed down as a cautionary and inspiring tale.
In the Naruto series, Naruto doesn't have a biological sister in the original story. So in this fanfiction, the author probably creates a new character to be his sister. It could be an original character with unique abilities and a complex backstory that leads to the situation where Naruto dies by her hand.
One possible storyline could be in a dark AU (Alternate Universe). Maybe there's a powerful new enemy that targets Hinata specifically because of her connection to Naruto. This enemy could have some sort of vendetta against the Hyuga clan and sees Hinata as the key to their downfall. Naruto is then left to deal with the grief and also find a way to avenge her death, which could lead to a whole new arc of him exploring darker powers or making some difficult moral choices.
Perhaps in this fanfiction, Naruto is fatally injured in a fight during the Chunin Exams. He might sacrifice himself to save one of his friends. This would cause a great outpouring of grief from his friends and mentors. The village would also be in shock, and there could be a change in the power dynamics as his absence leaves a void.
One possible storyline could be that Naruto is framed for a serious crime within the Blood Prison. The corrupt prison system then subjects him to various forms of torture and unfair treatment, which eventually lead to his death. Maybe he was protecting someone else inside the prison and took the fall for a crime he didn't commit.
One possible storyline could be that in a battle against a powerful dark wizard, Harry sacrifices himself to save Hermione from a fatal curse. Another could be that he gives up his life to protect Hermione from a dangerous magical artifact that is about to explode. Or perhaps he takes on a deadly disease that was meant for Hermione, knowing it would cost him his life.