Some might choose to make Sakura as Naruto's sister in a fanfiction of this type. Sakura has her own arc in the original series, but if she were Naruto's sister and neglected, it would completely change her character development. She might be more desperate for attention and recognition, and her relationship with Sasuke would also be affected. Additionally, a character like Ino could be reimagined as Naruto's sister. Her rivalry with Sakura could then take on a different meaning, and her family situation being that of a neglected sister would give her a whole new set of challenges and growth opportunities in the fanfiction.
One possibility could be an original character created specifically for the fanfiction. This gives the writer the freedom to shape her personality and backstory completely. Another could be a minor character from the Naruto series that doesn't get much attention, like Tenten's sister if she had one. It could also be a reimagined version of Hinata as Naruto's sister. Since Hinata has her own story in the original series, reimagining her as Naruto's sister with a neglected past could lead to some interesting fanfiction ideas.
Often, a common theme is the sister's feelings of isolation. Since she's neglected, she might feel all alone in the ninja world. She may not have many friends as people are more interested in Naruto. And also, there can be a theme of redemption or revenge. She might want to prove herself to those who neglected her, either by showing them how great she can be in a positive way (redemption for herself in their eyes) or by getting back at them in some way for the years of neglect (revenge, though this is less common in more positive fanfictions).
It could be a member of Naruto's family who is fueling the neglect. Maybe an older relative who believes that the sister has more potential or is more worthy of attention and resources. This person could actively try to keep Naruto down.
It could be a jealous ninja in the village. This person might see Naruto's sister as an easy target since Naruto is often preoccupied. They could spread rumors about her or try to make her life difficult at the ninja academy, taking advantage of Naruto's absence.
It's popular because it explores a different side of Naruto's story. The idea of him having a sister who cares when others don't adds an interesting dynamic. People like the concept of family loyalty and the sister being a support system that Naruto was lacking in the original story.
In such a fanfiction, perhaps the village's needs are always put first by Naruto, and his sister gets the short end of the stick. For example, he might not be there to protect her when she faces some bullies in the village just because he's too busy with village affairs. This could cause her to doubt Naruto's love for her, and she might even consider leaving the village in search of a place where she feels more valued.
One key theme could be family dynamics. Since Naruto is neglected, it might explore how his sister could potentially change his situation or their relationship. Another theme could be self - discovery. Naruto may find new aspects of himself with his sister's influence. Also, it might touch on the theme of redemption, perhaps for those who neglected Naruto in the first place.
Well, a typical plot twist is that Naruto leaves the village due to the neglect. He then returns as a much stronger and more mysterious figure. This forces his family to re - evaluate their actions. Another common plot twist is that the sister is actually in danger, and Naruto is the only one who can save her, despite the family's past treatment. It flips the situation and shows that Naruto is still the bigger person. And sometimes, a plot twist could be that Naruto has a secret heritage that was the real reason for the family's strange behavior towards him.
Some themes might include perseverance. Despite the neglect from his sister, Naruto continues to move forward. There could also be a theme of forgiveness. Maybe at some point in the fanfiction, Naruto has to decide whether to forgive his sister for neglecting him. And family drama is definitely a common theme. It can explore the complex relationships within a family, especially in the context of the Naruto world.
It could be that his sister has some special abilities or talents that the family or the village values more. For example, if she has a very rare and powerful bloodline limit, everyone's attention would be drawn to her. In a ninja world, power and potential are highly regarded, so Naruto might be overlooked because his sister seems to have more of that 'special something' at first glance.
Sasuke could be one of the main characters. He might be initially suspicious of the neglected emperor, thinking he could be a threat to the balance of power. But as the story progresses, he could come to understand the emperor's situation. Another character could be Kakashi. He would likely be the voice of reason, trying to analyze the situation objectively and guide Naruto and the others in dealing with the emperor.