One big issue is that it distorts the original intention of the Naruto story. Naruto is about friendship, hard work, and achieving one's dreams. Romantic relationships in the series are also based on mutual respect and normal relationships. 'Naruto x his sister fanfiction' violates these principles and can make the story seem dark and inappropriate. It also may put off a lot of fans who enjoy the positive and motivational aspects of Naruto.
I'm not sure about a great number of Naruto x his sister fanfiction specifically. But if they exist, they should be read with caution. In a proper fanfiction, the relationship could be more about mutual understanding and support. For example, the sister could be the one who understands Naruto's pain of being an outcast in the village at the start and helps him gain confidence, and Naruto in return protects her from the threats that come with being related to him in a world full of dangerous ninjas.
Well, a common theme could be the exploration of a unique family dynamic. Since Naruto grew up mostly alone, having a sister in fanfiction can bring a whole new aspect to his character development. It could also be about the sister sharing Naruto's dreams, like his goal of becoming Hokage. Maybe she also wants to contribute to the village in a big way and they support each other in achieving their goals. Additionally, themes of protection, both Naruto protecting his sister and vice versa, are likely to be present as they face the many threats in the shinobi world.
They could start by having some friendly competitions. For example, in a race to the top of a mountain or a sparring match. This would not only show their bond but also their competitive nature as siblings.
It's completely unacceptable. Naruto is a well - loved anime with a large and diverse fanbase. The idea of a relationship between Naruto and his twin sister in a 'lemon' (usually implying sexual content) way is not only against the ethics of the Naruto world but also goes against basic moral and family values. It would be seen as a perversion of the characters and the story by most fans.
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.
Obviously, Naruto and his sister are the main characters. Naruto is a well - known character from the Naruto series, known for his determination and his dream of becoming Hokage. His sister, though not part of the original series in this way, would be a new character in this fanfiction with her own unique traits and abilities.
Sasuke could be involved. He might be initially suspicious of Naruto's new - found sister but later come to respect her skills. Kakashi could also play a role as a mentor figure to both Naruto and his sister, guiding them in their ninja training. Another character could be Hinata. She could befriend Naruto's sister and help her adjust to life in the village.
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.
Well, in some fanfictions of this kind, Naruto's sister is often portrayed as having a special bond with him. She might have a unique ability that she uses to shield Naruto from the emotional pain of being neglected. For example, she could have a power to absorb negative emotions, and whenever Naruto is feeling down because of the neglect, she uses this power to make him feel better. There are also stories where she tries to expose the unfair treatment Naruto is getting to the village elders, but has to be very careful as she doesn't want to put Naruto in more danger.