At first, the relationship might be strained. Naruto could be jealous of his sister's favored status. However, as the story progresses, his sister might start to see the injustice Naruto faces and try to bridge the gap. They could gradually develop a more understanding and loving relationship.
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.
A possible plot is that the neglected twin sister is actually a key to an ancient prophecy that the village doesn't know about. As she grows up, she starts to have strange dreams related to the prophecy. She then embarks on a journey to figure out what it all means. Along the way, she befriends some unlikely allies, like a group of rogue ninjas who have their own reasons for helping her. In the end, she reveals the truth about the prophecy and her importance to the village, which makes Naruto and the others regret their neglect.
Her character might develop through self - discovery. Since she's neglected, she has to rely on herself. So she starts exploring her own strengths and weaknesses. For example, she might find out that she's really good at stealth because she's always had to hide her feelings. As she faces various challenges, like dealing with bullies in the village or trying to prove herself to her family, she becomes more confident and assertive.
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.
First, give her a distinct personality. If Naruto is all about determination and Sasuke is brooding, she could be the calm and wise one. Then, give her a backstory. Maybe she was separated from Sasuke at a young age and grew up in a different part of the ninja world. This would shape her view of things. Another way is to show her relationships. For example, how she interacts with Naruto's friends like Sakura and Kakashi. This will help to flesh out her character more.
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.
In a Gaara x Naruto twin sister fanfiction, their relationship might develop slowly. Gaara, with his past traumas, would be cautious. The sister, perhaps having grown up in the shadow of Naruto, has her own insecurities. Their connection could be based on mutual understanding of being outsiders in a way. They might bond over shared experiences that Naruto doesn't fully understand.
There could be. Fanfiction writers love to explore different 'what - if' scenarios. Naruto being Anko's twin sister is an interesting concept that could lead to a whole new set of storylines. Maybe in this fanfiction, Naruto would have a different upbringing because of the relation to Anko. It could change how he interacts with other characters, like how he approaches his training or his relationships with his friends. You should look for it on fanfiction platforms by using relevant keywords.
He might try to prove himself. Naruto has always been a determined character. He could focus on his ninja training more intently, aiming to show everyone his worth despite being neglected. Maybe he'd also start to distance himself a bit from his family situation and form closer bonds with his friends like Sasuke and Sakura, who might understand and support him through this tough time.