Sakura would grow to be a fighter, not just in a physical sense but also in terms of her mental and emotional strength. She would learn to stand up for herself and Sasori. Her relationship with Sasori would also be a big part of her character development. For Sasori, the abuse could initially make him bitter and resentful. However, as the story progresses, with Sakura's support, he might start to see a way out of the cycle of pain. His skills in puppetry could be used not just for self - defense but also as a form of art to express his inner feelings.
The main plot could center around their journey to break free from their parents. Sakura and Sasori might start to discover their own strengths and powers in the face of the abuse. For example, Sakura could be developing her medical ninjutsu skills not just for combat but also to heal the emotional wounds they both have. Sasori, on the other hand, may be using his puppet - making skills to create something that can protect them from their parents' wrath.
Their relationship could start off as a reluctant teacher - student one. Sasori may be initially dismissive of Sakura, but as she shows progress in her training, he might gain a grudging respect for her. Sakura, in turn, would be cautious around Sasori due to his past as a villain.
For Sasori, you can start by emphasizing his aloof exterior. He could be the type who doesn't easily show his emotions. For example, in class, he always sits alone and rarely participates in group discussions. But as the story progresses, show his hidden passion for art or a particular subject. With Sakura, you can highlight her determination. Maybe she's trying to improve her grades in a difficult subject. When she meets Sasori, she tries to break through his cold exterior with her positive attitude.
At first, their relationship would be very tense. Sasori is a former Akatsuki member and has done many cruel things, while Sakura is a Konoha ninja. But as they travel through time together, they would start to rely on each other. Sakura might see a different side of Sasori, perhaps a more vulnerable side that was hidden by his cold exterior. Sasori, in turn, would come to respect Sakura's strength and determination.
Gaara might start as a very introverted character in the highschool fanfic. He keeps to himself due to his past traumas. But as he interacts with Sakura, who is always positive and outgoing, he begins to open up more. He becomes more confident in expressing his opinions and feelings. Sakura, on the other hand, could develop her fighting skills further in a highschool context. Maybe she joins a self - defense class where Gaara also enrolls. Through training together, Sakura learns from Gaara's unique fighting style and Gaara learns from Sakura's tenacity. This mutual growth helps in the development of their characters.
Sasuke's character could develop by becoming more open and trusting. In the police environment, he would have to rely on his teammates, especially Sakura. He might start to let go of some of his lone - wolf tendencies. For example, he could learn to communicate better with Sakura about his plans instead of just going off on his own. Sakura, in turn, could become more confident in her abilities. Working alongside Sasuke, who is highly skilled, would push her to improve herself. She might also become more assertive when it comes to making decisions during investigations.
Sakura would likely develop her combat skills further. In the ANBU environment, she would face more dangerous opponents, which would force her to become more strategic. Itachi, already a complex character, might show more of his internal struggle between his loyalty to the village and his love for his family. Shisui could develop in terms of his leadership skills, as he and Itachi might lead Sakura in missions. He could also become more jaded as he faces the darker side of the ninja world.
I'm not entirely sure if there are a large number of them, but it's not uncommon for fanfic writers to come up with these sorts of unexpected character connections. In the Naruto universe, Sakura and Sasori are from different groups, but in a fanfic, the idea of them being siblings can lead to all kinds of interesting plot developments, like how it might change their interactions with other characters or their own personal growth within the story.
The fanfiction might develop their family backgrounds by showing their parents' occupations. Sasuke's father being a skilled ninja, his training methods and the way he taught Sasuke could be part of the story. Sakura's parents could be shown to have regular jobs in the village, like her father working in a shop, and how that normal family life still shaped Sakura in some ways. For example, she might have learned about customer service from her father, which translated into how she interacted with her teammates later on.
Sasori's character development might involve him opening up about his past traumas that led him to become so attached to puppets. Sakura's presence could be the catalyst for this change. She could also teach him about the importance of emotions and human connections. Sakura, on the other hand, could develop her diplomatic skills as she tries to reason with Sasori and convince him to use his skills for good. Their interactions could also lead to Sakura becoming more aware of the darker aspects of the shinobi world and how to handle them.