It could also be that Sakura, as Pain's sister, has some hidden powers that are related to Pain's abilities. She might struggle with controlling these powers at first. Meanwhile, the other characters in Naruto might be very suspicious of her due to her relation to Pain. However, Sakura would strive to prove that she is different from Pain and use her abilities for good, like protecting the innocent and helping to end the cycle of violence in the ninja world.
Well, one possible plot could be that Sakura, being Pain's sister, tries to change his extreme views. She might use her medical skills to heal the wounds of those affected by Pain's actions in the Hidden Rain Village, and gradually try to bring Pain back to a more peaceful state of mind.
In this fanfiction plot, Sakura could be on a mission to infiltrate Pain's group. However, during her time there, she gets to know Pain on a deeper level. They start to bond over shared experiences of loss and the desire for a better world. Their relationship then becomes a catalyst for change. Sakura tries to bring Pain to the side of good, and together they face many obstacles, both from the Akatsuki and from Konoha, as they try to navigate their new - found love within the context of the Naruto - like world.
One possible plot could be that Sakura, as Kisame's sister, has been secretly trained in combat skills by him. When the shinobi world discovers this relationship, it causes a stir. Sakura has to prove herself not to be a threat like her brother was perceived in the original story.
The plot could start with Sakura being hidden away by Pain for some reason, maybe to protect her from his enemies. As she discovers her heritage, she has to deal with the shock and also the expectations that come with being Pain's daughter. She might try to use her position to bring about change in the organization that Pain leads, trying to make it less violent and more about peace, which would be a huge contrast to Pain's original motives.
It could be about a very dark and twisted situation where 'pain' is personified and is physically restraining or harming'sakura' in some way. Maybe it's a psychological horror story where sakura is a victim of some malevolent force represented by 'pain'.
Well, it could be about Sakura forming a special bond with Sasori's sister. Maybe they start as enemies due to Sasori's actions, but then gradually come to understand each other. For example, they might discover they both have a love for a certain type of flower, which becomes a symbol of their newfound connection.
One plot idea could be that Sakura discovers her relation to Deidara later in life. This could lead to a conflict within herself as she has to reconcile her loyalty to her friends in Konoha with her new - found family connection to a former enemy. Another idea is that Deidara, knowing she is his sister, tries to protect her during battles without revealing their relationship at first.
One possible plot could be that they discover their relation later in life. Sakura, who has been with the Leaf Village, and Sasori, a former Akatsuki member, could be shocked by this revelation. It might lead to Sakura trying to redeem Sasori or at least understand his actions better.
One possible plot could be that Sakura is a new student in high school and Pain is the mysterious loner. They get paired for a project and initially clash due to their different personalities. But as they spend more time together, they start to understand each other. Sakura sees the pain (no pun intended) behind Pain's tough exterior and Pain begins to admire Sakura's determination.
Perhaps Sakura is dealing with family issues. She could be hiding the pain of having a difficult family situation, like an overbearing parent or a family member with an illness. In the fanfiction, she might focus on her school or ninja work to distract herself from her family problems.
The fanfic might focus on the relationship between Sakura and her sister. It could show how they support each other through difficult times, like dealing with school bullies or family issues. The sister could also have her own love interest in the story, which adds a romantic sub - plot.