At first, their relationship could be one of teacher - student in a way. Madara, with his vast knowledge of jutsu and the ninja world, could teach Sakura some ancient Uchiha techniques. Sakura, with her thirst for knowledge, would be eager to learn. Through this exchange, they would get to know each other better. As Sakura starts to master these techniques and use them in her own way, Madara might be impressed by her creativity. This could lead to a relationship that evolves from a simple teacher - student dynamic to a more equal partnership, and perhaps even something more romantic over time as they share more personal stories and experiences.
One challenge is to make their relationship believable. Madara is from a different era and has very different values compared to Sakura. Another is to balance their power levels. Madara is extremely powerful, and Sakura, while strong, is not on the same level. So, it's hard to create scenarios where she can hold her own against him without making it seem unrealistic. Also, staying true to their original characters can be difficult when creating new situations for them in the fanfiction.
One idea could be a time - travel plot where Sakura is sent back in time and meets Madara. She tries to change his path of destruction. Another could be a scenario where Madara is resurrected in Sakura's time and they have to team up against a new common enemy. Maybe a plot where Madara, in his search for power, discovers Sakura's unique medical and combat abilities and tries to use her for his own gain.
Well, a plot could involve Sakura and Madara being forced to team up against a new, powerful enemy that threatens the entire ninja world. Sakura initially distrusts Madara, but as they fight side by side, she begins to see a different side of him. Maybe there's a plot where Madara is cursed, and Sakura is the only one who can break the curse because of her unique chakra. As she tries to break the curse, they get to know each other better. Or perhaps in a parallel universe, Sakura and Madara are lovers from the start and they have to fight against the forces that want to tear them apart.
For Sakura, start with her established traits like her determination and her growth from a fangirl to a strong kunoichi. Show how her interaction with Shisui makes her more aware of different aspects of the ninja world, especially the Uchiha. For Shisui, emphasize his loyalty and his inner conflict. Their development can be shown through shared missions where they learn to trust each other and rely on each other's skills.
A story where Shisui survives and he meets Sakura during a mission outside of Konoha. Sakura is initially wary of him because of his Uchiha heritage, but Shisui's gentle nature quickly wins her over. They then team up to complete the mission and in the process, discover they have a lot in common. They start to exchange medical and combat knowledge, which deepens their bond.
One idea could be a time - travel fanfic where Sakura goes back in time and meets a young Shisui Uchiha. She could be on a mission to change certain events in the Uchiha clan's history and ends up forming an unexpected bond with Shisui. They might work together to prevent some of the tragedies that befell the Uchiha.
One of the most popular themes is redemption. Sasuke has made many mistakes in his past, and fanfictions often explore how Sakura can be a part of his journey towards redemption. For example, she might help him face his inner demons and find peace within himself.
There's a fanfiction where Sasuke and Sakura are on a mission together in a foreign land. They encounter many challenges that force them to rely on each other more than ever. This story could explore their growing bond as they face these difficulties, and how their feelings for each other develop in the midst of danger.
One idea could be a time - travel plot. Sakura somehow gets sent back in time and meets Shisui. They form an unlikely alliance as Sakura tries to prevent certain tragedies from happening in the Uchiha clan. This would involve a lot of mystery and action as they work together, with Sakura using her medical ninjutsu knowledge and Shisui his Sharingan abilities.