The plot could develop in a way where the village starts to notice her abnormal behavior. This could lead to her being ostracized or even hunted if they see her as a threat. Meanwhile, she's so focused on her love interest that she doesn't care about the consequences. Her yandere actions could also attract the attention of enemies who might try to use her emotions against her, adding more twists and turns to the fanfic.
The plot could start with the other characters being oblivious to her yandere nature. As the story progresses, her actions would start to raise suspicions. For example, if there's a training session and she gets overly aggressive towards someone who accidentally hurt her love interest during sparring.
At first, Naruto might be completely oblivious to the yandere Fem Sasuke's feelings. But as she starts to show her possessiveness more openly, he'll have to face it. This could lead to some arguments between them. However, over time, Naruto could start to see the good in her. He might realize that her love, although extreme, is genuine. And so, they could start to build a more trusting relationship. For example, she could open up to him about her past and why she's so protective, which would bring them closer.
Start with a strong inciting incident. For example, Kaguya could be resurrected with a yandere - like obsession for Naruto due to some dark magic. Then, build up the conflict as Naruto tries to resist her advances while also dealing with the chaos she causes in the ninja world.
Well, a yandere female Sasuke in a fanfic would likely be extremely possessive. She might go to great lengths to keep the object of her affection close. For example, she could be very jealous of any other character who gets too friendly with the person she likes. She'd probably use her ninja skills in sneaky ways, like spying on her love interest to make sure they're not interested in anyone else.
Think about a prophecy or a hidden power. Suppose there is a prophecy that says only the union of Uzumaki, Hyuga and Uchiha blood (represented by Naruto, Himawari and Female Sasuke respectively) can unlock a great power. This power is needed to save the ninja world from a coming darkness. The story can be about their journey to discover and master this power, with all the personal and external conflicts that come with it, like distrust from other ninja clans or internal struggles within the group.
Well, it could start with Sasuke joining the Akatsuki with the sole intention of protecting Naruto from within. He could form alliances with some of the less - evil members who might also have a grudge against those who want to harm Naruto. For example, he could team up with Zetsu, who has his own motives and might be persuaded to help protect Naruto in exchange for something.
One way it could develop is that the baby has some special powers that attract the attention of villains. Naruto and Sasuke then have to protect the baby while also trying to teach it right from wrong. As the baby grows, it could start to have its own dreams and goals, which might be different from what Naruto and Sasuke expect, adding more drama to the story.
In a more complex scenario, the female clone could be a result of some experiment gone wrong. She has Naruto's memories of his loneliness and uses that as a way to justify her yandere actions. She thinks she is the only one who can truly understand Naruto and wants to keep him in a world where it's just the two of them. She might even try to make Naruto believe that his real friends are against him so that he depends only on her.
A relationship could develop in a rather complex way. Yandere Koneko might first see Naruto as a target of her affection. She would do everything to get his attention, like sabotaging his meetings with other friends. Naruto, being the kind - hearted person he is, would initially think she's just a bit over - enthusiastic. But as her actions become more extreme, he realizes the seriousness of the situation. He could then try to help her overcome her yandere nature while also developing some sort of bond with her.
In many such fanfics, Naruto's character often becomes more vulnerable yet also stronger in a different sense. His pregnancy makes him rely on Sasuke more, but at the same time, he is determined to still be a great ninja. Sasuke, on the other hand, becomes more nurturing. He steps up to protect Naruto and the unborn child, showing a side of him that was not as evident before.
Well, the plot could involve the female Kyuubi being overly possessive of Naruto. Maybe she tries to keep him away from his friends and training, seeing them as threats to her relationship with Naruto. She might use her powers to intimidate anyone who gets too close to Naruto.