She might be overly protective of Naruto in fanfiction. For example, she could prevent other characters from getting too close to him or interfere when she thinks Naruto is in a potentially harmful situation.
One way Fem Kyuubi's possessiveness of Naruto manifests in fanfiction is through her extreme reactions. If Naruto is in danger, she might go to great lengths to save him, more so than what would be considered normal in the Naruto world. She may also be very territorial, marking Naruto as 'hers' in some way, whether it's through her actions or her words. For instance, she could be very vocal about her claim on Naruto when other characters question their relationship. And she might constantly seek Naruto's attention, always being by his side and trying to influence his decisions to keep him close to her.
In this type of fanfiction, the fem Kyuubi's possessiveness might be manifested in her protecting Naruto at all costs. She could be overly vigilant and not allow any harm to come near him. This could lead to her interfering in battles or situations where Naruto might be in danger, even if he doesn't necessarily need her help all the time. She may also try to monopolize his time, not wanting him to go on missions with other people or make new friends. Her possessiveness could also be expressed in a more emotional way, like getting sulky or angry when Naruto doesn't pay enough attention to her.
In this fanfiction, Gaara's possessiveness could be demonstrated in different ways. Firstly, he might be possessive in terms of her time. He wants to spend as much time as possible with her. Secondly, he could be possessive about her emotions. He doesn't want her to be too friendly with other guys as he fears she might develop feelings for them. Also, he may be possessive about her safety, always being on guard and ready to fight off any threats to her.
One way it could manifest is in his training methods. He might be more strict and dedicated with Naruto compared to other students. He could also try to monopolize Naruto's time for training, not wanting other ninjas to interfere with Naruto's growth under his guidance.
Well, in fanfic, Kushina's possessiveness can be seen in her reactions to Naruto's relationships. If Naruto shows interest in a girl, Kushina might be very possessive and try to interfere. She might think no one is good enough for her son. Also, she could be possessive about Naruto's time, always wanting him to spend more time with her instead of on missions or with his peers.
The fear might be manifested in the Kyuubi's attempts to negotiate with Naruto rather than fight. In fanfiction, the Kyuubi could offer Naruto things or make promises in order to avoid a situation where Naruto uses his power against it. This shows that the Kyuubi is aware of Naruto's strength and is scared of the consequences of going against him.
In the fanfiction, Kushina's possessiveness could be manifested in various ways. She might be very controlling of Naruto's daily activities. For instance, she would decide what he eats, when he sleeps, and how he spends his free time. Also, if there are any female characters showing interest in Naruto, Kushina would be quick to step in and make it clear that Naruto is 'hers' in a sense. This could create some interesting conflicts in the story, as Naruto might feel suffocated by her over - protectiveness at times, while also understanding that it comes from her love for him.
It's possible that Naruto frees Fem Kyuubi by making a sacrifice. Maybe he offers a part of his own life force or chakra in order to break the chains that bind her. This selfless act shows his deep connection with the Kyuubi and his willingness to do whatever it takes to set her free.
In many fanfictions, Fem Naruto might show kindness towards the Kyuubi. This kindness could be something the Kyuubi has never experienced before. For example, instead of just seeing it as a source of power, Fem Naruto might try to understand the Kyuubi's past and pain. This could lead to the Kyuubi gradually opening up to her and them developing a deeper bond.
In the fanfiction, Percy's possessiveness might also be demonstrated by his need to be included in all of Annabeth's plans. He may feel left out or threatened if she starts making plans with other people without him. He wants to be a part of everything she does, almost like he owns a part of her time and attention.
Well, in such fanfiction, Draco's possessiveness could show through his constantly trying to keep Harry within his sight. He may be overprotective and not want Harry to engage in any dangerous or potentially harmful activities without his presence. He might also be possessive about Harry's time, wanting Harry to spend most of it with him rather than on his own studies or Quidditch practice.