In many fanfictions, they interact on an emotional level. The fem furry Kyuubi might share her past traumas with Naruto, and Naruto, being the empathetic person he is, would offer support. This would create a bond between them.
One popular story could be about their adventures together in a new world created by some magical force. They might face challenges and grow closer as they overcome them.
Their powers could interact in a really interesting way. Naruto as Noble Six might have some unique combat techniques that could be enhanced by the Fem Kyuubi's chakra. For example, if Noble Six has some sort of speed - based ability, the Kyuubi's chakra could boost it even further.
The characters from RWBY could be initially afraid of the Kyuubi due to its powerful and somewhat menacing appearance. However, Naruto (if he also comes through with the Kyuubi) could act as a mediator, explaining the Kyuubi's power and how it can be used for good. For example, Weiss might be skeptical at first but then see the potential in combining her Dust powers with the Kyuubi's chakra.
One great fem Naruto x fem Kyuubi fanfiction could be one that focuses on their unique bond. It might explore how they interact in a world where Naruto is female and the Kyuubi also takes a female form. For example, it could show them teaming up against common enemies and how their combined powers are different from the original story.
The relationships could develop gradually. At first, Naruto might be a bit wary of the Fem Kyuubi and Fem Bijuu because they are so different from what he's used to. But as they fight together against common enemies, a sense of trust could start to form. For example, if they save each other's lives in battle, that would strengthen their bond.
Some writers develop their relationship by exploring their mental connection. Since Naruto has a connection to the Kyuubi from the start, when it's a fem version, this connection can be deepened and explored in new ways. They might be able to communicate telepathically and share emotions. This leads to a more intimate bond. Also, the Fem Kyuubi might teach Naruto new jutsu or skills, which is a form of bonding as Naruto becomes more powerful with her help and they grow closer through the learning process.
When writing the Fem Nibi and Fem Kyuubi characters in a Naruto fanfic, start with their core identities. The Fem Nibi could be portrayed as more of an enigma, with a calm exterior but a complex inner world. The Fem Kyuubi, being a symbol of great power, can be written as confident yet also a bit lonely. In relation to Naruto, show how they are drawn to his unwavering spirit. For example, the Fem Nibi might be intrigued by Naruto's ability to see the good in everyone, and the Fem Kyuubi might admire his tenacity. Their character arcs should be about not only their relationship with Naruto but also their own self - discovery within the context of the ninja world.
Naruto can be developed uniquely by showing his struggle to balance his normal ninja life with the new dynamic of having a fem Kyuubi around and his mother Kushina. He might develop new fighting styles that combine his Uzumaki heritage, his training, and the fem Kyuubi's powers. Kushina could be developed as a sort of mediator between Naruto and the fem Kyuubi. She uses her past experiences to guide them. The fem Kyuubi can be developed by having her adapt to the human world more, learning about emotions like love and friendship from Naruto and Kushina.
Obviously, Naruto and the yandere fem Kyuubi are the main characters. Naruto is the protagonist of the Naruto series, and in this fanfiction, he becomes the focus of the yandere fem Kyuubi's affections.
The main characters are clearly Naruto as the cryomancer and the female Kyuubi. Naruto, with his ice - based powers, and the fem Kyuubi, which is a very powerful and important figure in the Naruto universe.