A theme that also pops up is the struggle for control. Sasuke might be tempted by the power of the kyuubi and there could be a struggle within him on whether to embrace it fully or resist it. This internal conflict adds a lot of depth to the stories and makes for an interesting read as the reader wonders which way Sasuke will go.
One common theme is power. Since Kyuubi is a powerful entity, many fanfics explore how Sasuke either gains power from it or has to deal with the overwhelming power of Kyuubi. For example, some stories show Sasuke learning to harness Kyuubi's chakra in unique ways.
Another theme is growth. Sarada is constantly growing as a ninja, and Sasuke's influence on her growth is often depicted. For example, in some stories, Sasuke's combat experience and wisdom help Sarada overcome difficult challenges in her ninja career.
A common theme is identity crisis. Sasuke suddenly being a girl would make him/her question who they are now. Another theme could be acceptance, both from Sasuke herself and from the other characters. Also, there might be a theme of newfound friendship. As a girl, Sasuke might make new friends that he wouldn't have made before.
In kyuubi x oc fanfiction, a prevalent theme is the struggle between good and evil. The Kyuubi can be seen as a force that can be used for good or evil, and the OC often plays a role in influencing this. Another theme is redemption. If the Kyuubi has a dark past, the OC can be part of its redemption story. Identity is also a common theme. The OC may struggle with their own identity in relation to the Kyuubi, and the Kyuubi may also have an evolving identity as it interacts with the OC. Additionally, the theme of loyalty is often explored, as both the OC and the Kyuubi have to decide how loyal they are to each other in different situations.
One common theme is the power struggle. Since Kyuubi is a powerful force and Naruko is its host, there's often a struggle for control and dominance in the relationship which makes for an interesting dynamic.
There's 'Kyuubi's Influence on Sasuke'. This fanfiction focuses on how the power of the kyuubi affects Sasuke's growth and development. It shows how Sasuke starts to see the world in a different light due to the kyuubi's presence. The author does a great job of exploring the psychological impact on Sasuke, which makes it stand out from other fanfictions in this category.
The theme of growth is essential. All three characters grow both as individuals and in their relationships with each other. Sasuke has to overcome his thirst for revenge, Naruto has to become a stronger leader, and Itachi has to find a way to make peace with his past. Through their interactions, they help each other to develop new perspectives and skills. For instance, Sasuke might learn from Naruto's positive attitude towards life, and Naruto can gain a deeper understanding of the Uchiha clan's situation from Itachi.
Another theme is friendship. Even though the Kyuubi starts as a somewhat hostile force, over time in fanfiction, a friendship or at least a mutual understanding can develop between Naruto and the Kyuubi. This is seen in stories where they work together to overcome challenges.
One common theme is the exploration of their combined powers. Since Naruto has the power of the Kyuubi and Moka has her own unique vampire abilities, stories might focus on how they use their powers in battles or to protect each other.
One common theme is the power of friendship. Naruto and the fem Kyuubi often start as adversaries but gradually become friends and support each other. Another theme is self - discovery. Naruto discovers new aspects of himself through his relationship with the fem Kyuubi.