One common theme is redemption. Madara, who has a rather dark past, might find redemption through his relationship with Naruko. Another theme could be power balance, as both are quite powerful in their own ways and how they handle that in the relationship.
The theme of self - discovery is also present. As they travel through time, both Naruko and Madara may learn new things about themselves. Naruko might discover hidden powers or a different side to her personality, while Madara could gain new perspectives on his past actions and beliefs. This self - discovery often plays a crucial role in the overall plot of the fanfiction.
One common theme is family. Since they are mother and daughter, stories often focus on how they build or strengthen their family bond. Another theme is legacy. Kushina's legacy and how Naruko lives up to it or carves her own path while still being influenced by her mother.
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.
One common theme could be friendship. Naruko and Samaheda might be depicted as having a strong bond of friendship that develops over time. Another theme could be adventure, where they go on exciting journeys together.
One common theme is friendship. They often start as friends and then it might develop into something more. Another theme is adventure. They go on quests together. And love, of course, is a big theme as they are the main characters in the fanfiction and their relationship is explored.
Power is a common theme. Madara is extremely powerful, so often the oc either has to match his power level in some way or is in awe of it. For example, in some fictions, the oc might be a powerful ninja herself and they engage in epic battles together.
One common theme is power imbalance. Since Madara is a very powerful character, often the OC has to deal with his strength and influence, which creates interesting dynamics in their relationship.
One common theme is friendship. They often explore how Naruto, Naruko and Narumi form a strong bond of friendship through shared experiences. Another theme is adventure, as they go on various quests together.
One common theme is friendship. They all grew up in the same village and have different relationships with each other. Fanfictions might explore how they support each other through tough times. For example, during a difficult mission.
One common theme is friendship. Despite their differences, Madara, Hashirama, and the OC often form a unique friendship that transcends the normal boundaries in the Naruto universe. Another theme is power. The OC usually has some sort of power that either attracts or challenges Madara and Hashirama.