Power. Most fanfictions focus on the extreme power of Madara's Rinnegan. They explore how it can be used to dominate battles or change the Naruto world. Another common theme is mystery. Since the Rinnegan has many unexplored aspects in the original series, fanfictions often try to uncover its secrets.
One common theme is power exploration. Writers often delve into how Madara's Rinnegan powers could be used in different scenarios, like battles against other powerful foes. Another theme is redemption. Some fanfictions might explore if Madara could be redeemed with his newfound power. And of course, there are also stories about his past and how he obtained the Rinnegan in the first place.
In some fanfictions, it could be through a strange and powerful jutsu transfer. Maybe Madara, on the verge of defeat, decides to transfer his Rinnegan power to Naruto for some unforeseen reason, like seeing a new path for the ninja world in Naruto.
He could combine the Rinnegan's ability to control gravity with his Rasengan, creating a super - powerful and hard - to - dodge attack.
Naruto would probably win. He has an indomitable will and has always found ways to overcome powerful foes. His experience and the unique powers he might gain with the Rinnegan could give him an edge over Madara.
One common theme is power and its consequences. When a female Naruto has the Rinnegan, she has to deal with the great power it brings. For example, she might face envy from other ninjas or the temptation to use it for wrong reasons.
A frequent theme is adaptation. When the Rinnegan is introduced into a crossover, characters have to adapt to this new power dynamic. For example, in a Naruto - Harry Potter crossover, the wizarding world has to adapt to the existence of the Rinnegan. Also, redemption can be a theme. A character who has misused the Rinnegan may seek redemption in the crossover story.
One implication is that Naruto becomes an even more powerful force in the ninja world. With the Rinnegan, he can access new abilities like the Six Paths techniques, which would make him nearly unbeatable in combat.
One common theme is loyalty. Their loyalty to each other as brothers is often explored, whether it's tested by the events in the ninja world or by their own personal goals. For example, in many fanfics, they have to choose between their loyalty to the clan and their loyalty to each other.
Love and relationships are also common themes. It could be her relationship with other main characters in Naruto. Maybe she has a romantic interest in a character like Naruto or Sasuke, which creates a whole new dynamic in the story. Or it could be about her friendships or rivalries within the ninja world.
One common theme is the power dynamic. Since both Naruto and Madara are very powerful characters, exploring how their powers play into their relationship is often a key aspect. For example, in some fanfictions, their powers are what initially attract them to each other.