A plot idea could be that Naruto's devil wings are a result of some experimental jutsu gone wrong. The wings start to change Naruto's personality, making him more aggressive and power - hungry at first. His friends notice the change and try to help him. Naruto then has to struggle with his inner self while also dealing with the physical and mental changes brought by the devil wings. He might have to go on a journey to find a way to reverse the effects of the jutsu and regain his true self.
If Naruto has devil wings in the fanfiction, they could enhance his physical strength. He could use the wings to generate strong gusts of wind during combat, either to blow away opponents or to create a diversion. Also, the wings might have some sort of defensive ability, like being able to harden and block incoming attacks. This would change his fighting style to be more aggressive and versatile, as he now has new ways to both attack and defend.
One idea could be Naruto discovers a hidden realm where devil hunters operate and he has to learn their ways to save his village from a devil invasion.
One idea could be that Naruto discovers he has the power to manifest angel wings. This new power could make him an outcast at first, as it's so different from his normal ninja abilities. People might fear or envy him. But then he uses these wings to save the village in a unique way, like flying above to spot an approaching enemy army early.
A really cool plot idea would be that Naruto is part of a prophecy where the one with bat wings will save the ninja world from a new, flying - based threat. His bat wings give him unique abilities in combat, like the ability to perform aerial acrobatics that no other ninja can. He has to train hard to master these new skills. His friends initially might be a bit shocked but then support him as he embarks on this new adventure to protect the world.
One unique plot idea could be Agent Naruto being sent on a mission to a modern - day world to stop a group of villains who are using ninja techniques for evil in a world not used to such powers. Another might be Agent Naruto having to team up with his own enemies from the Naruto universe, but in a different, more complex political setting within the fanfiction's world.
Perhaps there's a fanfiction where Naruto and Katara get transported to a different dimension. In this new world, they have to rely on each other completely to survive and find a way back home. They might face strange creatures and new forms of ninjutsu that they have to adapt to. This would really test their bond and show how well they can work together outside of their normal environments.
Another interesting plot is the soul - swap. Imagine Naruto and Sasuke swapping souls. They have to deal with living in each other's bodies and understanding each other's perspectives in a very literal way. It leads to some hilarious and also very heart - warming moments as they learn more about each other.
One idea could be a crossover where an Ice Devil Slayer from another dimension arrives in the Naruto world. They could team up with Naruto to fight against a new ice - based enemy that is freezing the land. This would bring a new element of magic to the Naruto universe.
Perhaps the Devil's Advocate could be a figure from Naruto's past who returns with a new, more devious ideology. They could tempt Naruto to abandon his traditional values of friendship and hard work in favor of a quicker, more self - serving path to power. This could create an internal struggle within Naruto as he battles between his old beliefs and this new, tempting but dangerous perspective.
Maybe the wings are related to a new form of chakra she discovers. As female Naruto experiments with different chakra natures, she accidentally unlocks this winged form. This form could have unique abilities like being able to fly at supersonic speeds or creating powerful wind-based attacks with the flaps of her wings. It could also lead to a storyline where other ninja clans become jealous or fearful of her new power and try to either steal it or get her to suppress it.