Maybe Naruto could be corrupted by some dark force. He might start using his powers for evil, like attacking Konoha instead of protecting it. He could form alliances with villains from the series and use his knowledge of the village to undermine it.
One possible plot could be that Naruto is possessed by a devil - like entity. This causes his personality to change completely. He begins to manipulate his friends and turn them against each other. He could also start to hunt down those with special powers in order to increase his own strength, all while having a menacing and devilish appearance.
He could eat the Pika Pika no Mi (Glint - Glint Fruit) which gives the power of light, allowing him to move at the speed of light and create powerful light - based attacks. And perhaps the Yami Yami no Mi (Darkness - Darkness Fruit) which can absorb other attacks and create a gravitational pull. Combining the powers of light and darkness would be quite a unique and powerful combination for Naruto in this fanfiction.
Perhaps Naruto, in this fanfiction, makes a deal with a devil - like entity to gain ultimate power, making him godlike. But this power comes with a price, like losing his connection to his friends. So he has to struggle between his new - found power and his old self. He could be on a path of destruction until someone or something makes him realize the error of his ways. This would create a complex plot full of internal and external conflicts.
In 'Naruto Life as a Devil' fanfiction, the plot could center around Naruto being sent to a different dimension where he is turned into a devil. In this dimension, there are different rules and power hierarchies. He may have to form alliances with unlikely characters in order to survive. He could also be on a quest to find a way to return to his normal self and the Konoha he knows, all while learning to control his devilish powers which might include things like shadow manipulation or enhanced physical abilities.
Well, in a Naruto becomes a devil fanfiction, perhaps Naruto is tricked into becoming a devil. There could be an ancient evil force that disguises itself as a friend and convinces Naruto that the only way to protect his friends and the ninja world is by becoming a devil. His appearance would change, with horns and a more menacing look. His fighting style would also change to be more brutal and less about honor, using devil - like powers such as summoning demonic creatures to fight for him.
One possible plot is that Naruto is transported to the DxD world and discovers he has the latent powers of a Devil Saiyan. He has to learn to control these new powers while also dealing with the complex politics and power struggles in the DxD world. He might form alliances with some of the devil clans or the angels, depending on the situation, all while trying to find a way back to his own world.
Well, the plot might start with Naruto being cursed by an enemy with the Devil Bringer power. At first, he doesn't understand it and it causes him problems. But as he delves deeper into the mystery, he realizes that he can use it to his advantage. He could train with Kakashi or Jiraiya to master this power and then use it to fight against the new threat that cursed him in the first place. Along the way, he might face challenges from the Hidden Villages who see his new power as a threat.
Well, it could be about Naruto having some sort of dark powers inherited from the 'devil' figure. Maybe he has to struggle with these powers and how they are perceived in the ninja world. He might face a lot of prejudice from his friends and the village at first.
Well, the plot could center around Naruto being a godlike figure who decides to attend the high school in the DxD world to understand the devils better. He ends up getting involved in a conflict between different devil factions. His Naruto - like determination and his unique powers, which are a blend of his original ninja powers and new devil - like abilities, help him to resolve the conflict and bring peace to the school. He might also make some good friends among the devils and other supernatural beings, which changes his perspective on them.
Maybe the devil loses his powers while falling in love with the mortal. This would turn the tables as he is now vulnerable and has to rely on the mortal for support. It could also lead to other supernatural beings coming after them, seeing the devil's weakened state as an opportunity.
Maybe Naruto gets really into Vocaloid music. He could start incorporating Vocaloid - inspired moves into his ninja techniques. For example, using the energetic and unique rhythms of Vocaloid songs to create new jutsus that are both flashy and powerful.