In this fanfiction concept, perhaps there are some ancient prophecies in the Naruto world that are now being fulfilled with Naruto as the reincarnation of Sauron. This could bring in elements from Middle - earth into Naruto's world. The Sharingan or other powerful ninja abilities could be related to Sauron's magic in some way. And Naruto would have to figure out how to either embrace or reject this new identity while still protecting his village and friends.
Well, one way it could work is if the power of Sauron somehow transferred to the Naruto universe. Naruto's strong will, like that which he used to overcome the Nine - Tails, could be seen as a counter to Sauron's dark influence. Maybe Naruto's journey to become Hokage is disrupted by these new, Sauron - like powers emerging within him, leading to a whole new set of challenges and conflicts.
In a Naruto fanfiction with Broly's reincarnation, perhaps it was a prophecy that led to his reincarnation. The gods or some powerful entity in the Naruto universe foresaw the need for a being with Broly's power. His reincarnation could start as a young ninja - to - be, and as he grows, he discovers his past life as Broly. This could lead to an internal struggle as he tries to balance his new ninja values with his Saiyan instincts. And his presence could also attract the attention of the Akatsuki or other powerful villains in Naruto, who see his power as a threat or a means to an end.
In reincarnation game novels, usually the character is reborn or respawned within the game world. For example, in some cases, when the character dies, they start over from a certain point, like a new life. It could be with some retained knowledge or skills from the previous 'life' in the game.
Well, Naruto leading bandits could be an interesting twist. Maybe he's been brainwashed somehow. He could use his ninja skills to lead them in a different way than typical bandits. For example, instead of stealing for greed, they could be stealing from the rich to give to the poor, like a ninja Robin Hood situation.
Well, one way it could work is if Naruto somehow enters the Dragon Ball universe. Naruto's skills like his shadow clones could be interestingly pitted against Frieza's power. Maybe Naruto would be initially in awe of Frieza's strength but then find ways to outwit him using his ninja tactics.
Well, one way it could work is by exploring Naruto's sense of justice in the context of Lucifer's world. Naruto is all about friendship and protecting the village, while Lucifer has his own complex view on good and evil. Maybe Naruto could be transported to Lucifer's realm and try to bring his values there, causing a clash or an interesting fusion of ideologies.
Well, one way it could work is if Naruto's world somehow got merged with the dark and chaotic world of the Joker. Maybe Naruto, after facing so much pain and loss in his own world, starts to adopt the Joker's nihilistic views. He could use his ninja skills in a more unhinged way, like the Joker uses his chaos-creating abilities.
Well, one way could be through some sort of dark magic crossover. Maybe a powerful dark wizard in the Naruto universe decides to experiment and accidentally fuses Naruto's chakra with Sauron's essence. Another possibility is that a strange interdimensional rift opens and Naruto is pulled into Middle - earth and somehow gets corrupted by Sauron's power and gradually transforms into him.
It could work if Jupiter had some connection to the chakra system in Naruto's world. For instance, Jupiter's power could be the origin of a very powerful and rare type of chakra. Naruto, being his son in this fanfiction, would have a natural affinity for this special chakra, allowing him to perform feats that no other ninja could. This would change the power dynamics in the Naruto universe significantly.
Well, one way it could work is that Naruto's spirit or essence somehow gets trapped within Ichigo's Zanpakuto. This could lead to Ichigo having access to Naruto - like abilities when he wields the sword. For example, Naruto's shadow clone jutsu could be translated into some sort of sword - based ability where Ichigo creates multiple sword strikes at once that are illusions at first but can become real attacks. Another aspect could be that Naruto's strong willpower and determination influence Ichigo's relationship with his Zanpakuto. Maybe it makes Ichigo able to access more of his Zanpakuto's power more quickly or in new ways.
Well, it could start with Naruto accidentally stumbling upon a strange scroll or object that has some essence of Freddy Krueger's power. This exposure makes him curious about who Freddy is. Naruto's always been one to face his fears head - on. So, instead of being scared off, he delves deeper into learning about Freddy. He might even try to incorporate some of Freddy's fear - based tactics into his own combat, but with his own moral spin on it. For example, using illusions that play on the fears of his enemies, but not in a way that tortures them like Freddy does.