Naruto's chakra powers could potentially counteract Jenova's invasive and corrupting abilities. His positive and life - giving chakra might be able to purify areas affected by Jenova. For example, if Jenova spreads its cells to take over a region, Naruto could use his Rasengan, charged with his pure chakra, to destroy those cells.
I'm not entirely sure if there is a specific fanfiction with exactly that premise. However, given the popularity of both Naruto and the concept of sealing powerful entities in Naruto's world, it's quite possible. Fanfiction writers love to experiment with combining different fictional elements, so it wouldn't be surprising if someone has written a story where Jenova is sealed in Naruto. You can try searching on popular fanfiction websites like Fanfiction.net or Archive of Our Own to find out for sure.
One possible plot twist could be that Naruto, despite being raised by Jenova, still holds onto his core values from the Naruto world. For example, he might use Jenova's power in a way that is unexpected, like using it to bring peace to his original world. Maybe he discovers a way to combine the strange powers he gains from Jenova with his own ninja skills. Another twist could be that Jenova has a hidden agenda all along, and Naruto uncovers it, leading to a conflict between his loyalty to Jenova (who raised him) and his sense of right and wrong.
Well, Naruto's powers would likely be drastically altered. He might gain some of Jenova's abilities, like regeneration or the power to infect others with her cells. His personality could also change as he struggles to control this new, alien power within him. The other characters in the Naruto universe would be very suspicious and maybe even afraid of him.
In naruto and jenova fanfiction, characters might interact through the sharing of knowledge. The scientific minds in Naruto, like Shikamaru or Orochimaru, could study Jenova and its powers. Meanwhile, Jenova - related characters might be interested in the chakra system of the Naruto world. This exchange of knowledge could lead to new power - ups for both sides. Also, there could be situations where Naruto's friends and allies have to team up with characters associated with Jenova to face a common, greater threat.
One interesting concept could be a crossover of Naruto's ninja skills with Jenova's unique abilities. For example, Naruto's clones might interact in strange ways with Jenova's regenerative powers. Another concept could be the characters from Naruto having to face the threat of Jenova in their world, leading to new alliances and strategies.
The most unique aspect is the combination of two very different universes. Naruto's world of ninjas and Jenova from Final Fantasy VII. It creates a whole new set of power dynamics and story possibilities.
Perhaps in this fanfiction, Jenova's influence causes Naruto to view his village and the shinobi world in a different light. He could start to question the long - held traditions and hierarchies. And as he is adopted by Jenova, he might have to deal with the enmity that the shinobi world has towards anything related to Jenova, thinking he is a threat.
One possible plot could be that Naruto, with his strong sense of justice and determination, discovers Jenova being held captive in some strange, other - worldly prison. Using his ninja skills like shadow clones and rasengan, he battles the guards or forces holding Jenova. He then frees her, not fully understanding the implications. Jenova, being a complex and powerful entity, initially sees Naruto as a tool but eventually starts to respect his unwavering will.