A really interesting plot might be that the Kyuubi's chakra has an unforeseen effect on the Oriko Jutsu. For example, it could mutate the jutsu into something completely new and powerful. This new form of the jutsu could then be used to either save the ninja world from a great disaster or, if misused, become a threat to it. The story could explore the moral implications of this new power as well as the political ramifications within the different ninja clans.
One idea could be a story where the main character uses Oriko Jutsu in a unique way to communicate with the Kyuubi. Maybe they form an unexpected alliance to face a new, powerful enemy in the Naruto universe.
A potential new character could be a mysterious sage who has a deep understanding of both Oriko Jutsu and the Kyuubi. This character could be a mentor figure to the protagonist, guiding them in their journey to master the jutsu and deal with the Kyuubi's power.
Well, perhaps a plot where the harem no jutsu is used not just for comical effect but to actually solve a complex political situation in the Naruto world. The various characters in the 'harem' could use their unique skills and influence to bring about peace. It could also be interesting to see how Naruto manages this new dynamic among the characters in his 'harem' and how it changes his relationships with them on a deeper level.
One idea could be exploring the bond between Naruto and the Kyuubi in a new way. For example, they could have a shared dream where they are in a strange, alternate world and have to work together to find a way back. Another plot could involve Naruto using the Kyuubi's power to save a village from a new, powerful enemy that no one else can defeat. And a third could be about the Kyuubi revealing a long - lost secret about Naruto's family that changes his perspective on his own powers.
Here's a cool idea. In a 'Naruto Shadow Possession Jutsu Fanfiction', the jutsu could be passed down through generations in a family, but with a curse. Every time it's used, it slowly drains the user's life force. A young heir of this family has to find a way to break the curse while still using the jutsu to protect their loved ones. Another plot could be that an enemy uses the Shadow Possession Jutsu to create an army of shadow - controlled puppets. Naruto and his team must find a way to stop this without harming the people who are being controlled. And then there could be a story where the jutsu is combined with a new type of chakra, creating a whole new set of abilities that the main character has to master.
One idea could be that Naruto accidentally uses the Reverse Harem Jutsu on himself instead of an opponent. He then has to deal with the chaos of multiple versions of himself with different personalities. For example, one might be super confident, another shy, and they all have to work together to solve a problem in the village.
One idea could be a story where Naruto discovers a new, ancient space - time jutsu that allows him to travel to alternate universes. In these universes, he meets different versions of his friends and enemies, and has to find a way to return home while also dealing with the chaos caused by the jutsu's power.
Maybe in the fanfiction, the Kyuubi has a soft spot for Hinata. Since Hinata is always so kind - hearted and gentle, the Kyuubi starts to protect her in its own way. This could create some interesting situations, like when Naruto is in danger, the Kyuubi takes over not just to save Naruto but also because it doesn't want Hinata to be sad. It would be a different take on the relationship between the three.
One plot idea could be that Naruto and Kyuubi have to work together to stop an ancient evil that is threatening the ninja world. This would require them to fully trust each other and combine their powers in new and unique ways.
One idea could be Naruto exploring the ancient powers of the Kyuubi that were long forgotten. He could discover hidden techniques that only the Kyuubi knew in its long existence.
Perhaps a plot where the female Kyuubi has to take on a human form to protect Naruto from a new, powerful enemy. In the process, they develop feelings for each other while fighting side by side.