Perhaps a fanfiction in which Kaguya's return is somehow linked to the Shinju's overgrowth. Naruto has to figure out how to stop this while also dealing with the revelations about Kaguya's true intentions and the origin of the Shinju. It could involve a lot of research into ancient ninja lore and a race against time to save the world.
One idea could be a fanfiction where Naruto discovers a hidden power within the Shinju that was left behind by Kaguya. This power could either be a threat or a means to bring about a new era of peace in the ninja world.
A cool fanfiction could be about Naruto having to make a deal with a part of Kaguya's consciousness that still resides within the Shinju. In order to gain its power to defeat a new, greater evil that threatens the entire shinobi world. This would involve Naruto having to face his own beliefs and values as he negotiates with a being that was once considered a great villain.
A plot could be that the shinju has been transported to the Marvel universe and is causing chaos. The Avengers think it's a new kind of alien threat. Meanwhile, Naruto, who has somehow also ended up there, realizes it's the shinju. He has to convince the Avengers that he can handle it his way. But some of the Avengers don't trust him at first. So, there's a conflict between Naruto's way of dealing with the shinju and the Avengers' methods.
Maybe in the fanfiction, Kaguya's power is split among several individuals in the Naruto world and Naruto has to find a way to reunite it without causing chaos. Along the way, he discovers hidden secrets about Kaguya's origin and her true intentions.
One idea could be that Naruto somehow gets trapped in a dimension where Kaguya has become a yandere for him. She tries to keep him there all to herself, while Naruto has to figure out a way to escape and also deal with her obsessive behavior.
One idea could be that the Shinju's power somehow connects the Naruto universe and the Justice League's universe. Maybe the Shinju's energy creates a rift, and Naruto characters end up in the Justice League's world. They could team up to fight a common enemy that is attracted by the strange energy of the Shinju. For example, a powerful demon from Naruto's world could be drawn to the new universe and the Justice League, with their high - tech and superpowers, join forces with Naruto and his friends who have ninja skills and chakra abilities.
The original Naruto plot focuses a lot on Naruto's growth within the framework of the ninja villages and his relationships with his friends and mentors. In a fanfiction with Shinju and Kaguya, the scope would be much larger. Naruto could be on a journey that takes him across different dimensions or time periods related to the Shinju and Kaguya. The fanfiction could also introduce new characters or races that are related to the Shinju or were once under Kaguya's rule. This would completely change the feel of the story, making it more of an epic adventure on a cosmic scale rather than just a story about a ninja's growth in a village.
Perhaps in the fanfic, the Shinju has a consciousness that has been dormant for a long time. A ninja accidentally awakens it and has to deal with the consequences. The Shinju could have its own goals and desires that conflict with the ninja world's current state. This could lead to a story of negotiation, understanding, and ultimately, a new way of coexisting between the Shinju and the ninjas.
Some fanfictions might explore a plot where Kaguya's presence is still felt in a spiritual or energy - based way. Her essence could be influencing certain events or characters in the Naruto world without her physical form. For instance, it could be causing strange phenomena or affecting the chakra of certain individuals. This could lead to a mystery - like plot where Naruto and the others have to figure out what's going on and how to stop it if it's causing harm.
One interesting plot idea could be a story where a new character discovers they have a hidden Kaguya bloodline ability that has been dormant for generations. They struggle to control it at first, causing chaos in their village. Another could be a time - travel fanfic where a character goes back to the era of Kaguya and tries to change the course of history regarding the bloodline. Maybe they want to prevent the spread of the more dangerous aspects of the bloodline.
One idea could be that the reincarnation of Kaguya has partial memories of her past life. So she struggles between her new identity and the remnants of Kaguya's desires. Maybe she tries to prevent the same mistakes Kaguya made in the past.
One plot idea could be that Naruto, using his unique ability to understand and reach out to others, tries to find a way to redeem Kaguya. He might journey through different dimensions to learn more about her past and what led her to become so power - hungry. This could involve him facing challenges in these strange dimensions and having to rely on his ninja skills as well as his compassion.