Kurama might start to lose his power in Naruto's jail. Since he's confined, his connection to the natural chakra sources could be severed, causing him to weaken gradually. Naruto would then have to find a way to restore that connection, perhaps by finding a hidden key within his own memories that unlocks the jail and restores Kurama's power.
It's possible that in the fanfiction, the jail in Naruto's mind where Kurama is trapped is not a normal jail. It could be a sort of purgatory where Kurama is forced to relive his past mistakes over and over again. This could be a test for Kurama, and Naruto, through his strong bond with Kurama, might be able to enter this purgatory - like jail in his mind. There, they could work together to break free from this cycle and emerge stronger than ever, with a deeper understanding of each other.
One idea could be that Kurama is trapped in a special jail within Naruto's mind. Maybe it's a result of some dark magic or a side effect of a new jutsu Naruto attempts. In the fanfiction, Naruto could be desperately trying to find a way to free Kurama while also dealing with the internal chaos that Kurama's imprisonment causes within him.
In such a fanfiction scenario, Naruto might use his knowledge from the future to prevent some disasters. For example, he could stop the Uchiha massacre by warning the clan early. He could also teach his younger self some advanced jutsu techniques, which would make him stronger much earlier in his life.
In the 'naruto kids meets kurama fanfiction', it could be that the kids are initially scared of Kurama. But as the story progresses, they come to understand his importance and his past with Naruto. They might even form an unexpected bond with the great fox, leading to all kinds of adventures where Kurama uses his wisdom to guide the kids through tough situations.
One possibility is that Naruto's power becomes uncontrollable at first. Since Kurama is a huge source of chakra, Naruto might struggle to handle all that extra power. He could accidentally cause destruction around him. For example, his simple movements might create shockwaves that shatter nearby rocks or buildings. But as time passes, he would start to learn how to channel this newfound power for good, like using it to protect the village from a powerful enemy invasion.
In this kind of fanfiction, Naruto might gain unique powers. Since Kurama is a powerful being, being trained by a female Kurama could lead to Naruto having a different combat style. He may learn more about chakra control in a new way. For example, he could develop a special jutsu that combines his own natural abilities with the knowledge imparted by the female Kurama.
One possible outcome could be that the Hidden Leaf Village enters a period of great mourning. Naruto is a hero to them, and his sacrifice would leave a huge void. His friends like Sasuke might be filled with regret for not being able to stop him. They could also be inspired by his selfless act and strive to protect the village even more fiercely in his memory. Kurama, on the other hand, might be filled with a sense of guilt and a newfound determination to protect the village in Naruto's absence.
Immediately after, they could share a knowing look and then rush off to face a new threat. Their combined energy from the fist bump gives them an extra boost.
In such a fanfiction, Naruto might become extremely powerful at a young age. Kurama could teach him unique jutsu and survival skills. He would also likely have a very different view of the tailed beasts compared to canon Naruto.
One possibility is that Kurama senses a new threat approaching and decides to team up with Boruto. They could go on an adventure together, with Boruto having to learn how to work with the powerful and sometimes grumpy Kurama. Along the way, Boruto could learn more about the nature of chakra from Kurama, which would be a great development for his ninja skills.
In the fanfiction, since Naruto has Kurama, he has a great source of chakra. Hinata with Nibi might also have enhanced abilities. They could team up against common enemies. Naruto's brash and bold nature combined with Hinata's calm and gentle demeanor, along with their newfound powers from Kurama and Nibi respectively, would make for an interesting dynamic. Maybe they would develop new jutsus together that utilize both Kurama and Nibi's powers.