In this fanfiction, it's possible that Naruto's friends have also grown and changed significantly. They might have developed new jutsus and combat styles. Some of them could even be in positions of power within the village. Naruto will have to readjust to these changes and also deal with his own post - sealing situation.
Maybe the village has changed a great deal while Naruto was sealed. When he finally breaks free, he has to face a whole new set of challenges and enemies that have emerged in his absence. There could be new political situations in the Hidden Leaf Village as well.
The story could also focus on the efforts to unseal Naruto. His friends and the characters from the crossover world could embark on a dangerous journey to find the key or the magic to break the seal. In a Naruto - Harry Potter crossover, Hermione might use her vast knowledge of magic to research a way to free Naruto from the seal.
Perhaps an old enemy has returned, stronger than ever. They might have been plotting during Naruto's sealing and now are ready to take on Naruto and the Hidden Leaf Village. This could be someone like Orochimaru who found a new way to gain power in Naruto's absence.
One interesting aspect could be how Naruto's character has evolved during the long - time sealing. Maybe his skills have developed in unique ways or his relationships with other characters have deepened in the context of this fanfiction.
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 some fanfictions, if Naruto was sealed in the Shinju, it could lead to a major shift in the power balance. His friends might go on a desperate quest to free him. The ninja world could be plunged into chaos as his absence leaves a huge void in terms of power and leadership.
In such a fanfiction scenario, many things could occur. One possibility is that the world would be thrown into chaos as Naruto is a major force for stability. His friends might embark on a dangerous mission to rescue him. They would have to figure out the mechanism of the seal on the moon and find a way to break it. It could also lead to power struggles on Earth as various factions try to take advantage of Naruto's absence.
One possibility in such a fanfiction scenario is that Kushina's own chakra, which was already special as an Uzumaki, could have an impact on Naruto while he's sealed within her. It could either strengthen him in some ways or cause unforeseen consequences. Also, characters like Minato would have a different relationship with the situation. Instead of seeing Naruto as his son on the outside, he might be more focused on the presence of Naruto within Kushina, which could change how he approaches protecting his family and the village.
Naruto is surely one of the main characters since he is the one being sealed. His friends like Sasuke, Sakura, and Kakashi might also be main characters as they would likely be involved in the events related to Naruto's sealing.
Imagine Harry Potter sealed in Naruto fanfiction. Firstly, his appearance would be quite out of place. His robes and wand would draw a lot of attention. He might be imprisoned or studied at first. His ability to apparate could be seen as a form of high - level space - time ninjutsu. However, his lack of understanding of the ninja code could get him into trouble. He'd have to adapt to the different cultures of the ninja villages, like Konoha's values, and find a way to use his magic in harmony with the existing power structures, if he wants to avoid being constantly on the run or used as a tool.
In fanfiction, if Juubi Naruto was sealed in him, he might gain an incredible amount of power. This could potentially make him nearly invincible. He could have enhanced physical abilities, such as super strength and speed. His chakra reserves would likely be off the charts, allowing him to perform powerful jutsu without much strain. However, it could also come with risks. The power might be too much to control, leading to a struggle between the host and the Juubi's influence.