One possible reason could be that his godlike powers were seen as a threat. The village elders or some powerful forces might have feared that Naruto, with his immense strength, could lose control and cause destruction. So, they decided to seal him away to protect the village and the world at large.
Well, it changes the power dynamic. With Naruto sealed away, the villages that once relied on his strength would be in a more vulnerable position. His friends and allies would also have to find new ways to protect their homes. It might lead to new alliances forming as different groups try to fill the power vacuum left by Naruto.
One interesting Naruto fanfiction could be where Naruto is sealed away and his friends have to find a way to break the seal without his power. They might have to seek out ancient knowledge or form unexpected alliances.
There is a fanfiction called 'Naruto's Sealed Existence'. In this, not only is Naruto sealed, but the seal also affects the chakra flow of the entire village. The story focuses on how the village tries to survive and adapt while also trying to free Naruto. It has a lot of interesting plot twists and political intrigue within the village.
Well, Naruto being sealed away would face many difficulties. Firstly, he'd lose the opportunity to train and grow stronger with his friends. Secondly, he might struggle with self-doubt and fear of being forgotten. And lastly, there'd be the constant battle to keep his hope alive in that sealed state.
In such a fanfiction, the Fairy Tail guild might be thrown into chaos. They could initially be confused about this strange event from another world. Some members might see Naruto's sealing as a threat to their world's balance, while others might be more curious and try to find a way to break the seal.
It could be a powerful dark wizard in the Fairy Tail world who mistakes Naruto for a threat. Maybe they sense his chakra and think it's some kind of dangerous magic they need to contain.
In some fanfictions, Kushina was sealed into Naruto through a complex jutsu. It might be a modified version of the sealing jutsu used to seal the Nine - Tails. The process could involve special incantations and chakra manipulations.
Well, in some Naruto fanfictions, Bardock might be sealed by powerful jutsu. Maybe a dark ninja uses a forbidden sealing technique to lock him away, preventing him from interfering with their evil plans.
Well, one reason could be that the author wants to explore an alternate universe. Maybe in this fanfiction's version of the Naruto world, the events leading to the sealing of the Kyuubi never occurred. It could be due to different political situations among the ninja villages, or perhaps a different chain of events that prevented the Kyuubi's attack on Konoha in the first place. So, without the attack, there was no need for the seal.