In the past, their relationship could be more complex. Kakashi might be suspicious of Naruto's sudden appearance and his knowledge from the future. Naruto would have to prove himself to Kakashi. However, as they work towards a common goal, like saving Konoha from a threat in the past, they would gradually build trust. Their relationship could also change in terms of how they interact with others in the past. For example, they would need to pretend to be normal villagers or ninjas from that time, and this new situation would impact how they relate to each other.
Since Naruto has more knowledge of the future, Kakashi might start to rely on him more, which could shift their relationship. Naruto could also see a different side of Kakashi from the past, and this new understanding could deepen their connection. For example, they might have to face some challenges together that make them trust each other more than before.
One reason could be for guidance. Naruto often looks up to Kakashi and might need his advice on a difficult situation, like dealing with a new powerful enemy.
Well, one possibility is that they could completely rewrite the history of the ninja clans. Naruto, with his positive influence, might be able to make the Uchiha clan feel more accepted in the Leaf Village, preventing the Uchiha massacre. Obito, having seen the destruction his actions caused in the future, could help Naruto in these efforts. Also, they could work together to train younger versions of themselves and their friends to be even stronger, which would have a huge impact on future battles.
In a time - travel fanfiction like this, they could also have the opportunity to meet long - lost characters or discover secrets that were lost in time. Naruto and Shikamaru could learn about the origin of some of the powerful jutsus in their world. And perhaps they could use their knowledge of future technology or ninja tools to create something revolutionary in the past. This could potentially change the balance of power among the ninja villages. However, they would also have to be careful not to be discovered as time - travelers, as that could lead to all sorts of complications.
Well, they could change a lot of things. Maybe Naruto would prevent some of the tragedies that happened in the past. He could stop the Nine - Tails attack on the village, which would completely change his own life and the lives of many in Konoha.
If Naruto and Hinata went back in time in fanfiction, one possibility is that they could change the course of many events. For example, Naruto might be able to prevent some of the tragedies that occurred in his childhood. Hinata could also use her knowledge to help her clan earlier. They might also have the chance to influence the relationships between different characters in a positive way, like improving the relations between the Uchiha and the village.
Well, they could also change their own relationships. Maybe Naruto wouldn't be so alone as a child, and Ino could become a stronger ninja earlier. They might train together in ways they didn't before, using the knowledge of future jutsu and strategies. They could also influence the relationships between different ninja clans, like improving the relations between the Uzumaki and the Yamanaka clans.
It could be the same antagonists as in the original Naruto series at first, like the Akatsuki. But if Naruto and Ino change things, new antagonists might emerge. Maybe some ninja who were once allies turn against them because they fear the changes Naruto and Ino are making to the ninja world order.
One possible main plot could be that Naruto and Kakashi go back in time to prevent a great disaster. For example, they might aim to stop the Nine - Tailed Fox attack on Konoha that happened in the past. This would involve them having to deal with different versions of their friends and enemies. They would need to be careful not to change too much of the past, as it could have unforeseen consequences on the future they came from.