If Naruto and the Bijuu go back in time, Naruto's relationship with Madara could be completely transformed. Instead of being enemies in the future timeline, Naruto could try to understand Madara's motives from the start and perhaps prevent him from going down the dark path. The Bijuu, on the other hand, might have a different relationship with the Uchiha clan in general. They could offer their power to the Uchiha in a more positive way, rather than being something the Uchiha might try to control in the future.
Well, when it comes to Naruto and the Bijuu going back in time, their relationships with the various ninja villages' founders would be unique. Naruto could share his experiences of a united ninja world with the founders, and the Bijuu could show their true power in a non - threatening way. This would change how the founders view the concept of power and unity. Also, Naruto could have a more personal relationship with the past Akatsuki members, trying to reform them before they turn into villains, and the Bijuu could play a role in that by showing that they don't have to be used for evil purposes.
One possible plotline could be that Naruto uses his newfound ability to go back in time to prevent some of the tragedies that occurred in the past related to the Bijuu. For example, he might try to stop the initial capture and sealing of the Bijuu into different vessels, which could change the entire history of the ninja world. Another could be that the Bijuu themselves, with Naruto's help, go back to a time when they were free and try to establish a new world order where they are not feared and hunted.
Naruto himself is often a popular character in such fanfictions. Since he has a strong connection with the bijuus, especially Kurama, his time - traveling adventures can create really interesting stories. Another popular character is Sasuke. His power and his complex relationship with Naruto can add depth to time travel plots.
Well, their relationships might become more complex. For example, Percy and Thalia might have a different dynamic as they see each other in a new light in the past. Since they are in a different time, they may rely on each other more for survival, which could strengthen their bond. Nico, being a bit of an outsider among them, might find himself more in tune with Percy and Thalia as they face the challenges of the past together. They may also form new relationships with people from the past, which could in turn affect their relationships with each other.
When Naruto can control the bijuu in the fanfiction, his relationships shift. His friends might be more protective of him as they know his power makes him a bigger target. The villagers who once shunned him could now either idolize him or be even more suspicious. And in the ninja world at large, other villages may try to form alliances with him more eagerly, while some might plot against him out of fear that he'll use the bijuu to dominate. Naruto's newfound control over the bijuu is like a catalyst that stirs up all kinds of reactions in his relationships.
His relationship with his father would be completely different. Instead of growing up without him, he could have a normal father - son relationship. His father could teach him ninjutsu from an early age.
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.
There could be a relationship based on mutual respect. Naruto respects the power of the bijuu, and the fem bijuu respect Naruto's strength of character. It might start as an attraction from the bijuu side, but grow into a deep bond as they get to know each other better.
The relationships could develop gradually. At first, Naruto might be a bit wary of the Fem Kyuubi and Fem Bijuu because they are so different from what he's used to. But as they fight together against common enemies, a sense of trust could start to form. For example, if they save each other's lives in battle, that would strengthen their bond.
Harry might be more confident. Since he already knows what will happen, he won't be as scared or uncertain. Ron could be less jealous. He has seen how his jealousy got in the way in the past. Hermione would probably be more laid - back. She won't have to worry as much about grades and knowledge because she already has it all.
If they go back in time, their relationships with Damon and Stefan could be very different. For example, Elena might see Stefan in a new light if she meets him at a different point in his life. Caroline could also have a different relationship with Klaus if they go back to a time when he was more of an enigma. Their friendships with Bonnie might also change as they might be able to prevent some of the hardships Bonnie faced, which would then affect how they interact in the new timeline.