His relationships with his guildmates would be transformed. He might go back and meet some of the older members of the guild when they were younger and more inexperienced. This could make him more of a mentor figure to them when he returns to the present. Regarding his enemies, he could understand why they became what they are if he goes back in time and sees their pasts. This might change his approach to dealing with them in the future.
Natsu's relationship with his dragon parent (if he has one in the story) could be completely different if he goes back in time. He could have more time to bond with the dragon, learn more about his origins and his magic. And this new - found knowledge and connection could make his relationships with other dragon - slayers more complex and meaningful, as he might have insights that they don't.
If Natsu goes back in time, his relationships would be very different. With his friends, he might have a new level of understanding. For example, he could see how they grew up and the challenges they faced in the past. He might be more protective of them, especially if he knows what's going to happen in the future. His relationship with Lucy could also change. He could see her in a new light, perhaps realizing things about her that he didn't before when he first met her in the present.
One interesting plot could be Natsu going back in time to prevent a great disaster that happened in the past of his world. For example, he might try to stop the initial attack of a powerful dark guild that had long - lasting negative impacts. Another plot could involve Natsu traveling back to his own childhood and having to deal with his past self, which could lead to some comical and heartwarming moments as he tries to impart some of his current wisdom.
If Natsu travels to a time when Fairy Tail was just starting, he would be more eager to prove himself. His competitive side would be even stronger. In a more distant past, like when dragons were still around, he might be more in awe and a bit more reserved as he encounters these powerful and mysterious creatures. In a future where magic has evolved, he could be a bit out of place at first, but then adapt and become more open - minded to new forms of magic.
Well, for Naruto and Sasuke, their relationship might become even stronger earlier. In the past, they could train together more and understand each other's pain from the start. Sakura might be more assertive in her relationship with Sasuke, as she has the knowledge of what will happen in the future. She could try to prevent Sasuke from going down a dark path right from the beginning. And among the other members of Konoha 12, they might form closer bonds as they rely on each other more in this strange new situation of being in the past.
If Merlin travels back in time, his relationship with Arthur would be very different. In the past, Arthur might not trust him at all at first. Merlin would have to prove himself all over again. With Gwen, he might be more aware of her future importance and try to protect her in a different way. And his relationship with the other knights could be completely new, as they might see him as a stranger with strange powers.
If Team 7 went back in time, Naruto and Sasuke's relationship could become stronger earlier. Maybe Naruto could understand Sasuke's pain from the past better and be able to prevent some of the rifts that formed between them. Sakura might also be more confident around Sasuke in the past, knowing what she knows now. Their bond as a team could be tighter as they work together to change things in the past without making big mistakes.
Their relationships would likely become stronger. They would have to rely on each other more in the unfamiliar past environment. For example, Naruto might look up to Kakashi even more as he sees how much Kakashi has grown and changed. Sasuke might be more open to the idea of teamwork as they face challenges together in the past.
Regarding his family, Hikaru could understand their support for his Go journey better. He might go back in time and be more open with them about his passion for Go. This could lead to his family being more involved in his Go - related activities, like attending more of his tournaments and providing more emotional support. Maybe his family could also play a role in promoting Go in the community because of Hikaru's influence.
Mira, on the other hand, might become more reliant on Natsu at first. But as time goes on, she would start to assert her own independence. She could challenge Natsu's ideas and they would have healthy debates. This would change their relationship from a simple one of Natsu being in charge to a more equal partnership where they both respect each other's opinions.
His relationship with his father, Ned Stark, would be different. He could finally have a real father - son relationship instead of the hidden one. He might be able to learn from Ned and become an even better leader in the North.
It's possible that there could be some strain on their relationships. The stress of being in a different time and the fear of changing things could cause arguments. Maybe they have different ideas about what they should do while in the past. For instance, Fred and George might want to have some fun and explore, while Harry is more focused on achieving a specific goal related to the future, which could lead to some friction between them.