A Naruto and Tsunade time travel fanfiction can be really interesting. It could involve them going back in time to change certain events in the Naruto universe. Maybe they go back to prevent a great tragedy or to save a beloved character. For example, they might travel back to the time of the Uchiha massacre and try to stop it, which would completely change the course of the story.
At first, Tsunade might be skeptical of Naruto. But as they face challenges together during their time - travel, she would start to see his value. Naruto, on the other hand, would be in awe of Tsunade's potential at a young age. Their relationship could develop into a strong friendship as they rely on each other's skills. For example, Naruto could protect Tsunade from physical threats while she uses her medical skills to heal him when he gets injured.
Also, in the past, they might have to adapt their fighting styles. Naruto, used to fighting with his friends and allies from his own time, now has to work with different ninja in the past. He may have to learn new teamwork strategies and combine his abilities with those of the past - time ninja in a different way. Tsunade might also have to rely more on her brute strength and less on her developed medical and strategic skills from the future, at least until she can adjust to the past situation.
Maybe they travel back to a time when Tsunade was just starting to develop her medical ninjutsu. Naruto, with his understanding of modern medical knowledge (from Sakura perhaps), could help her make great leaps in her medical skills. They could also team up to deal with a powerful enemy that was a threat at that time. Naruto's strength combined with Tsunade's budding abilities would make for an exciting story.
Perhaps they time travel to a period when a great evil was first emerging. They then have to figure out a way to stop this evil from taking root without using the knowledge and power they have in their own time. This could involve finding and training local ninja in the past to fight against this new threat, and in the process, they learn new techniques and strategies that they can bring back to their own time.
Tsunade would probably be very suspicious at first. Naruto suddenly appearing from the future? It's not something that happens every day. She might think it's some kind of enemy's trick or a genjutsu.
One common theme is redemption. They might go back in time to give a character a second chance at a better life. Another theme could be the exploration of different relationships. For instance, how Naruto and Tsunade's relationship changes when they are in a different time period.
Often, it could be the same antagonists from the original Naruto series but in a different context. For example, Orochimaru might still be an antagonist if he tries to use the time - travel situation to his advantage, like getting his hands on some ancient forbidden jutsu.
One common theme is redemption. Tsunade often travels back to correct her past mistakes or the mistakes of others in the Naruto world. For example, she might try to save a character who died prematurely in the original story.
In Naruto fanfiction, Young Tsunade can be a really interesting character. She was already strong - willed even as a young girl. Her skills in combat and medical ninjutsu were budding. Fanfiction often explores her relationships with other characters, like how she might have interacted with the younger generations earlier on. For example, she could have been a mentor figure to some, guiding them in their ninja training, especially in the medical aspects. This can add depth to the Naruto universe as it shows different possible dynamics that weren't fully explored in the original series.