In a Team 7 time travel to the Warring Era fanfic, Naruto's Nine - Tails chakra would be a huge factor. It could be seen as a powerful and dangerous force. He might have to learn to control it better as the ninjas in the Warring Era might be more ruthless in dealing with such a power. Sasuke's abilities would be both a boon and a bane. His Sharingan could make him a target for those who want to steal its power. He'd need to learn how to use it subtly. Sakura's intelligence and quick thinking would help her a lot. She could study the medical practices of the era and combine them with her modern knowledge to create new and more effective treatments. Also, her combat skills could be improved by learning the ancient martial arts of the Warring Era.
Naruto might find that his Rasengan is not as effective as he thought. In the Warring Era, ninjas might have different ways to counter it. He'd have to learn new techniques or adapt his existing ones. Sasuke could find that his Sharingan gives him an edge, but he also has to be careful not to overuse it and draw too much attention. Sakura's strength would be a novelty as brute force might not be as common in the Warring Era. She could use it to her advantage in combat.
Well, it could be about Team 7 going back in time to the Warring Era. Maybe they would try to change certain events that had a big impact on the future of their world. They might meet their ancestors or important figures from that era and get involved in epic battles.
In the past, Team RWBY's abilities could change in various ways. Ruby's semblance of speed would give her an edge in battles, but she might also attract unwanted attention as people in the past may not be used to such swift movements. Weiss's Glyphs could potentially be more powerful in the past if the Dust in that era has different properties. Blake's ability to create clones could be misinterpreted as some kind of dark magic, causing her to have to be more careful about using it. Yang's power might be more difficult to control as the technology to understand and manage it might not exist, making her a bit of a loose cannon in the past.
Kakashi's abilities would likely be enhanced in the past. He has all the knowledge and skills he's gained in the future. So, his combat skills would be more refined. His Sharingan would be even more powerful as he would know better how to use it. He might also be able to teach his younger self some new jutsu that he learned over the years.
When the Konoha 12 time - travel to the past, their abilities would change significantly. Take Rock Lee for example. In the past, there might be different training methods that could further boost his physical strength and taijutsu skills. He could learn from the masters of old and bring back new techniques. For Ino, her mind - transfer jutsu might work differently in the past due to the different mental states and chakra signatures of the people then. And for Shikamaru, his strategic thinking would have to adapt to the different political and combat situations of the past. Their abilities would not only change in terms of power but also in how they are applied in the context of the past's ninja world.
Their friendships could become stronger. Facing the unknown future together would likely bring them closer. They would rely on each other more than ever.
A power - hungry warlord who sees Sakura as a threat to his plans of total domination could be the main antagonist. He might fear that her knowledge or the changes she brings could disrupt his hold on power, so he tries to eliminate her at every turn.
Luffy's rubber ability might not change directly due to time travel, but his understanding of how to use it could be enhanced. For example, if he travels to a time where there are different fighting styles, he could incorporate new techniques. Robin's ability to sprout body parts on any surface could be used in really creative ways. If they travel to a time with different architecture, she could use the structures to her advantage in combat or for exploration in ways she hadn't thought of before.
Sasuke's abilities would be both advanced and out of place. His Sharingan skills would be very powerful compared to most in the Sannin era. But he would lack some of the basic knowledge and skills that were common in that time. For example, he might not be as well - versed in some of the traditional ninjutsu styles.
Orochimaru's experiments and his knowledge of forbidden jutsu would be far ahead of the time he travels back to. He could use this to his advantage, perhaps by creating new techniques based on the limited knowledge of the past. However, he also has to be careful not to change the future too much as his actions in the past could have unforeseen consequences for his future self.
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.