It could also be a member of the village leadership who has a deep - seated prejudice against the Uchiha. This person is constantly trying to undermine the Uchiha's position and is willing to start and fuel the wars in order to get rid of them. They see the Uchiha as a threat to the stability of the village.
Sasuke Uchiha would be an obvious choice. He's a central Uchiha character in the Naruto series. His journey to avenge his clan and his complex relationship with the rest of the Uchiha could be further explored during the clan wars. Another could be Itachi Uchiha. His actions and the secrets he held were crucial to the Uchiha's situation, and in a fanfiction about the clan wars, his role could be even more in - depth.
One plot idea could be a young Naruto somehow getting transported back in time to the Uchiha Clan Wars Era. He could use his knowledge of future events and his unique skills to try and prevent some of the tragedies that occurred. For example, he might attempt to stop the initial conflict between the Uchiha and the village leadership from escalating.
A good choice could be a young Itachi Uchiha. He was a prodigy even at a young age, and his story during the clan wars era could be really interesting. He was torn between his loyalty to the Uchiha clan and his understanding of the bigger picture in the village.
If Naruto saved the Uchiha clan, the story of the Hidden Leaf Village would be rewritten. The history of the Uchiha's massacre would no longer be a dark stain on the village's past. The Uchiha would contribute their unique skills and abilities to the village's development. For example, their Sharingan abilities could be used for better security or in battles against common enemies. There would also be a change in the relationships between characters. People who were once enemies of the Uchiha might have to learn to work with them.
One idea could be exploring the hidden powers within the Uchiha clan that were never fully revealed during the actual wars. For example, there might be ancient Uchiha techniques passed down secretly. Another could be focusing on the relationships between different Uchiha members during the chaos of the wars, like how they support or betray each other. Maybe a young Uchiha discovers a new way to use their Sharingan that gives them an edge in the battles.
The Akatsuki could still be the main antagonists. Since Naruto now has Uchiha powers, they might be even more interested in him. They could see him as a threat or a valuable asset to their plans, just like they did with Sasuke.
It could be a young Naruto Uzumaki, exploring his family's past during the clan wars era. He might discover secrets about the Uzumaki clan that have been long forgotten.
It could be the elders of his clan. They are often the ones who make decisions in the clan, and if they see Naruto as a threat for whatever reason, they could be the main antagonists. They might be afraid of Naruto's growing power or his different way of thinking that could disrupt the traditional ways of the clan.
Obviously, Naruto is one of the main characters. He is usually at the center of the story, using his skills and determination to navigate the clan wars. Sasuke is also often a main character, as his past and connection to the Uchiha clan play a big role. Sakura might be there too, using her medical ninjutsu to help those injured in the wars. And then there are the clan leaders, like the Nara clan leader or the Hyuga clan leader, who have their own agendas and power dynamics within the story.
Danzo could be a main antagonist. He was always paranoid about the Uchiha clan's power and was involved in many of the events that led to their downfall. In a fanfiction where Naruto is trying to save the clan, Danzo would likely oppose Naruto's efforts as he sees the Uchiha as a threat to his own power and the village's stability in his own twisted way.