Naruto would probably first try to find a peaceful solution. He has always been one to believe in the power of friendship and understanding. He might try to talk to the leaders of both villages, like Gaara in the Sand, to find out what's really going on and resolve the misunderstandings.
One possible reason could be a misunderstanding over a shared resource. For example, if there's a new chakra - rich area discovered on the border between the two villages, both might claim it as their own, leading to conflict. Another reason could be due to the actions of a rogue ninja who frames one village against the other. Maybe a Leaf ninja is made to look like they attacked Sand shinobi, sparking anger and calls for war.
Well, in this fanfiction, perhaps the 'agents mist' are actually a secret group within the Mist Village that has been causing trouble. So, the Leaf decides to go to war to stop them. The story could involve Naruto learning about the motives of these agents and trying to find a diplomatic solution while also being prepared for combat. There might be some betrayals and unexpected alliances along the way. For example, some members of the Mist Village might side with the Leaf against the agents. And Naruto's friends from the Leaf, like Sasuke and Sakura, would play important roles in the battles and the diplomatic efforts.
Obviously, Naruto would be one of the main characters as he is from the Leaf Village and would likely lead the charge against the agents of Mist. Sasuke could also be there, as he often teams up with Naruto in important battles. Sakura might be involved too, using her medical and combat skills. And from the Mist side, there could be some important ninja agents who are the antagonists, though their identities would be developed as the story progresses.
The characters from both villages. You have iconic characters from the Leaf like Naruto, and from the Sand, Gaara. Fanfictions can create new storylines involving their relationships, rivalries, or collaborations. For example, a fanfiction might show how Naruto and Gaara's friendship evolves in different scenarios.
There's also 'Leaf and Sand Alliance'. This fanfiction explores how the two villages work together against common threats. It's full of action scenes and interesting political intrigue within the Naruto universe.
Most likely, there would be the leaders of the Leaf Village. And of course, the members of the Agents Mist. Maybe there's a young, brave ninja from the Leaf Village who befriends a member of the Agents Mist, and they become the central characters.
Well, it could be about the Leaf Village facing a powerful enemy and the 'Agents Mist' playing a crucial role. Maybe they have some special powers or skills that turn the tide of the war. They might be a new group in the Leaf Village that was previously unknown, and now they are the village's last hope.
Sakura from Leaf could be a key character. Her medical skills would be in high demand on the battlefield to save the wounded. Temari from Suna, being a strong kunoichi, would be important in leading Suna's forces. Also, Shikamaru from Leaf, with his strategic mind, could be the one devising plans for Leaf's military operations against Suna.
In this fanfiction, Naruto might find allies among the shinobi who were also wrongly exiled from their own villages. They would share a common bond of being outcasts and would fight together against the system that exiled them. Additionally, there could be some rogue ninja with a sense of justice who believe in Naruto's cause and decide to stand by his side in the war.