Naruto is the central figure for sure. But there could also be other trainers he meets along the way. Maybe a mysterious trainer who has a special connection to the Pokemon world and helps Naruto understand it better. And of course, the Pokemon that Naruto catches and trains, like a Charmander that he raises to become a powerful Charizard, they all play important roles as main characters in different aspects of the story.
Obviously Naruto would be the main character since it's about him being reborn as a Pokemon fan. His Pokemon partners could also be considered main characters. For example, a Pikachu that he befriends early on and they go on adventures together.
The main character is Naruto, who brings his ninja spirit into the Pokemon world. Alongside him, there might be a female trainer who becomes his rival and later his friend. She could have a unique set of Pokemon. Also, an old Pokemon sage - like character could be introduced. This character would guide Naruto in his journey in the Pokemon world, teaching him about the secrets and powers of different Pokemon.
There could be new Suna shinobi that Naruto befriends. For example, a young and talented sand ninja who has a unique jutsu related to the desert environment, like being able to manipulate sandstorms on a small scale. Another potential character could be an elder in Suna who has a lot of knowledge about the village's history and secrets, and who helps Naruto understand his new role in Suna.
A student who is not from a traditional Pokemon - training family but has a natural talent for understanding Pokemon behavior. They face some discrimination from other students at first but gradually prove themselves. Their main Pokemon could be a Bulbasaur that they've had since they were a child, and together they navigate the complex social and academic environment of Pokemon University.
An older trainer who has retired from the Pokemon circuit but is pulled back into action by a mysterious event related to a strange Pokemon. This character would have a wealth of knowledge and experience that they can draw upon during their new journey. They might also have some old rivalries that resurface during the story. Another potential main character could be a Pokemon itself. Maybe a Pikachu that has unique abilities and decides to embark on its own journey to find out more about its powers and where it came from.
A young Pokemon researcher could be a great main character. They're eager to learn about the unique Pokemon in Hoenn and end up getting involved in all sorts of adventures while studying them.
Obviously Naruto is one of the main characters as the title implies. Since it's a 'reborn' story, his new self with all the changes is central to the plot.
The main characters would likely be the Pokemon trainers. Ash, Misty, and Brock from the original series are obvious choices as they are well - known and loved. They could be traveling and stumble upon a hot spring area. Their Pokemon, like Pikachu, Togepi, and Onix, would also be part of the story, enjoying the hot spring or having adventures around it.
A possible set of characters could include a healer in a Pokemon village. Salazzle gets injured and is brought to this healer. The healer, who has a gentle and kind heart, takes care of Salazzle. There could also be some of the village elders who are skeptical about having a Salazzle around. And a wandering adventurer who passes through the village and has some knowledge about Salazzle's rare abilities, which helps the healer and the village deal with Salazzle in a better way.
Obviously Naruto himself would be a main character. He could bring his unique ninja skills and his determination to the story. Another could be Noctis from Lucis Caelum. His powers and his role as a prince could add a lot of drama and action to the fanfiction.
Obviously Naruto and Sasori. Naruto as the'son' would be the central figure in terms of the story's development. And Sasori, as his 'father' in this fanfiction, would play a crucial role in shaping Naruto's growth.
One potential main character could be a new ninja who discovers they have the Ink Release. They are an outcast in their village at first because of this strange power but then learn to master it and become a hero. For example, a young orphan who is bullied for having this unusual ability.