Sasuke could also be an interesting main character in this type of fanfiction. His cool and brooding nature would contrast well with the majestic and often wild nature of dragons. He could be on a quest to master dragon taming in order to gain more power to seek revenge or protect what he holds dear.
Sasuke could also be a great choice. His cool and calculated nature would make for an interesting dynamic when dealing with Pokegirls. He might focus more on training powerful Pokegirls and using his Sharingan to analyze their moves and weaknesses.
It could be a new character created specifically for the fanfiction. Maybe a young ninja who discovers the neglected dragon and forms a bond with it.
Sasuke could also be a great main character in this fanfiction. Given his drive for power, he might be the one to seek out the dragon armor and use it to further his own goals. He could have an interesting journey of learning to control the power of the armor while also dealing with his inner demons.
It could be a new student at Hogwarts who comes from a family of non - magical beast tamers in the Muggle world. They bring their unique skills and perspective to the wizarding world of beast taming. For example, they might know how to calm a spooked horse in a way that wizards don't, and apply that knowledge to magical steeds.
It could be an existing character like Naruto who, through some strange turn of events, gains the Wood Dragon Slayer power. This would completely change his fighting style and how he approaches challenges. He could use the power in creative ways, like combining it with his Rasengan to create a new, more powerful attack.
Most likely Naruto is the central figure. However, if the great dragon is a sentient being, it would also be a main character. In addition, it's possible that new characters created specifically for this fanfiction could be main characters too. For instance, a dragon keeper who helps Naruto understand the dragon. And we can't rule out the presence of Naruto's mentors like Kakashi, who might play an important role in guiding Naruto in his interactions with the dragon.
The main character could be a rebellious student who is tired of the teacher's rules and decides to take action to 'tame' the teacher.
I don't know for sure as I haven't read this particular 'dragon tamer novel'. But it could have a young and brave dragon tamer as the main character. There might also be a wise old dragon that serves as a mentor to the tamer.
It could be Naruto himself. Imagine Naruto obtaining the powers of the Red and White Dragon Emperor. He would be an even more formidable force, using his ninja skills along with the dragon powers to protect the Hidden Leaf Village.
It could be an original character. For instance, a ninja from a small, unknown village who has a unique power and is forced to participate in the war. They could be the underdog that everyone underestimates at first.