It could be a new character created by the fanfic writer. Maybe a young orphan who discovers their seal - making talent by accident.
Perhaps it could be one of the existing minor characters from the Naruto series who has always had an underlying potential for seals but was never fully explored in the original story. For example, that one student in the Ninja Academy who was always doodling strange symbols that turn out to be the basis for advanced seals.
Perhaps there is a wise old seal master who takes the prodigy under their wing. This character could have a lot of knowledge about the history and secrets of seals, and they would play an important role in the prodigy's growth. Additionally, there could be some antagonists, maybe a group of rogue ninjas who want to steal the prodigy's seal knowledge for their own evil plans.
There's also a chance that the main character could be a completely new character from a minor clan in the Naruto universe. This character could have some hidden bloodline limit that makes them a prodigy in the ANBU. They might start as an underdog but quickly rise through the ranks due to their exceptional skills and intelligence.
In a 'naruto seal prodigy fanfic', it may tell the story of a young ninja who has a natural gift for seals. This prodigy might start off as an unknown in the ninja world but quickly rises to prominence because of their seal - related abilities. They could be mentored by an old and wise seal master or they might be self - taught. Their skills could attract the attention of both good and bad forces in the Naruto universe. They might get involved in a plot to protect a powerful seal from falling into the wrong hands or use their seal knowledge to unlock ancient secrets.
Since it's a fan - made story, the main character could be anyone. It could be an OC (original character) designed to be the center of this forgotten prodigy narrative. They could have a backstory full of hardships that led to their being forgotten. Or, as I said before, it could be a familiar Naruto face but with a whole new story arc that focuses on their previously unacknowledged prodigious nature.
Maybe an entire rival village decides to target the prodigy. They see the potential threat that the prodigy poses to their own village's dominance, so they send their best ninjas to take the prodigy down.
It could be an original character created by the fanfiction author. This character might have a special background or power that makes them a ninjutsu prodigy.
It could be an old enemy of the village who has been waiting for the seal to break. Maybe someone who was imprisoned by the same seal long ago and now wants revenge on the village for sealing them away.
The title 'naruto seal master lemon fanfic' gives some clues but doesn't clearly define the main character. The seal master is a likely main character as they are associated with the important concept of seals in Naruto. But 'lemon' could also take on the main role. It might be a story where Lemon is a unique individual with a special connection to the seal master, and the story is told from Lemon's perspective, making Lemon the main character. Or perhaps the story focuses on their relationship equally, in which case there may not be a single 'main' character in the traditional sense.
In 'The Prodigy of Konoha', the main character is a young ninja named Kaito. He has this amazing ability to quickly learn and master new ninjutsu. He stands out among his peers and often catches the attention of the more experienced ninjas like Kakashi.
In a 'naruto the uchiha prodigy fanfic', the main focus would be on the Uchiha prodigy. But considering the context of the Naruto universe, there would be a whole host of other characters involved. Naruto would most likely be present, as his story is intertwined with the world of the Uchiha. Sakura could also be part of the story, perhaps as a healer or a friend to the Uchiha prodigy. And then there are the villains from the Naruto series. Orochimaru, for instance, might be interested in the powers of the Uchiha prodigy and try to manipulate or use them for his own purposes. So, the main characters would be a mix of the Uchiha prodigy, Naruto - related characters, and potential antagonists.