Another option could be a completely new character. This character could be an outcast from a small village who discovers the dragon's blood. They then enter the world of the main Naruto story, interacting with the well - known characters. This new character could bring a fresh perspective and new relationships to the Naruto universe, all while dealing with the power and mystery of the dragon's blood.
Sasuke could also be a great choice as the main character in a 'dragon's blood naruto fanfic'. Given his thirst for power and his Sharingan abilities, if he were to obtain the dragon's blood power, it would add a whole new layer to his character. He might use it to seek revenge in a more powerful way or to uncover secrets about his clan that are related to the dragon's blood.
Perhaps an old member of a forgotten clan who was exiled because of his dark blood. He returns with a vendetta against the village that shunned him. He sees Naruto as a symbol of everything he hates and tries to destroy him. The main antagonist could also manipulate other ninja to turn against Naruto by spreading fear about his dark blood.
Might be one of the powerful guards who has a grudge against Naruto for some reason. Maybe he believes Naruto is a threat to the order in the prison and tries to get rid of him secretly.
"I recommend" Blood Dragon Martial God "to you. The main character has a blood dragon pearl and other heaven-defying items. His background is mysterious, and he holds a dragon token. The dragon race reappears on the continent and struggles to become a supreme martial god. I hope you like this fairy's recommendation. Muah ~😗
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 long - lost relative of the founders. Maybe a distant cousin of Gryffindor, Ravenclaw, Hufflepuff and Slytherin. This person might have been hidden away for years and now resurfaces.
Goku could be the main character. Imagine Goku being hypnotized and having to fight against the control while still trying to protect his friends and the Earth. It would be a great twist on his usual heroic self.
It could be a novice Ugioh player who is just starting to understand the game. The call of the dragon could draw them into a more complex and dangerous part of the Ugioh world.
It could be the person who finds the doll - dragon. Maybe a young adventurer who is curious about the strange doll.
It could be a character who is jealous of Naruto's new dragon powers. Maybe someone who has always been in competition with Naruto and now feels even more threatened by his enhanced abilities.