A young girl who is an expert in water - based ninjutsu but was self - taught because she had no proper teacher in the Land of Waves. She could join Naruto's team temporarily and teach them some unique water - related techniques.
Maybe an old fisherman who has seen many things in the Land of Waves over the years. He could be a source of hidden knowledge, like knowing the secret paths through the dangerous waters that the villains are using. He might not be a fighter, but his wisdom could be crucial for Naruto's mission.
A mysterious traveler from a far - off land who has his own reasons for being in the Land of Waves. He could be a powerful shinobi with abilities that neither Naruto nor his enemies have seen before. His presence could add a whole new layer of mystery and intrigue to the fanfic.
Another plot could be a time - travel fanfic where Naruto and his friends are sent back in time to the events that led to the Land of Waves' situation in the first place. They then have to figure out how to change things for the better without changing the future too much.
Obviously Naruto himself. He is the main character and his growth and development during this arc are crucial. Then there's Zabuza and Haku. Their story of being outcasts and their complex relationship is very interesting to explore further. Tazuna also plays an important role as he is the reason Naruto and his team are in the Land of Waves in the first place.
Sasuke could be the main character in a 'naruto new eyes fanfic'. Imagine Sasuke discovers a new evolution of his Sharingan that gives him additional powers. This could add a new layer to his character arc, as he struggles to come to terms with this new power and how it affects his relationships with Naruto and the rest of the ninja world.
A young Kryptonian girl who was sent to Earth in a different pod than Superman. She has different powers and a different view of Earth. She could try to mediate between Batman and Superman, seeing the good in both of them and believing that they should work together instead of fighting. She might also bring new knowledge about Krypton that could be useful in dealing with threats.
A foreign ninja who uses a completely different form of kekkai tota. This character could introduce Naruto to new ways of using and combining kekkai tota techniques, leading to new and exciting battles and strategies.
An older, retired shinobi who is forced to come out of retirement during the shinobi wars. He has old - fashioned techniques but a wealth of experience. He could mentor a group of young shinobi and help them develop new strategies based on his years of combat knowledge.
Sasuke could be a great main character. He already has the Rinnegan in the Naruto series. Imagine him in the Avatar world, using his Rinnegan - enhanced skills to learn about the elements and become an avatar - like figure, but with his own dark and brooding personality.
A young orphan with no known ninja heritage could be a great new character. This character stumbles upon the Executioner's Blade and discovers they have an innate ability to use it. Despite lacking formal training, they have a strong will and sense of justice, which drives them to learn how to control the blade's power and become a hero in the Naruto world.
A foreign ninja from a far - off land who has heard tales of the Totsuka Blade and travels to the Naruto world to seek it out. He could have unique abilities that interact in strange ways with the blade.
A wizard from a far - off land who comes to Hogwarts as an exchange student. He could have a whole new set of magical abilities that are different from what the Hogwarts students are used to, like being able to control the weather in a very specific way. This would add an interesting dynamic to the story as Harry and his friends learn from him.