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.
It could be Naruto himself. Since he is the main character in the original series, it would make sense for him to be in a fanfic with a 'for your eyes only' concept. Maybe he discovers a secret about his parents that he has to keep to himself for some reason.
It could be a new character. Maybe an orphan who discovers they have these reanimation eyes and has to figure out how to use them while also dealing with the fact that they are different from everyone else in the ninja world.
Maybe the 'naruto new eyes fanfic' could revolve around a character who is born with these new eyes but doesn't know how to control them at first. As they go through various challenges in the Naruto world, like battles and making alliances, they gradually learn to master their new eye power. For example, they might be able to use it to see through illusions that are even more powerful than those usually created in the Naruto universe.
It could be an original character created specifically for this fanfiction. Maybe a young ninja who discovers they have these cursed eyes and the power of prophecy unexpectedly.
It could be a jilted lover. Someone who has been betrayed in love and now has angrily eyes, promising pain to the one who broke their heart. This character would be filled with emotions like anger, hurt, and a desire for revenge.
In 'naruto new eyes fanfiction', Naruto is the central figure. But characters like Kakashi could play a significant role. He has a lot of knowledge about different types of eyes and their powers, so he could be mentoring Naruto on how to use his new eyes effectively. Also, characters from other villages might be introduced as they are interested in Naruto's new power and either want to steal it or form an alliance with him.
Obviously, the new Hokage would be one of the main characters. It could be a character we already know like Naruto's son, who has inherited his father's determination and strength.
A powerful rogue ninja who has mastered a forbidden jutsu that gives him the ability to control minds could be a great main antagonist. He could use this power to turn Naruto's friends against him, creating a lot of internal conflict within the group.
The Joker could be a great antagonist. His chaotic and unpredictable nature would contrast with Naruto's more straightforward sense of justice.
Naruto himself could be the main character in a Shinju fanfic. He has always been about finding new ways to bring peace and understanding. His connection to the nine - tails could play an interesting role if he were to interact with the Shinju. Maybe he could try to convince the Shinju that the ninja world has changed and it doesn't need to be a source of fear and destruction.