It could be Naruto himself. Maybe he discovers the mask and when he puts it on, it causes a big reaction among his friends and foes.
Sasuke is also a possibility. If he were to find the mask and use it for some purpose, his actions with the mask could shock everyone, considering his complex character and his past actions in the Naruto series.
Another option could be a new character created specifically for this fanfic. This new character might have a special connection to the mask, and their appearance with the mask on or their actions related to the mask are what shock all the other characters from the Naruto universe.
Well, it could be that the mask in the fanfic has some sort of special power or significance. Maybe it's a mask that reveals a hidden identity of a character, like Naruto himself or someone else in the Naruto universe. And this revelation shocks all the other characters.
It could be Sasuke. He often has a cold exterior, like a mask, and if in a fanfic his mask breaks, it could mean he finally shows his true feelings towards Naruto, whether it's friendship, rivalry, or something more complex.
Another possibility is that it could be a new character created specifically for the fanfiction. A character who wears a mask for some secretive purpose, and when the mask breaks, it sets off a chain of events that are unique to the fan - created storyline.
Naruto could also be the main character in such a fanfic. Even though he doesn't have the Rinnegan in the original, in a fan - created story, he could be involved in a plot where he has to deal with the secrets of the Rinnegan. For example, he might be trying to help a friend who has the Rinnegan and is in danger because of its secrets.
The main characters in 'naruto shattered mask fanfic' could vary greatly. It might be a team of ninjas that are investigating the shattered mask. This team could consist of some well - known Naruto characters like Sakura, who could use her medical and combat skills to figure out what happened. And there could be a mysterious figure who is either protecting or trying to destroy the remnants of the shattered mask, and this figure could be the key to the whole story, whether they are an old character with a new twist or a completely new addition to the Naruto fanfic universe.
Obviously, Naruto would be one of the main characters since it's his mask in the fanfic. There might also be his friends like Sasuke and Sakura. They could be involved in the story in different ways, either helping Naruto understand the power of the mask or being affected by the changes it brings to Naruto.
Maybe a new, powerful and evil ninja from another land. This ninja could have come to the village and caused a lot of chaos, making Naruto believe that no one in his village was capable of protecting themselves or him. So he blames everyone for their weakness and starts to hate them all, with this new ninja being the root of the problem.
His friends would be affected. For example, Sasuke might see Naruto in a new light and realize that they are more similar than he thought, both having their own inner struggles. Sakura would also be more empathetic towards Naruto and might try to be a better friend, offering more emotional support.
It could be Sasuke. He might be wearing a mask for some mysterious reason, like hiding his new powers or a new allegiance. Maybe he's on a secret mission that even Naruto doesn't know about at first.
Sasuke might be the main character. Since he's always on the hunt for power, he might come across this strange mask. And when the mask starts to 'eat' his face, it would be a test of his willpower and his ability to handle the unknown and dangerous forces that come with it.