Obviously, Harry would be one of the main characters. There might also be his friends like Hermione and Ron. They could play important roles in the story related to the mask. For example, Hermione might be the one to research about the origin of the mask.
Given the title 'harry the mask fanfic', Harry is surely a main character. There could be other characters like Harry's friends or family members who are affected by his discovery of the mask. Maybe there is a scientist or an old wizard (depending on the genre of the fanfic) who has some knowledge about the mask and becomes involved in Harry's journey. It could also be that there is a love interest for Harry who plays an important role in the story, either supporting him in his adventures with the mask or causing some complications.
Often, Harry, Hermione, and Ron are still main characters in 'Harry Potter Mask Fanfic'. They might be the ones to discover the mask and its powers. Neville could also be a main character, perhaps using the mask to gain confidence and show his true potential. And sometimes, even Draco Malfoy could be involved if the mask has something to do with the Slytherin side of the wizarding world.
Obviously, Beast Boy is likely to be one of the main characters. Since it's in the title, he's probably at the center of the story. He could be the one wearing the mask and dealing with whatever situations it brings.
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.
Well, Percy Jackson himself is usually a main character. He's the son of Poseidon, so he often takes the lead in any adventure involving the mask. Annabeth Chase, his smart and strategic girlfriend, is also likely to be a main character. She can use her knowledge to help Percy figure out the secrets of the mask.
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.
Naruto himself is often involved. Imagine a fanfic where Naruto finds a strange mask that gives him new powers, but also has some negative side - effects. Sasuke can also be a main character in such fanfics. He might be on a quest to find a mask that has a connection to his clan's history.
Since we don't know the details of 'the mask novel', the main characters could be various. There could be a young adventurer who stumbles upon the mask and becomes the central figure in the story. There might also be a wise old mentor figure who helps the protagonist understand the true nature of the mask. And of course, there could be some side characters like friends or foes of the main character that play important roles in the plot as the story unfolds.
I don't know for sure as it depends on the specific fanfiction. But it could be Stanley Ipkiss, the main character from 'The Mask' movie. He's the one who typically dons the mask and goes on wild adventures.
I'm not sure specifically what 'harry the mask fanfic' is about as there could be many different interpretations. It might be a fan - created story involving a character named Harry and a mask, perhaps in a fictional or superhero context.