The hollow mask could symbolize Naruto's hidden or repressed side. In fanfiction, it might represent a part of him that he keeps locked away, perhaps related to his past traumas or unacknowledged emotions.
It could be a new character created specifically for this fanfiction. Maybe a powerful wizard who has been in hiding and uses the mask to conceal his true appearance while he moves around Hogwarts or the wizarding world.
It might be related to a secret society or a dark magic object. In the Harry Potter universe, there are often mysterious items with special powers. The hollow mask could be one such item, perhaps used for disguises or to access hidden places.
It could be a powerful and mysterious shinobi. Maybe someone from an ancient hidden village who has been observing Naruto for a long time and decided to give him the mask as a test or a way to unlock his true potential.
Well, if Naruto got a hollow mask in fanfiction, he might gain new powers. The hollow mask could potentially enhance his speed and strength, like how it did for characters in Bleach. He could also use it to intimidate his enemies. Maybe it would give him a new form of chakra or a special jutsu that combines his ninja skills with the power of the hollow mask.
In such fanfiction, Naruto's personality could be a mix of his old self and a new, more complex version. He would still be the determined and kind - hearted Naruto at heart. However, the power of the hollow mask might make him more secretive. He might keep things from his friends and mentors for fear of them trying to take the mask away. This internal conflict between his old and new self could be a major part of his character development.
His combat abilities would likely be boosted. With the hollow mask, Naruto could have increased physical capabilities, such as stronger punches and kicks. His reflexes might also be enhanced, allowing him to dodge attacks more easily. He could potentially use the mask's power to disrupt his opponents' chakra or energy, similar to how hollows can disrupt spiritual energy in Bleach.
In the 'naruto has a mask fanfiction', it might be that Naruto finds the mask himself. He could stumble upon it during one of his adventures, perhaps in an ancient ruin or a hidden cave. The mask could be enchanted or have some special property that draws Naruto to it, and he decides to keep it and figure out its secrets on his own.
One idea could be a character with the hollow mask bloodline having the ability to enter a shadow realm, similar to the Sharingan's genjutsu world. They could use it for stealth or to surprise enemies.
One interesting concept could be exploring the power dynamics. If Naruto were to don a hollow mask, how would it change his relationship with his friends? For example, they might be initially scared or distrustful. Another idea is the origin of the mask. Maybe it's an ancient artifact that was sealed away and Naruto accidentally discovers it during a mission. It could also be related to some dark chakra that Naruto has to learn to control, adding a new layer of struggle to his character development.