Well, the male mute student could be a descendant of an ancient wizarding family with a special power that has been dormant until now. His muteness is somehow related to this power. In the fanfiction, he might be bullied at first because of his inability to speak. But as the story progresses, his unique skills start to shine. He could be able to manipulate time in a small area around him, which he discovers accidentally. This discovery could change the way others view him and put him in the middle of a power struggle within Hogwarts.
One idea could be Naruto being a transfer student to Hogwarts. He might use his ninja skills in the wizarding world, like using his speed to be great at Quidditch. Another could be that Naruto discovers he has magical powers in addition to his chakra, and he has to learn to balance both. And perhaps he makes friends with Harry Potter and they teach each other their unique skills.
Well, one possible plot could be the male mute reader being a mystery to his classmates at Hogwarts. Since he can't speak, he might communicate through magic, like using a spell to project his thoughts. He could be really good at non - verbal magic and befriend some outcast students who appreciate his unique way of being. For example, he might form a bond with a shy Hufflepuff who also feels a bit different. And he could have some sort of special power related to his muteness that gets revealed as the story progresses, like being able to understand the language of magical creatures without speaking their tongue.
One plot idea could be Naruto finding unique ways to communicate his ninja skills despite being mute. For example, he might use hand signals in a more complex way than normal. Since he's blind, he could develop an extraordinary sense of hearing to detect enemies. Another idea is that he forms a special bond with an animal that helps him 'see' the world around him, like a seeing - eye hawk or something.
A possible plot is that Naruto, mute as he is, discovers a new form of magic in the DxD universe that is related to silent communication. This could lead to him becoming a very powerful figure as he can communicate secretly with his allies during battles. Also, his backstory from Naruto could be intertwined with the DxD lore. For instance, his experience with loneliness in his own world could make him more empathetic towards the devils in DxD who are often misunderstood. He could then try to bridge the gap between different factions in the DxD world.
One idea could be that the mute prodigy has a unique form of ninjutsu that doesn't require speaking. Maybe they can use sign language to cast powerful jutsus. Another plot could involve the character being misunderstood because of their muteness, but gradually proving their worth. For example, in a mission, they use their silent skills to outwit the enemy.
One idea could be Naruto being mute in a crossover with the Harry Potter universe. He might communicate through magic signs or a special spell - created device. This could lead to him being misunderstood at first, but then his unique abilities, like his ninja skills, would shine through as he helps Hogwarts students in a new way.
A possible plot could be that Hermione is mute from a very young age. She has to work twice as hard to be noticed in the wizarding world. As she enters Hogwarts, she uses her intelligence in unique ways to make up for not being able to speak. She might create a special magical device that can 'speak' for her when she types in her thoughts. This device could also be a target for villains who don't want her to spread her knowledge.
A plot could involve a group of Hogwarts students accidentally ending up at Ilvermorny and having to adapt to the new school's rules and culture while also trying to find their way back home. It would be a story of discovery and friendship as they interact with the Ilvermorny students.
One idea could be Draco being sorted into a different house by mistake. Maybe the Sorting Hat has a moment of confusion and puts him in Hufflepuff. This would lead to him having to adjust to the very different values and atmosphere of that house, and it could be a journey of self - discovery as he realizes there's more to life at Hogwarts than just the Slytherin way.
An OC could be a Muggle - born with a very special family heirloom that turns out to have magical properties once they arrive at Hogwarts. This heirloom could be the key to solving an ancient mystery within the castle walls, like a hidden chamber or a long - forgotten spell.