There could be an older, wise ghoul teacher who serves as a mentor to the students. This character could have a lot of knowledge about the school's history and the ways of the magical world of ghouls.
A group of misfit ghouls could be the main characters. They each have their own unique quirks and abilities, and together they form a sort of found family. They might face discrimination from the more 'normal' ghouls in the school but ultimately prove themselves to be just as good, if not better.
A young witch named Lily who is new to Salem School and is trying to find her place among the different cliques. She has a natural talent for potion - making but struggles with charms.
The main characters could include a group of neko students. There could be a fearless leader named Kitty, who is always ready to stand up for her fellow nekos. Then there's a shy neko named Whiskers, who has amazing magical powers but is too timid to show them. And there could be a human teacher at the neko school, Professor Brown, who has to learn about neko culture while teaching them magic. These characters could go through various adventures together, like exploring a hidden part of the school or facing a powerful dark wizard who wants to use the nekos' powers for evil.
Obviously, Harry Potter himself could be a main character. He has so much experience with the school and its magic. He could be the one to discover a new aspect of the school wards and lead the effort to protect or repair them.
Obviously, Harry could still be a main character. He'd be the brave new kid in high school, trying to make friends and figure out his place. Hermione would also be there, the super - smart girl who is always acing her classes and getting involved in every club. Ron could be Harry's best friend, the laid - back but loyal guy. And Draco could be the rich, snobby kid from the 'popular' group who constantly gives Harry a hard time.
There could be a group of Japanese students who are initially skeptical of Harry but later become his allies. For example, a shy girl who is really good at Japanese magic but lacks confidence. And a tough - looking boy who is actually very kind-hearted and they all form a sort of magical study group together with Harry. There might also be a mischievous Japanese magical creature that befriends Harry and causes some chaos in the school.
Maybe Harry Potter, as a ghoul, has to hide his true identity from his friends at Hogwarts. He might struggle with his newfound nature while still trying to fight against the dark forces in the wizarding world.
Fred and George Weasley could be really fun characters to have an adventure in Ghoul School. They'd be intrigued by the different prank opportunities and would surely come up with some wild schemes to liven up the spooky school, like creating new types of joke products specifically for the ghouls.
Often in fanfiction like this, Hermione would also be a prominent character. She might be intrigued by the Kitsune magic and study it intensively. Maybe she tries to find books in the library about Kitsune to understand how their magic works compared to wizard magic. Ron could also be there, perhaps being a bit skeptical at first about these new magical beings in their school.
For a Harry Potter battle school fanfic, the main characters could include some of the more under - rated students at Hogwarts. For example, Seamus Finnigan, who has shown his magical abilities in the past but could really shine in a battle school setting. Ginny Weasley, being a strong - willed and talented witch, could be a main character as well. Additionally, Draco Malfoy could be a complex main character, as he could either be a rival in the battle school or, over time, learn to work with the others against a common enemy.
Perhaps the story could start with her transformation into a ghoul due to some dark magic gone wrong. As a female Harry Potter - turned - ghoul, she might then be on a quest to reverse the transformation. Along the way, she could meet other ghouls and learn about their culture and society, all while still having her ties to the wizarding world and the people she cares about there.