Lupin would be a crucial character. Since he is a werewolf himself, he could mentor Harry. He could teach Harry about the dos and don'ts of being a werewolf, how to deal with the full - moon transformations, and how to live with the stigma. Sirius might also play a role, as he was Harry's godfather and would be protective of him even in this new situation.
Hermione would definitely be one of the main characters. She would be trying to research a way to either reverse Harry's transformation or help him control his werewolf side. Ron might also be there, at first a bit scared but then standing by Harry's side.
There could be some new characters introduced. For example, a powerful witch or wizard who has a special connection to werewolves and is the only one who knows the true secret to breaking the werewolf curse. This character could be either an ally or an antagonist, depending on their motives in relation to Harry's new state.
Remus Lupin would likely be a main character. Since he is a werewolf himself and has a connection to Harry, he could play an important role in the story. He might be Harry's advisor on werewolf matters, or even help him in leading the pack.
Hermione would likely be a main character. She might support Harry in his new role as a divination teacher, perhaps helping him to research and find more scientific ways to approach divination.
The members of Wildwind would surely be important characters. They could interact with Harry, maybe give him backstage passes or even ask him for his opinion on their new songs.
Hermione would likely be one of the main characters. She's always been Harry's intelligent and resourceful friend. In this fanfiction, she could use her vast knowledge of magic to help Harry on his journey to becoming a powerful lord. For instance, she might research ancient texts to find spells that can enhance Harry's power.
The Ministry of Magic could be a main antagonist. They have a history of being discriminatory towards werewolves. They might see Harry as a threat now that he's a werewolf and try to lock him up or restrict his movements. For example, they could pass new laws specifically targeting him, like making it illegal for him to attend Hogwarts as a werewolf.
Sirius Black's relatives would be likely characters. For example, Kreacher, the house - elf of the Black family. He could play an important role as he has a deep knowledge of the Black family secrets and the Black family manor. Also, Narcissa Malfoy, as she is related to the Black family, might be involved. She could either be an ally or an adversary to Harry depending on how the story unfolds.
Hermione could be one of the main characters. She would be very helpful as she is smart and well - read in magic. She could offer advice on the best spells to use for building the castle and how to make it structurally sound.
Hermione could be a main character. She might try to figure out why Harry hates himself and be the one to pull him out of that dark place. Ron could also be there, maybe at first not understanding Harry's self - hatred but later becoming a source of support. Dumbledore could be another key character, as he often has insights into the students' minds and could play a role in helping Harry deal with his self - hatred.
Madame Maxime, the headmistress of Beauxbatons, could play an important role. She could be a mentor to Harry, guiding him in his new magical studies at Beauxbatons. She might also be involved in some sort of conflict or mystery that Harry has to help her solve, which could involve the relationship between Beauxbatons and other wizarding schools or some ancient magic within the school.
The adoptive family members could be main characters. For instance, the adoptive parents who might have their own unique personalities and backstories. They could be former Aurors who retired early to focus on raising Harry. There could also be an older sibling in the adoptive family, who might initially be jealous of Harry but later becomes his closest ally.