A group of misfit soldiers could be main characters too. They are all a bit different and don't quite fit the typical military mold. But together with Harry, they form a unique unit. There might also be a high - ranking officer who takes an interest in Harry's progress and either helps or hinders him depending on the situation.
There could be his drill sergeant, a tough but fair character who helps shape Harry into a good air force member. Maybe a fellow recruit named Tom who becomes his best friend and they support each other throughout their training.
Ron and Hermione could still be important characters. Ron might be super excited for Harry and offer some support and advice. Hermione could be the one making sure Harry doesn't neglect his studies while being on the team.
There could be an old and wise elf elder. This elf has lived for centuries and has a vast knowledge of elf magic and history. He could be a mentor to Harry, guiding him in the ways of the elf council.
There could be the leader of the coven. This person might be an old and powerful witch or wizard who has been in the coven for a long time. They would be the one to guide Harry into the ways of the coven.
Snape could play a crucial role. Given his past with both Voldemort and his role at Hogwarts, he might be torn between his loyalty to Dumbledore's cause and his complex relationship with Harry. He could be the one who has to make a difficult decision when Harry starts to side with Voldemort. Additionally, Draco Malfoy could be involved. He might see Harry's change as an opportunity to gain more power within Voldemort's ranks, or he could be jealous of Harry's new - found position with the Dark Lord.
Another character could be a fellow inmate who has been in jail for a long time. He befriends Harry and teaches him the ropes of surviving in jail.
Dumbledore could also be an important character. He might be the one who tries to figure out what's wrong with Harry and tries to reverse this hatred. Another character could be Snape. He might see this as an opportunity to make Harry's life even more difficult or, on the other hand, might be secretly trying to help him get over this hatred.
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.
There could be his drill sergeant, a tough and no - nonsense character who has to whip Harry into shape. Maybe there's a fellow recruit who becomes Harry's best friend. They could support each other through the difficult training.
One of the main characters could be a Protoss high templar. This character could be the one who first discovers Harry and decides to take him under his wing. Another could be a Protoss zealot, who is initially skeptical of Harry but later becomes his ally in battles.