There could be some original characters introduced in this fanfiction. For example, there might be a spirit or entity that serves as a messenger between Lady Death and the wizarding world. This character could be used to explain some of the more unusual happenings in Harry's life. Also, some of the Death Eaters might play more prominent roles as they sense a change in the power dynamics with Harry's new connection. They might either try to recruit him or destroy him, depending on how they perceive his relationship with Lady Death.
Dumbledore would still be an important character. His interactions with Harry, who is raised by Lady Death, would be filled with a lot of mystery and caution. He might try to understand the implications of Harry's upbringing and how it affects the balance of power in the wizarding world. Hermione and Ron could also be main characters. Their friendship with Harry might be strained at first as they try to understand his new and rather dark - influenced personality, but they would still be important in Harry's life as they support him in different ways and help him navigate the challenges he faces at Hogwarts.
Hermione could be a main character. She might be the one who first notices the strange changes in Harry after he becomes friends with Death. She could try to research about this unusual friendship in the library, using her vast knowledge to understand the implications. Ron could also be important. He might be initially skeptical about Harry's new 'friend' but then come to accept it as he sees the positive effects it has on Harry and the help it provides in their fight against dark forces.
Death, of course, would be a major character as it's training Harry. Maybe Dumbledore could also play an important role. He might be the one who initially guides Harry to this encounter with Death or acts as a moral compass during the training.
Besides Harry, death is the central character in this concept. But there could be other magical creatures or beings involved. Maybe thestrals, since they are associated with death in the original Harry Potter lore. They could play a role in facilitating the friendship between Harry and death. And of course, Harry's other friends from Hogwarts, like Neville and Ginny, could also be part of the story, either being curious about or affected by Harry's friendship with death.
Hermione is often involved. Since she's Harry's best friend, she might be the one trying to prevent his death in some fanfictions. Or she could be the one who has to carry on his legacy after he dies.
One of the main characters would likely be Death itself, who could take on different forms and interact with Harry throughout his life. Dumbledore would also be an important character as he tries to understand and guide Harry, despite his unusual upbringing. And then there are Harry's friends like Hermione and Ron, who would have to adjust to Harry's different perspective on life and magic due to his being raised by Death.
Voldemort would remain a major character. Harry's new abilities and perspective from being raised by Death would make their conflict even more complex. Harry might approach the fight against Voldemort with a different strategy, one that is influenced by the teachings of Death.
Hermione could be one. She could come to Degrassi to help Harry. She'd be really good at handling the academic side of things there, like helping students with their studies. And also, she could use her magic knowledge to figure out any magical mysteries.
Hermione Granger would likely be a main character. She could use her vast knowledge to help Harry in his efforts to fix Hogwarts, whether it's researching ancient spells for repairs or coming up with new educational strategies.
Their parents' old friends could be main characters. They might come to check on Harry and his sister, bringing gifts and stories about their parents. These friends could offer guidance and protection when needed.
Hermione would likely be one of the main characters. She would be curious about Harry's new heritage and might help him research more about Nyx. Ron could also be important. He might have some initial doubts or even jealousy about Harry's newfound powers, but in the end, he would stand by Harry. Dumbledore would definitely be a key character as well. He would try to guide Harry in understanding and using his connection to Nyx in a positive way.