There could be other Black family members like Bellatrix's husband, Rodolphus Lestrange. He might see Harry as an intruder into the Black family power structure and try to oppose him. Then there are the ghosts that haunt the Black family manor. They could be important as they hold memories and knowledge of the family's past. And of course, Harry's friends like Hermione and Ron could be there. Hermione would probably be very interested in the Black family library full of ancient and rare magical books, and Ron would be there to support Harry in any confrontations.
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.
Besides Harry, Andromeda Tonks could be a significant character. Since she was a Black, she could help Harry understand the family's history and values better. Her daughter, Nymphadora Tonks, might also be involved. She could use her skills as an Auror to protect Harry from any threats against his new position as Lord Black. Additionally, the portraits in the Black family manor could be characters in their own right. They could offer advice or try to manipulate Harry based on their own agendas during their lifetimes.
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.
Hermione would definitely be there. She would be intrigued by Harry's new heritage and would probably try to research all about Ra in the Hogwarts library. Ron too, would be by Harry's side, though he might be a bit more skeptical at first about this whole Ra business.
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.
The Weasley twins could be part of it too. Suppose Harry yells in excitement or anger about a new prank idea that the twins have come up with that might be a bit too dangerous. They could either encourage his yelling or try to tone it down, depending on their mood. And Malfoy might overhear Harry's yell and use it as an opportunity to taunt him, adding more conflict to the fanfiction.
Dumbledore might play an important role as well. He would be guiding Harry through this new and strange situation. He could have some secrets about the Lord of Azkaban that he reveals to Harry over time. Also, some of the Azkaban guards or prisoners could become significant characters as Harry tries to reshape Azkaban.
There could be new characters introduced, like old family retainers of the noble family Harry is now part of. Maybe an old wizard who serves as an advisor to Harry on matters of the lordship. And of course, some antagonists such as rival lords or wizards who don't want Harry to gain too much power.
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.
Potential characters could range from the well - known witches at Hogwarts to those from other magical institutions. Fleur Delacour could be in the harem, given her beauty and magical abilities. And there could be characters from the wizarding world outside of Britain too. Maybe a Japanese wizard or witch who has unique magical techniques and is drawn to the Harem Lord's power and charisma.
Hermione would surely be one of the main characters interacting with Harry. She might try to bring him back from the dark side, constantly arguing with him about his choices and trying to remind him of their old friendship and the good they used to fight for.
Ron is also there. He could be Harry's right - hand man in some adventures related to his lordship. For example, when Harry has to deal with some dark wizards threatening his lands, Ron might be by his side, using his Weasley - family - taught magic skills.