Another idea is that the 'Black Prince' is a self - proclaimed title of a character who has risen within the ranks of the Black family. He might be a younger wizard who has discovered some hidden power within the family heritage and decided to use it for good or evil, depending on how the story is written.
I'm not sure as I haven't read it, but based on the title, it could be the 'black prince' himself.
Well, in many Harry Potter fanfictions, the 'Black Prince' could be a completely new character that the author has introduced to add more depth to the story. It might be a figure who has been hidden from the main plot in the original books but has a significant impact on the wizarding world. For example, they could be a long - lost heir of the Black family with a mission to redeem the family's name or uncover some dark secrets that are related to both the Blacks and other important wizarding families. They could also have a special connection to Harry Potter himself, perhaps being a mentor figure or an unexpected ally in his fight against Voldemort.
Well, without reading it specifically, it could be about a character who is seen as a 'black prince' within the Harry Potter universe. It might involve a new adventure, a different take on existing characters' relationships, or perhaps a new plotline that focuses on this mysterious 'black prince' figure.
It could be an original character created just for this fanfiction. Maybe a prince from a hidden magical realm that has been kept secret from the wizarding world until now.
It could be an ancient and powerful dark wizard who has been dormant for a long time. Maybe someone from the time before Hogwarts was even founded.
The 'Black Prince' could be a heroic figure, perhaps a long - lost relative of Sirius Black. He might be on a quest to restore the Black family's honor and fight against the dark forces in the wizarding world.
It could be a new villain that the fanfiction author has introduced. Maybe a long - lost relative of Voldemort who has emerged to continue his dark legacy.
It could be Sirius Black's younger sister who was not mentioned in the original series but is created for the fanfiction. She might have similar rebellious traits as Sirius but also her own unique charm that attracts Harry.
One possible reason could be a misunderstanding. Maybe some false information was spread about Harry that made Sirius believe he had done something unforgivable. For example, if there were rumors that Harry was involved with dark magic in some way, Sirius, who has a strong aversion to the dark side, might be quick to disown him.
Hermione would definitely be one of his allies. She is smart and resourceful and would be able to help Harry navigate the new political and magical situations he faces as a prince. For example, she could research ancient laws and prophecies related to his new status.