There could also be an original character created specifically for this fanfiction who becomes the Dark Phoenix. This character would then be a central focus, with their transformation and the resulting events driving the story forward. Their backstory, motives, and relationships with other characters would be important aspects of the narrative.
Since it's a fanfiction, the main characters could vary greatly. It might introduce new original characters who are somehow related to the dark phoenix concept. However, it's also likely that popular characters from the original series like Ron would be involved. He could be by Harry's side as they both encounter the challenges brought by the dark phoenix rising. It could also involve some of the Hogwarts professors, like Dumbledore in spirit (if it's set after his death) guiding the students to face this new and dangerous situation.
Harry Potter himself is often a main character. Since he has a connection to the Phoenix through Dumbledore's Phoenix, Fawkes. He might be the one to face the threat of the Dark Phoenix. Hermione Granger could also be a main character. Her intelligence would be crucial in trying to understand and combat the Dark Phoenix. Ron Weasley might be there too, providing his loyalty and friendship. Another character could be Draco Malfoy, perhaps in a situation where he is either an ally or an adversary in the face of the Dark Phoenix.
I don't know for sure as I haven't read it. It could feature characters like Harry Potter, Hermione Granger, or Ron Weasley as they are central to most Harry Potter fanfictions. Or it might introduce new characters related to the phoenix's birth.
Well, of course, Harry Potter himself is likely to be one of the main characters. He might have a special bond with the Royal Phoenix.
I'm not sure who the author of this fanfiction is. There are so many fanfiction writers out there, and without more specific information, it's difficult to determine the author.
Obviously, the Dark One is a main character. Harry Potter himself also often plays a crucial role as he is usually the one who has to face the Dark One in some way.
It's possible that the main character is the 'dark child' of course. There could also be a mentor - like figure, maybe an older wizard who tries to guide the child towards the light. And it wouldn't be surprising if there were some antagonists as well, such as other dark wizards who want to use the child's power for their own evil purposes.
Well, Harry Potter is most likely one of the main characters as it's a Harry Potter fanfiction. He would probably be at the center of the new revelations and story developments.
In this fanfiction, the main characters could be quite diverse. Since it's about a 'dark heir', there would likely be a character who embodies this role. It could be a previously unheard - of character with a complex backstory related to a dark legacy. Harry Potter might be involved to oppose this dark heir or to try and understand their motives. His friends, like Hermione and Ron, could also be part of the story. Additionally, there could be other magical beings or characters from the 'Harry Potter' lore, such as members of the Order of the Phoenix or Death Eaters, who are drawn into the plot due to the emergence of the dark heir.
Voldemort could also play an important role. Since Harry is now the dark prince, there could be a complex relationship between them. Voldemort might see Harry as a potential ally or a threat, and their interactions would surely be a major aspect of the fanfiction, along with how Harry navigates this new relationship with the most feared dark wizard.