Maybe Dumbledore, if he were still alive in the fanfiction. Dumbledore was highly respected and had a great influence. Knighting Harry would be a way for him to publicly recognize Harry's achievements and heroism on a grand scale.
In the 'Harry Potter gets knighted' fanfiction, perhaps Harry is honored for his heroic deeds against Voldemort. He might be knighted in a grand ceremony at Hogwarts, with all his friends and professors present. The Ministry of Magic could finally recognize his great contributions to the wizarding world.
I'm not sure specifically as there could be many different interpretations in fanfiction. It might be about a female character who is seen as the 'Black Queen' in the context of the Harry Potter universe. Maybe she has dark magic powers or is involved in some sort of power struggle within the wizarding world.
In some fanfictions, the Queen might be a long - lost relative of a pure - blood wizarding family. This would lead to her being involved in the complex politics of the wizarding world. She could use her position as the Queen to try and bring about change in the wizarding world's old - fashioned pure - blood - supremacy - based society.
Maybe it's a university student who is majoring in music and is doing a project on Queen. She's at a local pub where there's an open - mic night and Harry, who is there to experience Muggle culture, hears her talking passionately about Queen. He's immediately attracted to her passion and they start to get to know each other, leading to their engagement later.
In this type of fanfiction, the story could revolve around how the female Harry Potter's love for Queen influences her magic. Maybe she discovers a spell that can only be cast while listening to Queen's music. Or perhaps her Patronus takes the form of a character related to Queen, like Freddie Mercury. This completely changes the way we view the magic in the Harry Potter universe as it ties it to a Muggle - born form of art.
Since I haven't read this particular fanfiction, it's hard to say for sure. But it's likely to be the Black Queen herself. She would probably be the central figure around which the story revolves.
There could be fanfictions where the Queen has some sort of magical ability in the world of Harry Potter. For example, she might be a Squib who has a special connection to the wizarding world. In these stories, she could use her Muggle knowledge and influence to help the wizarding world in some way, like promoting peace between Muggles and wizards.
Well, it could be about the Queen of England being a secret witch and having a connection to the wizarding world of Harry Potter. Maybe she helps Hogwarts in some way during a crisis, like providing a safe haven on the castle grounds that are protected by magic and Muggle secrecy charms at the same time.
Well, in this 'harry potter son of hell queen fanfiction', it could be that the author is taking the idea of Harry Potter's origin and twisting it. Maybe the 'hell queen' is some sort of powerful, otherworldly being and Harry being her son means he has unique powers or a different destiny. It could also involve a whole new set of characters related to this 'hell queen' concept and how they interact with the existing Harry Potter characters.