Well, perhaps Harry Potter could use his magic to solve some sort of mystery in the Queen's palace. Maybe he'd help protect a valuable magical artifact that was in the Queen's possession without her knowledge of its true nature.
Well, it could be that Harry Potter, while on a magical mission, somehow gets transported to Star City where Oliver Queen operates. Oliver, being the vigilant Arrow, at first mistakes Harry for a threat. But then they realize they both fight for justice in their own ways. Harry could use his magic to assist Oliver in taking down some really tough villains that the Arrow alone couldn't handle, like some dark magic - infused criminals.
It would probably be Harry Potter himself. He's from a world full of magic and mystery, and seeing him interact with the very real and regal world of the Queen would be fascinating.
It really depends on the situation. If they are in the wizarding world, Harry Potter would likely be more dominant as he knows the ins and outs of magic and the wizarding society. He can use spells to his advantage and has a deep understanding of the magical threats. But if they are in Oliver Queen's world, in Star City, Oliver would be more in control. He knows the city, has his team, and his combat skills are more useful in a non - magical urban environment.
Well, it could be that the Queen, being a symbol of order in the Muggle world, has to deal with the sudden appearance of Harry Potter and the chaos that magic can bring. Maybe she initially mistakes his magic for some sort of advanced technology and there are a series of misunderstandings that lead to an interesting adventure. Harry could introduce her to the concept of Hogwarts and she might be fascinated by the idea of a school for magic.
Since I'm not familiar with this specific 'queen of the crunk harry potter fanfic', it could be a character that the author has made up to be the central figure. Maybe she's a witch who has a very different approach to magic compared to the characters in the original Harry Potter series. She might be the one who brings the 'crunk' element into the story, like having a very wild and unorthodox style of using magic.
The main characters would be Harry Potter and the Queen. Harry, as the hero from the wizarding world, brings his magic, courage, and sense of justice. The Queen represents the Muggle royalty and all the power and traditions that come with it. There could also be some secondary characters from the wizarding world like Hermione and Ron, who might give advice to Harry on how to interact with the Muggle Queen.
Well, he might use his magic to show the Queen some amazing things. Maybe he'd conjure up a beautiful display of Hogwarts' magic, like floating candles or flying books. And the Queen would be both surprised and fascinated.
There could be some of Harry's friends who might play a role. They could be the ones who encourage Harry to meet the Queen or who give him advice on how to behave in front of her.
Probably when Harry shows the Queen his magic wand for the first time. Just the idea of a real magic wand in the hands of a wizard in front of the Queen would be thrilling.