Well, in 'Harry Potter goes dark fanfiction', a common concept is the alteration of the wizarding world's power structure. Maybe Voldemort wins in a different way and Harry has to survive in a much harsher, more tyrannical regime. Or perhaps Harry himself becomes a sort of anti - hero, using the dark side of magic to fight against what he perceives as a greater evil, even if it means sacrificing some of his principles. And there could be the idea of dark magical creatures being used as weapons instead of just threats in the background.
Well, Sirius Black can be quite interesting in 'Harry Potter goes dark fanfiction'. If Harry goes dark, Sirius, who has always been a protector figure, might have to make some very difficult choices. He could either try to save Harry from the darkness or be forced to oppose him. Dumbledore is another character that stands out. His wisdom and manipulations would be under a new light in a dark fanfiction. And the Weasley family, especially Ron. His friendship with Harry would be severely tested if Harry goes dark, and his own character development could take some very different paths.
Well, one possibility could be that Harry is driven by a deep sense of betrayal. Maybe he discovers some dark secrets about the wizarding world that make him question everything he has believed in. For example, if he finds out that Dumbledore has been using him all along for some self - serving purpose. This could push him towards the dark side as he feels that the so - called good side is just as corrupt.
Well, Harry could be really confused at first. Ouran is a very different world from Hogwarts. He might be shocked by the opulence of Ouran Academy and the strange club system there. Maybe he'd try to find a way to fit in while still being true to his wizard self.
Voldemort would surely be involved. He might initially be suspicious of Harry's sudden change but then see it as an opportunity to use Harry's power for his own dark ends. He could try to mentor Harry in the ways of dark magic.
He might meet international aurors. These are highly skilled wizards from different countries who are experts in dark wizard catching. They could teach Harry some new combat spells.
He could meet Fleur Delacour's family. Since Fleur is from France, her family might be an important part of the French wizarding community that Harry interacts with.
Hermione would be a likely companion. She loves learning and exploring, so she'd be eager to go on a traveling adventure with Harry. Ron might also tag along, especially if there's a chance of food and adventure. Neville could be another option. He has grown a lot in courage and his knowledge of plants could come in handy in different magical environments. Luna Lovegood would be a very interesting companion too. Her unique perspective on magic and the world would add a lot of fun and mystery to the journey.
Harry could meet some local magical creatures that are unique to Africa. For example, there could be a magical creature similar to a hippogriff but with different characteristics. And he may also meet African witches who are experts in herbal magic, which they use to heal and protect their communities. They could teach Harry some of their techniques and knowledge.