A unique plot could be that the plague doctor is actually an Animagus. In their normal form, they are a Hogwarts student, but they transform into a plague doctor to secretly fight a dark magic - created plague that is slowly spreading through the wizarding world. They use their knowledge of both magic and old - fashioned medical techniques to try and find a cure.
One idea could be that the Plague Doctor arrives in the wizarding world during a mysterious illness outbreak. He might have unique magical remedies that are different from what the wizards are used to. Maybe he teams up with Harry Potter to find the source of the disease, which turns out to be a dark magic - created pathogen.
Here's a different plot. The shark animagus is a transferred student from a far - away wizarding school. At this new school, Hogwarts, they are an outcast because of their strange form. However, as the story progresses, it is revealed that the shark animagus has a special power related to their form that can heal the magical core of the Hogwarts castle which has been slowly deteriorating due to dark magic. But there are forces within the school, including some of the teachers, who don't want this to happen because they have their own dark secrets and plans. So the shark animagus has to fight against all odds to save Hogwarts while also trying to fit in and make friends.
Well, I'm not sure about a specific 'Harry Potter plague doctor fanfic' off - hand. But generally, in such a fanfic, the plague doctor could be a mysterious figure who arrives at Hogwarts during a strange epidemic. Maybe they use their traditional plague - fighting methods combined with magic. You could start your search on platforms like Fanfiction.net or Archive of Our Own.
The Ministry of Magic would likely be in chaos. They would try to find a way to stop the spread and hold Harry Potter accountable. There would be a lot of panic among the wizards and witches, with many trying to flee or find a cure on their own.
One idea could be exploring what would happen if Harry had a twin sister who was sorted into Slytherin. It would add a whole new dynamic to the story, with her having different views and friends than Harry. She could be caught between loyalty to her house and loyalty to her brother.
The Plague Doctor could be a magical healer from a far - off land. His strange appearance and methods are initially met with suspicion in the Harry Potter world. But as the story progresses, his skills in dealing with diseases become invaluable. For example, he could use his beak - like mask not just for protection but also as a tool to channel magic for healing.
A possible plot could involve a new, powerful dark sorcerer who has found a way to combine magic from both universes to become invincible. Doctor Strange tries to stop him but is quickly overpowered. Meanwhile, Harry Potter senses the danger through his connection to magic. He travels to Doctor Strange's side. Harry uses his knowledge of magical creatures from the Forbidden Forest. He summons a group of Centaurs who help him in the battle. With their combined strength and Harry's strategic use of spells like the Stunning Spell, they are able to defeat the dark sorcerer and save Doctor Strange.
Well, the plot might involve them facing a threat that only their combined skills can defeat. Harry Potter is good at spells and dealing with magical creatures, and The Doctor is a time - traveling genius. So they could be fighting an enemy that has the ability to manipulate time in the wizarding world, something that neither of them can handle alone. Harry could use his invisibility cloak to sneak around while The Doctor figures out the science behind the time - manipulation.
Maybe in the fanfic, Harry is forced to play the role of a doctor during a wizarding war. He has to quickly learn how to heal the wounded soldiers on the battlefield. This could involve him using his knowledge of magic in innovative ways and also facing moral dilemmas about who to save first. It would be a story full of action and tough decisions.
Well, perhaps a story where some witches and wizards from different houses are transported to a parallel magical world that is in a state of chaos. The magic there is unstable, and they need to figure out how to get back home while surviving attacks from rogue magical beings. They might also have to find a way to cooperate despite their house differences, which adds an interesting layer to the survival aspect.