In this fanfiction, Percy could be teaching Defense Against the Dark Arts. He would bring his own unique perspective, having grown up in a wizarding family. He could teach the students about the political implications of the dark arts as well as practical defense spells. Maybe he even shares some stories from his own experiences with dark wizards during his time at the Ministry.
Well, perhaps Percy could be teaching a new and difficult subject like Ancient Runes. He might use his strict and studious nature to get the students to really focus on the complex rune translations.
One possible plot could be that Percy is teaching Muggle Studies. Since he has a somewhat rigid view of things at first, he might start off with a very traditional view of Muggles. But as he gets to know his students better and they share their own experiences and curiosities about Muggles, Percy begins to see Muggles in a new light and his teaching style becomes more inclusive and interesting.
Maybe Percy teaches Potions. He could start off by strictly following the textbook but then discovers a new potion ingredient while exploring the Hogwarts grounds. This discovery could lead to a whole new line of potions research in the fanfic. He would then involve the students in this exciting discovery, making potions class much more interesting than it was before.
Hermione would likely be one of his favorites. She is extremely studious and always eager to learn, just like Percy. They could bond over their shared love for books and knowledge.
Perhaps the story could revolve around them facing challenges within the Hogwarts faculty. There could be some old - fashioned professors who oppose their modern teaching methods. Harry and Hermione then have to prove that their ways are beneficial for the students. They might also discover new magical abilities in some of the students that were previously overlooked, and help those students develop their skills.
Perhaps Harry is teaching Potions in the fanfiction. Since he had a bit of a rocky start with Potions in his student days, he could be a very understanding teacher. He might encourage students to experiment more, which is different from Snape's strict methods. He could also share stories about how important Potions were in his adventures, like when they made Polyjuice Potion. This would make the class more interesting and inspire students to take Potions more seriously.
Well, perhaps Harry Dresden could introduce his unique brand of magic from his own world into Hogwarts. He might teach the students new ways of dealing with magical creatures that are different from the traditional Hogwarts methods.
One possibility is that Merlin brings his ancient magic knowledge. He might introduce spells and magical concepts long forgotten in the Hogwarts curriculum. For example, he could teach students about pre - Hogwarts era potion - making techniques that are more in tune with nature.
The fanfiction could start with Percy reluctantly taking on a teaching job at Goode. He tries to keep his demigod identity a secret at first. But then strange things start happening at the school, like students having prophetic dreams or unexplained disappearances. Percy realizes he has to use his knowledge and powers to solve these mysteries and also teach his students about the hidden world of gods and monsters. He might even bring in some of his friends from Camp Half - Blood to help out.
One possible plot could be Castiel trying to understand the unique magical system of Hogwarts. He might initially struggle as his angelic powers work differently. For example, he could be confused by the use of wands when he's used to his own celestial abilities. But as time goes on, he starts to blend his knowledge with the wizarding world's, creating new spells or teaching methods that combine angelic and magical concepts.
One spell she could teach is a charm for protecting books from any kind of damage. Given Hermione's love for books, this would be a great addition to the curriculum. Also, a spell for magically highlighting important parts of textbooks as you read them would be very useful. This spell could be activated by just thinking about the relevant information while reading.
Well, perhaps Percy and Nico could be transferred to Hogwarts through some sort of magical accident. Maybe they'd have to deal with the different magical system there compared to their own world. They could make new friends among the Hogwarts students and get involved in the typical Hogwarts adventures like the Triwizard Tournament or dealing with a new dark threat.