It could be an alternate version of Dumbledore. Maybe in this universe, Dumbledore has been corrupted by power and his thirst for knowledge leads him to do dark things. He could be trying to control the entire wizarding world using some powerful and forbidden magic.
Well, it could be about Harry Potter finding himself in an alternate universe where he is a king. Maybe he has to deal with different magical politics and power struggles that are far more complex than in his original world. He might have to form new alliances and face new enemies all while trying to figure out how this new world's magic works compared to his own.
Well, if Snape turns Harry into a vampire in fanfiction, it would completely change the dynamic. Harry would have to deal with new instincts like the thirst for blood. His relationships would be strained as his friends might be scared of him. Also, his role as the 'Chosen One' would be redefined as he's now a different kind of being with different needs and abilities. He might have to struggle between his human side and his new vampire nature.
Well, in an Alter Universal Fanfiction, there could be a scenario where the Sorting Hat sorts students based on different criteria. For example, instead of sorting by courage, intelligence, etc., it sorts by potential for a new kind of magic. Also, Voldemort could be a hero in this alternate world. He might have been misjudged in the original timeline, and in this new universe, he uses his power to fight an even greater evil. Additionally, the houses in Hogwarts could have different alliances. Maybe Gryffindor and Slytherin form an alliance against a new threat.
In this fanfiction, it could be a group of corrupted magical nobles who oppose Harry's rule. They are used to having all the power in the alternate universe and don't want to give it up to an outsider like Harry. They could be plotting all sorts of schemes to undermine Harry, from spreading false rumors to outright attacking him and his supporters.
If Harry Potter becomes Lord Slytherin, he might bring about a new era of unity in Hogwarts. Since he has friends from different houses, he could bridge the gap between Slytherin and the other houses. He may introduce new rules or traditions within the Slytherin house that are more inclusive. For example, he could encourage more cooperation in Quidditch matches instead of the cut - throat competition that has been the norm. Also, his magical abilities, which are already quite remarkable, could be enhanced or used in different ways as Lord Slytherin, perhaps leading to new spells or ways of magic being discovered.
In such a fanfiction, Hermione's magical abilities could potentially be enhanced or different. Since Tom Riddle was a very powerful wizard, his genes might have passed on some unique magical traits to Hermione. This could make her an even more formidable force in the wizarding world. It would also change the way she approaches magic. Instead of relying solely on books and study, she might have an inborn understanding of some dark magic, which she would have to struggle to keep in check. Her relationship with Dumbledore would also be complex. Dumbledore would be both cautious and intrigued by her connection to Riddle.
Well, if James and Lily are alive, Harry doesn't grow up an orphan. He has his parents to guide him. For instance, he might not go to Hogwarts with the same sense of longing for family as he does in the original. His character development would be different as he has a loving family environment.
Well, it might be that in this fanfiction, Snape has a change of heart due to some event. For example, he could discover some hidden truth about Harry that makes him sympathetic. This new - found niceness can bring out a different Harry too. Harry, who is used to Snape's harshness, might be initially suspicious but then grow to trust Snape. This would then change the way he interacts with the other characters as well, since his relationship with Snape is so central in the original story.
There are often masters who play important roles. For example, Shirou Emiya can be one of the key characters in the Fate - related stories. He has his own goals and ideals which interact with Saber Alter's story.