Harry Potter himself is often a main character. Since he has a connection to Voldemort, he's likely to be involved in any dark discoveries related to the Dark Lord.
Obviously, Harry Potter himself is often involved. He's the hero of the original series, so in fanfiction about a dark dragon, he'd be the one to step up and face the new threat. Hermione and Ron would likely be by his side too, as they are his closest friends.
Hermione Granger might also be a central character. Her thirst for knowledge could lead her into situations where she is in the dark, like exploring a new area of magic that has many unknowns. As a child in Hogwarts, she might be trying to solve a mystery that no one else has been able to, and she has to start from a place of not knowing much, or being 'in the dark' so to speak.
In addition to the main trio, characters like Draco Malfoy could be a major part of the story in 'Harry Potter Dark Paladin' fanfiction. Draco's complex relationship with the dark side in the original series could be further explored in relation to the Dark Paladin. There could also be original characters created specifically for the fanfiction, who might be fellow Dark Paladins or those who have a connection to the dark powers that the main Dark Paladin is using.
However, there could also be new characters introduced. Maybe a mysterious new student who has a connection to the dark side of magic. This character could be a catalyst for the 'dark discoveries' that the story is centered around. They could bring new knowledge or powers that the other characters have never seen before.
Harry Potter himself is often a central character. Since he's the main character in the original series, it makes sense that in 'Harry Potter Dark Gifts Fanfic' he would be involved. Writers might explore how he copes with or uses a dark gift.
Harry Potter himself is often involved. He might be the one to encounter the first signs of inflation, whether it's a magically inflating potion or an enchanted object. His friends, like Ron and Hermione, are also likely to be part of the story, helping him figure out what's going on.
Ron Weasley could also be a key figure. He might be Harry's loyal friend as always, standing by his side during all the changes that Harry is bringing about in the wizarding world as a god. And there could be new characters introduced as well, perhaps other gods or magical beings that interact with Harry in this new fanfiction realm.
In some cases, Albus Dumbledore could play an important role. His wisdom and power in the wizarding world would make him a key figure in any situation where the two different universes collide. He might be the one to first discover Alexstrasza's presence and figure out how to make use of her abilities in the fight against the dark forces in the Harry Potter world.
Obviously, Harry Potter himself is always a main character. He is the one most directly associated with the concept of death in the original series, what with his parents' death and his multiple near - death experiences.
Ron Weasley could be another main character. He might be initially skeptical about the piano's magic but then be amazed when he sees the extraordinary things it can do. Maybe he accidentally discovers a new function of the piano while fooling around with it in the Gryffindor common room.