New original characters are also common in 'Harry Potter human experiment fanfiction'. These could be rogue wizards who are obsessed with pushing the boundaries of magic through human experiments. They might kidnap other wizards or even Muggles to carry out their experiments, and then the main Harry Potter characters have to stop them.
Severus Snape could be a key figure in such fanfictions. Given his complex character and his knowledge of dark magic, he could either be involved in conducting human experiments for some greater good (in his mind) or be trying to prevent others from doing so. Another character might be Draco Malfoy. He could be forced into participating in a human experiment by his family's allegiance to the Dark side, and then have to deal with the consequences.
Harry Potter himself is often involved. Writers might explore what would happen if Harry was a mutant, like having an enhanced ability to resist the Imperius Curse. Hermione could also be a main character in such fanfictions. She might use her intelligence to study the mutant phenomenon and try to find ways to control or utilize it. Ron could be there too, perhaps with a mutant ability related to his family's Weasley magic, like being able to make their old magical items work in a completely new and powerful way.
Often, Naruto himself is a main character in these fanfictions. Since he has a unique genetic makeup with the Nine - Tails inside him, he becomes a prime subject for genetic experiments in many stories. Sasuke is also common. His Sharingan and the secrets of the Uchiha clan's genetics make him an interesting focus. Orochimaru is another character who is frequently involved. He is known for his unethical experiments in the original series, so it's natural for him to be part of genetic experiment fanfictions.
Often, Naruto himself is involved. Since he is the main character of the original series, many fanfictions like to put him in the center of bloodline experiment stories. He might be the subject of an experiment or be the one trying to stop a dangerous bloodline experiment.
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.
Harry Potter himself could be one of the main characters in such fanfiction. Maybe he gets an automail limb after a particularly dangerous encounter with Voldemort. Hermione might also be involved, using her vast knowledge to help understand and improve the automail technology within the wizarding context.
Well, of course, Harry Potter himself is often the central figure. He's usually the one who discovers the amulet or is tasked with dealing with its powers or secrets. Hermione Granger also frequently appears, using her vast knowledge to help Harry understand the amulet.