In fanfiction, he could be seen as more of a hero. The original books don't fully explore his redemption arc as much as fanfiction might. So when he reads it, he'd notice that he's often given more agency and a more positive light.
When Regulus Black reads Harry Potter fanfiction, he'll see that his character is perceived quite differently from the original books. In the original, he's a side character with a mysterious past. However, in fanfiction, he could be the central focus. Fanfiction writers may explore his relationship with Voldemort in more depth, or they might create scenarios where he survives and has a major impact on the wizarding world. He could also be portrayed as having different magical abilities or alliances that were not even hinted at in the original story. This shows how fanfiction can expand and reshape a character in ways that the original author may not have envisioned.
Well, in the original books, Regulus Black is a somewhat shadowy figure. But in fanfiction, he can be depicted in all sorts of ways. He might find that some fanfictions turn him into a love interest, which is very different from his role in the original. Others might make him out to be a mastermind behind events that in the original he was only a small part of. So when he reads it, he'd see a much more diverse set of portrayals compared to the rather limited one in the original books.
He might be quite surprised. Fanfiction often takes the original story in new and unexpected directions. He could be intrigued by different interpretations of his own character or the events at Hogwarts.
In fanfiction, Dobby is often given more agency. In the original books, he is very much a servant - like figure at first. But in fanfictions, he can be a leader in the fight against the dark forces. For example, he might lead a group of house - elves in a rebellion against the Death Eaters who are cruel to them.
In the original books, goblins are mainly shown in relation to Gringotts Bank. But in fanfiction, they can have more diverse roles. They might be shown as having their own political agendas outside of the bank operations.
In fanfiction, plants like the Mandrake might have different growth rates. For instance, instead of taking a certain number of months to mature as in the books, it could take years or just weeks. This change can be used to create unique plotlines, such as a wizard needing a fully grown Mandrake urgently but having to deal with the unexpected growth time.
The power of augureys is often enhanced in fanfic. While in the books, their significance was somewhat limited. In fanfic, they might have the ability to heal with their feathers, or their song could have the power to put dark creatures to sleep. This expansion of their abilities makes them more interesting and central to the plot in many fan - created stories.
In the original books, Thestrals were not as prominently featured. But in fanfic, they can be the main focus. For instance, in some fanfic, Thestrals are shown to be more intelligent and able to communicate in ways not shown in the books.
His character arc can be very different. In the books, his development was somewhat limited, but in fanfiction, he could have a complete transformation. He might start to oppose the dark side more actively and become a hero - like figure, which is a big contrast to his original role.
One major difference is in the area of the Patronus Charm. In the original books, it mainly serves as a defense against Dementors. However, in Prodigy fanfiction, it could be used as a form of communication between characters. The charm's light or shape could carry messages, which is a new and creative take on the charm.
In the original series, Hedwig is mainly a faithful owl companion. But in fanfiction, she can be much more. She could be a magical entity with her own backstory and motives. For instance, some fanfictions might explore her origin in more detail, like she was bred from a special line of owls with unique abilities.
Some fanfictions might depict the Dursleys as having a more complex relationship with Harry. They could be in a situation where they have to protect Harry from a greater threat, which makes them put aside their differences. For example, a dark wizard could be targeting Harry, and the Dursleys realize that their home is the safest place for him at the moment, so they have to work together with Harry to keep him safe.