In the original books, Hedwig's personality is somewhat limited. However, in fanfiction, authors often give her a more complex and developed personality. She could be sassy or extremely intelligent, and she might interact with other characters in ways that are not seen in the original series, like having conversations with other magical animals or even some human wizards.
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.
In fanfiction, the Chunin Vest can be more personalized. While in the original series it mainly represents rank, in fanfictions, it might have custom embroidery or markings added by the character themselves to show their individuality.
In the original series, squibs like Filch are more on the sidelines. But in fanfic, they can be the main focus. Fanfic might give them more agency and explore their unfulfilled magical desires more deeply.
One way it can be different in fanfic is in the control aspect. In the original series, legilimency was a complex and somewhat restricted magic. But in fanfic, a character might have perfect control over their legilimency, being able to turn it on and off at will, or even target specific thoughts within a person's mind with great precision.
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.
A lot of fanfictions play around with the Dursleys' relationship with Harry. They could be depicted as having a sort of begrudging respect for Harry. For instance, when Harry starts to show real courage and power, the Dursleys might start to see him in a new light. This is different from the original story where they mostly just try to suppress Harry. Also, some fanfictions might give the Dursleys magical abilities of their own, which completely changes their dynamic with Harry and the wizarding world.
In fanfiction, a female Harry Potter may interact with Viktor Krum more emotionally. For example, she might be more open about her feelings. In the original series, Harry was a bit more reserved. In fanfiction like 'Female Potter and Krum's New Dynamic', their interactions are filled with more subtleties of a potential romantic relationship which was not really explored in the original.
Well, in the original, Harry is very much guided by the values of the wizarding world. However, as a demon lord in fanfiction, he often rebels against those values. His character development may involve him forging his own path, which might not always be a positive one in the eyes of the traditional wizarding community. He could be more self - serving at times, focusing on his own power and survival rather than the greater good of all wizards. Also, his relationships with other characters like Hermione and Ron can change drastically. Instead of relying on them, he may view them as either allies he can use or obstacles in his way.
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.