Another character could be Neville Longbottom. In some fanfictions, Neville is neglected by his family not just because they think he's not as magically talented as they hoped, but they actively try to suppress his magic. This can lead to Neville having a more difficult time at Hogwarts initially as he has to overcome both the lack of support from his family and his own self - doubt.
In some fanfiction, Harry's friends might accidentally neglect him because they are too caught up in their own problems. For example, Hermione might be so focused on her studies and her activism for house - elf rights that she doesn't notice Harry's distress. And Ron could be too busy with his insecurities and family issues to be there for Harry, which is a different take on the idea of neglect within the Harry Potter fanfiction world.
Obviously, Harry Potter himself is the central character as the one being abused and neglected. The Dursleys are also key characters as they are the ones who abuse and neglect him in the original story. Hermione and Ron might also be involved as they could be the ones to discover Harry's situation and try to help him. Dumbledore could also be a part of it, perhaps as someone who failed to notice or prevent Harry's abuse initially.
One key theme is often Harry's struggle for self - worth. Since he is abused and neglected, he has to find his own value within the magical world. Another theme can be the search for true family. He may seek out people who truly care about him instead of the Dursleys who are so cruel. Also, the theme of resilience shows up as Harry overcomes the hardships of his upbringing and still manages to thrive in the wizarding world.
In Harry Potter fanfiction, when a character is abused or neglected, it often adds a darker and more complex layer to the story. For example, if Harry was more severely abused by the Dursleys than in the original, it could make his journey at Hogwarts more about overcoming deep - seated trauma. This can also change his relationships. He might be more distrustful at first, which would impact how he interacts with his friends like Ron and Hermione.
The original Harry Potter story has a theme of the underdog rising above. In fanfiction with abuse and neglect, this can be amplified in a negative way. Harry might become more broken and less of the heroic figure. But on the other hand, it can also show how, even in the worst circumstances of abuse and neglect, there is still a chance for him to find his strength and fight back, which could be seen as a new take on the original theme.
Well, one reason could be that some fanfiction authors prefer to focus on other characters like Hermione or Draco. They might find those characters more interesting to explore in different scenarios. Maybe they think there are already so many stories about Harry in the original series, so they want to give other characters a chance to shine.
There could be fanfictions where Harry is sent to a different magical school where he encounters abusive teachers or fellow students. Or maybe it's a story that explores the psychological impact of abuse on Harry's magic and his relationships with others.
It's popular because it offers a different take on the well - known Harry Potter story. Fans like to see new interpretations. The idea of a neglected Harry and a harem adds an element of novelty.