Well, if Hermione were Tom Riddle's sister in fanfiction, it would completely rewrite the whole Hogwarts saga. For one thing, Hermione's values of friendship and justice would be in direct conflict with Tom's path to becoming Voldemort. Maybe she could have tried to steer him away from the dark side early on. But it's also possible that her presence in his life could have been used by him to gain more power and knowledge, using her intelligence for his evil ends.
It would change the future of the wizarding world a great deal. Hermione is a smart and kind - hearted witch. With her as Tom's mother figure, she would likely encourage his academic pursuits in a positive way. He might grow up to be a great wizard who uses his powers for good instead of evil, thus changing the whole power dynamic in the wizarding world.
One way this could be somewhat plausible is through a time - travel or alternate universe scenario. Maybe in a world where the rules of magic are bent, Tom Riddle's dark past is rewritten, and he somehow meets Hermione in a different context. However, it goes against the canon nature of their characters. Tom Riddle is a dark wizard with very different values from Hermione. In the original story, they exist in different eras. But in fanfiction, creative liberties can be taken to explore how their personalities might interact in such a situation.
If Hermione adopts Tom Riddle, it could potentially prevent the rise of Voldemort. This would mean a much more peaceful wizarding world. There would be no First or Second Wizarding Wars, and countless lives would be saved. Families like the Potters and the Weasleys would not have to endure the pain and loss they suffered in the original timeline.
One possible plot could be Hermione discovering the truth about her godfather being Tom Riddle and struggling with her own identity. She might be torn between her loyalty to her friends and the new - found family connection.
Well, in fanfiction, anything can be possible. It could be possible through some dark magic or a complex time - travel plot. Maybe a spell went wrong and created a connection between Hermione and Tom Riddle that led to her being his daughter. However, in the original "Harry Potter" lore, it's completely against the nature of good and evil as Hermione is on the side of good and Tom Riddle is the evil Lord Voldemort.
Well, if Hermione were Malfoy's sister in fanfiction, it would completely turn the story upside down. First of all, Hermione's values of friendship and equality would clash severely with the Malfoy family's pure - blood supremacist views. She might try to change her family from within. And her relationship with Harry and Ron would be much more complicated. They might be initially suspicious of her because of her family name. Also, Draco's attitude towards Hermione would be different. Instead of being rivals, he might have a sense of protectiveness over her, which would add a whole new layer of drama to their interactions.
Hermione would likely approach Tom's dark past with a great deal of research. She'd probably dig into the history of Voldemort's early years to understand what led him down that path in the first place. By knowing the root causes, she could try to prevent the same things from happening to Tom. For example, if she found out that loneliness and a sense of being an outcast were factors, she'd make sure Tom had a strong support system at Hogwarts.
Their family dynamics would be extremely complex. Tom was already a troubled child, and having Hermione as a sister would add another layer. Hermione is intelligent and empathetic, so she might have tried to understand Tom's problems, but Tom, with his growing darkness, might have resented her. There could be a power struggle within the family, with Hermione trying to uphold good values and Tom being drawn to the dark arts.
In some fanfictions, Hermione might end up in a time - travel scenario where she encounters Tom Riddle before he fully becomes Voldemort. If they had a daughter, the story could explore the girl's struggle with her dual heritage. She might have Hermione's intelligence and determination but also be haunted by Riddle's dark past. It could be a complex exploration of nature vs. nurture.
Well, if Hermione was Remus Lupin's sister in a fanfiction, it would change the story in many ways. For one, Hermione would have a different family background. She might grow up with knowledge of the wizarding world in a different way, as Remus is a werewolf and that would bring a whole new set of experiences and challenges to her family life. Also, her relationship with Harry and Ron could be affected. Maybe they would be more cautious around her, knowing she has a connection to a werewolf. It could also change the way she approaches her studies, as she might have learned some things from Remus before coming to Hogwarts.