Fanfiction often takes liberties with the established canon. For Hermione to be Sirius' daughter, it could be that a powerful magical force was at work. Maybe a prophecy was involved that forced a connection between them. Writers might also use this concept to explore how Hermione's character would be different if she had Sirius as her father. She might have inherited some of his rebellious and brave traits in a more direct way. And it could also add a whole new layer of drama to the existing relationships in the Harry Potter world, like how it would affect her friendship with Harry and Ron.
In fanfiction, this idea might be explored through alternate timelines. For example, if there was a divergence in the wizarding world's history, Sirius could have had a relationship that led to Hermione being his daughter. It could also involve some kind of spell or charm that altered the normal course of family relations. Fanfiction writers love to play with these concepts to create new and interesting stories.
Well, in fanfiction, anything can be possible. Maybe it could be a result of some time - turning magic gone wrong. Or perhaps there was a secret relationship between Sirius and Hermione's mother that was never revealed in the original story. It's all about creative interpretations in fanfiction.
In fanfiction, anything can be possible. It could be due to some dark magic or a convoluted plot twist. Maybe a spell was cast long ago that altered Hermione's true parentage, or Voldemort could have used some form of mind control on her real parents to make them believe she was theirs when in fact she was his. However, this goes completely against the original lore of the series.
In fanfiction, anything can be possible. Maybe a powerful spell was cast that altered memories or blood relations. It could be part of a complex plot where Hermione was secretly switched at birth.
In fanfiction, this could be possible through some creative plot twists. Maybe there was a secret relationship between Severus and Hermione's mother that was hidden. It could also be a result of some magical interference or a prophecy that was misinterpreted at first. Another idea could be that Severus used some advanced magic to protect Hermione and in doing so, a special bond was formed that led to this unexpected 'father - daughter' relationship in the fanfic world.
It could be due to a time - travel related plot. Perhaps Hermione goes back in time and through some unforeseen circumstances, her family line gets intertwined with Sirius' family, making her his sister in an alternate timeline. This could involve her interfering with past events that change family structures.
Well, in fanfiction, some authors might come up with the idea that there was some hidden connection or a secret affair in the past. Perhaps Voldemort had a relationship with Hermione's mother before he fully embraced the dark side. This would completely change the dynamics of Hermione's character and her place in the wizarding world. It could lead to her having to deal with the stigma of being related to the most evil wizard ever while still trying to uphold her values.
Well, in a fanfic, anything can be made possible. Maybe it could be that Severus had a relationship in the past that was kept secret, and Hermione was the result. Magic could also be involved in hiding the truth all those years.
In fanfiction, anything can be possible. Maybe a time - travel or a powerful magic spell gone wrong could be used to create this strange relationship. For example, if there was a spell that messed with people's memories and lineages, it could make Hermione seem like Bellatrix's daughter.
In fanfiction, anything can be possible. Writers might create a scenario where time - traveling or some sort of magical alteration to the past occurred. Maybe a powerful spell was cast that changed the course of events so that Hermione could be born to James and Lily. However, it's a huge departure from the original story's timeline.
One possibility could be through a powerful and misfired spell. Maybe a spell that was intended for something else, like a transfiguration gone wrong during a complex magic experiment in Hogwarts. For example, if a spell was being tested to enhance learning abilities by temporarily taking on the mental characteristics of a top student, it could have accidentally caused a full physical and mental transformation into Hermione.
In fanfiction, it could be possible through a complex backstory. For example, perhaps there was a secret adoption or a spell that was cast long ago which altered the family relations. Writers might also play with the idea of a hidden blood relation that was covered up for some reason. This could create a whole new dynamic between the two characters and lead to different story arcs.