Well, it could change things a great deal. For one, it might add a whole new layer of family drama. Bellatrix being Harry's aunt could mean that there are secrets in the family history that were previously unknown. It could also make Voldemort's connection to Harry even more complex, as Bellatrix is one of his most loyal followers. Maybe it would lead to some internal conflict within Bellatrix herself, having to balance her loyalty to Voldemort with this newfound family tie to Harry.
The relationship would likely shake up the story. Since Bellatrix is a Death Eater, Harry might be in more danger than ever. But at the same time, it could also open up opportunities for her to protect Harry in some way. This new relationship might also make the wizarding world view Harry differently. They might be more suspicious of him, thinking he could be influenced by Bellatrix. Or it could lead to some characters trying to use this connection to their advantage in the fight against Voldemort.
Well, it would change a great deal. Bellatrix being Harry's godmother would mean a completely different relationship with the Dark side. Instead of being a feared Death Eater out to kill Harry, she might be in a position of protecting him, which would create a very complex and strange dynamic within the wizarding world. It could also lead to some really interesting plot twists where Bellatrix has to choose between her loyalty to Voldemort and her role as Harry's godmother.
Well, if they are siblings in fanfiction, they would probably have a more protective relationship. Harry might be more over - protective of Hermione, like a big brother. And Hermione could be constantly looking out for Harry's well - being too. Their bond would be deeper and based on family loyalty from the start.
In the wider wizarding world, the public who once saw Harry as a hero would be horrified. The Ministry of Magic would likely get involved, and there could be a manhunt for Harry. This would also change the power dynamics among the different wizarding factions. Those who were against Harry all along would use this as proof of his 'evil' nature, while those who supported him would be in a state of confusion and disbelief.
This alternate plot would turn the story on its head. Bellatrix's loyalty to Voldemort could put Harry in a difficult position. He might be forced to choose between his mother's side and the side of good. The relationship with Sirius would be extremely different too. Instead of being his godfather, Sirius might be an enemy. And the final battle against Voldemort would have different implications as Harry's connection to both Voldemort and Bellatrix would be a major factor.
If Bellatrix was Harry's mother in this fanfiction, the whole plot would be a mess. Harry would be born into a family of pure - blood maniacs. His magical education would likely be focused on the dark arts rather than the normal curriculum at Hogwarts. His relationships would be warped. He may not have the same friends like Hermione and Ron. And his relationship with Voldemort would be extremely complex, as Bellatrix was one of Voldemort's most loyal followers. It would be a story full of moral and ethical dilemmas for Harry.
Well, for one, the relationships change. If Harry is a girl, the Marauders might be more protective or interact with her in a different way. For instance, James might be more chivalrous towards her. Also, the way she is perceived in the wizarding world could be different. A female hero might face different expectations compared to a male one.
In this fanfiction scenario, their relationship dynamics would change significantly. Since they are siblings, they would probably grow up together. This means they would share more childhood memories, both good and bad. Hermione might be more protective of Harry and Ron as her brothers, and she could use her intelligence not just as a friend but as a sister to keep them out of trouble. Ron would also be more possessive in a brotherly way. They would also face family - related issues together, like dealing with their parents' expectations or family secrets.
If Ginny is Harry's sister in fanfiction, the power dynamics within the Weasley family might change. Ginny, being related to Harry, could bring a new status to the family. Also, their combined abilities and resources as siblings could be a new focus. They might have a secret language or a special bond that only siblings understand, which could be used to outwit their enemies. And the whole Hogwarts environment would see them in a different light, perhaps with more respect for their family connection.
In the fanfiction, their relationship as siblings could be a source of strength. They could combine their different skills and knowledge. Hermione is known for her intelligence and studiousness, while Theo might have his own set of skills from his Slytherin upbringing. Together, they could solve problems that neither could solve alone. Their relationship might also be a way to bridge the gap between Gryffindor and Slytherin in the story, promoting unity among the houses.
It could completely shift the power balance and moral compass of the story. With Dumbledore on the 'dark side', the usual alliances and conflicts would be turned upside down.