The relationship might affect the plot in that it could create a bridge between the two very different universes. If Harry is Bella's cousin, he could potentially introduce her to a world of magic, which would be a huge shift for Bella who is so used to the world of vampires and humans in Forks. It could also mean that the Cullens might have to interact with the wizarding world more, leading to all sorts of new storylines.
Well, it could add a whole new layer of complexity. Maybe Harry's wizarding world knowledge could help Bella in some way in the Twilight world. For example, if there are some dark forces in Forks that are not just vampires and werewolves, Harry's magic might come in handy. It could also lead to some interesting cultural clashes between the two families.
In this fanfiction, the cousin relationship between Harry and Bella can change the plot significantly. First, it might change the way Bella views the supernatural. Instead of just vampires and werewolves, she now has to consider magic. Second, it could bring the wizarding community into the Twilight realm. This could lead to conflicts or alliances between wizards and the other supernatural beings. For instance, wizards might have different ways of dealing with vampires, and this could either cause trouble or create new ways of co - existing.
Well, it could have a huge impact. If Harry is Bella's brother, it might change the entire dynamic of both the Harry Potter and Twilight universes. For example, Harry's magic could potentially be used to protect Bella from the vampires in Forks. Or perhaps he could use his knowledge of the wizarding world to help her understand some of the strange things happening around her. It could also lead to some interesting crossovers, like having the wizards interact with the werewolves and vampires in a different way than in their original stories.
If Annabeth is Bella's cousin in the fanfiction, it could introduce a lot of conflict too. The two come from very different backgrounds. Annabeth is from a world of Greek mythology and Bella from a more modern, vampire - centric world. Their different beliefs and values could clash. But this conflict could also be a driving force in the story. For instance, Annabeth might try to convince Bella that some of the vampires are too dangerous to be around, while Bella could be defensive of her new friends. This would add depth and drama to the plot.
Well, think about Harry and Jacob. They could bond over their shared protectiveness of Bella. Harry might be intrigued by Jacob's werewolf abilities and Jacob could be fascinated by Harry's magic. Also, Ron could have some really funny interactions with the Cullens. He might be a bit clumsy and out of place in their refined vampire world, but it would be entertaining to see how they all react to each other.
Well, their family relationship could add a whole new layer of complexity. It might mean that Percy, being related to Bella, gets dragged into the vampire - werewolf drama in Bella's world. Maybe she calls on him for help when things get tough with the Cullens or the Volturi. It could also mean that Percy has to keep his demigod identity a secret from Bella's new family, which would be really hard.
At first, it might be a bit rocky. Harry would be confused about this new place and Bella, and Bella would be a bit overwhelmed by the sudden presence of a magical child. But as time goes on, they would start to bond. Bella would see Harry's vulnerability and his need for love and protection, and Harry would see Bella as a source of stability in this strange new world.
His magic could make the Queen see him as a valuable asset. She might rely on his magical abilities for protection or for solving problems that normal means can't handle.
If Naruto is Bella's brother in this fanfiction, it could completely rewrite the Twilight saga. His upbringing in the Hidden Leaf Village would give him a different perspective. He might introduce some of the ninja concepts like chakra to the Twilight world. His relationship with Bella would also mean that he'd be involved in her love story with Edward, perhaps trying to understand Edward's motives more deeply or even challenging him to prove his love for Bella.
The protective brother can change the plot significantly. For instance, if he's highly skilled in magic, he can prevent Harry from getting into some of the dangerous situations he faces in the original series. He might be able to stop Harry from entering the Triwizard Tournament by interfering with the Goblet of Fire's magic. This would then change the entire course of that year at Hogwarts and Harry's relationship with Cedric Diggory and others.
One idea could be that Hermione, being Bella's cousin, uses her magic to protect Bella from the various dangers in Forks. For example, when the vampires start to show interest in Bella, Hermione could create protective spells around her. Maybe she'd also use her knowledge of potions to make something that would hide Bella's scent from the vampires, which is a big part of the 'Twilight' series.
Yes, there are likely fanfictions out there with such a concept. Fanfiction writers often come up with creative and unexpected crossovers, and making Bella Swan Harry Potter's twin is one of those very imaginative ideas. However, the quality and nature of such fanfictions can vary greatly. Some might focus more on the magical aspects of the Potter world combined with Bella's story from Twilight, while others might take a more comical or even angsty approach.