Maybe Bella turns out to have a connection to an ancient vampire lineage that has a feud with the Cullens. This would create a lot of tension and conflict as she tries to navigate her feelings for the Cullens while dealing with this newfound connection.
Edward is also a fascinating character. His struggle with his vampire nature and his growing feelings for Bella can be explored in more depth in the fanfiction. Maybe we'll see new aspects of his character, like his relationship with his vampire siblings in the context of Bella being in their lives.
One interesting plotline could be Bella discovers Edward's vampire nature in a more dramatic way than in the original. For example, she might witness him using his super speed to save her from an immediate danger like a speeding car. Another could be that Edward is initially more hesitant to be around Bella because he fears his vampire instincts more strongly, creating more tension in their relationship.
One idea could be that Bella already has some latent vampire powers herself when she meets Edward. Maybe she can sense other vampires from a distance. This would add a new dynamic to their relationship as they both figure out what it means.
Edward is often well - written. Fanfiction authors can delve deeper into his internal struggle with his vampire nature and his love for Bella. They can show more of his vampire abilities and how he uses them to protect Bella. Bella too can be very well - written. Authors might give her more agency and make her less of a damsel in distress, showing her strength in the face of the vampire world.
You could make their relationship more unique by having them communicate in a different way. For example, instead of just talking, they can have a mental connection from the start that only they can understand. This would make their bond more special and exclusive.
The abuse could change Bella's personality completely. She might become more rebellious in an effort to fight back against Charlie in the fanfiction. However, this could also lead to more physical harm from Charlie. On a more long - term note, if the abuse continues, she may have difficulty forming healthy relationships in the future. Her view of family and love could be distorted, and she may constantly be on guard, even in non - threatening situations.
Edward could use his mind - reading ability. He reads Charlie's intentions and plans his moves accordingly. If Charlie is about to make a decision that Edward believes will be bad for Bella, he can intervene at the right time. He might also be able to manipulate the situation subtly so that Charlie changes his mind without realizing it.
One possible reason could be that Edward believes Charlie is a threat to Bella in some way that Charlie doesn't realize himself. Maybe Charlie unknowingly gets involved with some dangerous elements, and Edward, with his vampire senses, detects it.
One key element is the family bond. Since they are father and daughter, fanfictions often explore the depth of their relationship. Another element could be Charlie's protectiveness over Bella.