Some fanfictions may show their relationship evolving in a more spiritual way. Since they both have eternal life now, they might start to explore the deeper meaning of their existence together. They could have long discussions about the purpose of their lives, their place in the world, and how they can use their abilities for good. This would add a new dimension to their relationship, making it more than just a romantic connection.
In some fanfictions, their relationship becomes even stronger. They've been through so much together by the end of Breaking Dawn that they have an unbreakable bond. They understand each other on a deeper level and are more in tune with each other's needs.
Some fanfictions might show them becoming more independent within the relationship. Bella could become more assertive, and Edward would respect her new - found confidence. For instance, she could start making decisions about their future without always relying on Edward's input.
In Eclipse fanfiction, their relationship often evolves through increased trust. Bella starts to trust Edward more with her safety and future decisions. For example, she may be more willing to let him take the lead in dangerous situations.
Edward may become more protective. After New Moon, he realizes how much he almost lost Bella. So in fanfiction, he might be constantly on guard, which could sometimes cause tension in their relationship as Bella wants more independence. For Bella, she could become more confident in her relationship with Edward. She's no longer the hesitant girl she was in New Moon, but a stronger person who knows what she wants.
Another idea is that they get involved in vampire politics more deeply. With their unique family situation and Bella's newfound abilities, they could become important figures in the vampire world. They might work towards changing some of the old vampire laws and traditions, especially those related to hybrids like Renesmee.
In fanfic, Bella's character can become more assertive. Instead of always being the damsel in distress, she might take charge in certain situations. For example, when facing threats to the Cullen family, she could be the one coming up with plans. Edward, on the other hand, may become more in tune with his human side. He might start to enjoy human activities more, like going to concerts or art galleries, which he previously avoided. This evolution can make their relationship more balanced and interesting.
One interesting plot could be Bella exploring her new vampire powers in more depth than in the original. For example, she discovers unique ways to use her speed and strength that no other vampire has thought of. Another plot might involve Edward and Bella facing a new threat to their family that is specific to their situation as a vampire - human - vampire family. It could be a new type of vampire with different abilities that challenges their way of life.
Edward and Bella are the top ones. Their love story has a huge fan base, and in fanfiction, writers often delve deeper into their characters. Jacob also remains popular. Even though his relationship with Bella has changed, his loyalty to her and his role in the werewolf pack make him an interesting character to write about. Also, the Cullen family members like Alice are popular as they add more depth and mystery to the stories with their special abilities.
Often, their relationship deepens. The car crash makes them realize how much they mean to each other. Edward might become even more protective, and Bella more trusting. For example, Edward could vow to never let Bella be in a dangerous situation again, and Bella might start to fully embrace the vampire world because of the near - death experience.
In some fanfictions, their relationship deepens on a spiritual level. Since they've both been through so much, they start to understand each other's souls better. They communicate without words, and their love becomes more of a profound connection that goes beyond the physical and emotional aspects.
One interesting fanfiction could be about an alternate ending where Bella and Edward face a different kind of vampire threat in Breaking Dawn. It might show them using new powers or strategies to protect their family.