One possible storyline could be that they discover a family secret together. Maybe something about their parents or their family heritage that has been hidden from them. This discovery could lead them on a journey to uncover more about their family's past.
In this fanfiction, they might have a very close and protective relationship. Since they are sisters, Bella could be always looking out for Elena, and vice versa. They might share secrets, support each other through difficult times, and be each other's confidantes.
Elena might show her jealousy by being overly critical of Bella. For example, she could constantly find fault in Bella's actions or decisions in the fanfiction.
By showing them having heart - to - heart conversations. For instance, late at night when they can't sleep, they talk about their dreams, fears and hopes. This can deepen their understanding of each other.
Well, it could be due to a number of reasons. Maybe in the fanfiction, Bella has some unique abilities or qualities that Elena lacks. And this makes Elena feel envious. Also, if the story portrays Bella as getting more attention from other characters, especially those that Elena values or is interested in, that would surely make Elena jealous.
Well, the storyline could be really interesting. Since Bella is from the 'Twilight' universe and Elena from 'The Vampire Diaries', combining them as twins could lead to a lot of crossovers. Maybe they both discover their vampire heritage together. Bella's brooding nature and Elena's more social and empathetic side could create a great dynamic. They might have to face different vampire clans together, with Bella's knowledge of the Cullens and Elena's experience with the Salvatores coming in handy.
Well, Bella's deep loyalty, especially to Edward, could be something that Elena might envy or admire. On the other hand, Elena's ability to handle multiple relationships in 'The Vampire Diaries' might seem strange to Bella. However, they would probably learn from each other. For instance, Bella could teach Elena about the more solitary and self - controlled nature of the Cullens, while Elena could show Bella how to be more open with her feelings towards others in a group setting.
Maybe Elena just doesn't like the way Bella is portrayed in fanfiction. It could be that she has a different view of the original Bella character and the fan - made versions deviate too much from it.
In this fanfiction, Bella is likely the main focus. Because the whole premise is about Elena being jealous of Bella, which implies that Bella is at the center of whatever relationship or situation is going on with Damon. Elena's jealousy is directed towards Bella, so the story would probably revolve around Bella and how she deals with Elena's jealousy and her relationship with Damon.
The fanfiction could also focus on Bella's character development as Felix's sister. She might have her own dreams and goals, but at the same time, she always puts Felix first. For instance, if Felix gets into trouble with some other characters, Bella could use her charm or intelligence to get him out of it. It could be a story about loyalty, family, and growing up together in a fictional universe.