A possible plotline could be that Bella's new status as Emmett's sister makes her more confident in the vampire world. Since Emmett is a strong and outgoing vampire, he might teach Bella how to better use her vampire abilities if she were to become one in the story. This could lead to her getting involved in more dangerous situations but also growing as a character.
A plotline could involve Bella's family's reaction to her relationship with Emmett. Given her blindness, they might be even more worried about her getting involved with someone like Emmett. Also, the fanfiction could show how Bella and Emmett communicate on a deeper level. Since she can't see, they might develop a stronger telepathic or emotional connection that is unique to their relationship.
Well, perhaps they discover they are siblings after some long - lost family mystery is unraveled. As they adjust to this new reality, they might face jealousy from other members of their coven. And for the 'lemon' part, it could be that there are some intense emotional moments between them that border on inappropriate feelings, which they have to overcome as they realize the importance of their family connection. Maybe they are in a situation where they are forced to rely on each other in a very close way, and those feelings start to develop, but they know it's wrong because they are siblings.
A plotline might involve Bella having to choose between different aspects of her relationships with Jasper and Emmett. For example, Jasper could offer her a more cerebral and controlled relationship, while Emmett might represent a more passionate and physical connection. Also, they could all be on a journey to discover more about the origin of their unusual mating bond.
One possible plotline could be that Emmett, as Bella's landlord, is very protective of her. Maybe he notices some strange things going on in the neighborhood related to the vampire - human world in Twilight, and he tries to keep Bella safe without revealing his own true nature (if he's a vampire in the fanfic).
A possible plotline could be that the Winchester sisters are magically transformed into Bella Swan right before a major event in the 'Twilight' series. They then have to quickly adapt to her life and relationships while also trying to figure out a way to get back to their own world. They might use their combat skills to protect themselves from the vampires and werewolves in a more aggressive way than Bella usually does.
One common plotline could be them facing challenges from other vampires who don't approve of their relationship. Since Emmett is strong and Bella has her own allure, others might see their union as a threat to the vampire hierarchy or social order.
There are numerous potential plotlines. For example, a story could focus on how Emmett and Jasper's relationship with their 'mother' figure (if there is one in the fanfiction) changes because of their new connection to Edward. Another could be a coming - of - age type of plot where they struggle to find their place in the family while also dealing with the challenges of being vampires. There could also be a plotline where they discover secrets about their new family heritage that Edward has been hiding. This could lead to a rift or a stronger bond between them, depending on how the story unfolds.
A possible plotline could be that Bella's sister is initially in danger, and Carlisle saves her. This event sparks their connection. Then, they start to secretly meet, trying to hide their relationship from both the human world and the Cullen family. Another plotline might be that Bella's sister has a special power that attracts Carlisle, and they explore their relationship while trying to figure out what this power means for them.
Well, Emmett's physical strength can also have an impact on Bella. In some stories, seeing Emmett's power makes Bella strive to become stronger herself. Maybe she starts training with him, and through this process, she not only becomes more physically capable but also gains more confidence. This new - found confidence then affects her relationships with other characters as well. Moreover, Emmett's jovial personality can bring out a lighter side of Bella. When she's around him, she might find herself laughing more and being less brooding, which is a big change from her usual self in the original story.
Some fans might be shocked as it goes against the established relationships in the Twilight series. Bella was mainly associated with Edward. Others might be interested in the creative deviation, seeing it as a new and different take on the characters.