It might be that Caius is on a mission outside of Volterra. He crosses paths with Bella's sister in a small town. She is doing some mundane task like shopping, and he is there to hunt (not for her, of course). But her scent catches his attention, and he approaches her. She is shocked to see such a pale and intimidating figure, and this is their first encounter.
One plot idea could be that Bella's sister discovers Caius's true nature as a vampire but instead of being afraid, she is intrigued. She starts to secretly study vampires and their lore, and in the process, catches Caius's attention. He then decides to keep an eye on her, leading to a series of tense yet fascinating encounters.
One common theme is identity. Bella has to re - define who she is as Caius' sister instead of just being Edward's love interest. Another theme is family loyalty. She has to figure out where her loyalties lie between the Cullens and the Volturi.
Well, Caius could be very possessive and see Bella's blindness as something that makes her even more his. He would be by her side all the time, guiding her physically when needed. He might also share his vampire senses with her in some way, like describing the world around them in vivid detail so that she can 'see' through his words. And he would definitely be very angry if anyone made fun of or took advantage of her blindness.
There could be a story where Caius has a change of heart after meeting Bella. In the Twilight world, Caius is known for his strict and often cruel ways. But when he encounters Bella, he starts to question his own beliefs. Maybe Bella gets lost in the Volturi territory and Caius finds her. Instead of punishing her, he is intrigued by her. This could lead to a story of him trying to understand her human - vampire relationship with Edward from a different perspective. He might even start to envy Edward in a way, which could create a whole new dynamic in the fanfiction.
There's a fanfiction titled 'Sister to Caius: Bella's New Life'. This story delves deep into how Bella's life is turned upside down when she realizes she's Caius' sister. It shows her struggle to fit in with the Volturi's ways and also how she tries to maintain her relationships with her old friends. It's a long and detailed fanfic that really gets into the emotions and conflicts of the situation.
One way their relationship could develop uniquely is through a shared interest in art. Suppose Bella has an appreciation for ancient vampire art that Caius is also fond of. They start to bond over discussing different artworks and the stories behind them. This common interest bridges the gap between them, and Caius begins to see Bella not just as a human or Edward's mate, but as an individual with her own charm. As their relationship grows, Caius might even start to protect Bella from the Volturi's harsher rules because of this newfound connection.
Yes, it is quite popular. Many Twilight fans are intrigued by the idea of Bella having a different kind of relationship, like being true mates with Caius. It offers a new perspective on the characters and the story. People enjoy exploring different pairings and how they could change the dynamics of the Twilight world.
At first, it might be a bit rocky. Bella, being human and now blind, is in a very vulnerable state. Caius, as a powerful vampire, may come off as intimidating. But as time goes on, they start to develop a deep bond. Caius learns to be more gentle and caring, and Bella starts to trust him more and more.
One common theme is family dynamics. Since it's about Bella's sister, it often explores how the sister fits into the family structure, especially with Bella being so central in the original Twilight story. Another theme is love triangles. Just like in the original, but now with the sister involved in some way.