There is also a possibility that a lone vampire, who has a sense of justice or who has been secretly observing Bella and has grown fond of her, decides to take on the Volturi and rescue her. This vampire could have some special abilities or knowledge that gives them an edge against the powerful Volturi.
Definitely Aro. He is the leader of the Volturi, so he will have a lot to do with Bella.
In the Twilight universe where this fanfiction is based, the Volturi kings are Aro, Caius, and Marcus. They are the leaders of the Volturi, an ancient and powerful coven of vampires.
One possible plot development could be that the Cullens launch a rescue mission. They might gather other vampire clans to help them, as the Volturi are very powerful. Another could be that Bella discovers some long - hidden secrets about the Volturi while in captivity, which changes her view of the vampire world completely.
There could be other vampires that Bella meets during her time as a vampire before the Volturi. For example, some lone vampires who are also trying to stay out of Volturi's radar. They could become her allies or foes depending on their motives.
Well, she may try to use her position to influence the Volturi's decisions. Maybe she could try to prevent them from taking actions against the Cullens or other vampires she cares about. Also, she would likely have to deal with the other Volturi members who are very powerful and perceptive. She'd have to be constantly on guard not to be discovered. And her relationship with Edward would be put to the test as she has to keep this huge secret from him. It could lead to a lot of tension and drama in the story.
Bella is a key character. She is usually the one who disrupts the status quo in the Volturi world. Aro is another mainstay. His thirst for power and knowledge makes him a formidable force in the fanfiction. Sometimes, other Volturi guards like Felix and Demetri also become important as they interact with Bella and Aro. And let's not forget Edward Cullen, who might be part of the story as Bella's former love or a rival in some interpretations.
Caius is another important character in such fanfictions. He is usually portrayed as quite strict and unforgiving, and his reactions to Bella joining the Volturi can range from suspicion to begrudging acceptance. Also, Jane, with her special ability, has interactions with Bella that can be both menacing and oddly fascinating.
Bella is the central figure in this fanfiction. Then there are the Volturi leaders like Aro. He would play a significant role as he might be the one guiding Bella's upbringing in the Volturi way. Marcus, with his unique ability to sense relationships, could also be important as he might have insights into Bella's development. Caius, known for his strict and often harsh views, would add conflict and tension to Bella's story.
There could also be other vampires or humans who play important roles. For instance, some fanfictions might introduce new vampires who are either allies or enemies of the Volturi and have a connection to Bella's situation. And there might be human friends of Bella who get involved in the story, like Jacob or her school friends, although their roles might be secondary compared to Bella and the Volturi.
Well, obviously Bella is one of the main characters. She is likely to be the central figure around which the story revolves. The Volturi leaders, like Aro, Caius, and Marcus, are also main characters as they play a significant role in any story involving the Volturi.