Maybe it's a group of rogue vampires who see the tension between Bella and the Volturi Queen as an opportunity. They want to overthrow the Volturi and see Bella as a key piece in their plan. They might try to kidnap her or force her to side with them, which would put her in direct conflict with the Volturi Queen who would see this as a threat to her rule.
The Volturi Queen herself could be the main antagonist. If she views Bella as a threat to her power or the Volturi's way of life, she would be a very powerful foe. She could use her influence over the Volturi guards and her own powers to try and stop Bella.
Perhaps there is a rogue vampire within the Volturi's ranks who doesn't want Bella and Alice there and tries to undermine their purpose. This vampire could be jealous of their relationship or afraid that they will expose some of the Volturi's secrets.
The Cullens could potentially be the main antagonists. Since Bella is secretly a Volturi fan, the Cullens' views and actions that oppose the Volturi might be seen as obstacles in Bella's new - found admiration. For example, if the Cullens try to keep Bella away from Volturi - related things, they would be acting against her interests.
It could be one of the traditional Volturi members who oppose Edward's presence. They might see him as an outsider who could disrupt their long - established order. For example, Caius might be against Edward joining as he's often portrayed as more rigid and less accepting of new vampires in the Volturi.
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.
There are many interesting aspects in this kind of fanfiction. Often, it explores a different power dynamic for Bella. She might be seen as a strong and influential figure within the Volturi world, bringing new ideas and changes. Writers may also play with her relationships, like how she interacts with the existing Volturi members in a more dominant role.
A power - hungry noble could be the main antagonist. This person might be jealous of the Queen's position and wants to overthrow her, and sees Harry as an obstacle in his way.
Well, one common theme is the transformation of Bella. Not just physically in some cases, but also in terms of her personality as she takes on the role of the Volturi queen. Her relationships also play a big part. Her relationship with the Volturi coven, whether it's friendly, hostile, or something in between. Also, the theme of ruling and leadership often comes up, like how she makes decisions for the Volturi. For example, in some fanfictions, she has to deal with internal disputes within the Volturi, which is all about her leadership skills. And then there's the theme of how the outside world, like the other vampire covens and the werewolves, react to her new position.
Yes, there are quite a few. You can start by looking on popular fanfiction websites like Fanfiction.net or Archive of Our Own. Just search for the specific tag 'bella is the volturi queen' and you'll find a variety of stories with different plotlines and writing styles.
It could be another powerful enchantress who is jealous of Bella's powers and wants to steal them for herself. She might constantly try to set traps for Bella and undermine her at every turn.
Maybe there's an evil sorcerer or wizard who sees Bella's weakness as an opportunity. He or she might want to use Bella's weakness to gain something, like access to a powerful artifact that only Bella can reach because of her limitations. The sorcerer would be constantly trying to manipulate her into doing his bidding.