There's also a possibility that some of the more morally grey characters in Gotham, like Catwoman, could be Bella's allies. Catwoman has her own code of ethics, and she might relate to Bella's struggle between good and evil. They could work together in certain situations, especially if there are mutual benefits involved.
The werewolf pack that Jacob belongs to would be obvious allies. They have a loyalty to Jacob and would fight alongside him against the newborn vampires. Also, some of the Cullen family members could be potential allies as they have a connection to Bella and would want to protect her.
There could be Klaus. Since he is Rebekah's brother, he would likely be part of Bella's life in some way. He might be a protective uncle or a source of conflict if he has different ideas about how Bella should be raised. Another character could be Elijah. He might act as a mentor to Bella, teaching her about their family's history and values.
Caroline could be in the story. She might be Bella's friend or a rival. If she's a friend, she could help Bella navigate the supernatural world. If a rival, it could be because of her relationship with Damon or Stefan in some way. Also, Klaus could be a character. He might see Bella as a means to get to Damon, or he could be interested in her unique abilities if she has any.
Perhaps some of the other Cullen family members would be her allies. They are already vampires and could help her adjust to her new powers and the vampire lifestyle. For instance, Alice might use her power of seeing the future to guide Bella in making important decisions. Jasper could teach her how to control her new vampire instincts, like the urge to hunt. And Emmett could be her sparring partner to help her improve her combat skills.
A potential main character could be Bella's best friend. This friend could provide support and a different perspective as Bella navigates her new identity. There might also be a mentor figure for Bella, someone who knows a lot about Elijah's world and can guide her. This could be an old friend of Elijah's or a wise elder in their community.
Well, it could be about Bella trying to break free from her father's, the Joker's, evil influence. Maybe she has a good heart in contrast to him and wants to use her skills for good, like helping Gotham in a more positive way.
I'm not sure as I haven't read that specific fanfiction. But generally in a fanfiction, Bella being the daughter of Trigntins would likely mean she has a special role within the story's universe created by the fanfic writer.
Well, one possibility could be that Bella Swan has to deal with the chaos that comes with being the Joker's daughter. Maybe she struggles to balance her normal life, like in Forks, with the dark and unpredictable world of her father. She might have some of the Joker's traits, like a wild sense of humor but also a bit of madness that she has to control.
Edward could be one of her allies. He could use his vampire abilities such as super - speed and strength to assist Bella in dangerous situations. His centuries - old knowledge could also prove invaluable in understanding the motives and actions of the CIA's enemies. Another ally could be Jacob. His shape - shifting abilities would give the team an extra edge in combat or in covert operations. He could also use his connection to the werewolf pack to gather information from areas that the CIA might not have easy access to.
Obviously, Bella and the Joker are the main characters. Bella could be a completely original character created for this fanfiction, or she could be a reimagined version of an existing character from another story. The Joker, of course, is the well - known villain from the Batman universe.