In this fanfiction, Bella's vampiric allure might attract the Joker in a different way than he's used to. He could start to see her as a new kind of plaything. Bella, however, might see the Joker as a way to break free from the monotony of her vampire existence. Their interactions would be filled with tension, as Bella tries to keep her vampire identity a secret while the Joker is constantly probing for more information about her.
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.
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.
One possible plot could be that Bella discovers she has slayer powers. She then starts training in secret while still being involved with the Cullens. As she gets stronger, she uncovers a new vampire threat that is not like the normal vampires in the 'Twilight' world. This new threat is more powerful and she has to use her slayer skills to defeat them and protect both the humans and the vampires she cares about.
One common theme is the clash of two different worlds. Bella often represents a more innocent or 'normal' world while the Joker is all about chaos and anarchy. Another theme is the idea of transformation. Bella might be changed by her encounter with the Joker, or vice versa.
In this fanfiction, perhaps Bella became a vampire through a different means than in the original story. As a vampire before meeting the Volturi, she might have developed her own unique set of skills. For example, she could have a special ability to blend in with humans better than other vampires. When she meets the Volturi, they are intrigued by her and want to either recruit her or eliminate her because she doesn't fit into their normal understanding of vampire creation.
One possible plot could be that Bella, as a 2000 - year - old vampire, has amassed a great deal of power and knowledge. She could be a sort of mentor to the younger vampires in the Twilight universe. Maybe she has secrets about the origin of vampires that she has kept hidden for centuries. And she might be trying to prevent a war between different vampire clans by using her influence and wisdom.
One possible plot could be that Bella discovers her great grandfather's vampire nature through old family diaries or stories passed down. This knowledge could then put her in danger as there might be other vampires or vampire hunters who don't want the secret out.
Maybe Bella turns out to have a connection to an ancient vampire lineage that has a feud with the Cullens. This would create a lot of tension and conflict as she tries to navigate her feelings for the Cullens while dealing with this newfound connection.
One possible plot could be that the Joker somehow finds his way into the wizarding world. He starts causing chaos in Hogwarts, and Harry Potter has to figure out a way to stop him without using the Killing Curse. Maybe the Joker uses his mind - games on the students and teachers, creating a lot of confusion and mistrust within the school.
Well, it could be that the Joker discovers Harry's power over death and wants to use it for his own evil schemes. Harry has to fight against the Joker's manipulations while also trying to figure out how to get back to his own world. The story might involve a lot of mind games between the two, with Harry using his magical skills to outwit the Joker at every turn.