One idea could be that the Joker is trying to protect his baby daughter from his enemies in the criminal underworld. He might use his unpredictable and chaotic methods to keep her safe, while also struggling with his own inner demons as a father.
Perhaps the fanfiction could explore the daughter growing up in a world where her father is the infamous Joker. She could have a conflicted relationship with him, loving him as a father but hating his actions. The story could show how she tries to come to terms with who her father is and find her own identity in the process. It could involve her trying to use her own wits to reform her father or at least distance herself from his criminal ways. For example, she might try to get him to see the harm he causes to innocent people, which would create a lot of internal and external conflicts in the story.
One idea could be the daughter's struggle to come to terms with her father's villainous nature. She might try to break away from the Joker's influence and find her own path in Gotham, perhaps becoming a vigilante of sorts. Another could be a story where she is kidnapped by Batman's enemies to use as leverage against the Joker.
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, it could be about the Joker somehow getting transformed into a baby. Maybe he retains some of his villainous traits even as a baby, causing chaos in a comical way. For example, he might still have that evil laugh and try to play pranks on the other characters in the story.
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 the Joker discovers he has a daughter he never knew about. At first, he might be skeptical or even angry. But as he spends time with her, he starts to feel a strange sense of protectiveness. He tries to keep her away from his criminal life, but his enemies find out about her and then he has to fight to keep her safe.
One idea could be that Harley Quinn and Joker have a baby, and the baby inherits their chaotic and unpredictable nature. Maybe the baby starts causing mayhem in Gotham from a very young age, and the other villains and heroes are all shocked and don't know how to deal with this new situation.
One idea could be that Batman has to protect his baby daughter from his rogues gallery who see her as a way to get to him. For example, the Joker might try to kidnap her in a really twisted plan.
Well, it could be about the Joker's Daughter having her own origin story within the Suicide Squad universe. Maybe she's trying to prove herself to her father while also dealing with the chaos of the Squad.
To develop the Joker's baby daughter, you can focus on her growth. Start from her infancy, showing her innocent and vulnerable side. As she gets older, give her some traits that are a mix of her father's and her own. For example, she has the Joker's ability to think on his feet but uses it for good. She could also have a kind heart, which is constantly at war with the dark influence of her father's reputation. Her appearance could also play a role in her character development. Maybe she has the Joker's signature green hair or some other unique physical feature that makes her stand out and affects how others perceive her and how she perceives herself.
A possible plot could be that Bella has a special talent, like being able to communicate with animals. Eric doesn't believe her at first and thinks she's just making things up. But as she proves it more and more, they both have to deal with the implications of this strange ability, and it brings them closer together as they figure out how to handle it.