There could also be some original characters in the joker and harley baby fanfiction. These could be other henchmen or women working for the Joker, or neighbors in the area where they live with the baby. They might add more depth to the story, for example, by showing how the Joker and Harley interact with the normal people around them, or how these original characters react to the presence of the baby in the middle of all the chaos.
In addition to the Joker, Harley, and their baby, there could also be other characters from the DC universe making appearances. For instance, Batman might show up as he is always on the lookout for the Joker's misdeeds. He could be a threat to the family unit in the fanfiction, or perhaps an unexpected ally in some situations. Also, other villains like Poison Ivy, who is Harley's friend, could play a role. Maybe she helps Harley take care of the baby or gives advice on how to deal with the Joker's wild behavior.
The main characters are obviously The Joker and Harley Quinn. The Joker is the infamous criminal mastermind in Gotham City, known for his chaos and unpredictability. Harley Quinn was once a psychiatrist named Dr. Harleen Quinzel who became infatuated with The Joker during her work at Arkham Asylum and then transformed into his partner in crime.
The relationship might become more complex. Harley would likely be more protective and demand more stability from the Joker for the sake of the baby.
The main characters are, of course, the Joker and Harley Quinn. The Joker is a chaotic and unpredictable criminal, known for his maniacal laughter and disregard for human life. Harley Quinn was originally a psychiatrist named Harleen Quinzel who fell in love with the Joker during her attempts to treat him, and then she became his partner in crime.
Well, the fanfiction could start with Harley Quinn finding out she's pregnant. The Joker is shocked at first but then decides to keep the baby as part of his 'grand plan'. As the baby grows, they have to deal with raising it in their chaotic world. Harley tries to give the baby a normal life as much as possible, while the Joker is constantly getting into trouble that puts the family in danger. It could also explore how the baby affects their relationship, whether it brings them closer or drives them further apart.
One interesting plot could be the Joker and Harley trying to raise their baby in a world that is constantly against them. Maybe they have to protect the baby from other villains who want to use it for their own gains.
Batman would definitely be a main character. He's the Joker's arch - nemesis, and when the Joker becomes a baby, Batman might be the one who first discovers him. He'd be in a moral dilemma about what to do with this baby version of his greatest enemy.
One idea could be that the baby has the Joker's chaotic nature but Harley's charm. For example, the baby might play pranks on the henchmen in a really cute yet mischievous way. Another could be that the baby has some special powers, like being able to make people laugh uncontrollably just like the Joker, but also has Harley's acrobatic skills at a very young age. Maybe the baby could be the key to a new, more 'family - oriented' life for the Joker and Harley, leading them to try and reform for the sake of their child.
The relationship can be portrayed as a journey. At first, the Joker and Harley might not know how to be parents. They could be clumsy and make mistakes. But as the baby grows, they start to adapt. The Joker might start to soften a bit, realizing that his actions could affect the baby's future. Harley would be the glue that holds the family together. She could be the one who arranges family dinners, even if it's just pizza in their hideout. The baby could also bring out a competitive side in them, like who can teach the baby the coolest trick or skill.
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.
The Riddler could also be a good character. His riddles and puzzles could be a part of the plot where the Joker and Harley Quinn are either trying to solve them or are being set up by the Riddler for some devious plan. And his intelligence can create interesting power dynamics with the Joker.