A third storyline could be Harley Quinn becoming a vigilante of her own kind. Tired of the chaos and destruction caused by the Joker and other villains, she decides to use her skills and knowledge to fight crime in her own way. She might not be as morally upright as Batman, but she has her own code. She could target criminals who are preying on the weak, and in the process, have run - ins with both the police and the traditional superheroes.
One interesting storyline could be Harley Quinn trying to break free from the Joker's control. In fanfiction, she might start to realize his true nature of using her and decides to rebel. This could lead to a power struggle between them.
One possible storyline could be Harley Quinn adjusting to the idea of motherhood while still dealing with her chaotic life. Maybe she's trying to figure out how to raise a child in a world full of villains and heroes. Another could be her relationship with the father of the baby, whether it's the Joker or someone else, and how that dynamic changes during the pregnancy.
One interesting storyline could be them going on a heist together. They use Poison Ivy's plant powers to create distractions and Harley Quinn's acrobatic skills and unpredictability to get past security. Another could be a story where they rescue each other from the clutches of a common enemy. For example, if the Joker tries to harm Harley, Poison Ivy uses her vines to snatch her away. And they could also have a story where they go on a journey to find a rare plant that has the power to make Harley immune to all toxins, which would be very useful in their dangerous Gotham lives.
Harley Quinn could also be shown as a tragic figure. In the Dark Knight fanfiction, she could be a product of Gotham's corrupt system. Maybe she was failed by the very institutions that were supposed to protect her, which led her to a life of crime. This would add depth to her character and make her more than just a crazy villain.
The Dark Knight's version of the Joker adds an extra layer of darkness to their relationship in fanfiction. Writers might explore how the Joker's chaos affects Harley even more in this darker context. For example, Harley could be torn between her love for the Joker and the realization of the horror he spreads in Gotham.
Well, a really cool storyline might be that in the all - female universe, Harley Quinn discovers a hidden society of female superheroes. At first, they're suspicious of her because of her villainous past, but she convinces them that she wants to change. Together, they fight against a new threat that is trying to destroy both the villain and hero worlds. It could involve Harley using her unique skills and the female superheroes using their powers in a combined effort. And there could be some great character development along the way as Harley tries to fit into this new world of heroes.
Another could be a love triangle of sorts. In the fanfiction, Poison Ivy might be jealous of Harley Quinn's growing friendship with Batman. Harley is caught in the middle, torn between her loyalty to Ivy and her newfound respect for Batman. This creates a lot of tension and interesting character dynamics.
A great plot idea for this fanfiction could be that Harley Quinn is haunted by the memories of her time with the Joker during the Arkham Knight scenario. Batman, noticing her distress, tries to help her. As they interact more, Harley starts to see Batman in a new light and decides to assist him in his fight against the Arkham Knight. Along the way, they face many challenges, like dealing with Harley's old gang who don't trust her new alliance with Batman, and also the Arkham Knight's devious traps. This would make for a complex and engaging fanfiction story.
Obviously, the Joker and Harley Quinn are the most popular. The Joker's chaotic and unpredictable nature makes for great story - telling. He can be the main source of conflict and drama. Harley Quinn, on the other hand, has a complex character. Her love for the Joker despite his abuse, and her own journey of self - discovery are very interesting to explore in fanfiction.
In fanfiction, the Joker and Harley Quinn can have a huge impact on Gotham. Their antics can range from small - scale chaos like random acts of vandalism to large - scale threats like trying to take over key parts of the city. They are often portrayed as a force that the police and Batman constantly struggle to contain.