One common theme is the exploration of madness. Since the Joker is known for his insanity, OC characters often get caught up in his world of chaos and have to deal with their own sanity being tested.
One common theme is chaos. The Joker is all about chaos, and when you introduce an original character (oc), it often shows how the oc either thrives in or tries to combat that chaos. For example, in many fics, the oc might be trying to bring some order to the Joker's madness.
One common theme is the power struggle. The Joker is a powerful and chaotic character, and the OC often has to find a way to either match his power or outwit him. For example, in many stories, the OC might have a unique ability that gives them an edge in this struggle.
One common theme could be the power dynamic between the Joker and the OC. Since the Joker is such a complex and powerful character, exploring how an OC interacts with him in terms of power can be interesting.
One common theme could be the struggle of the OC (original character) with the unexpected pregnancy in the chaotic world associated with the Joker. Another might be how the relationship with the Joker (if there is one) changes due to the pregnancy.
Another theme is the battle between good and evil, especially within the OC themselves. They might start out with good intentions but be slowly corrupted by the Joker's influence. This internal struggle is often explored in great detail in these fanfictions, showing how the Joker's presence can be a catalyst for change, even if it's a change towards the darker side of human nature.
One common theme is the corruption of innocence. The male oc often starts out with some sense of normalcy or goodness, and the Joker gradually chips away at that. Another theme is the exploration of chaos and order. The Joker represents chaos, and the male oc may be trying to bring some order or may be completely swept up in the chaos. Power dynamics is also a theme, with the Joker usually being in a position of power over the male oc, at least initially.
The theme of unpredictability is quite common too. The Joker is famously unpredictable, and when you add a criminal OC into the mix, it amps up the element of surprise. Readers never really know what they are going to do next. Whether it's a sudden change in alliance or a new scheme they come up with, this keeps the readers on the edge of their seats. It also allows for a lot of creativity in the writing as the authors can take the story in unexpected directions.
Well, a frequent theme is the struggle for power. The Joker is a power - hungry character. In these fanfictions, the OC might be trying to gain power within the criminal underworld that the Joker and Harley operate in. Also, the theme of redemption can sometimes be there. Maybe the OC tries to redeem Harley from her life with the Joker. There are also themes of loyalty and betrayal as the characters' relationships shift and change.
A theme that is often explored is the relationship with other characters, especially Batman. How she taunts him, tries to outwit him, and their cat - and - mouse game is a big part of many 'female joker fanfictions'. It adds an interesting dynamic as the female joker may bring a different kind of challenge to Batman compared to her male counterpart.
One common theme is the eternal struggle between good and evil. Batman represents justice and order, while the Joker is chaos incarnate. Another theme is the psychological battle. They constantly try to outwit and out - psych each other. For example, in many fanfictions, the Joker tries to break Batman's will by targeting his loved ones.