In this fanfiction, perhaps Naruto's transformation into a 'Joker - like' character could be a result of some extreme event. Maybe he experiences a great loss or betrayal that makes him question his values. Similar to how the Joker's backstory in the Batman universe shaped his character, Naruto could start to view the ninja world in a different, more cynical light and thus adopt the Joker's traits.
Another aspect could be his relationship with other characters. If Naruto is the Joker, his interactions with Sasuke could be really interesting. Sasuke, who is often serious and brooding, might be constantly frustrated by Naruto's new - found chaos. Naruto could play mind games with Sasuke, which would be a complete shift from their usual dynamic of rivalry and friendship.
One idea could be that Naruto somehow gets trapped in a strange dimension where the rules are set by the Joker, and Ino has to use her mind - reading abilities to figure out how to rescue him. Another could be a scenario where the Joker is after some powerful ninja art in the Naruto universe and Ino and Naruto team up to stop him. Maybe there could also be a story where Naruto's positive attitude starts to influence the Joker in a strange way while Ino is caught in the middle, trying to keep Naruto safe and also deal with the unpredictable Joker.
A Joker and Harley Quinn crossover with the Suicide Squad but in a different way. Instead of being part of the Squad, they form their own rebel group within the Squad and cause chaos in a more strategic and comical way. They could play mind games with the other members and the villains they are supposed to fight.
A third idea is that the OC is a mental health professional who gets the chance to treat the Joker in Arkham Asylum. Through their sessions, they learn about his past traumas and how they've shaped him into the monster he is. But the OC also has to be careful not to be manipulated by the Joker, which creates a tense and psychological story.
One interesting 'Joker Naruto' fanfiction could be where the Joker's chaotic nature disrupts the ninja world of Naruto. For example, he might play mind games with the Akatsuki members, causing internal strife. Another could involve Naruto trying to understand and rehabilitate the Joker using his own beliefs in friendship and redemption. There could also be a story where the Joker somehow gets ninjutsu powers and uses them in the most unexpected and dangerous ways in the Hidden Leaf Village.
Some fanfictions might focus on the psychological aspects of their relationship. The Joker's insanity and Batman's unwavering sense of justice create a really unique dynamic. In slash fanfiction, this could be explored in terms of how they understand each other on a deeper level, perhaps a level that no one else can fathom.
For a joker and harley lemon fanfiction, you could write a story where they get lost in a magical forest. In this forest, they have to face their inner demons together. Harley could use her charm and wits to help Joker deal with his insecurities, and in the process, their relationship deepens. You could also explore a scenario where Joker is injured and Harley has to take care of him. This would show a different side of their relationship, a more tender side. Additionally, a story about them stealing a precious artifact from a powerful villain and how they celebrate their victory with some passionate moments could be interesting.
One idea could be exploring a world where Batman and Joker have to team up against a greater evil. Maybe a powerful alien force arrives in Gotham and they realize they need to combine their skills, even if reluctantly.
One idea could be that the Joker, in his twisted way, tries to 'convert' Robin to his side. He could play mind games with Robin, showing him the so - called 'dark truths' of Gotham. Another could be a scenario where Robin is captured by the Joker, and Batman has to race against time to save him while Robin is forced to endure the Joker's demented antics.
One idea could be that Harley tries to hide her pregnancy from Joker at first because she's not sure how he'll react. Another could be that they go on a wild adventure while Harley is pregnant, facing various villains who either try to use her condition against them or are unexpectedly helpful. Or perhaps there's a plot where Harley has to deal with her own insecurities about becoming a mother while still being in a relationship with the unpredictable Joker.
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.