Batman is extremely common. Since the Joker and Batman have such a long - established relationship in the original comics, it's natural to see them cross over in fanfics. Their eternal battle of wits and the Joker's attempts to outwit Batman in new and different universes make for great reading.
Another concept is the Joker's influence on the story's tone. In a crossover with a more light - hearted or comical universe, the Joker could still bring his dark and menacing presence, which would create a really interesting contrast. His actions and words could disrupt the normalcy of that universe and force the other characters to deal with a level of chaos they're not used to.
Ruby would likely be very confused at first. She's used to fighting Grimm and more straightforward villains. The Joker's erratic behavior and mind - games would be a new and challenging thing for her. She'd probably try to understand his motives and find a way to stop him from causing more harm. Weiss would be distrustful right away. She's from a high - society family and the Joker's unruly nature would be completely opposite to what she's used to. She might see him as a threat not just to the world, but also to the order she values.
Yes, it could be a very interesting creative crossover. Naruto and Hinata are from the Naruto universe, and the Joker is from the DC Comics world. In a fanfiction, you could have the Joker somehow end up in the Naruto world. Maybe he tries to cause chaos in Konoha, and Naruto and Hinata have to work together to stop him. It would be a unique combination of different story elements.
Perhaps the Joker discovers a way to mind - control some of the Avengers. He targets Hulk first, making him go on a rampage in a major city. The other Avengers are caught off - guard. They soon realize it's the Joker's doing. Spider - Man, who has recently joined the Avengers, swings in to help. He uses his agility to dodge the Hulk's attacks and tries to figure out a way to break the mind - control. Doctor Strange is called in to use his magic to counter the Joker's mind - games, and the team must fight both the controlled Avengers and the Joker's minions to save the day.
A great storyline might involve a fusion of the two worlds' mechanics. For example, the Velvet Room from Persona could have some connection to Joker's world. The Igor-like figure could offer Joker and his friends some new kind of power or knowledge that they use to combat a common foe. Or perhaps the Persona characters learn about Joker's Metaverse Navigator and try to replicate it in their world, which leads to all sorts of unforeseen consequences and adventures.
Some characters might not get along so well. For instance, a more serious Persona character might find Joker's carefree attitude a bit off - putting. However, as they face challenges together, they would start to understand and respect each other. The Persona characters could introduce Joker and his friends to the concept of the Collective Unconscious in more detail, and the Phantom Thieves could show them how to use their skills in a more urban, modern - day setting. There would be a lot of banter and friendly competition between the two groups as they learn from each other.
There might be. Fanfic writers are very creative and like to make unexpected crossovers. If Naruto is the Joker fan in a fanfic, it could be a really strange and exciting concept. The Joker's dark and anarchic personality is very different from Naruto's usual positive and determined self. This contrast could create a lot of tension and interesting character development in the story.
One interesting plot idea could be that the Joker somehow gets transported to the RWBY universe. He might start causing chaos in Vale, tricking the villains and heroes alike. For example, he could convince Roman Torchwick to do his bidding in a more extreme way, which would then draw the attention of Team RWBY. Another idea is that he teams up with Cinder Fall, but his chaotic nature eventually causes their alliance to crumble as he doesn't follow her grand plans in the way she expects.
The Female Joker's character can be developed by exploring her backstory. Maybe she had a difficult childhood, like being bullied or growing up in poverty. This could have led to her developing a warped sense of humor and a desire to create chaos as a way to cope.