Lex Luthor could be an interesting antagonist in this scenario. He could be using his intelligence and resources to create a weapon that could neutralize both Batman and Wonder Woman. He might be working with some of Batman's rogues gallery or even some of Wonder Woman's enemies. His presence would add a different dynamic as he's a human villain but with extraordinary cunning and resources.
Lex Luthor could be a great antagonist. He could be jealous of the new alliance between Wonder Woman and Batman and see them as a threat to his own plans for world domination. He might use his intellect and resources to try and turn the public against them or create some high - tech weapons to take them on.
The Cheetah could be a good choice too. She could be working with some high - tech criminals to steal some powerful artifacts. Her speed and ferocity combined with the new allies she has made could put Batman and Wonder Woman in a tough spot as they try to stop her from achieving her evil goals.
Lex Luthor would be a great antagonist. He could play on the differences between Batman and Superman, trying to turn them against each other while he pursues his own evil plans. Maybe he creates a situation where it seems like Superman is a threat to Gotham, causing Batman to be on high alert.
The Joker could also be a main antagonist in this fanfic. He could be interested in causing chaos not only in Gotham but also in the world of Wonder Woman. His unpredictable nature and love for mayhem would make him a formidable foe for the two heroes. He might come up with a plan that plays on their differences and tries to drive a wedge between them while also causing destruction.
At first, it might be a bit rocky. Batman is used to working alone and being in control, and Wonder Woman is a powerful and independent hero. But as they face challenges together, they would start to respect each other's abilities. They could develop a friendship based on mutual admiration for their different skills.
Cheetah could be a great villain. She has a connection to Wonder Woman already, but in a crossover, she could be working with some of Batman's rogues like the Penguin. The Penguin could provide the resources while Cheetah does the dirty work in combat against Batman and Wonder Woman.
It could be an evil ninja from Naruto's world who has somehow gained the powers of a DC super - villain. For instance, Orochimaru could merge with Lex Luthor's intelligence and resources. He would be a formidable foe as he combines Orochimaru's snake - like abilities and knowledge of jutsu with Luthor's strategic mind.
Lex Luthor would be a great villain. He could be plotting to destroy Superman once and for all while also trying to outsmart Batman. His intelligence and resources make him a formidable foe for both heroes.
It could also be a matter of miscommunication. In some fanfics, Batman and Wonder Woman may not communicate well. Batman is often a man of few words and his actions can be misinterpreted. He might be so engrossed in his own investigations that he doesn't take the time to listen to Wonder Woman, giving the impression that he's ignoring her. This can add an interesting layer of conflict to the fanfic story.
It's really hard to say. Batman has his incredible intellect, gadgets, and martial arts skills. But Wonder Woman has superhuman strength, speed, and her lasso of truth. If it's a fight in a small, enclosed space where Batman can use his gadgets to his advantage, he might have a chance. But in an open area where Wonder Woman can fully utilize her powers, she would likely be the victor.