One possibility could be that Batman, after facing one too many betrayals in Gotham, decides to take a different path. Maybe the constant struggle against crime with little real change in the city makes him cynical. He could start using his skills and resources to control the underworld instead of fighting it. For example, he might start dictating which criminals can operate and where, creating a new order that is still dark but under his command.
He might be motivated by a sense of futility. After years of fighting crime and seeing no real end to it, he could think that the only way to bring about change is to control the criminal underworld himself. So, he becomes a villain to enforce his own version of order.
The Joker could be a great villain. Imagine if the Joker - like character emerged in the My Hero Academia world. Izuku, with his new Batman - inspired skills, would have to use his wits to outsmart this chaotic and unpredictable foe.
His relationship with other villains can change. After saving Batman, he might be shunned by his fellow villains, which could lead to him further exploring his new - found moral side. He could then form an uneasy alliance with Batman to fight against the other villains who now see him as a traitor.
If Naruto loses all his friends in a tragic way, perhaps in a battle against an overwhelming enemy that the village could have prevented. His grief could turn into hatred towards the shinobi system. He may decide that the existing order is what causes all this pain and destruction, and then he starts to work against it, becoming a villain in the eyes of the village.
The Joker is probably one of the most popular. His chaotic and unpredictable nature makes him a great character to explore in fanfiction. Writers can come up with all kinds of crazy scenarios for him. Harley Quinn is also very popular. Her relationship with the Joker and her own journey of self - discovery are often the focus of fanfictions. Another popular one is Bane. His physical strength and strategic mind are interesting to write about, especially in battles against Batman. And then there's Catwoman, who has that alluring and complex personality that draws in readers and writers alike.
One interesting concept could be exploring the backstories of the villains in more depth. For example, in some fanfictions, they might delve into how the Joker became the deranged criminal he is, perhaps giving him a more tragic origin story that makes the reader sympathize with him to a certain extent. Another concept could be alternate universes where the villains team up in unexpected ways. Maybe in one such story, the Penguin and Catwoman form an alliance not just for personal gain but to take on a greater threat in Gotham. Also, there could be fanfictions that focus on the psychological battles between Batman and his villains, like a mind - game where the Riddler challenges Batman in a more complex and cerebral way than in the original comics.
It could be Sam and Tucker. Since Danny has become a villain, his former friends would likely try to stop him. They would be the main antagonists from Danny's point of view now. They would use their knowledge of Danny and their own skills to try and bring him back to the good side.
There were a few novels that traveled across the universe and became villains, including " The Great Villain: Let the Female Lead Save Me in the Finale,"" I Am a Villain in the Movie World,"" I Am a Villain in the Universe,"" I Am a Big Boss in the Universe,"" The Days of Being a Villain in the Universe,"" The Villain Chat Group in the Universe,"" The Counterattack of the Villains in the Universe,"" Crossing the Universe as a Villain,"" The Great Villain in the Universe," and so on. These novels covered different topics and storylines, and readers could choose to read them according to their interests.
If Batman becomes Joker in fanfiction, Gotham would be in chaos. Batman is the symbol of justice and order, while Joker represents chaos and anarchy. Without Batman to protect the city, criminals would run wild. And as the new 'Joker', Batman might use his intelligence and skills in a very different and dangerous way, perhaps creating more harm than good.