Another interesting approach is to make an OC that is a sidekick to Batman. Maybe a young orphan with extraordinary detective skills. The fanfiction could explore how this character trains under Batman and how they grow to become an important part of his team. For example, they could help Batman solve a mystery that even he was having trouble with, by seeing things from a different perspective.
One idea could be creating an original character (OC) who is a new villain in Gotham. This OC could have a unique power, like the ability to control technology. They would target Batman's high - tech gadgets and try to disrupt his crime - fighting efforts.
You could also create an OC who is a journalist in Gotham. This character is always on the hunt for the big story about Batman. In the fanfiction, they might start out suspecting Batman of being a menace, but as they dig deeper, they discover the truth about his good deeds and end up becoming an ally, using their media influence to help Batman in a more subtle way, like changing public perception of him.
One idea could be a crossover with the Teenage Mutant Ninja Turtles. Batman could team up with the turtles to take on a common enemy like the Shredder and the Joker working together. They could combine their unique fighting styles and gadgets to outwit the villains.
An interesting idea is to write a story where Catwoman discovers a secret about Batman's past that even he doesn't know. This could lead to a strange alliance between them as they both try to figure out what the discovery means. It would also add a new layer to their relationship.
An Hatter OC could be a fashion - obsessed villain who thinks Batman's costume is a crime against style. He creates hats with various gadgets not just to fight Batman but also to 'improve' the fashion sense of Gotham. His hats could have things like glitter bombs to blind opponents while also making a flashy statement.
One interesting crossover idea could be Naruto visiting Gotham City. He'd be shocked by the dark and gritty environment compared to his own village. His ninja skills could help Batman in fighting villains in unexpected ways, like using his shadow clones to create distractions during a heist. Another idea is Batman somehow ending up in the Naruto world and learning about chakra. He could use his detective skills to figure out how to use it in his own unique way.
One interesting concept could be exploring Batman's early days as a vigilante in fanfiction. Writers might show his struggles with learning to fight crime effectively while also dealing with his own inner demons.
One idea could be an OC who is a brilliant detective in Gotham, trying to solve cases alongside Batman but often having a different approach. For example, the OC might focus more on the psychological aspects of the criminals, while Batman is more into the physical evidence. Another idea is an OC who has a special power, like the ability to communicate with animals, which helps Batman in his fight against villains who use animals in their crimes. A third idea could be an OC who is from a different dimension and has a different set of values, creating interesting conflicts and collaborations with Batman as they try to understand each other.
Another interesting plot could be that the OC is from another dimension and gets stranded in Gotham. Batman, being the detective he is, tries to figure out how to send the OC back while also dealing with the chaos the OC's presence causes in the city, as their technology or powers are not from this world.
Another interesting concept is an OC who is a tech genius. He creates new gadgets and technology that even Batman is impressed by. He could be a young prodigy who looks up to Batman and wants to contribute to making Gotham safer through his technological innovations.
One idea could be a fanfiction where Poison Ivy teams up with another villain, like the Joker. They could have a really strange alliance. Maybe she uses her plant powers to help him with one of his crazy schemes, but in the end, she double - crosses him because she realizes his plans are too chaotic even for her. It would be an interesting exploration of her character and how she interacts with other villains in the Batman universe.
One idea could be creating an OC who is a reformed criminal trying to make amends in Gotham during the events of the Arkham series. They could have a unique skill set, like being an expert hacker, and get caught up in Batman's fight against the rogues gallery while also trying to prove their new - found goodness.