Well, it could lead to all sorts of dramatic and unexpected turns. Maybe Commissioner Gordon has a hard time coming to terms with it or uses the knowledge to protect Batman in a new way.
Well, it might happen when Gordon stumbles upon some crucial evidence or has a moment of realization based on his long-term observations of Batman's actions and behavior.
In many 'Batman Beyond' fanfictions where Dana finds out, it could be about her finding out Bruce Wayne is Batman. Maybe she stumbles upon some evidence in the Batcave or notices some similarities in Terry's behavior to Bruce. For example, she might notice Terry's fighting style is similar to what she's heard about Batman's. It could also be that she discovers some secret technology related to Batman that leads her to the truth.
Well, he might be initially confused. Batman is so focused on his mission in Gotham that fanfiction about a character like Slade might seem very strange to him. He could start investigating if he thought it had any connection to real - world threats or if it was somehow influencing public perception in a negative way.
One possible consequence is that Batman's loved ones would be in great danger. His enemies could target them to get revenge on Batman. Also, the public's perception of Batman might change. Some might see him as a hero who has been hiding his true self to protect them, while others could think he has been deceiving them all along.
If Joker finds out Batman's identity in fanfiction, it could lead to a total breakdown of Batman's world. Joker might target Bruce Wayne's loved ones directly. He could expose Batman's identity to the public, causing chaos in Gotham as the people lose their faith in the symbol of Batman. And he would likely use this knowledge to create the most elaborate and cruel traps for Batman, knowing his true self.
One great 'Batman Barbara Gordon Fanfiction' is 'Oracle Rising'. It really delves into Barbara's transformation into Oracle. It shows her strength and intelligence in a way that's both engaging and true to her character.
One more theme is the exploration of her dual identity. As Barbara Gordon, she is a librarian or a normal citizen, but as Batgirl/Oracle, she is a crime - fighter. Fanfictions play with this duality, showing how she balances her two lives. Sometimes she has to keep secrets from her friends and family, and this creates interesting plot twists and character dynamics.
Well, Gordon's reaction could be complex. On one hand, he might feel honored that Batman has chosen to disclose his identity to him. On the other hand, he could also be worried about the implications. Knowing Batman's identity means he has a greater responsibility to protect that secret. He might start to think about how this new knowledge will affect their working relationship and the safety of Gotham. For example, if the wrong people find out that he knows Batman's identity, it could put him and his family in danger.
She could find out some secret plan that Bruce and Terry are working on. This could put her in danger as she now knows something she wasn't supposed to. She may have to be protected by Batman, which would be an interesting turn of events.