One possible plot could be that Thomas Wayne somehow time - travels to the present where Bruce Wayne is Batman. Thomas could initially be shocked at how Bruce has turned out, but then come to understand his motives. He might offer some old - fashioned wisdom that helps Bruce in his fight against crime.
One possibility is that Thomas Wayne Batman comes from an alternate timeline. He meets Bruce Wayne in the current timeline and shows him a different way of approaching crime - fighting. Maybe he has more brutal methods, which causes Bruce to question his own more restrained approach. They could then learn from each other and create a new, more effective Batman strategy for Bruce's Gotham.
Obviously, Bruce Wayne (Batman) is a key character. Then there are the members of the Justice League like Superman, Wonder Woman, Flash etc. They all play important roles as they interact with Bruce Wayne.
Well, in this fanfiction, there could be an epic showdown against a common enemy. The Justice League might initially be skeptical of Bruce Wayne's methods, but then they come to respect his strategic mind.
Joker is chaotic and unpredictable. He thrives on disorder and finds joy in causing mayhem. Bruce Wayne, on the other hand, is all about order and justice. He's constantly trying to keep Gotham in line. So when they meet, Joker's wild and unhinged behavior directly clashes with Bruce's calm and calculated nature. Joker might do something completely random just to see Bruce's reaction, while Bruce is trying to analyze Joker's motives to stop him.
Perhaps they start off as rivals at first. Bruce might be a bit suspicious of Barry's powers and his more light - hearted approach. But as they get to know each other better, they realize they can learn a great deal from one another. Barry could teach Bruce to loosen up a bit, while Bruce could show Barry how to be more strategic in his superhero work.
One possible plot could be that Joker, in his twisted way, tries to make Bruce Wayne see the 'fun' in chaos. He might set up elaborate pranks around Gotham that target Wayne Enterprises, forcing Bruce to confront him not as Batman but as Bruce. Another plot could involve Joker finding out Bruce's identity in a unique way and using that knowledge to toy with him psychologically, perhaps by threatening the people Bruce cares about in his civilian life.
Well, they might start by comparing their high - tech gadgets. Tony would show off his Iron Man suit with all its amazing features, while Bruce would talk about the tech in his Batmobile and other gear. Then, they could end up working together on a project to fight a common enemy, combining Stark's genius in energy and robotics with Wayne's skills in detective work and combat strategy.
In such a fanfiction, they might start by sizing each other up. Bruce would be intrigued by Tony's high - tech gadgets and playboy lifestyle, while Tony would be curious about Bruce's dual identity and his more brooding nature. They could end up collaborating on a project, perhaps something to do with improving Gotham's infrastructure using Stark technology.
One possible storyline is a competition between them. They could bet on who can solve a particular global threat faster. Bruce would use his detective skills and resources in Gotham, while Tony would rely on his Stark tech. Another could be that they get framed for a crime together and have to work together to clear their names while also finding the real culprit.