Another theme is 'legacy'. It looks at how Thomas Wayne's actions as Batman would affect the future of Gotham and the Wayne family name. His actions could set a different precedent for the Bat - mantle compared to Bruce. Also, it might change how future generations view the Wayne family's role in Gotham.
The dynamic could be complex. Thomas might be both proud and worried seeing Bruce as Batman. Proud that his son is carrying on the legacy, but worried about the dangers. He could be overprotective at first.
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.
Their relationship could develop through a series of adventures. For example, they might have to stop a powerful villain together. In the process, Damian's impulsive nature could clash with Thomas' more methodical approach. However, over time, they realize that they can complement each other. Thomas could help Damian think more strategically, while Damian could inspire Thomas to be more bold and take risks in their fight against evil.
One possible scenario could be a time - travel or alternate universe situation. Thomas Wayne might be shocked to see Damian, his grandson, considering his own early death in the normal Batman timeline. He could initially be skeptical or even a bit hostile, thinking Damian is some sort of threat. But as they start to communicate, Damian could show his skills and determination, and Thomas might start to see the family resemblance not just in looks but in spirit.
One great piece of Thomas Wayne Batman fanfiction is 'The World That Could Have Been'. It explores an alternate universe where Thomas Wayne becomes Batman instead of Bruce. The story delves deep into how his approach to crime - fighting might be different, considering his more mature and established position in Gotham society compared to Bruce when he started. It also shows how his relationships with the other characters, like Alfred and Commissioner Gordon, would be unique.
In certain comic arcs, Thomas Wayne is shown to be the father of the Joker. However, comic universes can vary greatly, and this isn't a universal truth for every Joker-related story.
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.