One possible storyline could be Damian Wayne taking on the role of Batman in the Batman Beyond future. He might struggle with the high - tech gadgets and a more dystopian Gotham. Another could be Damian having to face off against an old enemy of Bruce Wayne's that has re - emerged in this new era. Maybe he has to deal with a new breed of super - villains created by the advanced technology of the future.
A great storyline in a Batman Beyond Damian Wayne fanfiction could involve Damian trying to uphold the Wayne legacy in a world where the original Batman is a legend of the past. He could have to team up with Terry McGinnis' old allies while also bringing in his own skills and training from the League of Assassins. He might also have to deal with the public's perception of him as a more violent and unpredictable Batman compared to Terry.
Damian would likely become more cynical in the Batman Beyond setting. The darker, more technologically advanced yet decaying Gotham would harden his already tough personality. He'd probably be less trusting, especially with all the new threats that come with advanced technology.
One possible storyline could be exploring the immediate aftermath of Bruce's death. How does Terry McGinnis handle the loss? Another could be flashbacks to Bruce's final days, showing his last words of wisdom to Terry.
Perhaps a story where Damian gets kidnapped by an old enemy of Batman. Batman then has to race against time to save him, all the while reflecting on their complex father - son relationship. This could involve flashbacks to how Damian came into Batman's life and how they've grown together.
Grief is a very common theme. All the characters who were close to Damian, like Batman, Robin (if there's a new one), and the rest of the Bat - family, have to deal with the intense pain of losing him. Another theme is revenge. Batman might be driven to seek revenge against those he believes are responsible for Damian's death.
One interesting storyline could be Damian training his pet to be a crime - fighting sidekick. His pet, let's say a dog, could have special abilities or be highly intelligent, and Damian would use his skills to train it for detective work and combat situations.
One great story is one where it focuses on Batman's internal struggle after Damian's death. It shows how he blames himself and withdraws from the world for a while. Another story might be about how the other members of the Bat - family cope with the loss. They might have different ways of dealing with grief, like Dick Grayson trying to step up more as a leader to fill the void left by Damian.
The Joker is always a classic choice. His chaotic and unpredictable nature would create a great contrast to Damian's more disciplined upbringing. It could also put a strain on the relationship between Batman and Damian as they deal with the Joker's madness in different ways.
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.
There might also be a storyline where an old enemy discovers Batman's harem and tries to use them against him. So Batman has to not only protect Gotham but also safeguard the people he cares about in his harem. This would add an extra layer of drama and tension to the fanfiction.