Sure was. Batman Beyond was indeed a comic that explored the adventures of a new Batman in a dystopian future. It had unique storylines and art styles that attracted many fans.
Terry McGinnis could face off against a time - traveling Ra's al Ghul. Ra's al Ghul has always been obsessed with immortality and the betterment of the world through his own extreme means. If he had the power of time travel, he could try to reshape history to his liking, which would put him directly at odds with Batman Beyond. Ra's al Ghul's long - term plans and strategic mind would make for a complex and engaging conflict.
Another potential villain could be a corrupt time - keeper or someone who has control over the time travel mechanisms. They might see Terry's interference as a threat and try to stop him by any means necessary. This villain could have the power to manipulate time, creating loops or erasing parts of the timeline to keep Terry from achieving his goals. They might also have their own ulterior motives, like trying to reshape the world in their own image by controlling the past and future.
Brother Eye could be a possible main antagonist. If it were to gain the ability to time - travel, it could try to rewrite history to create a world where it has complete control. It could manipulate events in different eras to eliminate any threats to its dominance, and Batman Beyond would have to stop it from achieving its goal.
In terms of Batman's growth, in the harem fanfiction, his personal relationships force him to reevaluate his loner - hero approach. He starts to rely on the members of his harem for emotional support and different kinds of help. This is a big change from the original where he was more self - reliant and solitary in his crime - fighting journey.
Robin, in all his incarnations, is also a popular character in fanfiction related to Batman. He represents the sidekick aspect and the growth and development that comes with it. In Batman Beyond, Commissioner Barbara Gordon also features prominently in some fanfictions. Her connection to the original Batman era and her role in the new one can be explored in interesting ways.
One interesting concept could be exploring alternate universes where Batman has different powers or allies. For example, a fanfiction might imagine a world where Batman has the ability to control shadows like a metahuman. Another concept could be delving deeper into the relationship between the original Batman and the new Batman in Batman Beyond. It could show how the legacy and lessons are passed down, and how the new Batman copes with the huge shoes he has to fill.
A really cool 'Batman Beyond' fanfiction is 'Future of Gotham'. This one takes a look at the future of Gotham City itself, with Terry as Batman facing threats that could change the city forever. It has a unique take on the technology in the 'Batman Beyond' universe.