I would love to know some backstories of the Rogues in your Batman AU
this is a very broad question considering how many rogues i have in my au, so i'll start out by linking some of them which i have elaborated on before to various degrees, and if you have further questions about them feel free to ask specifically:
SCARECROW - SCARECROW - MORE SCARECROW (his backstory is kind of convoluted and scattered around. i get a lot of asks about him)
BLACK MASK (somewhat outdated - i intend to update it at some point)
and here's the cliff notes on some obvious players not mentioned above - again, if you want more specific elaboration, or anyone else i forgot, feel free to ask:
THE JOKER: i guess this is a bit of a spoiler if you like ambiguity, but i've said it on this blog many times already so there's really no point in being coy about it - the joker in my au is an extra-dimensional eldritch creature who, quite literally, eats chaos to survive. it possesses the body of an ACE chemicals employee named Jay Doe after it influences them into jumping into a vat of acid where "the veil between worlds is thinner in that unstable substance" (per writing of mine). the joker is obsessed with the balance between comedy and horror that generates the "food" it needs to survive in our dimension. very few people in-universe are aware of the joker's origin or the true extent of its abilities. it is a genuinely unlikable creature bur very lonely at its core, as it is the only one of its kind on earth and cannot easily exit back to its old dimension. Jay Doe's soul is still around, though kept separate from the body via storage in the joker's personal pocket dimension, the "funhouse" (mainly used for storage to enable looney-tunes esque physical gags, but can be put to much more sinister use. this funhouse is also where the joker puts jason todd.)
HARLEY QUINN: Harleen Quinzel was a fairly average woman who made a comfortable salary at her job working as a psychiatrist at Arkham State Hospital. She was also deeply miserable. The constraints of the cookie-cutter life and career path she was forced into by the expectations of her controlling mother and other adults around her instilled a pervasive repressed need to escape from her own life and "do something wrong". She encountered the joker during one of his on-and-off stints in captivity at Arkham and immediately - and unwillingly - became infatuated with the sense of unique nonconformity he seemed to embody. The following affair between them was less about the joker's manipulation and more about harley grasping for power in the only way she knew how (through the joker did inarguably have his own part in it, because he liked harley and saw her as a potential cure for his lonliness). Eventually it culminated in her own descent into the same acid vat that had "transformed" Jay Doe, but rather than possession, harley emerged with a... heightened sense of clarity about herself and the world around her. The acid also had some malignant effects on her, gradually causing her skin to rot and fall off her body. She compensated by sewing herself back together with colorful patches of fabric. I wrote a rather long fanfic about harley and the joker's relationship (and following breakup) for 2023's nanowrimo, which sadly has not been released yet because i am still editing it. hopefully one day soon it will reach the public.
THE RIDDLER: The riddler's conception is a little fuzzier than other backstories I have, because I'm still working on it, but the main gist of it is that Edward Nygma (born E-------- Nashton) spent many years essentially singlehandedly raising his younger brother, William Nashton. They lived alone with their father (their mother having left the picture years earlier) who was a chronic deadbeat, physically abusive, an alcoholic for good measure, and altogether put very little effort into raising his own children. Edward was a very strange child from the get-go and over time and circumstance his asynchronicities developed into a compulsive need for control and structure. He turned to his most genuine talent - puzzle-solving - and put it to work where it seemed most logical: computers. Edward became a very dedicated and effective hacker, largely by his methods of viewing code as a literal cipher or riddle that he had to untangle to "win". He gained a genuine reputation for the obscure and highly guarded databases he was able to gain access to, which generally served to inflate his ego. Meanwhile, two things: one, the more stress he was put under, the more his obsessive worldview began to take over other parts of his life, especially interpersonal ones - especially his interactions with his father and other antagonistic figures in his life. he became convinced that if he could "solve" the "pattern" of their behaviors, he could escape their abuse or in a sense control them. Two, these insecurities expanded to target his deeply protective instincts over his little brother, who around the time Ed was, say, sixteen or so, in a completely random accident, got hit by a car while crossing the street with Edward (who was spared) and later died from his injuries. Edward's father blamed him for this event, despite Ed having no possible control over the situation. The trauma of his brother's sudden death caused Edward's psychological state to degrade quickly and devastatingly. He began to devote his "puzzle-solving skills" largely to esoteric coping mechanisms, and expressed that if he could "find the pattern in the world around [him]" he could prevent an accident "like that" from happening again, to anyone, ever. His obsessions later expanded to focus upon the Batman, who at the time was less of a public figure and more of a local ghost story - the ultimate mystery for Edward to solve, and prove everyone else wrong, and finally win.
CATWOMAN: Selina Kyle's backstory is fairly straightforward compared to the above tales and hasn't been tampered with very much since its original conception. She grew up very poor and in an unhappy household; as a child she spent a lot of time with her kid neighbor Effy Lynns (later Firefly), who was also in a bad familial situation, and they began to view each other as siblings. As adults they moved into an apartment together. Selina was never very well off, but scraped by working odd jobs over the years, most notably a job at the local animal shelter, which she was genuinely happy at - unusual luck for her. She liked it so much, in fact, that she was trying to save money up to finally finish her degree, so that she could start to pursue a career as a veterinarian. During this time she also lived in an apartment above a chain pharmacy. Her "criminal" career was kicked off when her she learned that her downstairs neighbor, an elderly woman who she was fairly close with, had been denied by insurance to receive insulin due to a gap in coverage and, as she couldn't afford a trip to the emergency room, was in danger of dying. As she lived right above a pharmacy, Selina saw the workers going in and out every day and knew what the code to the back door was. She also knew which breaker would turn the power to the security cameras off. Well, her neighbor was too grateful to really care about where she got the medication from, and Selina asked for nothing in return, except to call if she needed help again. Was it against the law? Sure. Was it a crime? No. Selina never faced any consequences for her actions that day, and was instilled with a (perhaps unearned) sense of confidence - she had learned how easy it was to steal. Her ambitions expanded somewhat worrying quickly, though she resolutely stuck to ethical targets - chain stores, corporations, and eventually the homes of the ultra-wealthy. If asked, selina would say - truthfully so - that it was a genuinely good-hearted attempt at redistribution of wealth. What she was less willing to admit was that there was a significant element of adrenaline-seeking and even kleptomania to it that she wasn't ready to confront in herself. She was doing all the right things for all the wrong reasons. The only harm, she supposed, was to herself.
FIREFLY: Like I mentioned in the previous entry, Firefly is the eventual vigilante identity* of Effy Lynns, Selina's adopted sibling. Effy worked for many years in an oil refinery to make ends meet. It was hard, grueling work and the floor workers were treated badly in many respects. One day they were involved in a factory explosion that left them with third degree burns on the right side of their face, neck, shoulder and chest, along with blinding them in that eye and reducing the hearing of that ear. It was later made known to them that the accident was only allowed to occur because of the gross negligence and poor working conditions of their wealthy supervisors. They were also let go by the factory due to not being able to work any more, putting them in financial strife. Understandably, this series of events was a snapping point for Effy, and, inspired by Selina's nighttime activites, they adopted a fire-themed vigilante persona to enact public revenge against the corporate conglomerates that were ruining theirs and other people's lives. Effy's backstory is fairly vague and subject to change, since it's more recent than the others and therefore less developed. I haven't decided if their suit is their own invention or if they collaborate with some other source to design it.
*"Firefly" is actually just their full first name. Friends and family call them Effy more often. They start to embrace use of their full name when things go off the rails, though it only becomes known to the public after their (hypothetical) eventual apprehension.
MR & MRS FREEZE: Victor Fries and Nora Selvam met at a scientific convention in England in their twenties. Both of them had immigrated with their families in their teens, Victor from Russia and Nora from South India. They clicked immediately and were married a year later. Their story together doesn't deviate very far from typical batman canon, with the notable exception that in my version of the story, Victor is the one with an incurable terminal illness. Per usual Victor and Nora work together to attempt to push forward the research on Victor's illness, moving to Gotham somewhere in the process. Over time they both get more desperate, facing their own respective demons: Victor becomes desolate and even suicidal, hopeless as to his own future; Nora becomes erratic and fixated, determined to prove her husband wrong and save him. She takes unreasonable risks for the sake of the research and Victor does nothing to stop her. Victor poses the idea of putting himself in cryostasis until a cure can be invented, not really believing in the idea, mostly just wanting to die in the ice. Nora, though, latches onto the idea and begins working on designs for a stasis machine. She overworks herself to the point where she can no longer recognize dangerous flaws in its internal structure. When the machine is "complete" she has Victor come to the lab and offers to demonstrate the effects of the pod on a butterfly for him. He accepts, curious, and she does, but upon the subsequent unfreezing of the butterfly, it lies cold and unmoving. Frightened and demotivated, they get into a heated, emotional argument, which distracts them fatally from the stabilization alarms sounding on the cryostasis machine. The world turns white. When Victor returns to consciousness his skin is blue and bruised, like a frostbitten corpse, and every breath feels like ice stabbing through his lungs. The lab is encased in an explosion of unmeltable ice, kept supernaturally cooled by the malfunctioning power core of the machine. The lab becomes the only place that Victor can survive in without a cooling suit. The ice in the room is so thick and deep that he can't even see Nora's body inside. But she's in there, somewhere. She has to be. Right...? (Somewhere overhead a butterfly flaps by the skylight.)
TWOFACE: this is another story that is subject to change in the future, because i haven't decided on the exact details, but, Harvey Dent grew up with a physically and emotionally abusive father and an absent mother, as per much of his usual canon. He met Bruce Wayne when they were children and despite going to different schools, coming from different family backgrounds and living very different lifestyles, they made fast and inseparable friends with each other and were joined at the hip for much of their teenage years, even going to college together later in life. As his childhood progressed Harvey became increasingly and uncomfortably aware of "another him" in his head* - an alter, though he had no idea what that was at the time - who called itself Alastor**. Alastor served as Harvey's protector, facing their father's physical abuse instead of Harvey. Harvey was deeply ashamed and resistant to the idea of self-perceived mental illness and did everything he could to feign "normality", i.e. pretend that Alastor didn't exist, or at least that they were the same person. Bruce, being so close to him, had something of an idea that there was something going on with Harvey that he didn't know about - but Harvey was extremely resistant to the idea when Bruce attempted to bring it up, so he left it alone for a long time. Alastor did not have this hesitancy, Thus Bruce and Alastor met and knew each other to some degree without Harvey's knowledge. Despite his generally antagonistic views of almost everyone outside of the system, Alastor developed a begrudging "tolerance" (fondness) for Bruce as Bruce would treat him well in a general sense, having no reason to resent him, especially in their youth. Harvey's adult life also generally follows typical canon: he went to college with Bruce (and a young Thomas Elliot) where they remained close until Bruce suddenly dropped out and effectively fell off the earth, leaving Harvey to complete his studies and attend law school alone. Harvey nor Alastor ever really forgave Bruce for his disappearance and even when he reappeared in Gotham several years later, there was an awkward wedge between them. In his law career Harvey saw significant success, graduating from public defense to assistant DA to District Attorney at an admirable speed. His willingness to call out and prosecute the corruption in the city led to targets being put on his back, but he wasn't deterred and eventually started a campaign for mayor, promising to help make the city into something better. His campaign - though controversial - was ultimately successful. Unfortunately, the attention he attracted by his political outreach included that of a career criminal called the Joker. The Joker, being purely an agent of chaos, did not care about Gotham's politics by any means, except where they were funny to him - and watching Harvey Dent grapple his own brain for control was very funny indeed. Having been entranced by Harvey for several months, the Joker decided he was going to make a laughing-stock of him, on the day of his mayoral inauguration. The Joker broke into City Hall and, with a generous measure of spectacle, tied Harvey to a chair in front of every news camera he could find and ripped the left side of his face off. The Joker's abilities allowed this to be a largely harmless, albeit very painful, process. Harvey's career as mayor was over before it had begun. He escaped, humiliated and panicking, into the depths of the city, where he was not seen again for several months.
*Harvey probably has several other less distinctive alters, but Alastor is the most significant one and the one Harvey is most capable of recognizing.
**I wanted to give harvey's alter a name that wasn't just an altered version of harvey's own name. "Alastor" was taken from a fanfic i read a long time ago and have since hopelessly lost track of. Per google: "In Greek mythology, Alastor is an epithet of the god Zeus, meaning "avenger" or "defender of men". Alastor was also the name of a spirit or force that punished wrongdoing and upheld fairness. The name also symbolizes memory, as it conveys the importance of not forgetting wrongs." In canon, I imagine harvey read about the epithet in a book as a child and was influenced by it. Thus, i suppose Alastor is technically an introject.