"Take a hint, old boy, we may have had our differences, but you and me, we're made for each other." ―The Joker's views on his relationship with Batman[src]

The Joker was a notorious mass murderer, terrorist, and anarchist with white skin, green hair, and red lips with a tendency to wear purple clothing, concealing the true force of chaos underneath his colorful appearance. Appearing seemingly out of nowhere, his true identity and origin were never discovered. With no super-powers beyond his capacity for incredible violence and destruction, the Joker prided himself on being the one criminal in Batman's extensive Rogues' Gallery who shared a unique connection to the Dark Knight, often pushing the hero to his ultimate limits in physical and psychological battles.

As intelligent as he was violent, the Joker formulated countless plans to destroy Gotham City, which led to the brutal deaths of thousands of men, women, and children over the years, to simply feed his lust for anarchy and notoriety, torment Batman and his allies, and satisfy his sadistic sense of humor. Defining his life through his battles with the Dark Knight, whose unbreakable moral code greatly fascinated him, the Joker disturbingly viewed Batman as his greatest enemy and friend to engage in a game of cat and mouse with.

To this end, Joker embarked on an endless quest to corrupt Batman by attempting to entice the hero to take a life, even if it was the villain's own life, and create as much destruction and chaos as possible. Emerging within the criminal underworld on Christmas Eve to begin his reign of terror, the Joker was one of Batman's oldest enemies and often responsible for some of the most horrendous and tragic moments of his life, including the abduction, torture, and murder of Jason Todd, the paralysis of Barbara Gordon, and the death of Talia al Ghul.

With an aptitude to escape imprisonment and even cheat death on numerous occasions, Joker's battles with the Dark Knight waged on for over a decade. Towards the final stages of his battles with Batman, one of Joker's later plans would forever change the course of Gotham and serve as the catalyst for events that would rock the foundations of the city with the rest of the world in the crossfires.

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Biography

Forgotten Past and Mind of Madness

"Have you ever had a really bad day?" ―The Joker to Harleen Quinzel[src]

Allegedly, the man who became the Joker had gotten his start at a comedy club as a stand-up comedian. However, when he attempted to recite a joke, he ended up heckled by the displeased audience. Pushed to his limit, he ended up attacking his audience in both rage and terror and ruthlessly beat them unconscious. The man's troubles did not end there, however, as he was ambushed shortly thereafter by several gangsters under the command of the Falcone Crime Family, and was strong-armed into becoming the criminal mastermind, the Red Hood , which forced him into committing a heist at the Ace Chemical Processing Plant , threatening him with death if he didn't comply, and also showing him his pregnant wife, whom they presumably significantly injured to the point of death, to back up their threat.

However, he ended up ambushed by Batman (who, at the time, underwent his first year of crime-fighting), and was dunked into experimental chemicals. That, alongside the overall events of the "really bad day," caused the man, who renamed himself The Joker, to desire revenge against Batman. Whether the story was completely true or not was unknown, as the Joker himself had admitted that the encounter with Batman may have done permanent and significant enough damage to his sanity and mind that it deformed his memories. Sometime after, the Red Hood went missing, and Commissioner Gillian B. Loeb declared that the criminal had been "run out of the city," while his case still remained active in Batman's personal files due to his identity remaining a mystery and his status unknown.

It should be noted, however, that the Joker later became notorious for telling dozens of long and frequently fantastical tales of his past over the years, all of which were significantly different in every detail except for one: Batman. This made anything that the Joker said or remembered with regards to his past highly questionable as he himself may not have been able to remember and simply made up details as he went along. Due to this, Joker truly had no known name or backstory, which ranged from him being a broken family man to a sadistic criminal and hit-man, with the only clue closest to being true was that he suffered one, "bad day."

Additionally, it remained inconclusive to many psychiatrists if the Joker was indeed insane or purely an evil individual who hid behind a mask of insanity to serve his own purposes and avoid the death penalty. Regardless, the Joker clearly demonstrated on numerous occasions to be highly calculating and intelligent, bordering on a genius-level, and fully acknowledged the brutality and inhumanity of his crimes, knew that they were evil in nature, and simply committed them for enjoyment. This self-awareness implied that Joker might not truly be insane and was simply evil, but due to his often erratic behavior during his various therapy sessions and crimes, complete lack of empathy for any of his victims and associates, and disregard for even his own life, Gotham's legal system remained hesitant to deem him a sane individual.

The Joker's love of inhumane violence and torture were indicative of how he viewed the world: a sick joke with human atrocities showcasing what the core essence was of every person. Believing that there was no such thing as a truly pure person and people were only as good as society dictated or before they were broken from tragedy, Joker often sought to create a world of anarchy and chaos to show the world what truly comprised humanity. His laughs towards random and pointless acts of crime, war, and violence, including Arkham City, were a further indication of those nihilistic views, with his own immense carnage becoming his way of indulging in what he believed was the true nature of humanity if pushed into madness from enough bad days or tempting incentives.

Through those acts, Joker's only motive for creating deadly violence was simply for the sake of it, his own enjoyment, and becoming infamous to the world through doing so. Joker did not value money or absolute power, though he did make use of such aspects throughout his plans and relished in the level of control that he had over people and the city, but creating a world of destruction, starting with Gotham, and carving a legacy for himself, a legacy that would never be forgotten or pushed to the side, as he himself was so often in his early life. To Joker, Gotham was his stage and the people of Gotham, his victims, were his audience to watch and become engulfed in his sadistic showmanship in order to feed his insatiable lust for attention and never be forgotten, his only true fear.

When Batman proved himself to be his worthy rival and nemesis for years to come, the Joker became obsessed with occupying Batman's thoughts and proving to him first and foremost what he wanted to prove to the world: everyone was corruptible.

"Tonight, we're making some changes! Some big changes." ―The Joker while impersonating Black Mask[src]

During a particularly snowy winter, near Christmas, a man whom no one had ever seen or heard of emerged in Gotham with plans of destruction and chaos for the city simply for the sake of it. A man known simply as The Joker, a villain who was driven by a lust to create social disorder and desired nothing but anarchy to feed his sadistic appetites and morbid, dark sense of humor. With a particular hatred for the Dark Knight himself, having blamed the hero for making him who he was, and a hunger for revenge against him, the Joker began to make his schemes to destroy Gotham and make Batman suffer in the process.

Seeking to establish himself as one of Gotham's most iconic figures and carve a name for himself in the Gotham criminal underworld, the Joker began to target Roman Sionis, also known as Black Mask, the city's most powerful and sadistic crime lord. With Black Mask having unlimited wealth, resources, men, power, and complete control over the criminal underworld as he consolidated his power and eliminated his opposition, Joker saw Black Mask's criminal empire as the perfect means to gain control of the city and form his own gang for his agenda of chaos. Initially performing small-time, but extremely violent crimes, heists, and spree murders in order to introduce his image into the criminal underworld, including blowing up a senior health care residence, the Joker eventually gathered and consolidated a small gang of his own.

With some loyal followers under his control, the Joker began his grander plans and stole chemicals from Sionis' Steel Mill, a front that was used to create chemicals and drugs, to manufacture explosives, which enticed Black Mask to have the Joker followed and monitored in order to learn more on what he was planning. The Joker was already one step ahead, however, and began to stalk Roman's girlfriend, Tiffany Ambrose, as he kept tabs over her boyfriend's criminal activities. This understandably spooked Tiffany, who was placed within a safe house at Lacey Towers by Roman, until he could track the Joker down and neutralize him. Unfortunately for Black Mask and Tiffany, the Joker used his own connections in the underworld to learn of Tiffany's whereabouts, broke into the safe house, and waited for her to come home.

When Tiffany did so after holiday shopping, Joker violently smashed her head into the counter, which knocked her out, and tied the defenseless woman up to the chandelier in the living room. Black Mask soon began to suspect that something was wrong and had Giovanni Luchese, disguised as himself, enter the safe house as a diversion while he sneaked in the back to gain the upper hand on the Joker. When Luchese arrived through the front door, Joker gleefully waited in a chair and immediately shot the man through the chest, which instantly killed him, knowing that he was not his true target. The real Black Mask then sneaked up behind Joker and attacked him, but Joker proved to be an exceptionally competent fighter and overpowered and beat Black Mask, tying up his hands in the process.

To eliminate any evidence of him being at the safe house, Joker used a cocktail incendiary device to set the room ablaze. As Tiffany struggled from the heat of the fire below her, Joker then cruelly and sadistically made Roman hold his gun and shoot Tiffany through the heart in a game of Russian Roulette, which immediately killed her, as Joker dragged the struggling Roman out with him. Joker held Black Mask captive at a hidden location and tortured him over the course of several days, forcing him to reveal every detail about himself and his operations. Using those details to his advantage, Joker took Roman's mask and white suit, disguised himself as the crime lord, and took complete control of his gang, resources, and power. Joker then plotted to first destroy all of Black Mask's power and standing in the city, take his place, and institute his own brand of anarchy and social disorder.

With Black Mask's connections his own, Joker had access to nearly every level of Gotham's infrastructure through his inside agents, as well the entire Gotham City Police Department under his complete control to do his bidding as a secondary gang. Joker's ultimate desire was to make Gotham his own by sunrise and leave the city in a state of ruin for his own personal amusement. Knowing that Batman was the only one who could stop his plans, as well as having a hunger for revenge against the vigilante, Joker placed a $50 million bounty on the Dark Knight's head and hired eight of the world's deadliest assassins to take him down. The Joker also managed to take over an old amusement park on the outskirts of the city, murdering the owner in the process, stole a massive amount of carnival equipment, and began to manufacture excessive amounts of a poisonous gas that was known as Joker Toxin, which left victims violently laughing themselves to death, in preparation for his schemes that took further root later that night. Joker would proceed to horrifically test out this toxin on numerous abducted victims with the Sionis Steel Mill, until he obtained the desired effect, and disposed of the bodies within barrels of chemicals.

As the assassins arrived in Gotham, including Bane, Deathstroke, Deadshot, Copperhead, Killer Croc, Firefly, Shiva, and the Electrocutioner, with their respective gangs, and armed with weaponry that was provided by the Joker's agents or the Penguin, the city's body count and crime rate skyrocketed as they created wanton destruction throughout Old and New Gotham in order to lure Batman into their crossfires. However, Joker initially kept it a secret to each of the assassins that he had hired other killers to embark on the same bounty.

To this end, while still disguised as Black Mask, Joker began to lure Batman into the crossfires of his sadistic game by having Deathstroke arrange for a tip, that related to a briefcase, to serve as a trap for the latter to attack him. However, despite a grueling fight that nearly resulted in Deathstroke winning, Batman managed to escape, largely due to Deadshot's interference. Joker was later confronted by Deathstroke about his hiring of at least one other assassin besides himself, but Joker dismissed him, said that he had his chance and that the night was still young. After he noticed one of his henchmen begging for help due to being severely wounded from the blast, Joker then proceeded to approach the hapless henchman, grabbed a burning piece of rubble that was filled with nails, and brutally beat the man to death with it.

With the assassins arriving in Gotham and already laying out the foundations for their traps for the Dark Knight, Joker proceeded to institute the next steps of his operations to throw Gotham into anarchy by targeting the forces of the GCPD. Knowing that Commissioner Loeb, the corrupt leader of the police force, was planning a press conference at Blackgate Prison and also needed to be taken care of if the GCPD would take his more chaotic orders, Joker then handed down the order to Black Mask's Henchmen to abduct Warden Martin Joseph from Blackgate and brought him to "My Alibi", a night club that served as a meeting ground for the criminal underworld and was previously under the control of Black Mask. When Joseph was brought to Joker at the club, Joker tortured him with a lit cigarette, burned out his left eye, and threatened to slaughter his entire family if he did not lower his security at Blackgate.

Joseph reluctantly agreed and had the security for a portion of Blackgate become laxer in an effort to protect his family. With security lowered at the prison and Loeb perfectly in the line of fire, Joker then staged an attack on Blackgate disguised as Black Mask, with several dozen of his men and one of his assassins, Killer Croc, a cannibalistic killer with a rare condition that made him appear more and more reptilian as the years passed by. Murdering dozens of guards and leaving a path of bloodshed and destruction behind him, the Joker took Commissioner Loeb hostage; the Commissioner was present at the prison to oversee the execution of Julian Day, also known as Calendar Man, in order to gather massive support from Gotham's citizens and City Hall.

Joker had Calendar Man released from the Execution Chamber and set him loose, believing that his love for torture and murder on the holidays was the perfect setup for Christmas Eve, which eventually led to several deaths at Day's hands later that night. Joker then had Loeb forcibly placed within the Gas Chamber under the pretense that the Commissioner no longer served his best interests with so many of his men imprisoned and wanted to start off with "a clean slate". The reality of the situation was, however, that Joker sought to take complete control of Black Mask's criminal activities and eliminate anything that could be used as a benefit for the fallen crime lord. Loeb's murder also prompted chaos throughout the criminal underworld and instituted a power vacuum throughout the GCPD; chaos that fed the Joker's love for anarchy.

Loeb was then gassed in the Gas Chamber and died in mere seconds as Joker continued through the prison with Black Mask's henchmen and Croc, killing all who stood in his way. While in route to the roof, Joker discovered that he was being monitored by one of the Penguin's drones and ordered Croc to destroy it and grab the memory card. Though Croc merely smashed the device to the ground without obtaining the memory card, much to Joker's anger. Batman, however, who arrived at the prison just minutes prior, obtained the memory card from the remains of the device to later analyze at the Batcave.

Arriving on the roof to find a set of helicopters ready to make a quick escape, Joker left Croc to deal with Batman as he boarded one of the copters with several of his men and escaped. While Croc was aided by some of Black Mask's Henchmen, Batman was ultimately able to defeat them all and learned from Croc about the enlistment of seven other assassins. Batman subdued Croc, made a quick getaway himself in the Batwing and left him for Captain Captain Jim Gordon and the GCPD.

Shortly thereafter, Joker was informed by one of Black Mask's corrupt cops that the Penguin was invading Falcone's territory regarding the weapons business, but the Joker dismissed the event, as he didn't care about balance. As Joker consolidated several of the escaped convicts into his expanding gang, much of the honest, straight portion of the GCPD contained the situation at Blackgate, serving as the perfect diversion to keep the rest of Gotham under even more lax security than usual. Gotham itself began to descend into further chaos as Joker continued to control Black Mask's operations, including drug trafficking, sending out hundreds of his men to murder, steal, and wipe out all opposition, strike deals with corrupt GCPD officers, particularly SWAT Team Leader Howard Branden and his squadron, obtaining weapons and equipment from the GCPD Evidence Lockup in the process and promised them the entirety of the $50 million bounty if they succeeded in subduing Batman.

Branden instructed his squad to neglect their other responsibilities in light of collecting the bounty, which also ensured that a majority of the police department would be too distracted with finding and killing Batman to prevent any of Joker's plans from coming to fruition. This enabled Joker's Henchmen to commit a wide variety of crimes and heists throughout the night, including stealing countless equipment, weaponry, and trucks from AmerTek, a military-industrial corporation that specialized in the construction of steel for weapons manufacturing. Meanwhile, the murder of Commissioner Loeb also prompted the hand of many second-rate gangs and mobs to overtake territory and begin wars with the other fractions for ultimate control while other gangs broke off their previous deals with the corrupt police force, no longer trusting them with Loeb gone, and retaliated against their efforts to resume their deals. Additionally, more outlandish criminals began to surface and took advantage of the rising destruction to further their own designs, and caused chaos throughout all of Gotham just as the Joker had planned.

Joker also hired the services of Edward Nashton, a master hacker with plans of his own for the city, and had him ideally situated within the GCPD thanks to his newly acquired connections throughout Gotham's infrastructure to work as the head of the Cyber Crime Division. Within his new position of power as an additional inside agent, Enigma used his resources and access privileges to take complete control of all the GCR Towers throughout Gotham in order to block Batman's auto-navigation trackers that were used for the Batwing and kept watch over the entire city. Enigma further added to the chaos by using his surveillance over the city to collect incriminating information on countless political individuals in Gotham, placing them all within extortion files that were hidden around the city, and blackmailed the individuals for money and power.

Regardless of their actions, however, Enigma intended to release the data to the press, which would result in resignations, murders, and utter chaos throughout the streets as he worked on his plans to eliminate all of the corrupt and the unintelligent. To further aid in his mission and plans, Enigma used the extensive funding that came from Joker to hire a wide variety of street thugs, muggers, and killers to collect information, store them in extortion files, hide the files for eventual pickup, and guard the GCR Towers. Enigma also set up close to a hundred relays throughout Gotham in order to prevent his own network from being hacked and keep tabs over all of Gotham, while also rigging the security controls of GCR Towers to blow if anyone tried to interfere, leading to the death of David Shannon. Those modifications were done with the help of a third party, a low-level thug named John F. Baker, who was hired by Enigma and later killed by him in order to further cover up his tracks.

As Batman was hunted down from all fronts and continued to fight against the assassins, he learned of the Joker's existence when he investigated the apparent murder Black Mask and Tiffany at Lacey Towers. Batman concluded however that it was not Black Mask, but a simply a decoy; he broke into the GCPD Building to gain access to the National Criminal Database in order to learn more about the crime scene. At the same time, Joker sent scores of Black Mask's Henchmen to infiltrate and take control of the sewer systems through a secret passageway from the Steel Mill. Once there, Joker's Henchmen set up shop and placed hundreds of demolition explosives underneath the foundations of countless buildings, including the Gotham Fire Station, the Train Station, the GCPD, and many others in order to leave Gotham in a state of ruin by sunrise. While Batman was able to subdue Joker's men, preventing them from putting automatic timers on the explosives, and gained access to the National Criminal Database, he was ultimately unable to deactivate the bombs as they were also being remotely controlled and too sensitive to disarm himself.

"What kind of monster forces a man to kill the ones he loves?" ―Batman[src]

As he looked through the GCPD's files, Batman learned that Sionis owned and had complete control over the Gotham Merchants Bank, which he used as a front to launder much of his ill-gotten fortune. Batman soon realized that Joker had taken Black Mask hostage after forcing him to kill Tiffany and intended to use him to gain access to Gotham Merchants Bank, which had security measures that only Sionis could deactivate. When Batman asked Alfred Pennyworth to check any records that could be related to the Joker, Alfred found nothing in the Gotham Criminal Database or any other that could shed light on this new criminal, making it seem as the Joker had simply appeared out of nowhere. With nothing to go on other than the implication that the Joker was heading next to the Gotham Merchants Bank, Batman left for the bank in Old Gotham to meet his new enemy just as the clock struck midnight and Christmas day officially began in Gotham.

True to Batman's detective work, the Joker explosively arrived at the bank in a stolen ambulance, murdered over two dozen of the bank's employees, sadistically torturing many of them with the use of the bank's Christmas decorations and television sets. Joker then took the bank manager hostage and forced her and Sionis to open up the vault that contained much of Roman's laundered money. Joker then had his men steal billions of dollars and loaded it up onto the ambulance while Roman was tied and gagged. The Joker injected the bank manager with a lethal dose of his newly created Joker Toxin, which caused her to gradually laugh more and more uncontrollably. When Batman arrived on the scene by crashing through the roof, the Joker finally revealed himself to be the impostor Black Mask after he viciously beat and kicked Roman into unconsciousness for not 'playing along'.

"Can't... you just... play... along!?!" ―The Joker while violently beating Sionis unconscious[src]

As Joker revealed that most of Black Mask's men were loyally working for him due to the benefits that they now reap, expanding his gang into over a thousand followers as a result, his men donned new Joker masks as the villain informed Batman that his attempts at assassinating him were simply part of a much larger plan. After he threw the laughing Bank Manager at Batman, Joker detonated the bombs that were rigged in the vault, before driving away with both the money and Roman in the stolen ambulance, laughing insanely and leaving two of his own men behind to perish in the blast. Batman grabbed the bank manager and barely managed to lunge away from the massive explosion, but she, unfortunately, succumbed to Joker's Toxin and died with a smile on her face. After he anticipated that Batman may have survived the explosion, Joker sent in a handful of his men to check the bank, which led to confirmation that Batman was indeed still alive.

Amazed that Batman could survive both his gunshot wounds and the explosion, Joker nevertheless remained in cheerful spirits as he embarked on the next phase of his plans. Batman subdued all of Joker's men, leaving one for interrogation, who informed him that Joker had murdered over a quarter of Black Mask's men who would not turn and took complete control of all of Roman's operations at the Steel Mill. The Steel Mill contained a secret entrance to a massive drug manufacturing facility, where Black Mask received shipments of materials and chemicals that were constructed into drugs and then sold onto the streets, as well as a torture chamber to contain his enemies for slow and agonizing deaths.

When he arrived at the Steel Mill, Batman learned that Joker had been using it to manufacture explosive chemicals and had his men take Sionis down to his old torture chamber to brutalize and interrogate him for any remaining secrets on his operations and then murder him. At the same time, Joker's men used the facility to continue manufacturing and sending out shipments of chemicals and drugs to add to Gotham's descent into anarchy. Batman was able to subdue Joker's men and rescued Sionis, who had nothing but raw hatred for both Batman and Joker, intending to kill them both. Batman began to brutally interrogate Roman for Joker's location until Copperhead arrived, intending to collect Joker's bounty, poisoned Batman and allowed Roman to escape at the same time. As Batman began to hallucinate and see his worst fears come to life, he scanned the poison and sent an analysis of it to Alfred in order to manufacture a cure and drop it off to him.

As Batman arrived at ground level, he was forced to fight Copperhead until Alfred sent him the cure via the Batwing, which restored him back to health and allowed him to finally subdue her. After he locked up Copperhead in the back of one of Sionis' trucks, Batman learned that Joker had called a meeting with the remaining assassins. Tracking down the electronic signals from one of the assassins, the Electrocutioner, Batman learned that Joker had taken control of the Gotham Royal Hotel, murdered over a hundred of its employees, taken the guests hostage, reconstructed portions of the hotel into a hellish funhouse with stolen carnival items to torture and slaughter the guests, and rigged the foundations with explosives and laughing gas.

Joker also continued to send out his men to commit crimes, wipe out the last pockets of opposition, allowing them to keep all of their ill-gotten gains, much to their delight, so long as they created chaos and destruction. As his men took complete control of Old Gotham, Joker converted the Royal Hotel's Penthouse into his secondary base of operations and, still disguised as Black Mask, had Branden and SWAT form a perimeter around the hotel to look out for Batman and keep Gordon and the media away. As Gordon was kept busy with the murder of an amusement park worker, most likely the same one that Joker had killed for the stolen carnival items, Batman infiltrated the Royal Hotel after fighting past scores of Joker's men and Braden's SWAT team. Inside, Batman navigated through a river of mutilated corpses, makeshift carnival attractions, several traps and explosives, and more of Joker's Henchmen.

At the same time, Joker, while he humorously held the meeting in a similar manner to a business financials review meeting, revealed himself to all of the remaining assassins, including Bane, Firefly, Deadshot, Shiva, and Electrocutioner (Deathstroke and Copperhead were defeated and captured by Batman earlier). Disappointed and annoyed in particular at Electrocutioner's attitude and inability to kill Batman (he was knocked out cold by a single kick from Batman several hours earlier on the Final Offer), Joker kicked the assassin and his swivel-chair from the Penthouse and to his death. Joker instructed the rest of the assassins to go out and find Batman while Bane stayed, the latter of whom knew that the hero was undoubtedly coming for the Joker. Batman was able to take the Electrocutioner's Shock Gloves from his corpse and made his way further up.

As Batman continued through Joker's sadistic traps and Bane's mercenaries, he grew increasingly disturbed at the psychotic nature of the Joker as he saw more and more corpses, some of them being Joker's own men, attached to decorations and crude carnival games. Once Batman managed to get through the rigged, newly developed amusement park traps and exit, Joker ended up taking his fury out and executed the chief architect for incompetence regarding Batman being able to escape the otherwise inescapable death trap alive.

Batman uncovered a plot by the Joker to detonate a large part of the Royal Hotel at midnight on December 31st and attempted to disarm Joker's "Snowman Bombs" with the Cryptographic Sequencer. However, Batman, to Joker's amusement, was unable to disarm the bombs and instead only succeeded in significantly reducing the time of detonation to within 20 seconds, which forced the Dark Knight to bail from a nearby window and grapple onto a news chopper to get to the roof before the bombs exploded.

When Batman finally arrived at the Penthouse, Bane brutally grabbed him, threw him around the hallway and into Joker's quarters. As Bane attempted to kill Batman, Joker forced Bane to leave under the threat of blowing up both the Royal Hotel and themselves. As Bane reluctantly left, giving him one minute alone, Joker revealed that he had placed a series of explosives all throughout Gotham and detonated one, which caused the entire top portion of the Ellsworth Building directly in front of the Royal Hotel to explode.

Batman grabbed the Joker, infuriated, and asked him how many people he had just murdered. Joker, after denying that there were any people in the building (at least, none that he was aware of), gleefully revealed that the building was merely a construction site, a demonstration of the real carnage soon to descend onto Gotham. Batman slammed his laughing enemy into the adjacent table and flung him across it as several of the detonation devices fell on the floor next to Joker. Grabbing one of the devices, Joker revealed that the detonation device that he held would not be as friendly, and laughed sadistically.

Having been pushed to his limit, Batman grabbed the device, broke it, and smashed it into Joker's face. As Batman punched him, Joker simply laughed as Bane reappeared and punched Batman off his nemesis. Bane grabbed Batman's face, intended to kill him in order to achieve his peace of mind through the dominance of the hero and his city, and flung him through the window. After falling through a ceiling window into the Penthouse Library, Batman prepared himself for a brutal battle with Bane as Joker gleefully watched.

While Batman was able to hold his own during the fight, Bane revealed his trump card: a storage tank that was attached to his body that pumped a deadly chemical known as Venom through his body, which gave him enhanced strength and adrenaline. The brutal fight then continued on the snowy balcony that overlooked the destroyed construction building with Joker commentating from above as Alfred called the GCPD in an effort to save Batman. However, Batman was able to fight off Bane long enough for two GCPD Helicopters to arrive on the scene. Unshaken Joker took out a machine gun and began to fire wildly at the choppers, ordering his men to do the same.

The police retaliated and opened fire on the Joker's Henchmen, killing them all, while Bane was merely grazed. Realizing that the tides had turned, Bane decided to make an escape as his men arrived in their own stolen choppers and fired on the police choppers, which caused them to both collide and explode upon impact. As Bane jumped into one of his choppers, Batman threw a tracking device on him to locate him later. Joker was annoyed that Bane attempted to escape rather than finish the job and fired on him as well. Bane responded with a rocket launcher, which missed the Joker, who remained completely unshaken and continued smiling, as the explosion from behind him flung him off the balcony.

As the Joker laughed insanely towards his impending death, Batman jumped to save the mass murdering psychopath, who began to fight him as Batman tried to rescue him, due to his belief that Batman "came back for more." Batman attempted to grapple them both to safety, but the amount of debris that fell from the explosion caused the line to break, resulting in the pair falling through the glass ceiling and into the Hotel Lobby. Violently crashing down onto the floor, Batman was surrounded by two of Joker's men as the Joker composed himself and aimed his gun at Batman. Joker was shocked that Batman would actually risk his own life in order to save his own, even after he killed so many people in just one night, as well as attempted to have him killed.

"Now...Why? Why? Why would you do that? Newsflash: I'm the one who's trying to kill you!" ―The Joker[src]

Instead of shooting Batman, however, Joker simply shot both of his henchmen dead and told Batman that they were very bad men who performed such horrendous actions that they were unspeakable, much like his own actions. Laughing, Joker then aimed the gun at himself until Batman knocked it away, punched him to the ground, and cuffed him. Branden and SWAT then arrived, still intent on collecting the bounty on Batman's head for themselves. Batman, however, called the Batwing and escaped as Gordon and Harvey Bullock arrived and took the Joker into custody. As he put the Joker in the back of his police car, Bullock assumed that Batman was working with the Joker since he saved him from a deadly drop. Joker laughed at the notion, wondering the same exact thought himself and realized that Batman was unlike anyone that he had ever met before.

Joker was sent to Blackgate, where he underwent a psychological examination by the intern of Professor Hugo Strange, Harleen Quinzel. Having sympathy for the Joker, Harleen allowed him to tell her his view on the world and how the brutality of life had made him into who he was. At the same time, Joker remembered portions of his past (at least how he remembered it at the moment) as a failed stand-up comedian and being strong-armed into becoming a criminal known as the Red Hood, as well as his first encounter with Batman at the Ace Chemicals Processing Plant, which led to him falling into a tank of experimental chemicals, revealing the reason for his initial hatred of Batman. However, Joker saw a new purpose in life with the emergence of the Dark Knight, whom he had met through what he believed was fate, after he saved his life and proved to be much more complex and interesting than he initially perceived.

Seeing Batman as a monster like himself, created from a very bad day, Joker felt that Batman was finally someone that he could rely on to play his sadistic games. Excited at the prospect of such a person bringing new meaning to his life, Joker made Harleen believe that he was talking about her while he was, in reality, referring to Batman. Harleen was taken in by the Joker's false charms and was essentially seduced by the psychopath in a matter of mere minutes, and gently touched his hand. Joker smiled as he had crafted the perfect pawn to manipulate from within Blackgate.

Despite Joker being locked up, the destruction that occurred in the city reached a peak again as the remaining assassins were still after the bounty that was promised to them by the Joker with Deadshot destroying a police chopper and holding a civilian hostage at the Gotham Merchants Bank in order to lure Batman out in the open and Shiva and her ninja forces murdering bent cops and criminals as part of their own grand designs. Worst of all, Bane deduced Batman's identity, endangering both his home and Alfred, while Firefly began destroying portions of the Gotham Pioneers Bridge, placing four bombs that were constructed from materials that were stolen from GothCorp in critical locations throughout the bridge with the aid of his hired forces, and took several people hostage. With Joker still destroying Gotham from inside Blackgate with his bounty, Batman had no choice but to take out his remaining assassins before he ensured Alfred's safety from Bane.

After defeating Lady Shiva, who escaped after alluding to her master's plans to destroy Gotham already taking effect, apprehending Deadshot and Firefly, and saving Alfred's life after an attack by Bane that left the Batcave in ruins, Batman heard on the police radio that Joker had escaped Blackgate (it was heavily implied that he escaped with the use of security codes that were given to him from Harleen) and was leading riots that completely destroyed the prison and killed hundreds. After being motivated by Alfred, who finally understood that Gotham always needed a hero like Batman with people like the Joker attacking the city, the Dark Knight prepared himself to finally put an end to the Joker's night of destruction once and for all.

Arriving to see Blackgate completely engulfed in flames and destruction, Batman fought through scores of escaped convicts and Bane and Joker's forces. Making his way to the Panopticon, Batman found Joker holding Warden Joseph hostage. Joker revealed that he understood Batman and his code of ethics, and made it his new mission in life to induce the hero to give up his one rule by forcing him to take a life and cement their similarities as corrupt monsters of a broken society. Joker then declared that Batman would soon wish that he had let him die earlier, and cited with sadistic amusement that he killed hundreds of people, brought Gotham to its knees, and crippled the GCPD, all long before it was even time to open presents on Christmas Day as Bane arrived.

Revealing that Bane held a heart monitor that would charge up an electric chair, Joker sat in the chair and told Batman that either he kill Bane to stop his heart from charging up the monitor and the chair or Batman dies and Joker would be electrified to death; either way, Batman would be responsible for someone's death. Bane put on the monitor, told Batman to use all his hatred and anger from the loss of his ally in battle, and was unaware that Alfred was actually still alive, as Joker's men strapped him to the chair. To ensure that Batman and Bane did indeed battle, Joker revealed that he had placed a bomb within the facility, which would detonate and slaughter everyone if the heart monitor was removed. As Batman and Bane battled, Gordon arrived and shot Joker's men non-fatally, who held Joseph and incapacitated them.

As Joseph and Gordon attempted to get Joker out of the chair, Joker elbowed both men, knocking out Joseph, held Gordon at gunpoint with his own gun, and put the headpiece of the electric chair on Gordon, raising the stakes even higher for Batman. Coming up with the plan to send Bane's heart into temporary cardiac arrest, Batman used the Shock Gloves to defeat Bane and stop his heart, which made Joker gleefully laugh as the last barrier and difference between him and Batman was seemingly torn down. Joker then attempted to shoot Joseph dead when he awoke and stood up to the mass murderer, but Gordon jumped in front of him and took the bullet instead. Joker continued to laugh, left the room, and intended to escape from Blackgate in order continue his reign of terror and detonate the bombs that he had placed across Gotham with the aid of his forces and the escaping convicts.

Batman revealed to Gordon, who was not severely injured due to his bulletproof vest, that Bane could still be revived and told him and Joseph to arrest the Joker before he could escape. As Batman revived Bane, Joker was tracked down to Death Row by Gordon and Joseph, with virtually all exits sealed. Unfortunately, Joker anticipated their pursuit and had them pinned down.

After one final and grueling battle, Batman was able to finally subdue a TN-1 enhanced Bane after he strapped him to a pair of electrified pacification devices with the Remote Claw. However, Joker remained on the loose, shot Joseph via sniper, and was nearly out of the prison. Batman and Gordon protected Joseph from Joker's Henchmen and Batman left Gordon to watch over Joseph until medical units arrived as Batman went after Joker in the Prison Chapel.

"You just can't get it through your thick skull! We both exist because of them!" ―The Joker[src]

Inside the Prison Chapel, Batman found Joker laying at the front of the altar, exhausted, but laughing hysterically at all the brutal events throughout the night. Driven by immense hatred and anger towards the Joker for nearly destroying everything he cared and fought for, Batman grabbed Joker, who was thirsty for him to take another life, but Batman revealed that Bane was still alive, much to the villain's displeasure. After he verified Batman's claim by looking at the heart monitor, Joker pulled out Gordon's gun, only for Batman to drop him. Holding the gun to Batman's head, Joker told Batman that both he and himself were the same: they were born from very bad days, and existed because of a broken society and a corrupt law system. Batman refused to believe in the Joker's words and kicked him across the room and into several pews. Joker continued to goad Batman into killing him and told him that there was no hope for him.

Batman threw Joker into one of the windows, at which point Joker took shards of the broken glass and attempted to slit Batman's throat. Batman knocked the pieces of glass off of him and punched Joker dozens of times before he smashed him into the ground. Batman began to strangle Joker, who continued shouting to kill him in between his laughter and grunts (he once again hallucinated Batman as a demonic creature), but Batman resisted the urge and knocked out Joker once and for all instead. Gordon arrived on the scene and expressed his respect for Batman for not killing the Joker before declaring that he still had to take him in. However, as Gordon informed Bullock that the Joker was neutralized, Batman disappeared, an action that Gordon later admitted to Barbara that he partially allowed to happen due to his new-found respect for the Dark Knight.

As GCPD retook control of Blackgate, Gordon told Barbara how she was right to think of Batman as a hero and believed that he could indeed be a symbol of hope for the people of Gotham. Back inside Blackgate, the police rounded up the last of Joker's men and convicts and found Bane strung up and still incapacitated. Joker was then escorted back to his cell strapped to a gurney, ultimately accepting his defeat for the time being, but also laughing at Batman's deception. As Harleen smiled at him, Joker stated his belief that his future battles with Batman would indeed be "fun."

Ultimately, by the end of the long and brutal night, the Joker was successful in building up a criminal empire of his own with thousands of followers, billions of dollars worth of revenue and resources, and carved a legacy for himself in Gotham's criminal underworld as its most notorious criminal, who had found a new purpose in his own life through mindless chaos and Batman, the hero who would feel the brunt of the villain's schemes and 'punchlines' for many years to come as his dedicated nemesis.

Joker was last heard during the night singing an altered version of the song, 'Cold, Cold Heart', as he was escorted by guards through various security measures before he was ultimately locked up in a cell. Later that evening, Quincy Sharp, a political activist, revealed his intentions to reopen Arkham Asylum, partially due to the manipulation of Shiva under Ra's al Ghul's orders, in light of the night's events in an effort to create a more secure facility for Gotham's more dangerous criminals.

This essentially revealed that Joker's actions led to the reopening of Arkham Asylum and, thus, started the chain of events that made up the entire Arkham Series. In addition, Joker's earlier riot resulted in 20 Blackgate Prisoners escaping into Gotham, which necessitated in Batman in rounding them up as part of a favor for Gordon, which cemented the newfound trust that the police captain found and formed with Gotham's Dark Knight after all the inmates were rounded up.

While the Joker's plans were ultimately ruined, the effects of his presence in Gotham were still felt even after he was neutralized and locked up at Blackgate. Joker's actions on Christmas Eve, particularly the murder of Commissioner Loeb, unveiled the massive amount of corruption and conspiracy within the GCPD, which led to riots throughout North Gotham in anger to Loeb's influence on the criminal underworld, while Anarky's remaining followers resumed their operations in South Gotham in response to the breaking news.

Other criminals, particularly the Penguin, also escalated their own criminal activities in order to ensure that they could withstand the massive amount of power and influence the Joker had accumulated when he took control over Black Mask's criminal empire and operations. The Joker's earlier hiring of the eight assassins was also briefly referenced by the Penguin while he was trapped in ice at GothCorp, who cited Batman's survival "like a bad joke."

Additionally, Joker's previous associate, Enigma, further added to the chaos by subtly revealing to major media organizations throughout the city about the corrupt nature of potential new Commissioner, Peter Grogan, and his ties to the criminal underworld. In the end, however, the protests ended on a peaceful and celebratory resolution with the resignation of corrupt Mayor, Hamilton Hill, and the rise of Captain Gordon to the rank of Commissioner.

Despite Joker's chaotic influence, which led to nearly a thousand deaths since his emergence, the ramifications of his sick and deadly plans ironically and unintentionally had at least some positive influence as it enabled Batman and Gotham's citizens to finally rid their city of some of their most corrupt political leaders and ensured that much more noble and ethical individuals took their place.

Over the next few months at Blackgate, Joker began to see the prison as the perfect fortress to serve as his base of operations and lusted to slaughter the rest of the prison staff and inmate population in order to acquire Blackgate for his own purposes. After he had frequent therapy sessions with Harleen at her insistence towards her superiors, Joker was able to further seduce the young therapist to the point that she was under his complete and psychological control. Harleen soon became so obsessed with Joker, that she went on to call him 'Mr. J' and even kept a detailed journal of her infatuation with him.

With Harleen in love with him, Joker was able to easily persuade her to smuggle in several spray cans of food from the cafeteria during work hours. Using a unique filtering device, which Joker fashioned out of old pipes and pieces of cloth from his own clothing, Joker was able to isolate specific particles within the spray cans that were instrumental to creating his Joker Toxin. After he studied the blueprints for the entire prison, as well as the ventilation system, that was also smuggled into his cell by Harleen, Joker planned to take over the entire facility and pump his deadly toxin through the air ducts to slaughter nearly everyone, which would leave him and his gang as the ruling elites.

Three and a half months after he was captured by Batman, Joker, along with Penguin and Black Mask, took over Blackgate, following a massive explosion that was engineered by Amanda Waller in order to find suitable recruits for the Suicide Squad, and each of them controlled a section of the facility. After he perfected his Joker Toxin and mass produced large quantities of it, Joker unleashed it throughout Blackgate and left countless dead guards in his wake, all of whom were strung up and horrifically grinned with a dead smile from the toxin or had a Glasgow Smile carved into their faces, while he kept himself and his gang safe with gas masks that were stolen from the prison.

Joker then took complete control of the Administration Building, redecorated it into his own image, and targeted the Assistant Warden. After he forced the unfortunate man to draw an elaborate map of the Administration Ward, particularly the layouts around Warden Joseph's Office, Joker learned of an emergency hatch that was built into the sewer network below the prison and was connected to a secret passageway to the Warden's Office. After he took the completed map and tore out the portion that was most useful to him, Joker then cruelly forced the man to get on his knees and beg for mercy, at which point Joker shot him, execution-style, through the head.

Using the map drawn by his latest victim, Joker abducted Joseph again by sneaking into his office through a sewer network that was connected to his emergency escape hatch. After a brutal fistfight, which resulted in Joseph losing his glass eye, Joker had Joseph tied to a series of explosives that were rigged in with the prison's security control box wiring systems and left the bombs in a fragile condition if they were tampered with incorrectly. Joker then rallied dozens of the prisoners to become part of his expanding army, consolidated his hold over the administrative section of the prison, set up shop in the Warden's Office, obtained all of the riot control gas that was held within the facility, and began to alter it to transform it into Joker Toxin.

Knowing that Batman would interfere with his plans once again, much to his delight, and eager to resume his cat and mouse game with him, Joker also rehired Deadshot (through a crudely written contract in his recent victims' blood). However, Deadshot also secretly lent his services to Penguin and Black Mask within Blackgate to collect triple the amount of money through killing Batman, as well as moved through all three sections of the facility freely, but promised to ensure that Batman was slowed down before he journeyed too far into the Administration Building. In the meantime, Joker had his men patrol the corridors and held several staff members hostage to use as collateral and further slow down Batman.

When Batman met his nemesis once again, Joker set off a series of bombs that destroyed a large portion of the building, as well as released gas when Batman attempted to pursue and rescue the prisoners in the Library, as Deadshot targeted Batman when he navigated outside to reach and confront Joker in the Warden's Office. After Batman defeated Deadshot, rescued Joseph and the surviving staff, and reached Joker in the Warden's Office, Joker revealed his plans to release his Joker Toxin into the air conditioning ducts and poison the entire prison.

After he implemented an automatic timer to run the ventilation system and release his Joker Toxin, the Joker then gleefully engaged Batman in a brutal fight, as his men cheered from above and threw grenades at Batman. In the end, Joker was defeated by Batman, who then stopped the timer and the rest Joker's operations within the prison. However, Batman also discovered that despite what Catwoman told him, Joker never actually interrupted the airflow to the Arkham Wing and caused Batman to become suspicious of her.

However, as a fail-safe, Joker made a deal with Catwoman (the plot point varied from game to game and the villain that Catwoman struck a deal with was determined by which boss the player defeated last), who was also in the prison as part of her own designs, and gave her his explosives that were wrapped up as presents and were placed all throughout the prison. While Catwoman had no intentions of the explosives going off and simply used them as a diversion to keep Batman busy while she smuggled Bane, her true objective, out of the prison at the behest of Waller, Batman was forced to disarm them all in order to save Blackgate.

After he stopped all of Joker's explosives, Batman ensured that both Catwoman and Bane were put back into custody, which ended both Joker and Catwoman's plans once and for all. However, before Joker could be put back into his cell, he managed to murder two riot officers when they arrived to arrest him, disguised himself as one of them, and used the disguise to escape from Blackgate to wreak further havoc on Gotham.

Before Assault on Arkham

As the years went on, Joker's violence and influence over the criminal underworld, Batman, and Gotham itself continued to grow. Joker's presence within Gotham led to a massive escalation in crime within the city as more and more unique criminals, eventually branded, "super-villains", began to appear to counter Batman's methods. Joker rose to the top of the criminal underworld, began to control many of its operations, and became responsible for a majority of the crimes that were committed throughout the state. With inhumane experiments conducted on random victims to perfect his Joker Toxin, the Joker used that weaponized gas to a much more frequent degree during many of his crimes, which left dozens of people literally laughing themselves to death, complete with a dead smile on their faces.

While both Batman and the people of Gotham hoped that the reopening of Arkham Asylum would ensure that Joker would remain behind bars, the facility actually did little more than aid the Clown Prince of Crime. Becoming one of the first new inmates of the reopened asylum after Batman recaptured him following his escape from Blackgate and using his apparent insanity as a shield from the death penalty, though some psychiatrists believed his insanity to simply be an act, Joker formed connections with other villains and criminals within the asylum, including Scarecrow, Victor Zsasz, and Clayface, and even managed to bribe several guards with his ill-gotten fortune and converted them into inside agents. Due to that, Joker saw Arkham Asylum as simply another staging ground to perform his various plans, developed a unique connection to the institution due to its violent background, and even appeared to have the option to escape at will, even if that meant the staff never noticing.

Batman himself became aware of this when the brutal murders of three children displayed all the signs of the Joker. As a result, Batman visited Joker in his cell for the first time, beat him, and demanded to know how he got in and out of the asylum. Both shocked at Batman's sudden rage, Joker simply laughed at the Dark Knight, reveling in his anguish, and denied any involvement in the deaths of the children, which caused Batman to leave in disgust at both the villain and his own sudden anger and violence. As Batman left, Joker gleefully whispered to Quincy Sharp, now warden of the asylum after returning it to full operations, that he was in Batman's head. It was clear that Joker's influence over Batman was becoming stronger than ever, with the Clown Prince of Crime's unique sadism and disturbing nature haunting the hero's very thoughts.

Even the orderlies and psychiatrists were not immune to Joker's manipulation, as his sense of others was extraordinarily well developed and often influenced them to serve his own purposes. With his strong influence over both the inmate population and the staff, Joker often led riots and breakouts throughout and from the asylum, which lead to citywide panics, trails of destruction, and numerous deaths. However, Joker's ultimate inside agent came in the form of the simple-minded and easily impressionable psychiatrist, Dr. Harleen Quinzel, who came to the asylum to continue studying Joker after she was transferred from Blackgate. Continuing his manipulation of the young woman during their therapy sessions, Joker easily seduced Harleen and convinced her to set him free on several occasions, all the while brainwashing her into believing that he loved her and that Batman was the true villain.

Eventually, Harleen's mind completely snapped when Batman returned a bruised and battered Joker back to Arkham Asylum after one of his violent breakouts and crime sprees. The young psychiatrist assumed the alias of Harley Quinn, indicative of the court jester, Harlequin, broke Joker free from the Asylum, leading to the deaths of many security personnel and fellow employees alike, and became Joker's trusted sidekick, plaything, and sometimes girlfriend. From this point forward, Harley's reputation was forever tarnished by her diluted love for the Joker, making it her sole motivation in life to earn his approval and was often locked up at the Asylum as well. Tragically for Harley, Joker simply used her to perform his plans, engage in sexual activities if the mood suited him, and abused and beat her, sometimes within an inch of her life, in order to feed his sadistic appetites.

Having firmly etched his authority over the criminal underworld, Joker's sadism and megalomania also put him into conflict with other villains, leading to brutal gangs wars with the likes of Bane and the remains of his forces, with Joker possessing an underlying contempt for other super-criminals and believing that they were not of his stature. This became especially true with regards to the Penguin, who deeply respected Joker initially for conquering Black Mask's criminal empire, and invited him and Harley to his newly constructed and opened front and base of operations, the Iceberg Lounge, for a formal party among Gotham's elite and criminal underworld.

While Penguin initially hoped to form an alliance with Joker and share in the massive amounts of power and influence that he held, Penguin came to despise him after Joker murdered one of his waitresses with his acid spray for spilling wine on him and shooting and killing his doorman on a return trip, which caused massive and negative publicity for his restaurant. As a result, Penguin forbade Joker and anyone affiliated with him from ever entering his establishment. This ultimately caused a destructive and bitter rivalry between the two gang leaders, with both seeking to destroy the other and take control of the power base that was left in the wake.

As he made enemies with other villains and gained more followers, Joker eventually heard tales of a brutal pair of Russian twin brothers, conjoined since birth, known as the Abramovici Twins. After their mother tragically passed away giving birth to them, the twins' guilt-stricken and grieving father reluctantly abandoned them to the care of a traveling circus and freak-show, seeing them as reminders of his wife's death. Known for their brutality within their performances, Joker sent Harley to negotiate with the circus owner to acquire the twins, known as Mr. Hammer and Sickle, and their natural violence for his own purposes. Refusing to give up his prized performers, the owner eventually met with a grim fate three months later when Joker brutally murdered him with a knife, carving a smile into his face, and hired the twins to become a part of his expanding criminal empire.

While the twins proved to be an invaluable asset to the criminal mastermind, Joker eventually realized that their large stature from their conjoint state and brotherly rivalry made them less effective than they would be if they were separated. With the help of Dr. Thomas Elliot, a world-renowned surgeon who often offered his skills to the criminal underworld and black market as he made his own plans for revenge on Bruce Wayne, Joker was able to separate the twins. Keeping the right-armed one for himself (the joke being that he created a literal right-hand man), Mr. Hammer, the Clown Prince of Crime abandoned Sickle to the brutal and violent streets of Gotham. Infuriated that he was abandoned yet again, Sickle took up employment from the Penguin, believing that his brother had betrayed him, and made it his mission to prove himself to be the more worthy twin.

As he consolidated his numbers with Mr. Hammer as his literal right-hand man, Joker often used fear and torture to exert his control over his gang and satisfy his lust for violence. While many men were tortured and murdered by Joker on a whim, either because of failure, disloyalty, or simply for pure enjoyment, most of Joker's gang served him loyally due to their boss's inclination to allow them to keep all of the spoils from their various heists and exploits, paid them considerably better than the other crime bosses in Gotham, having no concern for money outside of what was necessary for his operations, and simply wished to create chaos in order to lure Batman into the crossfires. Others were often forced to perform acts of random and pointless violence, including one thug being ordered to murder his own sister, simply for a laugh and serve as a test of loyalty.

Joker's crimes themselves were both inhumanly brutal and bizarre, from unlicensed taxidermy and corpse desecration to cannibalism and even attempted omnicide, in his thirst for anarchy and carving a legacy for himself that would never be forgotten. Joker's deadly plans themselves ranged from small-time schemes that were meant to target Batman specifically to large-scale operations that threatened the entire city, country, and even the world itself on several occasions. Some were silly in nature, such as poisoning Gotham's waters to create 'Joker Fish' and copyrighted them even as they were a natural resource, to inhumanly brutal crimes, including a citywide massacre on the Fourth of July.

By using knowledge that he obtained from a felon and terrorist named Mark Mardon, who served a sentence at Blackgate, Joker was able to create an electrical storm with the use of Mardon's resources in his lab at Gotham City, which caused a blackout throughout the entire city and even rendered vehicles unusable and resulted in much of the populace going outside for the moonlight. While Batman tracked and apprehended Joker at the lab, Joker revealed that he had weaponized fireworks with Joker Toxin in powder form, which were shot over the entire city and took the lives of thousands of men, women, and children.

This crime, in particular, was immense reinforcement to Batman, who had a small sample of anti-toxin to use on himself and escorted Joker back to Arkham Asylum through a sea of corpses, on how depraved the villain truly was and even compelled the hero to question his own stance on refusing to kill his hated enemy. When Batman finally arrived at the Asylum with Joker, he was horrified when he realized that even the Clown Prince's very suit and skin were also covered with the laughing powder, which caused two orderlies to immediately drop dead when they attempted to escort Joker to a cell. Infuriated, Batman stripped Joker of his suit and threw him into a dark cell within an abandoned wing of Intensive Treatment, to be held and hosed down for several days until all the powder on his skin was completely gone. While imprisoned within the cell, Joker reveled in the Dark Knight's continued torment at his hands and occupied his time by planning a trap for Batman to be potentially used, within that very same cell, in the future.

In addition to his more elaborate plans to employ physical and psychological games on Batman and attack Gotham, Joker also relished in exploits that were purely random acts of barbarism meant to accomplish nothing beyond satisfying his love of sadistic torture and violence. Such acts included replacing holy water with hydrochloric acid during a baptism at Gotham Church, that presumably resulted in the horrific death of at least one child going through baptism, setting fire to a maternity ward, and killing a soprano by tearing out her vocal cords and keeping them as sadistic souvenir. Joker even managed to somehow get himself onto an election ballot, attempted to run for President of the United States, and even went as far as to released political ads that promoted himself to get into the Presidency for the occasion.

With thousands of victims claimed by his sick designs, Joker's presence within Gotham was a constant reminder to Batman of the true evil that could lurk within a human being and how easily it could be for the hero to lose sight of his moral compass as his battles with Joker continued to pile up. Joker himself hoped to push the Dark Knight into committing his first murder with his own death and believed that everyone was corruptible and a monster on the inside, especially Batman. That intent was layered within the foundations of nearly every one of his crimes and plans, with Joker letting Batman live on countless occasions when he had the chance to kill him and even refused to uncover his true identity, believing the reveal would be anti-climatic and would spoil their physical and mental battles.

Years after his arrival and rise to power within Gotham, the Joker had somehow managed to steal a dirty bomb with enough destructive power to wipe out more than half of the city's population with the Riddler's involvement and hid it somewhere inside Gotham while he was imprisoned at Arkham Asylum. Because of that, Batman was tasked with finding the dirty bomb, which resulted in him directly interfering with a separate operation that was conducted by Amanda Waller against the Riddler, although Joker kept its location a secret even from the Riddler. Joker's actions were also indirectly responsible for the Suicide Squad's initiation due to Batman's interference in Waller's operation.

Joker's reign of terror and gang wars with the Penguin also continued, as Joker and Harley lit fire to one of Penguin's delivery trucks, which contained cigarettes and contraband that was meant to be sold onto the streets and dumped it into the river for their own amusement. This caused the feud between the murderous couple and the Penguin to intensify even further, as the crime boss lost a considerable amount of expenses as a result. During the course of that crime, Joker kicked Harley out of their escape car while it moved and presumably gave her severe enough injuries to leave her with bruises, resulting in Harley temporarily breaking off her relationship from the Joker.

Eventually, Joker discovered that Harley seemingly dumped him in favor of a new guy, although he soon realized that her earlier assault on him just gave him an opportunity to escape. Joker then killed several guards and attempted to hold up whom he believed was Batman, although he soon discovered that it was Black Spider, who lost a fight to the Dark Knight earlier and had his costume swapped as part of the hero's attempt to neutralize the Suicide Squad.

He soon deduced the Suicide Squad's location based on Black Spider's earpiece that was still functional and made an ambush on the Suicide Squad with explosive marbles (shortly after the real Batman was exposed by the Riddler as having replaced Black Spider to the rest of the Suicide Squad). After accepting Harley back into his fold, though not before pistol whipping her for associating with Dead Shot, Joker attempted to kill the assassin for "touching his stuff."

However, Lawton was able to turn Joker's mind games back at him by implicating that the villain used the last of his bullets in order to distract and punch him. Despite this, Joker escaped with Harley, set off the timer on the bomb, revealed to have been hidden in Harley's mallet, and made a transmission to Batman that revealed that he intended to leak "tainted love" throughout the city, and also released all of the Arkham Asylum inmates, including Two-Face, Bane, Poison Ivy, and Scarecrow, in order to distract Batman long enough for him to escape with the bomb.

Joker and Harley managed to stow away on a helicopter that Deadshot had managed to hijack, and engaged in a fight with him, which resulted in Harley crashing into an under-construction building due to her inexperience with piloting a chopper as well as Batman pursuing them. Joker then confronted Deadshot, where the clown-like psychopath tried to kill his former hire in a toe-to-toe battle.

Joker eventually managed to subdue Deadshot after he knocked him into a glass panel, although with enough effort that he even admitted that he was "a real pain in [Joker's] ass" for someone who wasn't Batman. However, Deadshot managed to overpower Joker despite his wounded state, and even trapped him inside the crashed helicopter and knocked it down to the street below, although Joker laughed at his seemingly inevitable death. Batman managed to disarm the dirty bomb, thanks to explicit instructions left by the Joker, after he subdued Harley.

Despite being trapped in a helicopter crash, Joker managed to escape into the night. Waller later alluded to that when she taunted Batman. Additionally, it was implied by Joker's instructions to deactivate the dirty bomb that he truly had no intention of the device detonating and knew that Batman would eventually reach him as usual. That latest plan seemed to simply be another sick distraction in Joker's games with Batman and had much bigger plans in store for the hero.

Batman eventually recaptured Joker yet again and sent him back to Arkham Asylum. With breakouts that continuously occurred, Batman utilized his alter-ego, Bruce Wayne, and funded increased security measures at the asylum, while Warden Sharp implemented his own initiatives as part of his own agenda. Unaware to both men and Arkham's staff, Joker's most deadly plans were eventually formed on the foundations of the asylum where its grounds would play host to one of the longest nights in Batman's career and Bruce's life.

Before a Matter of Family

Eventually reaching his breaking point with the Joker, Sharp hired Dr. Penelope Young, a well-known and reputable therapist, to work at the asylum and authorized her to implement several research and experimental operations at the institution in order to cure the most deadly patients, especially the Joker. However, Sharp secretly knew that Joker could not be cured and longed to murder him himself, using Dr. Young's employment at the asylum to simply gain political points for his mayoral campaign.

In reality, Sharp was being manipulated via mind control drugs, disguised as medical pills to treat a heavily concealed mental illness, that were supplied to him by Professor Hugo Strange, a power-hungry psychiatrist who worked at the asylum with plans of his own to exploit both the nature of the institution and its inmates for his own ends. Joker became aware of this fact himself after he noticed Strange observe him in his cell on several occasions and Sharp's altered behavior, using this knowledge to his advantage and as leverage years later.

Among the most pivotal of Dr. Young's experiments was 'Project Titan', the research into formulating a chemical compound in order to bolster a patient's strength and invulnerability to help them cope with the more extreme forms of therapy. However, Dr. Young also became absorbed by her own ambitions and believed that the project could breed a strong class of meta-humans that could be sold throughout the globe to interested parties. To this end, the doctor became intrigued by the compound, 'Venom,' used extensively by Bane, and conducted therapy sessions with the brute when he was temporarily moved to Arkham Asylum before the Suicide Squad's mission, believing that the chemicals derived from Venom could be the perfect foundation for her own serum.

However, Dr. Young hit a wall in her research when she ran out of funding and could not contrive a method to obtain the Venom that she needed from Bane. This soon changed as, unknown to Dr. Young, Joker had learned of her project from his associate, Scarecrow, who was previously asked to use his chemical expertise to help in the project by Young, believing Crane to be well on his way to becoming reformed. However, the reality was that Crane lusted to use his own findings in Titan to perfect his own signature Fear Toxin and collaborated with Joker to plan a brutal riot at the Asylum that would serve both their purposes. Specifically, Joker planned to use the Titan Formula to create an army of mindless monsters under his complete control and use them to destroy Gotham and finish his battles with Batman, while Scarecrow lusted to unleash a new strain of Fear Toxin into Gotham to break the mind of every citizen forever and expose Batman's greatest fears.

Posing as one of his oldest aliases, Jack White, Joker used underground channels to fund Dr. Young's research with his ill-gotten fortune and pulled the strings to have Bane transferred out of Blackgate and into the asylum, with Gotham's populace believing that he escaped from the prison and fled Gotham. With everything that she needed, Dr. Young began to drain large quantities of Venom from Bane and ruthlessly experimented on many of the Arkham patients, which caused most of them the last remnants of their sanity. While it would take some time before the Titan Formula would be completed to suit Joker's desires, the foundation of his plans was in order. Joker then turned his attention towards ensuring that, when such a time came, the brutal battles that would play out would only be between him and his eternal rival and best friend; Batman.

A Matter of Family

"You've seen what happens when you drag your friends into this crazy little game of ours." ―The Joker taunting Batman on getting his allies involved in their battles

With Dr. Young and her projects under Joker's control, several of his successive plans formed into a gruesome campaign to target Batman's closest allies, which started with the second Robin: Jason Todd. While Joker adored and defined himself through his battles with Batman, he had nothing but contempt for the hero's allies and believed that they spoiled his game of cat and mouse with Batman. To this end, Joker once again escaped from the confines of Arkham Asylum, leaving a trail of death and destruction behind him, and embarked on a particularly violent crime spree that was meant to specifically lure Jason into a trap.

During the course of this campaign of mindless violence, Joker abducted, tortured, murdered, and dismembered an entire kindergarten class, knowing of Jason's empathy for children, and stitched their body parts together in horrendous and mocking formations, leaving a trail of blood from the crime scene to an abandoned and underground wing of Arkham Asylum. As Jason watched a mother cry and attempt to put her son back together, he noticed the blood trail and followed it to the forgotten sanatorium of Arkham Asylum and turned off all his communications and equipment in order to ensure that Batman did not track him and attempt to prevent Joker's death.

When Jason entered the wing, intent on killing Joker once and for all, this played directly into Joker's hand, who knocked out Jason with a crowbar, knocking out several teeth and breaking his ankle in the process, and abducted and entrapped him within the wing to torture him over the course of a year. The forgotten halls of the asylum served as the perfect grounds to torture and humiliate Jason as, even when he was eventually caught and locked up once again, Joker had access to the wing thanks to several guards on his payroll, and Batman never suspected that Jason was just below the surface of the fully functional asylum.

With plenty of time, access, and resources, Joker crudely tied Jason to a wheelchair with barbed wire and rope within the filthy and abandoned wing and regularly beat him within an inch of his life with a crowbar, brutalized him with electrical and surgical implements, and convinced him that Batman had forgotten about him by showing him a picture of his new Robin, Tim Drake. As Jason's torture continued throughout the months, Joker eventually strung Jason up by his arms from the ceiling and branded him with a red-hot iron rod, in the shape of a 'J,' on his face to signify that he belonged to him.

Filling Jason with raw emotion and rage toward Batman, Joker finally had Jason sit in front of a camera and voice his hatred of the Dark Knight before he asked him for Batman's true identity. As Jason prepared to answer, Joker quickly shot him in the chest, seemingly killing him, and sent the footage to Batman to further torture the hero, blaming Jason's death on the Dark Knight.

However, the truth was that Joker kept Jason alive and continued to torture him for several more months, deceiving Batman into believing Jason to be dead, as he felt Jason's hatred for his former mentor was too good of an opportunity to kill off. Abducting a doctor from the asylum, Joker had the unfortunate man patch Jason up, his armor had taken the brunt of the bullet, and then immediately murdered the doctor after his usefulness served its purpose. True to Joker's prediction, Jason eventually fled from Gotham after his final days of torture some months later and created a new identity for himself: The Arkham Knight, in order to plan his revenge on Joker and Batman and eventually kill him for failing to save him from the psychopath and apparently replacing him with Tim Drake.

While he tortured and brainwashed Jason into hating his former mentor, Joker also set sights on Batgirl and the second Robin, Tim Drake, and simultaneously began laying the foundations of a scheme to lure them into a trap and kill them. With Batman's surrogate family in disarray with Jason long gone, Joker and Harley formulated a brutal plan to murder the two remaining sidekicks. They knew that they needed the perfect location to embark on such an agenda: a desolate area that was custom made to suit their needs. To this end, Joker, with the help of Harley, targeted billionaire industrialist and oil baron, Edward Burke, who had the resources, finances, and just the right amount of tragedy in his life that was needed to complete their plans.

With Harley and Joker disguised as Dr. Harleen Quinzel and Jack White respectively, and knowing that Burke's young five-year-old daughter, Katie, had battled a case of cancer for years, Harley approached Burke and introduced him to 'Mr. White'. The pair eventually convinced the man to use his resources to construct an amusement park for his young daughter, as a way of uplifting her spirits. Joker helped Burke outline the blueprints for the park and formulated many of the layouts and attractions himself, in preparation for his plans to come, while Harley became Burke's psychiatrist to help him cope with his tragic situation, which allowed the villains full access in order to manipulate Burke's emotions.

With encouragement from Harley, Burke retired from his job and worked on the park full-time, using the drawings Katie made at her time in the hospital as inspiration for rides at the park and promised her that she would be the first to see the park before it opened. However, when Katie's condition worsened, Joker referred Burke to Dr. Young, an aspiring therapist who worked at Arkham Asylum. Unknown to Burke, Joker was also manipulating Dr. Young under the same alias for several other plans he was cooking up at Arkham Asylum and knew that, while her medication would help Katie in the short-term and allow the time that was needed to complete the amusement park, it would eventually worsen her condition and ensure a slow and painful death.

The alternative antibiotics that were prescribed to Katie were actually experimental chemicals and drugs of Dr. Young's creation, who was looking for useful test subjects in order to conduct clinical trials and hoped to accelerate her own research into creating new medication for her private practice and even serve as an asset for dangerous operations and unethical research being implemented at Arkham Asylum, specifically the Titan Project, all of which was also orchestrated by the Joker.

Eventually, Burke was able to complete Seagate Amusement Park as Katie seemed to finally be doing better, which was built off the coast of Gotham atop one of his oil rigs, with the only setback being several inspectors who threatened to shut the park down due to safety issues. In response, Joker murdered the inspectors, telling Burke that he managed to convince them to approve of the park, and was able to complete their project once and for all. However, Dr. Young's experimental medications finally began to take their toll on Katie as Joker instructed Dr. Young, who did not want to run the risk of disagreeing with her most viable financial backer and unaware of how much medication the young girl already took due to Joker's manipulative nature, to triple her dosage of "alternative meds".

As planned, this not only accelerated Katie's cancer, but caused a much more slow, painful, and agonizing death, which ultimately resulted in a drug overdose for the young girl. Joker, still posing as Jack White, blamed Burke for Katie's death, as he implied that Gotham General, the hospital that she stayed at prior to meeting Joker and Harley, was not the proper place to check Katie into. Joker managed to convince Burke to give him the lease for the park, now that his motivation and daughter were both gone, as Harleen reaffirmed to the man that his pain and misery would never go away. Pulling the last string, Joker convinced Burke to commit suicide and gave him his own medical pills to ensure a quick and painless death.

Burke agreed and hoped to reunite with Katie in the afterlife, but when he took the pills in his office at the park, it was revealed that they were laced with Joker Toxin, which caused Burke to slowly and painfully die on his bed and with a smile on his face, just as he finally realized the truth of his former friend. The park was left unopened due to never receiving a permit as Joker murdered the inspectors, and Burke's status was officially marked as "missing" by the GCPD due to a body never being found. Unknown to the authorities, Joker left Burke's corpse to rot away within his office, with the body eventually reduced to a mere skeleton, as he converted the park into a new base of operations.

With the park under their complete control, Joker escaped from Arkham Asylum once again with the aid of his inside agents and, with his Harley and dozens of his followers, attacked the GCPD and abducted Commissioner Gordon and over a dozen police officers. At least one of those unfortunate officers was brutally tortured and murdered by Joker, who then wore his blood-stained uniform. Acting as a hostage, Joker had several of his men guard him at one of their hideouts and waited for Batgirl to show-up, who worked off a tip, which was also orchestrated by Joker to commence his sadistic trap. After she arrived at the hideout and defeated all of Joker's men, Batgirl was startled and frightened when she realized that the apparent officer that she rescued was the Joker, having never faced him without Batman.

Taunting her, Joker informed Batgirl that Commissioner Gordon and several of his officers were held hostage at the Seagate Amusement Park and that only she and Robin were allowed to rescue him, threatening to murder Gordon if Batman was made aware of the situation. With all the pieces lined up, Joker escaped, allowed Batgirl to go to the park, and predicted that she would also inform Robin due to her inexperience with such a situation. Believing that Batman's sidekicks would distract him from his games of cat and mouse, Joker hoped that the death of Batman's remaining sidekicks would allow their battles to revert to their original circumstances of simply being between him and Batman.

Situating himself at the amusement park, Joker murdered some of his own henchmen, including a man named Paulie, in his own spare time as he waited for his intended victims to show up. Transforming the park into a death trap, setting off sections to blow with explosives and Joker Toxin, and holding the various police officers hostage, some of whom were viciously tortured and murdered and, with the holiday of Valentine's Day approaching, Joker planned to kill both Batgirl and Robin as a twisted holiday gift for Batman, who was still coping with the loss of Jason. As Batgirl and Robin made their way to the park on the lifts and rescued an officer who was held hostage, Joker fired an RPG at them and sacrificed several of his henchmen in the process.

Arriving at the derelict park, Tim and Barbara were forced to fight off scores of Joker's followers, navigate through death traps, deactivate the bombs, and ultimately faced off against Joker and Harley in a showdown. Despite the overwhelming odds, Joker and Harley were eventually defeated by Batgirl and Robin's combined efforts and their plans of further destroying Batman's family were ruined. Unfortunately, as the GCPD raided the park, Joker used Harley as a hostage and, after a failed attempt on Robin's life, jumped off the oil rig, opened a parachute, and escaped onto shore and into the night.

After she rescued Commissioner Gordon, Barbara's alter-ego as Batgirl, though greatly shaken from the experience, begun to further rise to fame within Gotham as Harley was arrested and sent back to Arkham once again, though Joker was still out there and ready to embark on his next schemes. With Batman's sidekicks shaken, Joker decided to specifically target Commissioner Gordon next, both in revenge for his earlier escape from Joker's plans and to further attack Batman's network of allies and hoped to additionally prove to both Batman and Gotham that even the noblest of men could be corrupted and pushed into madness.

To this end, Joker disguised himself as a delivery man with a candy package and headed to Barbara's Apartment, though he was unaware of her alter-ego. Upon Barbara (who was reading at home at the time) answering the door, believing that it was her friend Colleen, Joker then announced his presence and shot Barbara through her spine as she attempted to flee, which paralyzed her from the waist down. Taking violent photos of Barbara in various states of distress, Joker eventually left in gleeful anticipation of her father coming home to his daughter's violent assault.

Joker abducted Gordon once again, upon the Commissioner finding his bloodied daughter, and forced him to relive the same situation of being imprisoned within a theme park, presumably the Seagate Amusement Park once again as a sadistic calling card to Batman, though this time, he was forced to watch a crudely made slideshow of Barbara, bleeding and paralyzed, in an effort to drive the Commissioner insane. In the end, Gordon retained his sanity as Batman rescued him, cornered Joker and, in a rare moment of sympathy, genuinely reached out to his foe, and asked to help him give up his life as "The Joker," in order to finally end their inhumane war with each other before anyone else died.

In an equally unique moment of respect, Joker seemed to sincerely appreciate Batman trying to help him before he declared that it was far too late for him and that his life would forever be committed to their battles. As Joker recited a joke that personified his feelings on how the world viewed him, which entailed that society would eventually give up on trying to understand and redeem a man such as himself and would forever be an outcast due to his numerous crimes, the two rivals shared in a laugh as Batman once again resisted the immense temptation to end the Joker's life and apprehended him. The Joker was finally sent back to Arkham Asylum, but Barbara's life as Batgirl tragically came to an end, but also led to the chain of events that created her new persona as Oracle.

As Batman attempted to heal his family with Jason believed to be dead and Barbara paralyzed, Tim Drake's heroic actions at Seagate Amusement Park finally convinced Batman that the young man was fully qualified to bear the mantle of 'Robin.' Meanwhile, the Joker was far from finished and was prepared to unleash plans that were years in the making that would forever change the fate of Batman, Gotham, and the world itself.

Road to Arkham

After Joker was recaptured by Batman yet again and sent back to the asylum, Dr. Young's Titan project was nearing completion with little over a year of research and experimentation required. Continuing to experiment on Bane, Dr. Young pumped nearly every ounce of Venom from the villain's body to finally complete her project, leaving the unfortunate man strung up within a secret lab and barely clinging to life, and mutated plants within the Botanical Gardens to create unique plant hybrids to produce the desired chemical components necessary to complete the Titan strain, an act that infuriated Poison Ivy.

Believing Joker to be an ideal, first candidate for the research, as curing the apparent insanity of Gotham's most notorious and inhumane villain would further highlight her professional reputation and pave the way for additional research backers, Dr. Young was eventually horrified when Joker revealed during one of their therapy sessions that he was behind the entire project, having funded the research and pulled the strings to have Bane moved to the asylum. Realizing the true scope of the villain's plans and how much damage and tragedy her involvement has caused, Dr. Young was guilt-stricken with all that she has done under Joker's manipulation, transferred the money back, and put a block on her account.

Never one to appreciate when his partners back out of an agreement, Joker began to blackmail and threaten the doctor, before brutally escaping from the asylum after Sharp, under the influence of Strange, attempted to kill him with a knife. With the aid of Scarecrow's new fear toxin, Joker was able to stun Sharp and threaten him with his own knife, before letting him live (believing Sharp's mental state to be a valuable asset to him) and escaping, viciously murdering three guards in the process. For two months, Joker remained under the radar within Gotham City, carefully planning his every move to obtain the Titan formula and create his army himself. Sending threats to Dr. Young and her family, including an image of a deceased infant, Joker warned his former associate that he would be coming for her. Horrified, Dr. Young filed a resignation letter to the asylum and made plans to leave Gotham before Joker returned, as the villain acted on the next steps of his schemes.

Setting a massive fire to Blackgate Penitentiary via a mole among the Arkham personnel, the crooked security guard Frank Boles, Joker instigated a sequence of events that allowed over a thousand of his crew to be transferred from the prison and into the asylum. Meanwhile, Quinn had managed to convince some of the asylum orderlies that she was well on her way to becoming reformed, and was allowed to assist them in their day to day operations. This gave Quinn access to many security measures at the asylum, enabling her to secretly release several inmates who were informed and part of Joker's schemes, including Scarecrow and Zsasz, and would make it all the easier for Joker to take over the area. With everything in place, Joker just needed to give Batman an incentive to escort him back to the asylum.

Roughly a decade after his emergence in Gotham, and at the height of his power and influence, the Joker and his goons raided Gotham City Hall , claiming that the city had "a paucity of parking spots designated for clown cars," and took the Mayor hostage, tying him up and strapping a bomb patterned after the colors of the American Flag to his chest. As the Joker taunted the Mayor, he expressed his displeasure that Batman hadn't shown up who ironically attacked moments later.

The Joker tried to escape via a large parachute but was stopped by Batman, who proceeded to escort the Joker to Arkham. In addition, as a direct result of Joker's assault on the Mayor, the Mayor declared that he was resigning from his position, having had enough of the city. Batman, however, sensed that the Joker went down too easily. True to his instincts, Batman would eventually learn that Joker's latest crime spree and capture were all orchestrated by the Clown Prince of Crime to begin his latest schemes. Joker's most recent plans would involve Arkham Asylum itself and his continued manipulation of Dr. Young.

Batman: Arkham Asylum

"Welcome to the madhouse, Batman! I set a trap and you sprang it gloriously! Now let's get this party started." ―The Joker proclaiming his trap to Batman within Arkham Asylum[src]

Batman arrived at Arkham in the Batmobile, taking the Joker to the Intensive Care Facility personally, as the villain previously did not put up too much of a fight and seemed too happy to be back at Arkham Asylum. Overseen by the warden himself, the villain was strapped to a prisoner movement trolly and wheeled through Intensive Care by a variety of guards, including Boles, with Batman following close by.

During the escort, the Joker made shrewd remarks to many of the Arkham Staff including Warden Quincy Sharp, Officer Aaron Cash and Dr. Penelope Young. After spooking a member of the medical staff observing him for any injuries from his most recent fight with Batman, Joker was taken down to the lower levels via the elevator, while Killer Croc was being escorted back to his cell. During the elevator journey, Joker commented on the convenience of a fire occurring at Blackgate Penitentiary, as it enabled hundreds of his crew to be moved into Arkham, implying to Batman that it was no coincidence and allowed him to have a ready-made army at his fingertips. He also proceeded to give a veiled threat to Frank Boles when the latter yelled at him to keep quiet. Shortly afterward, a blackout occurred throughout the facility, causing the Joker to laugh hysterically before having his neck clutched by Batman as the lights turned back on.

As the Joker was moved into the lobby area, one of the guards remarked that he'll pay for killing three of his friends during his previous escape, to which Joker, in foreshadowing what's to come, expressed disappointment that he only killed three, and promised to kill more, namely aiming for a hundred more deaths of personnel. Upon arrival to the lobby area, he was unstrapped and escorted by a guard and medical assistant, while Batman and Commissioner Gordon looked on. Unknown to all but Joker, Harley Quinn was already in control of the asylum's security, while Scarecrow was monitoring the situation himself from a makeshift lair, waiting for Joker to commence their plans. Joker soon took the opportunity to break free at Harley's signal.

Pretending to stumble and trip, the Joker bashed his guard in the face with the back of his head when the guard demanded him to get up. He then used his handcuffs to strangle the guard, forcing the doctor to unhook the Joker to save the guard. Joker strangled the guard to death before the doctor could save him and, once his cuffs were off, fatally kicked the doctor down, breaking his ribcage and killing him as well. Taunting his latest victims, Joker signaled to Harley, who opened up the adjacent electrical doorway, allowing the Joker to access the cell controls.

He ran behind the energy screen just as Batman managed to break through the viewing window and into the room. He taunted the Dark Knight for springing his trap and released his followers from Blackgate out of their cells, officially commencing the Arkham riots. After Batman defeated a round of thugs, let loose from the adjacent cells, the Joker left the room and made his way to the patient transfer unit. Batman informed Gordon he would find a way out, but Joker told Batman not to make promises he couldn't keep, as he was in control of the asylum and therefore where Batman was able to go. As Batman told Joker he wouldn't let him escape, the villain goaded him into pursuing him.

Around the same time, Joker took complete control of the security systems, isolated Arkham Asylum from the network grid, and leaked a taped message to all the major news networks, claiming that he had placed bombs all throughout Gotham City, including a hospital, kindergarten, and Bruce Wayne's mansion, and would detonate them if anyone set foot on Arkham Island, including the police, newscasters, and any other vigilantes and heroes. As a result, Gotham descended into panic, as authorities restricted all access to the island, including air space, leaving the staff at the mercy of Joker's deranged designs and Batman to stop the riots by himself. However, Batman accurately predicted that there were no actual bombs and Joker's threat was simply a twisted diversion to keep the city occupied while Joker concentrated on his true objectives.

Joker and Harley released hundreds of inmates throughout the Asylum, causing the entire facility to go into lockdown. In addition to releasing hundreds of his own crew, Joker also rallied dozens of additional inmates from Blackgate, who were not initially part of his plans or gang, but hoped to use the riots as an opportunity to secure their own freedom and even make some profit by being in Joker's employ, though some ultimately came to regret this decision, while others simply joined due to their mutual love of the chaos Joker was unleashing.

With both the Asylum and Gotham in chaos, Joker made his way to patient transfer, murdering ten more guards who stood in his way and released his deadly laughing toxin into the air ducts of decontamination (the toxin having been prepared by his inside agents prior to his arrival), killing sixteen people, including several henchmen he left behind within the room. At the same time, the freed Zsasz slaughtered an Arkham guard and took another one hostage in patient pacification, strapping him to a chair wired with electricity.

After Batman incapacitated Zsasz and rescued the guard, Harley Quinn revealed herself via the area's monitor, took control of the room, trapping everyone behind the room's electrical gates as a result, and revealed that she had the warden tied up and as her hostage. Batman was able to easily escape from the room via one of the air ducts, turned the ventilation system back on in decontamination to clear out the laughing toxin, and followed Joker's trail of spray-painted smiles and arrows