The Joker is a maniacal anarchist criminal mastermind who terrorizes Gotham City and whose goal is to create "a world without rules".
Arrival in GothamEdit
Shortly after the death of Ra's al Ghul, Batman discussed with Lieutenant James Gordon the effect that he had made on Gotham City since his appearance. Gordon then revealed that a criminal with "a taste for theatrics" recently committed a double homicide and an armed robbery, leaving behind a Joker playing card as a "calling-card". Gordon also warned that just as escalation occurs in terms of the police force against crime, so might the scale and style of criminality change in reaction to Batman's appearance.
Some time later, the Joker would orchestrate the theft of a large shipment of ammonium nitrate from the Gotham Docks. The explosive chemical was saved for storage in the Gotham General Hospital and on two passenger ferries some time later.
Several months later a group of bank robbers, under the direction of the Joker, robbed Gotham National Bank which was used as a money-laundering front for Gotham's gangs. The clown mask wearing robbers whittled down their own numbers within minutes in a series of calculated betrayals. Finally only "Bozo" remained, who revealed himself as the Joker to the manager of Gotham National Bank, who had earlier confronted the robbers with a shotgun. The Joker then escaped with the bank's cash in a yellow school bus, concealing his identity by driving within a convoy of other buses.
Dealing with the MobEdit
Shortly following the bank robbery, Italian crime boss Sal Maroni mentioned the Joker's recent theft of Mob owned cash to his fellow crime leaders at a business meeting, dismissing him as a threat and saying that he was a "nobody" wearing a "cheap purple suit and make-up". The Joker, overhearing this comment and the plan presented to the Mob by Chinese mobster, Lau, arrived unannounced at the meeting while faking a laugh, as he saw their "so called plan" as a bad joke. He also described the meeting as a "group therapy session". The mobsters were at first unwilling to even hear him out, and Gambol, one of the crime lords who seemed to take the most dislike for the Joker when setting eyes on him, sent one of his men to take him out by force, but the Joker unexpectedly said he was going to perform a magic trick by making a pencil "disappear" and embedded the pencil in the table, and then when Gambols's goon was about to grab him, the Joker quickly countered his attack and shoved him head-first into the pencil where it indeed disappeared inside the man's head via eye socket, instantly killing him. The Joker also mentioned that his suit wasn't cheap and that they ought to know this since they bought it, which meant that he used the money he stole at the start of the film to buy his suit. He proposed that it was Batman's interference that had resulted in idealistic leaders like Harvey Dent rising in popularity, and offered his services to kill him for half of all the money that Lau, an illegitimate Chinese accountant, took away from Gotham for safe keeping. He also warned them that Lau would betray them if arrested, claiming to know a squealer when he saw one. While the Bratva mobster, the Chechen, and Maroni were interested, Gambol, angered by the Joker's lack of respect, attempted to attack him, forcing the Joker to reveal his insurance policy: several grenades hidden under his coat, allowing him to make a quick escape. Frustrated, Gambol proceeded to put a bounty on him. The Joker later took revenge that night by having his men come to Gambol, claiming to have killed the Joker. In a bit of unintended tragic irony regarding the fate of his actor, the Joker's 'dead' body is brought inside in a garbage bag before attacking Gambol and proceeding to tell him the origin of his mouth scars as a way of psychological torture and intimidation, then when Gambol is most terrified and shaken, the Joker proceeds to kill him with the knife. Then with the remains of Gambol's men overpowered and at his mercy, he takes a pool stick and breaks it in half, making it sharp-like and says that there is only one spot open at the moment to join his "team", then throws the piece of sharp stick at the middle of Gambol's scared men and has his gang, made up mostly of mentally-ill and unstable vicious crooks escaped from Arkham Asylum who seem to have taken the Joker as their leader, to make Gambol's men fight to the death with the stick until only one is left, and advising them to "make it fast".
The Joker's ThreatEdit
Eventually, realizing that Batman had retrieved Lau from Hong Kong and that the police had struck a deal to testify against them, Sal Maroni and the Chechen relented, finally hiring the Joker to kill the Batman. The Joker first kidnapped a Batman impersonator, filmed his murder and hung the body, complete with white make-up and a Joker scars, outside the mayor's office. In the murder tape he sent to the media, the Joker viciously mocks Brian Douglas (batman impersonator) as well as terrorize him to the point of leaving him absolutely frozen and weeping, as well as taunt his beliefs and his actions. Then when finished humiliating him and disturbing him into terror, he proceeds to give Gotham a ultimatum. Batman must take off his mask and turn himself to the authorities and every day the Batman refuses to do so, he will murder innocent people day after day. As a result of the Batman not turning himself in, the first major victims were Janet Surillo, the judge presiding over Dent's indictments, and then Commissioner Gillian B. Loeb.
Later the Joker and his gang stormed a fundraiser at Bruce Wayne's penthouse to kill Harvey Dent and was confronted by Batman. The Joker only managed to escape by throwing Rachel Dawes out a window, who Batman then lept after and saved.
The killings then continued with two innocents and an attempt on the mayor's life at a memorial for the murdered police commissioner. The Joker appeared in public without makeup, impersonating one of the Honor Guards, and shot his rifle at Mayor Anthony Garcia. Lt. James Gordon was struck in the back after willfully leaping in front of Garcia, in order to fake his death to avoid any future attempt by the Joker of attacking him with his family at home. As a result of this, Batman told Dent to call a press conference so he could reveal his identity and stop the killings. In a surprise move, Dent instead claimed to be the Batman himself and was subsequently arrested.
While being transported the Joker and his gang attacked the caravan of police vehicles to kill Dent with his machine gun, a shotgun and even a rocket-propelled grenade. Batman soon arrived to stop the assault, but stayed his hand at killing the Joker. The Joker prepared to unmask Batman but Lt. Gordon, newly resurrected from his hoaxed death, stepped behind him and aimed his shotgun at his back. The Joker was sucessfully jailed at MCU, and as a direct result, Lt. James Gordon was promoted to Commissioner by the Mayor.
Assault on GothamEdit
With the Joker in custody Gordon and Batman believed his madness was over, but became alarmed when informed that Harvey Dent had gone missing. Desperate, Gordon let Batman torture the Joker for information, but the Joker seemed unshaken by the pain. Instead, he gleefully told Batman his view of people as selfish and violent, only needing a little pressure before descending to madness. He also admited he could never kill Batman, considering him his only equal. Dent's kidnapping was part of a test, to see if Batman would save him or Rachel, whom the Joker could tell Batman cared for. The Joker willingly told him where both were located. After most of the police were gone, the Joker took his guard hostage and escaped by detonating a phone-activated bomb he surgically planted in the stomach of one of his men who was arrested with him, with Lau in tow. Gordon was disheartened when he realized the Joker wanted to be captured.
Dent and Rachel each awoke tied to chairs with barrels of explosive material surrounding them and a speakerphone hooked up to the other's location. Rachel confessed her love for him and agreed to marry him. Harvey fell on the floor and his left side was completely immersed in turpentine. Batman arrived but found Dent instead of Rachel. He realized that the Joker had lied about Rachel and Dent's whereabouts to further crush Batman's morale. Batman rescued Dent as the building exploded and Harvey's face was badly burned, while Gordon was unable to rescue Rachel before the explosion. In the hospital Harvey was driven to madness over the loss of Rachel, and blamed Batman, Gordon and the Joker. This act caused Sal Maroni to tell Gordon the Joker's location, finding him and his craziness "too much" for business. The Joker later met the Chechen in a container ship with Lau and was given his reward: half the mobs smuggled money, which he casually burned along with Lau. He then betrayed the Chechen and took control of his men.
The Joker then made a call to a news program where Coleman Reese was threatening to go public on the news with information about Batman's identity. He was interrupted by the Joker who stated he had changed his mind, believing Gotham to be too boring without Batman. To "give others the fun" he threatened that if someone didn't kill the employee in sixty minutes he would blow up a hospital. Gordon then abandoned his ambush on the Joker to focus on evacuating all city hospitals
Contact with Harvey DentEdit
During the mass evacuation, The Joker poorly disguised as a nurse (still wearing his trademark face paint), entered the hospital room of Harvey Dent. He first apologized to Harvey, maintaining that he was not responsible for Rachel’s death as he lacks any idea for the repercussions of his actions, while the restrained Harvey attempts in vain to kill him. The Joker introduces Harvey to his view of the world that his time in Gotham has introduced him to, that people, or "schemers" as he calls them, are the truest form of evil in the world, as it is them who lay out the plans of society, including when human lives are expendable. To prove his argument, he points out that if his threats were aimed at 'gangbangers' or 'soldiers', then people wouldn't really care as society trains them to see the death of such people as acceptable. Thus, he turns the disillusioned Dent against society and against the "schemers" who put his and Rachel’s life in danger, namely the corrupt cops who kidnapped them, as well as the "schemers" who viewed Rachel's life to be expendable, namely Batman and Gordon. Giving Harvey a gun, the Joker advised him to break away from the law that failed him and turn to anarchy and chaos, which the Joker describes as the only truly fair system, as the fate of everyone would be only be decided by chance, without the interference of the flawed laws of Man. Dent responded by flipping a coin to decide the Joker's fate, giving him the same chance Rachel had. Soon after Dent left, Joker detonated the Gotham General Hospital, skipping merrily away (pausing and hitting his detonator when most of the bombs temporarily fail to blow). He and his men then steal one of the nearby evacuation buses and kidnapped the TV reporter and his crew inside.
The Joker declared that he would rule the streets and that anyone left in Gotham would be subjected to his rule. He told people they could leave now but that he would have a surprise for them in the tunnel and on the bridge, which people then avoided, using instead two ferries, one ship full of ordinary civilians and one of criminals, as Gordon feared the Joker would want to recruit them. However, the Joker had loaded each of them with explosives. In hopes of showing everyone how evil and corrupt they can be, he gave the passengers of each ship the detonator to the bombs to the other and offers both survival if they detonate the other ferry. If they didn't choose by midnight, the Joker would blow up both ships.
Batman discovered not only the Joker's location at an unfinished skyscraper, but that the majority of his "gang" were actually hostages wearing clown-masks with unloaded guns taped to their hands and that the people dressed as hostages were the actual criminals. Batman was forced to fight not only the Joker's men but the SWAT teams as well to save the hostages. He finally confronts the Joker, which led to final battle between the Joker and Batman (with the Joker using two crowbars and a knife). But Joker manages to get the upper-hand and pins batman under the scaffolding. He gleefully waited as the ferry's deadline neared, and was visibly disappointed when both groups of passengers refused to kill the other to save themselves. The civilians voted to blow up the other ferry, but could not bring themselves to actually do so, while one of the criminals stepped forward and, taking the detonator, threw it out a window, saying that the cops should have done that from the start. Before he could detonate both ferries, Batman hit him with his shooting wrist-blades and threw the man over the edge. The Joker starts to laugh as he falls to die, but Batman, refusing to kill him, instead caught him with his grapple gun and leaving him hanging for the police to capture, much to the Joker's anger.
With this act, the Joker acknowledged that Batman really is incorruptible but that Dent is no longer the "White Knight"; he's unleashed the scarred man on the city. Joker states that Dent was his "ace in the hole" in his plan to show the people of Gotham that everyone is corruptible, thus undoing Dent's work before his transformation into Two-Face. Batman angrily left the Joker to dangle helplessly as he was approached by the SWAT team. As they approached him at gunpoint, he laughed maniacally, swaying on the line.
The Joker is hired by Magneto in the Alpha War.