The Joker (DC Animated Universe)

History
Jack Napier started out as a young enforcer working for the mob triad of Sal Valestra, Buzz Bronski, and Chuckie Sol. At one point early on, before his future accident, he and Bruce Wayne caught a glimpse of each other. One of his last jobs took place in Europe on the Mediterranean Coast. His target was Carl Beaumont, a businessman who had fled the states after the mob bosses discovered he'd embezzled a fortune.

Years later, Jack formed his own gang and staged their first robbery at the Ace Chemical Plant. It was during this heist that he first encountered Batman. It's unknown whether Jack was pushed or simply fell, but he did fall off a catwalk and into a drainage vat of chemical waste that washed him out into the river. The chemicals had an adverse effect on him: they dyed his hair green, his skin was bleached white, his clothes were dyed purple, and his lips were stretched into a permanently stained red grin. All this snapped Jack Napier's already twisted mind and sadistic nature, giving birth to The Joker. Vowing to show the world the triumph of his comic genius, the career of one of history's worst dangerous and intelligent psychopaths began.

Endeavors
Joker's plans have little prejudice. Although he has shown particular delight in playing his jokes on the most ordinary, innocent victims, like mild-mannered salaryman Charlie Collins, he is just as dangerous to Gotham's highest level officials, Commissioner Gordon or Mayor Hill. But the Joker has had his share of provocations. Joker was one of three villains to travel to Yucca Springs on an invite from Hugo Strange, who claimed to know the identity of Batman. Ex-businessman Cameron Kaiser deliberately made his newly built casino resemble the Joker's look to draw the villain out.

Depending on the joke, his plans can range from small-scale to global. On one occasion, the Joker tried to con his way to a local comedy trophy by using the Mad Hatter's mind control chips on the event's judges. Another time, the Joker stole a nuclear warhead and almost successfully set it off on the residence of Mayor Hill.

A frequent inmate of Arkham Asylum, the Joker was often psycho-analyzed, at one point by Dr. Harleen Quinzel. After one session, the Joker fooled Dr. Quinzel as he painted himself as a misunderstood soul crying out for the world to accept him. Quinzel soon found herself in love with the Joker, and broke him out of Arkham. However, a combination of Joker's ego and Quinn's lack of humor tends to push the Joker's buttons. More often than not, the Joker abuses and throws Quinn onto the streets until he decides he wants her again.

Batman shuts down the Joker's Gotham operations on a routine basis. But on a few occasions, the Joker really did go bankrupt. One such instance caused him to travel to Metropolis, where he briefly allied himself with Lex Luthor to kill Superman for one billion dollars. The Joker planned to use 'the Laughing Dragon', a collector's item actually made of Kryptonite. Joker's plans fell apart when Batman deduced what the antique was made of and headed to Metropolis. Consolidating his losses, the Joker kidnapped Luthor and hijacked his experimental LexWing assault vehicle. Joker returned to Gotham a month later, still bankrupt. He unwittingly received a $250 million inheritance from his ex-gangland rival, Edward "King" Barlowe. Joker immediately spent the first million on various pursuits, such as hiring a defense team to wipe his criminal record clean. However, the Joker was duped. The majority of the money was counterfeit and the IRS was claiming its dues. Desperate, the Joker tried to steal a routine money dispersal from the Gotham Mint without using any of his trademarks. Batman intervened again, and the Joker returned to Arkham.

During the seven-year anniversary of his transformation into the Joker, the Gotham Insider made a live report from Ace Chemical Plant. The Joker made an appearance and attacked the news crew. Jack Ryder was doused with the Joker's toxin, then shoved into a drainage vat. Ryder transformed as well, but the combination of the chemicals and the laughing gas pushed Ryder further. Fashioning himself into a crazed vigilante known as the Creeper, he went on a rampage to get revenge on the Joker. Somewhere along the line, the Joker was saved and Batman sedated the Creeper.

Other Schemes
In another routine shut out, Joker was forced to move his enterprises outside of Gotham. This time he chose Dakota City in Michigan. The Joker planned on forming a metahuman gang. Batman, Robin, and Dakota's own resident hero Static teamed up and escaped the Joker's death trap, arresting the Clown Prince of Crime in the process. Years later, the Joker wound up in Metropolis. He was just in time to meet Lex Luthor's Injustice Gang, which he conned his way into staying by providing his expertise on Batman. His one condition was this: after the Justice League was successfully destroyed, the Joker was promised Batman. However, the League survived and went after the Gang. Joker cut his losses and attempted to kill Batman, but it seemed Batman had manipulated the situation throughout the endeavor.

The Joker tried to form a metahuman gang once more. He discovered and entered a secret government compound dubbed Section 12. At the time, it was under the supervision of the Cadmus Project, a federal initiative to procure defenses against the Justice League. Joker freed their captives and fashioned them as a card deck hand, dubbing them his 'Royal Flush Gang'. He then purchased air time on several networks under the moniker of "Gwynplaine Entertainment" and broadcast a live feed of Las Vegas. The Joker secretly planted several dozen high explosives all throughout the city. Though the Justice League manage to disarm the bombs, the bomb stunt was merely to attract viewers throughout the world. The real plan was to use the powers of the Gang's fifth member, Ace. Joker transmitted Ace's thought waves across the air to render everyone under a mass psychosis. Batman confronted the Joker alone, and managed to reveal to Ace that the Joker held on to a special headband used to nullify Ace's powers. Ace, in turn, used her power on Joker and temporarily incapacitated him.

Final Joke
Years later, as he was deciding that the game between him and his nemesis was growing old, the Joker devised one last scheme, directed at Batman and his "family." The Joker kidnapped Robin(Tim Drake) while the Boy Wonder was alone on patrol. For three weeks, in the former Arkham Asylum, the Joker systematically pressured and brainwashed Robin. After several serum injections and shock torture, Robin revealed all his secrets to the Joker. He then dressed Robin as crude version of himself, completing the "makeover" by splicing their DNA together, and planned on using him to deliver the death blow to Batman. The Joker even went far enough to document Robin's torture and show it in the operating theater to Batman and Batgirl. While succeeding in enraging Batman, Joker delivered a knife to Batman's knee, crippling him. However, not even the Joker could fully turn Robin, and rather than shoot Batman and "deliver the punchline", Robin shot and killed the Joker, his last words being a sad "Th-that's not funny...". Though he was buried deep beneath Arkham, Joker's last bid tainted the trio and further engineered its end.

This was not the end of the Joker, though. While he had Robin in his possession, the Joker subjected Robin to another experiment of his own. Using stolen government nanotechnology, Joker encoded his DNA into a microchip and implanted it at the top of Robin's spinal cord. Over time, the Joker's subconscious awakened and began to assume control of Drake's body. Over the course of forty years, the Joker plotted his return. With Drake's knowledge of communications, Joker staged a series of corporate thefts utilizing a sub-group of Jokerz. With the technology, Joker created a satellite jammer and hijacked control of a Hyperion class defense satellite orbiting the planet. The new Batman (Terry McGinnis) deduced Drake had some connection and confronted the Joker. In the skirmish, the jamming system redirected the satellite's laser straight to Joker's hideout. Batman stranded Joker within the compound and fought him one on one. In the finale, Batman used Joker's own toy buzzer and electrocuted him. The surge destroyed the microchip and ended the threat of the Joker once and for all.

Abilities and Equipment
Throughout the years, the Joker used a wide variety of instruments to exact his comedic homicides. His equipment included guns (of the trick and real variety), joy buzzers (which electrocuted the victim), and a wide variety of laughing gases (which incapacitated the victim with laughter). Most famously, the Joker had a flower attached to his suit. This flower emitted a wide variety of chemicals, depending on the situation and the Joker's mood. Laughing gas and acid were popular variants, but the possibilities were limited only to the Joker's mind.

Joker also seemed strangely resistant to death, constantly surviving and coming back from things - including long falls, explosions and even being psychically mind-wiped, to name a few (the last one being possibly explainable by the complexity of his own mind) - that should by all rights have ended his career, until he finally died in Terry McGinnis era.

Originally, the Joker possessed little more than average physical strength, albeit enough to regularly hold his own against Batman. However, upon inhabiting the mind of Tim Drake, he acquired the training, conditioning, and knowledge of Batman and Robin.

Joker owns two pet laughing hyenas, named Bud and Lou, after Bud Abbott and Lou Costello.

Revamp
Along with the rest of the cast, the Joker underwent a revamp when Batman: The Animated Series streamlined into The New Batman Adventures. The Joker's change was relatively minor; however, he lost his trademark red lips, his hair was almost black, and his eyes were turned black. Joker is rarely shown alone in the revamp, He is generally joined by his main squeeze, Harley Quinn, and his hired muscle Mo, Lar, and Cur. The character was altered again for appearances in Justice League and Batman Beyond, and color was added to his eyes and lips once more.

Background Information
Although none of the identities revealed in the comics for The Red Hood/Joker ever gave him a full name (though some have given him the first name Jack and his cousin almost called him 'Cousin Ja..' before being shushed by The Joker) "Jack Napier" was used in Tim Burton's 1989 Batman and later utilized in the DCAU as well. In "Dreams in Darkness," Dr. Bartholomew refers to him by that name, and in "Joker's Wild," his name can be seen in a file about him. But for some reason in "Beware the Creeper" it is mentioned that his true identity is unknown and that he operated under a variety of aliases during his criminal career. This is may be attributed to the Joker hiring a team of shady lawyers to erase his criminal record, and possibly his identity, in "Joker's Millions." Either they or Joker himself could have altered his file to show that he had operated under a variety of aliases. It is also possible that Joker did indeed use a number of aliases, and that Jack Napier is simply his most commonly agreed-upon name.