Joker (Batman: The Killing Joke)

The Joker is a psychopathic, clown-like criminal of Gotham City and Batman's most widely known villain. He is the main antagonist of the 2016 animated adaptation of Batman: The Killing Joke during the main story and only one of two main antagonists of the film (the only other being Parris France for the Batgirl prologue).

He was voiced by Mark Hamill, who had previously voiced various other Joker incarnations, most notably the one from the DC Animated Universe, and the one from the Arkham series.

Early life
Supposedly, he had initially been an unknown engineer for Ace Chemicals that had been married and an expecting father before he quit his stable job, both due to his being creeped out by the location, and to do a dream job of being a comedian due to wanting to make people laugh and feel good. However, he ended up struggling regarding his job, and was forced to contend with a landlady who hated him. Upon returning from his job where he was uncertain that he did a good job (the people in charge of the club indicated that they may call him back, but he was certain he blew a punchline for one of his jokes). He eventually lashed out at Jeannie, his wife, when the latter gave an "oh" response, before profusely apologizing for his behavior. He then vowed to make sure they find a nice neighborhood for them rather than a cheap apartment.

Eventually, he became desperate enough to turn to two crooks for help regarding aiding them in a heist toward a card shop next to Ace Chemicals. The men then offered a means to conceal his identity: The infamous Red Hood, which the man recognized from papers as being the same guy who raided an ice company the month before. Despite his hesitance in doing it, he ultimately decided to do so, in the hopes of getting his wife and himself a better future.

On the day of the heist that weekend, he was prepared to go through with it, even making sure to claim he was going out to a gala to ease Jeannie's concern. Unfortunately, just before he could go through with it, the police arrived at the bar he was at, and proceeded to escort him outside. He then learned from the police that Jeannie had died from a baby bottle heater accident that electrocuted her, his child dying with her. Despite this, the crooks strongarmed him into committing the heist by heavily implying that they'll kill him if he doesn't cooperate, thus leaving himself with little to no options of backing out.

The man eventually arrived with the goons at the Ace Chemicals premises. The man then briefly reminisced about his walking to work. When noted that he had a funny-shaped head, in ominous foreshadowing of his future, he mentioned that he may become a clown over a comedian next time. The already bad events of that night got even worse when he discovered that the Ace Chemicals had managed to include security after his departure (he had earlier told them that there was no security). With the men strongarming him eventually killed by the security personnel, he then tried to flee. He then ended up cornered by Batman just as the former pondered out loud what he did to deserve it. The man then tried to bargain for his life, but then tripped and then broke a railing, falling into one of the drainage vats below. After his trip through the drainage vat, he removed his red hood, wondering why he's feeling itchy only to discover his face, and most likely his entire body, had been discolored due to the chemicals he was exposed to in the drainage vat, his hair being turned green, his face becoming chalk-white, and his lips becoming red, giving him the appearance of a clown. This, as well as the traumatic events of the overall night and what happened before, proceed to drive the man completely insane, causing him to laugh hysterically in anguish at the revelation, thus giving birth to the Joker. Whether this was actually true or not is unknown, as Joker later admitted that even he isn't sure exactly what transpired on his day since his memories tended to change every time.

Main events
He then spent time fighting Batman various times, and being locked up in Arkham Asylum, with his frequent escape attempts having him see prostitutes. Some time later, he ended up trapping people and gassing them with Joker venom.

Three years later, his earlier action attracted the investigation of Batman after they uncovered the gruesome crime. Batman, who was planning on seeing the Joker anyways due to being troubled by their bleak future of ending their feud by killing one or the other and hoping to avert such a future, then proceeded to visit Arkham Asylum. Unfortunately, by the time they had arrived, Joker had not only escaped from the Asylum, but even went as far as to leave behind a body double in his cell, which Batman realized when talking with "him" due to his white "skin" coming off. He then went over to an abandoned amusement park, and after conning the carny into giving him control, poisoned him with Joker venom after gaining control of the park. He then arrived at Commissioner Gordon's place, proceeding to shoot Barbara Gordon in the gut in a way to ensure paralysis, and made sure to do it right in front of her father. He then forcibly abducted Commissioner Gordon. He then proceeded to sexually violate her and take pictures of her in various states of undress, although not before telling Barbara that he's doing his actions specifically to prove a point to her father.

Afterwards, he then had his goons strip Gordon naked and, after giving a philosophical speech about how Gordon is to be an experiment in regards to how even the most common man can be driven insane, then proceeds to psychologically torture the commissioner with a song about going insane and showing a slideshow of Barbara Gordon in various states of undress with the implication that he raped her. Afterwards, he then caged him up and showed him off as an exhibit just as Batman arrived. He then briefly fought Batman before fleeing, dousing him with acid. Confident in his victory, Joker then proceeded to tell Batman that even if he arrests Joker, he's already too late as Gordon's now insane (or so he believes), and proceeded to deduce that Batman had a bad day just like he did. He then ambushed him and gave him a beatdown in the upside down room of the funhouse, and proceeded to rant about how monstrous and pointless the world and morality is before demanding to know why Batman not only doesn't see the funny side, but isn't even laughing. Batman then turned the tables on his nemesis, literally, by flipping him right on the upside down table, before telling him that it's because he had heard the joke before and it wasn't funny the first time. Batman then told Joker that Gordon had told Batman to bring him in by the book, making clear that despite Joker's actions, he actually failed to drive Gordon insane, with Batman then theorizing that maybe not everyone cracked and maybe it was just Joker. Joker widened his eyes briefly at this possibility, but then denied it before trying to shoot Batman. Batman then tackled him out of the funhouse. Joker eventually retrieved his gun, but it ended up being a flag gun. Joker, frustrated by the failures, and possibly affected by the revelation that maybe he had been insane all along, then told Batman to just beat him up and give a standing ovation. Batman, however, refused, citing that if what Joker said about his having a bad day being what drove him to insanity was indeed true, he can help him recover from his insanity. Although Joker seriously considered the possibility of redemption, he sadly declined, realizing it was far too late for him. He then chuckled due to it resembling a joke he heard about inmates in an asylum. The joke ended up being funny enough that Batman, normally stone-faced, couldn't help but share laughter with his nemesis.

Trivia

 * Mark Hamill, Joker's voice actor, had earlier expressed interest in doing an adaptation of The Killing Joke, and even offering to do it for free. DC Animation remembered this after the success of The Force Awakens.