Joker

One of Batman's oldest enemies and arch-nemesis throughout his crime-fighting career, the Joker is responsible for some of the most horrendous and tragic moments in Batman's life, culminating in an extremely long and brutal battle where there seems to be no end in sight. An insanely homicidal super-villain with no powers beyond his capacity for incredible violence and creating deadly mayhem, the Joker's white skin, green hair, blood-red lips, and purple suit belie the chaotic nature underlying his colorful appearance.

Road to Arkham
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 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 Asylum. 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: Arkham Asylum
Batman arrived at Arkham in the Batmobile, taking the Joker to the Intensive Care Facility. The Joker remained in high spirits, pleased that he was back in Arkham. He was strapped to a prisoner movement trolly and wheeled through Intensive Care by a variety of guards, including Frank Boles, with Batman following close by (Batman sensed that something was amiss, so he intended to follow the Joker in case Joker intended to do something within Arkham Asylum). The Joker commented on all the brand new security at Arkham and how it was rather funny that a fire at Blackgate Penitentiary sent over a hundred of his goons to Arkham, with Boles angrily remarking that he thought Joker was to keep quiet.

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 before being taken down the elevator. During the elevator journey, a blackout occurred 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, 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 the security control room, waiting. Joker soon took the opportunity to break free as Harley's signal.

Pretending to stumble and trip, the Joker bashed his guard in the face with the back of his head as 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 when his cuffs were finally off, kicked the doctor down, killing him as well. The Joker then coldly said to the dead guard "The choke's on you!", imitated a playful laugh, and pointed at the security door with a "Ta-da!". He looked up at the security camera and told Harley he was home. She then let him in by opening 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, saying "Now let's get this party started!". As Batman battled the thugs, Joker said over the monitor system that he was originally going to kill everyone in the room and watch cartoons, but decided to take a captive audience instead. After Batman defeated a round of thugs, the Joker left the room and made his way to the patient transfer unit.

Batman told Gordon he would find them 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 run, Joker cut off his "hero speak" and goaded him to just pursue him. Batman followed Joker's trail of smiles and arrows drawn by spray paint and dead bodies and found Joker. The Joker opened up a large patient transfer cell, releasing a large experimental monster. The monster attacked Batman before dying of biological causes, much to the Joker's annoyance, who murmured "Note to self: Need stronger test subjects!" As a result, the Joker allowed Batman one free shot at him, which would cause him to fall to his death and end the madness. Batman drew a Batarang, but hesitated and was unable to willingly kill his enemy, causing the Joker laugh at him and say that he was becoming "too predictable." He escaped via the patient transfer system and told Batman that he was organizing a "party" with the villains all over Arkham. Whilst Batman tried to get the transfer unit working again, the Joker appeared on a monitor showing Batman an image of a treacherous Frank Boles knocking out Gordon and taking him hostage, ready to kill him.

Batman attempted to track down Gordon anyway, by detecting the alcohol Boles left in the air. Along the way, Joker left traps with Joker Venom as well as many gag chattering teeth. The Joker soon caught onto the Batman's attempt and as a result had Boles killed, no longer needing him. The Joker took control of Arkham's intercom system, telling his goons to destroy the Batmobile as he took over the West side of Arkham Island.

His next target was the Medical Facility where he ordered his goons to round up all the doctors in the area, most importantly Penelope Young, who he needed the Titan formula from. To the Joker's annoyance, Batman defeated his goons and rescued the captive doctors. The Joker drew up a 'party list' which contained the individuals who would help take care of Batman. He enlisted the help of the Scarecrow, who proceeded to attack Batman in the Medical Facility. After escaping Scarecrow's Fear Toxin hallucination, Batman made his way to Gordon, who was conveniently placed near Bane's holding cell.

After Batman rescued Gordon from Harley, the Joker pumped a large amount of Titan into Bane, causing a fight with him and Batman. Joker was disappointed with Bane's inability to kill Batman, so he ordered his goons to assist him, though Batman defeated them all. The Joker's next order of business was to search Arkham Mansion for Dr. Young's formula, and Dr. Young herself, who had gone looking for said formula.

After finding Zsasz in the Botanical Gardens, the Joker enlisted his help to deal with Dr. Young. Zsasz held Young hostage in Warden Sharp's office and threatened to kill her if he saw Batman approaching. Joker told Zsasz to just kill her, as she was useless to him since he had already gotten both Venom and Titan. Batman incapacitated Zsasz and rescued the doctor, though an explosion set by Joker in the Warden's safe killed Young anyway. Harley then entered and had her thugs prepare Batman for the 'party'. He defeated them and followed Harley, rescuing Sharp by tracking his DNA. Harley was shown releasing Poison Ivy from her cell, despite Ivy not being on the 'party list', much to Joker's apparent pleasure. He then unleashed the more violent, insane inmates all over the island.

Batman went after Harley, who sent her thugs after Batman again, though he managed to defeat them all. Harley's failure prompted Joker to remove her from the 'party list', and Batman defeated and locked her up, using her DNA traces from around the island to track Joker to the gardens, where the villain unsuccessfully tried to slow Batman down after killing an Arkham guard, Thomas Armbruster.

He demonstrated the successful Titan strain he had managed to create by injecting two of his thugs and having them attack Batman before escaping. Batman defeated the monsters and pursued Joker, who revealed over the intercom that he had teamed up with Poison Ivy and injected her with Titan, causing her to become far more powerful and take control of the island surface with her evolved plants. Batman defeated Scarecrow and Killer Croc down in the sewers and successfully harvested the spores needed to make an antidote for the Titan injection in Croc's lair. Batman then went down further into the sewers and found that Joker was trying to pump Titan polutants into Gotham, telling his men to stop Batman from preventing this in a threatening, serious manner. After Batman shut off the pumps, Joker sent a Titan monster as a token of his displeasure.

Batman defeated the monster and escaped the sewers. Driven by more power hunger, Ivy betrayed Joker and swore to go after him once Batman was killed. Joker assured her that he would be prepared for her with an army of Titan monsters, saying the she could "bring the wine" and he would "make the salad". Batman managed to defeat Ivy in the gardens. With all of the enemies on Joker's 'party list' defeated, Joker had his men set off several fire works directing Batman, the 'guest of honor', to the 'party' at the Visitor Center by the Cell Block. Rather than fight Batman, upon his arrival and confirmation of being on the 'guest list', the goons acted friendly, cheered him and allowed him safe passage.

Batman found a bomb planted by Joker in the visitor center and upon its explosion, discovered the Joker's lair, a throne room atop various plastic toys from which he had been broadcasting to the island. Joker was holding Scarface the puppet and taking out his frustration on him by having a fictional argument before throwing him away. He then berates Batman for ruining everything by "Turning Bane into roadkill, feeding Scarecrow to Croc, "slapping around" Harley Quinn (which is apparently his hobby), and destroying his precious venom plants." The villain then dispatched two Titan fuelled security guards at Batman, who defeated them.

Joker then revealed that he had recaptured Gordon before he could escape back to Gotham. Firing a Titan-tipped dart at Gordon, Joker was overjoyed when Batman took the shot himself. However, he was angered when Batman resisted and fought off Joker's attempts to make him give in. Enraged that Batman would never allow him this final truimph, Joker shot himself with one of his Titan darts, claiming he had little more to live for. He quickly awoke and mutated into the most horrific Titan monster of all (possibly being his backup plan the whole time), while still retaining his intellectual faculties. He then directed the circling Gotham News helicopters and Jack Ryder to the rooftops of Arkham so that they could watch his final fight with Batman. Strapping Gordon to an electric chair above a makeshift fighting arena (making him the "referee"), the mutated Joker goaded Batman to give into his injection, as it was the only way they could be on even fighting terms. Batman refused and used the only antidote injection on himself, which the Joker found hysterical. The two, with assistance from Joker's henchmen, then fought a brutal battle, with Batman knocking Joker into the electrical generator used to torture Gordon.

The Joker got up from the attack and said he could take anything Batman threw at him, and asked if the Dark Knight was ready for the next round. Spraying Explosive Gel onto his glove, Batman declared that he would never let Joker win and would always be prepared for his tactics. Enraged, Joker prepared to kill his relentless nemesis as Batman charged him. The gel on Batman's fist then detonated as he struck his opponent, finally incapitating the most dangerous Titan subject of them all.

Following the Joker's defeat, the GCPD then retook control of Arkham Island, recapturing the escaped inmates and watching over the Titan-powered henchmen as they returned to normal. Joker's transformation back to humanity was quite painful compared to others, culminating with the severe injuries he received in his battle with Batman. He was taken to his cell by several police officers and surviving Arkham security personnel, his plans having ultimately failed. While locked up and recovering from Titan's effects, Joker was left humiliated, angry, and thirsty for revenge. While he planned his next move, Joker began to notice his body was not healing well after being injected with Titan and began to fear that his defeat at Batman's hands may have cost him more than just being locked up again.