|“||Why so jumpy? I merely took it off standby. It's this button you gotta worry about.||„|
Joker is the Bigger Bad and one of the main antagonists of Injustice: Gods Among Us. He appears as both a major character in the Main Universe and the posthumous villain in the Injustice Universe who is directly responsible for Superman's corruption and indirectly, the events of Injustice.
He was voiced by Richard Epcar.
He first appears in the interrogation room in the GCPD (Gotham City Police Department) after nuking Metropolis, where he was being interrogated by Batman. Batamn demanded to know where the Joker got the nuke, but this was then cut short when a grieving Superman broke into the interrogation room and confronted him. After taunting and insulting Superman multiple times, as well as strongly implying that he fully intends to escape and plan to "top" the destruction of Metropolis, the Man of Steel murdered the Joker in cold blood, as Batman watches in horror. The Joker manically shrieks with laughter as Superman tears his heart out. It is heavily implied that Joker deliberately engineered his own death at the hands of Superman to ensure the latter's fall into a villain.
Normal Joker first appears after the Justice League discover Lex Luthor gave him a nuke to blow up Metropolis. He is seen arming the bomb next to a statue of Superman in Metropolis, much to the excitement of his world's Harley Quinn. After Harley discovers Batman was teleporting to their location, the Joker forcefully makes Harley return to their van as he has a conversation with Batman and takes the bomb off standby. As he activates the bomb, multiple members of the Justice League quickly try to intercept him, only to teleport to the Regime universe, pulling Joker with them. Batman and Joker are separated from the others who teleported, namely Wonder Woman, Green Arrow, Aquaman and Green Lantern. The Joker, enraged that his trigger failed to detonate the bomb, blames Batman for their displacement and attacks him. Batman manages to subdue him, just as Regime troops appear and attempt to apprehend the two. Batman uses a sonar distrust or and smoke bomb to escape the troops, while Joker sneaks away during the ensuing chaos.
The Joker tries to find his old gang by hijacking and killing the troops in the van and traveling to Gotham City, where he discovers he is well known in the Regime world, exclaiming; "My fame proceeds me!". Batman, having followed the Joker to Gotham, attempts to launch a surprise attack. Joker becomes aware of Batman's presence beforehand, and counters him, injuring Batman's leg. Because of this, Joker defeated Batman and almost sprays him with Joker Venom. Just as Joker is about to "put a smile" on Batman's face, he spots alternate Hawkgirl and Yellow Lantern and runs off. Joker watches from afar as they arrest Batman and take him away. As the Joker retires to his original plan, he finds himself being approached at gunpoint by an altered Harley Quinn, now going by her real name, Harleen Quinzel. Though he tries to persuade her that he is in fact, the Joker, Harleen insists that the Joker is dead, and that he is just another impostor. Outraged, Harleen attacks him, but is quickly subdued by him. Recognizing his fighting style, Harleen realizes he is the Joker and embraces him. The two then travel to the abandoned Arkham Asylum, where Harleen introduces Joker to the "Joker Clan", a large gang that worships Joker as a martyr, and combats the Regime through acts of terror.
The Joker addresses the Joker Clan, introducing the 5-U-93-R pill to them under the name "Happy Pill". This would provide him and the gang members with superhuman durability. The event is then cut short when Hawkgirl and Nightwing (Damian Wayne) arrive with a fleet of Regime soldiers to attack the clan. The Joker is repeatedly shot with an assault rifle by a trooper, but survives and humorously thanks the "Happy Pill". Hawkgirl attacks the Joker, believing him to be the Joker from their world. The Joker defeats Hawkgirl and attempts to remove her feathers with his knife. Nightwing notices this and quickly charges towards him. The Joker throws his playing cards at Damian, overpowering him. He proceeds to mock Nightwing for leaving Batman and becoming Superman's 'pet', believing him to still be Dick Grayson. A fight ensues, and Joker defeats Nightwing. Altered Batman, Green Lantern, Aquaman, Green Arrow and Wonder Woman rush in, and both Hawkgirl and Nightwing retreat thanks to Harley's call for help. The group is surprised to see the Joker, which leads them to the conclusion that Batman was sent to the parallel dimension as well. Joker is apprehended by Insurgency Batman.
The Joker is later broken out of custody by Harley Quinn, despite her orders from Batman. The two of them hijack a Regime vehicle and confront Insurgency Lex Luthor on his way to assist the Insurgency forces against the Regime. The Joker orders Harley to take down Luthor and take his suit, but she fails. Annoyed with her, the Joker fires Harley and attempts to kill her, but Luthor intervenes and subdues him. Enraged by his attempt on her life, Harley tries to kill the Joker with his knife, but Luthor convinces her to stand down, saying she's outgrown him. In addition, Harley Quinn ruined any chances at his gaining control when the Joker Clan arrived, citing that Lex Luthor was on their side while Joker wasn't.
In the epilogue, the Joker is shown being lead at gunpoint by Harley Quinn to the portal that will take him back to his dimension.
Defeating Insurgency Superman in Injustice Mode with the Joker will reveal that the Joker, despite failing to gain control of the Joker Clan in the alternate dimension, managed to create a similar group in his original dimension, and managed to take power via various disasters and become a sort of messiah.