Leviathan is an organization founded by Talia al Ghul; upon leaving her father, Ra's al Ghul's League of Assassins. Leviathan's liturgy is staunchly anti-capitalist and seeks to dismantle society and impose itself as the leaders of a new way. Leviathan first became known to the heroes of Earth as a terror group who kidnapped the child of a Yemeni sheikh. However, Batman discovered that Leviathan was working with the sheikh and was planning to attack the world with mind-controlled children and engineered metahumans. Batman immediately connected the organization to an apocalyptic vision he had received while coming back from the dead, and positioned his Batman Incorporated organization to oppose them. After some moves, Leviathan seemed to form up behind Doctor Dedalus, a Nazi master spy imprisoned on the Falkland Islands, with a predicted lifespan of months due to Alzheimers. In the aftermath of Dedalus' breakout, further investigation showed that a paper trail showed a flow of child soldiers from training camps in the central African republic of Mtamba to locations around the world, for use by Leviathan in their campaign. In Batman Incorporated's struggle against Doctor Dedalus' master plan, they struck, and hit empty locations, which were in fact pre-prepared traps by Leviathan. Recovering, they realized that Dedalus was a feint, designed to make them show their hand on the eve of the war. Via a telephone, the leader of Leviathan, Talia al Ghul, spoke from their new headquarters opposite the cinema on Crime Alley. Talia stated Leviathan's goal was war with Batman's followers and the destruction of civilization. Talia took control of the League of Assassins and added its agents to the plan. The plan began by seeding mind-control chemicals in the Gotham food supply through the "Dark Tower" fast food chain, while taking control of the Brothers Grimm Syndicate, which controlled the club on Gotham's West Side. Using a combination of agents in the school system, the police, and the civil service, Leviathan worked to control Gotham's children. Talia soon tells Batman that her creation of Leviathan has been all out of spite. As revenge for denying her his love and unwavering dedication to his crusade for justice, Talia created Leviathan as an expressed antithesis of Batman Incorporated. The Heretic is eventually shown to be the eponymous "Leviathan" of the organization; the "Third Batman" that is prophesied to send Gotham into chaos and destroy it. However, the Heretic continuously fails Talia and proves himself to be just as defiant as his genetic template, the then-deceased Damian Wayne. After killing the Heretic, Talia attempts to activate a "death ring" around the planet, established by worldwide Leviathan agents. Batman Incorporated disables the weapon, and Talia is killed by Kathy Kane. Their leader dead, the intelligence agency known as Spyral took over Leviathan's resources and the organization presumably collapsed in the wake of their defeat. Upon returning from the dead, Talia ordered her most trusted assassin to kill one of Leviathan's underbosses, who had the intention to reveal the existence of the organization to the U.S. authorities. Trust inside the criminal network was shattered and when Talia died and then was resurrected, she was ousted from her position as leader of Leviathan. The organization then fractured into various factions, guided by competing leaders. Talia is taken to a Lazarus Pit in Khadym by those loyal to her and is resurrected from the dead.
Second incarnation
Another incarnation of Leviathan appeared in the pages of "Event Leviathan." Leviathan has even taken over Project Cadmus as Batgirl discovered.
Membership
Leviathan - New Head of Leviathan.
Talia al Ghul - Former Head of Leviathan.
Professor Pyg - Lazlo Valentin at first appears to be working for Simon Hurt, but it is later revealed that he is actually working for Talia al Ghul. He is incarcerated in Arkham Asylum after being captured by Batman and Robin in the first volume of Batman and Robin.
The Heretic - Mysterious agent of Leviathan in a bat-like costume. The Heretic is a clone of Damian Wayne, first seen as a fetus in the first volume of Batman and Robin, whose growth has been accelerated to adulthood by way of a bio-engineered whale carcass. After killing Damian Wayne, the Heretic is defeated by Batman when he is run through with a sword. He is then finished off when Talia al Ghul kills him and blows up his body along with Wayne Tower.
Son of Pyg - Son of Professor Pyg. Real name Janosz Valentin a.k.a. Johnny Valentine. Later defeated by Batgirl during a plot to turn a group of teen mercenaries-in-training into agents of Leviathan.
Dr. Dedalus - Former Nazi scientist, and agent of Leviathan and the biological father of Kathy Kane, the original Batwoman. Later killed by the new Robin using a concealed knife.
Goatboy - Gotham City-bred taxi driver-turned-assassin in light of Talia's billion dollar bounty on Damian. Later killed by Lumina Lux.
Silencer - Honor Guest was an assassin in Leviathan but quit.
Quietus - A Leviathan underboss.
Wishbone - Ran the magical division of Leviathan.
Gunn - A Leviathan underboss. He's killed while fighting Quietus and Silencer in Khadym.
Jonah 9 - A Leviathan underboss.
Raze
Rutger Orestes - A Leviathan underboss that was murdered.
In other media
Television
Leviathan appears as a secret organization in the Arrowverse series Supergirl, that now sees its historical manipulation of human events as insufficient to prevent humanity's perceived threat to Earth itself. Its currently revealed leaders include Rama Khan, Gamemnae, Tezumak, and Sela, extremely durable aliens from Jarhanpur, a sister planet of Krypton, with mutual knowledge of and language exchange with Coluans. The organization employs humans to assist in manipulating present day Earth society: an elderly human woman named Margo Morrison who works in middle-management, and an unnamed elderly human man and operatives like assassin Eve Teschmacher and Rip Roar. Rama Khan exhibits superhuman powers of seismic and earthen-materials manipulation including kinetic control of kryptonite, Gamemnae has technopathic abilities, Tezumak has pyrokinetic abilities, and Sela has electrokinetic abilities. The Jarhanpurians have also utilized advanced technology and cosmetic modification to advance their goals, to influence human society, as weapons against Supergirl and Martians, and manipulating events throughout Earth history, including the extinction of the dinosaurs, the destruction of Pompeii and the bubonic plague. Post-Crisis Leviathan was not aware of Crisis events; only Supergirl's core Crisis team retained knowledge of Leviathan's threat to human society. Lex Luthor, unaware of Leviathan prior to Crisis, worked with Lena Luthor in a plot to infiltrate the organization by winning the favor of Gamemnae, who has ties to the board of the Obsidian Tech and Andrea Rojas/Acrata. Lex orchestrated events of Obsidian's Platinum virtual reality system's flaws that lead to Margo overseeing the kidnapping of Platinum's comatose victims, and Margo's subsequent murder as Lex "rescued" the victims. Lex gifts Gamemae with the return of a long-ago-stolen Jarhanpur weapon, which is a threat against Kryptonians.
Film
The Heretic appears as a supporting antagonist in , voiced by Travis Willingham.
