During Acts of Vengeance, Loki grouped together Doctor Doom, Magneto, Red Skull, Kingpin, Mandarin and Wizard in a bid to rid themselves of the nuisance of superheroes. Loki also attempted to recruit Apocalypse, King Cobra, Mad Thinker and Namor to the group but all declined.
The Cabal was created by John Byrne and Mark Gruenwald and first appeared in an issue of Spectacular Spider-Man.
The original Cabal eventually fell apart due to each member's own superiority complexes and a mutual disdain for the Red Skull. Magneto left the team, taking with him a beaten Red Skull whom he buried alive, Wizard was captured and the Avengers fought the rest of the cabal who either made a hasty escape or were subsequently captured.
From the ashes of Secret Invasion this team was remade. Running the superhuman society in their favor. Composed of the villainous superhumans in the Marvel Universe, they are like a counterpart to the Illuminati. Their intentions are very clear: Rule the world even if every member has their own intentions, such has Dr. Doom wanting the "land" and Namor wanting the "sea". Whether or not the other members are sure like Emma Frost and Loki is not yet known. As for Norman Osborn, a.k.a Green Goblin, it seems that he knows a betrayal might occur. So, as an insurance policy, he has an as yet unrevealed "special friend" who he intends to help him keep the others in line. This mysterious friend of Osborn's (Later revealed to be the Sentry) was enough to silence Doctor Doom after he questioned Osborn's audacity to even invite them, and after the Hood asked what would stop them from turning on him later.
Over the duration of the Dark Reign storyline, the Cabal underwent various changes. Emma Frost and Namor both turned against Osborn following the Utopia crossover. Loki and Doom were next to follow, severing ties with the Cabal just before Norman Osborn's Siege on Asgard. Taskmaster joined the Cabal in it's final days.
In response to the Illuminati's inability to destroy other Earths to save their own, Namor reforms the Cabal, consisting of himself, Black Swan, Maximus the Mad, an alternate dimension Terrax, Proxima Midnight, Corvus Glaive and Thanos. Their first act is to destroy Earth -9004 to prevent an Incursion.
In Other Media
The Cabal appears in Avengers Assemble, with its members acting as the primary villains of the first season. In the series, the Cabal is assembled by the Red Skull to defeat the Avengers after he realizes that no one villain has the power required to stand against them. The group consists of himself, Attuma, M.O.D.O.K. and Dracula, with Hyperion joining later in the season. Doctor Doom is offered membership, but declines. At the close of the season, the Cabal disbands after the Red Skull absorbs the power of the Tesseract and becomes the Cosmic Skull, with Thanos subsequently replacing the group as the main antagonist of the second season.