According to Orion legend, Q was a formless entity (referred to by the male 'he' or the neutral 'it'), hungry and chaotic, that once walked among the people of the mirror universe, and conquered many races. When he set out to conquer the Terrans, however, they found some secret weapon against him, perhaps an ally of god-like powers or an ancient magical incantation, and banished Q to a prison outside the known dimensions.
From this place, Q was only able to communicate with his chosen people, the Orions, and only through certain religious ceremonies. It was Q's command that they spread suffering, confusion and fear. The Cabal's ultimate goal was to free Q, so he could then lay waste to the known Galaxy, punish the Terrans, and finally alter the laws of physics to elevate his loyal servants into powerful beings like himself, and together they could rule the fractured reality.
The birth of an animalistic Orion was seen as a sign of Q's favour, as one of his children. However, they were held in no high regard – they were apparently abused, mistreated, and either trained as Orion slave girls by the Procurer's Guild or sacrificed to Q in one of the Cabal's rituals.
However, beyond the claims of the Cabal priests, Q were not otherwise known to exist in the mirror universe, or they hadn’t revealed themselves to anyone else there.
Q was worshiped in ancient, obscene and bloody ceremonies, where Orion priests in robes and hoods assembled to sacrifice at least one of the animalistic Orions or a captured Terran, to feed him. The Cabal believed that Q could communicate with them only at these times, and for a few minutes, the luckiest of them could feel his evil presence and hear his orders. Some high-caste Orions would feel his power and gain incomprehensible abilities, becoming Assassins of Q.
Only around 10% of the Orion population fervently worshipped Q, and made up the core membership of the Orion Cabal, and were by large so insane as to be utterly fearless. A few Orion criminals were also peripherally involved in their illegal activities, but were not themselves members. Most other Orions however were uninvolved, though they did enjoy the fear that the Cabal struck in Terran hearts.
Not all members were Orions, however; other races could join. Terrans were actively prevented, while races closely allied with the Terran Empire, such as Andorians, Betazoids and Vulcans, found it nearly impossible to be initiated. In general, the more opposed a race was to the Empire, the more likely a member of that race was to be accepted.
The Cabal engaged in crime and terrorism for religious reasons, by the command of Q. Criminal activities ranged from unlicensed prostitution to theft and smuggling, kidnapping and sabotage, assassination, terrorism and Human sacrifice. Cabal priests had no objections to how their worshippers made their living, and even brokered their services, such as dealing with the Procurer's Guild and hiring out Assassins of Q. Even the Klingon intelligence agency Khak'ma hired instructors from the Orion Cabal to develop their covert operations.
The cult found good cover on lawless Rigel VII and on the frontiers of Tholian space. For the latter, one possibility was that Tholian space held a portal to another dimension where Q was already free; the Cabal and the Orion Syndicate of that universe may have begun talks.
- Through a Glass, Darkly presents four different concepts for mirror universe Tholians. In three, the Orion Cabal keeps hideouts on the Tholian frontier, one of which supposes a portal to the standard universe, as above.
The Orion Cabal has a particular hatred for Terrans, viewing them as the enemies of Q, banning them from membership and sacrificing those they can capture. However, it was possible for a Terran senator to hire the services of an Assassin of Q, using the Procurer’s Guild as go-betweens.
In turn, the Terran Empire's Imperial Security viewed the Cabal as a major threat. They arrested and killed every member they could find, but usually killed three innocent or marginal Orions for every genuine high-ranking worshipper, and when desperate enough, detained every Orion present, though the percentage of Q-worshipping Orions was too low to make this strategy cost-effective for general use.
The Cabal was skilled at discovering undercover Imperial Security operatives, however, and dealt with them accordingly. When the opportunity allowed, the agent was captured, interrogated and eventually sacrificed, and if not, they were murdered and mutilated.