The Cabal is a secretive society of magic users and researchers that was founded before written history, think Greece, Babylon. While other coalitions of Mages may exist in the world, the Cabal stands above them all both in scope of power and influence. Magic has always existed within the world along with those who can wield it and creatures that are part of it, the Cabal views itself as a sort of protector or keeper of the magical flame as it were. The Cabal consider themselves the elite of these select members of existence who are still aware of role magic still plays on our lives. They draw into their membership only those they believe to possess superior magical talent, vast wealth, prestige, and/or potential power. All others are viewed as nothing more than a means to an end or an unwitting public mass to protect. Its quite simple really, you are either one of them, or you aren't. There is no gray area.
That is not to say that all those who exist as a member of the Cabal are self-important, self-serving individuals concerned only with their own status; like any social organization their members are quite diverse. Discretion seems to be the order of the day for the Cabal as secrecy shrouds nearly everything about them. Membership and access beyond its garden party or Men's club walls is by invitation only. The Cabal are known to use force(their agents) in certain situations to make sure that their presence, or more importantly that of magic, is not made known or discovered. It takes more than possessing the gift of magic to earn an invitation into this group or to gain favor to the extent that they might actually employ you. In fact, the vast majority of the Cabal's members are completely ignorant of what the organization actually does and what it stands for beyond its sterling reputation as a club for the elite. The sense is certainly shared by any given such a welcome that is a particular honor to have been chosen to join the Cabal. Scholars, politicians, merchants, movie stars and world shapers; many castes and levels of magical ability or knowledge can be found within their ranks.
The Cabal is ruled by a governing body called the Covenant, an elite hidden Inner Circle of the society that take care of the general management of such a widespread body. They oversee not only the diverse number of seemingly benign social branch locations found across the face of the Earth via a networks of managers and outside businesses but also the vast hidden machine at work keeping magic alive, well and completely secret. Their goals, versus the Cabal as a whole, could most decidedly be described as self serving. When they choose to act, it is usually in channels that would perhaps raise questions with average members of the Cabal and the world society at large. They see the Cabal as a tool to use to their advantage. In their minds they are the crème de la crème of Mages in this world, separated and ascendant from the concerns of humanity, and woe to anyone who would stand in the way of their often clandestine designs. When you consider them think in terms of the mages of Mount Olympus, they enjoy their godhood, or rather the pretense of it.
Like any organization, they have their rules and their ways of asserting their control over their membership. All Cabal employees, including the Novus Ordo, must agree to wear a tattoo of magical origin. This ancient art, infused with magic for the Cabal's special needs, may allow certain members of the Covenant to gain temporary control of those wearing it. Such a tool can be exceedingly helpful when a reluctant agent's morals get in the way of his work. If a hierarchy of power were to be known, it would rest as such: The Covenant (the elite inner circle), Their Prized Confidantes (more often than not those with an eye on joining the inner circle themselves), Top Tier Agents (those of proven worth and experience, Second Tier Agents (those allowed to work individually and often without direct supervision, Junior Agents (work with supervision of a more experienced agent), The Useful (outside wealth, magical prestige or power the Cabal/Covenant seeks to use to its own purposes - including the very rarely employed Anna's Boys), Agents In Training (new recruits), General Membership (blissfully unaware beyond the parties and social connections enjoyed). In rare cases, an individual may be aware of the actual power structure, but most are ignorant of those who may be above them. It is safer that way.
The Cabal's main offices are located in Rome, London, Cairo, Boston and Hong Kong. Formerly, strongholds of magical influence were located in Babylon, Mount Olympus, Berlin before Hitler's fall, Stonehenge and of course the fabled courts of Arthur and the gently rolling hills of Avalon - to name a few. Regarding the Covenant, most who join or are employed by the Cabal will never meet them and only those employed as Top Tier Agents or as Confidants might actually be aware of the inner circles existence. Only Canon Characters may be present or past members of the Covenant.