GURPS Cabal

GURPS Cabal () is a book by Kenneth Hite that features a customizable campaign setting for the "GURPS" role-playing game system, based on the first edition of GURPS Horror by Scott Haring and further developed in the second edition by J. M. Caparula.
Contents.
"GURPS Cabal" depicts a modern-day secret society composed of vampires, lycanthropes and sorcerers who study the underlying principles of magic and visit other planes of existence and was integrated into Infinite Worlds, the "default" (core) setting for GURPS's 4th Edition.
Overview.
The Cabal, unsurprisingly, has roots in the Jewish study of Kabbalah, though it has appropriated concepts from Egyptian occultism and elsewhere to create a syncretic system of Hermetic magic.
The Cabal is strictly regimented. From lowest to highest, the ranks are: (Outer Circle) Initiate, Novice, Adept; (Middle Circle) Theorist, Practitioner, Philosopher; (Inner Circle) Master and Grand Master.
There are thirteen Grand Masters, listed below. 
Many Cabalists speculate that there should be one more rank above that of Grand Master. The identity of the person with this rank is subject to many rumors.
Cosmology.
In this setting, there are Four Realms of existence, based on the Jewish Sephiroth, or Tree of Life:
Only the thirteen Grand Masters have ever visited Atziluth and been face-to-face with the creator of the universe. Suspiciously, none of them act particularly devout.
Publication history.
"GURPS Cabal" is a soft-bound book written by Kenneth Hite and published in 2001 by Steve Jackson Games.