Hundreds of years ago, this world had a pantheon of gods like any other world, with good and evil gods and goddesses working through their worshipers to bring about good or evil things. Then, that changed.
Slowly but steadily, a new religion took hold: a religion claiming that the gods were all merely aspects of the one great deity. This deity, which they called The One, was supposedly so great and unknowable that only a few aspects of him could be understood by any one being. The One was also so vast and powerful that it never actually took action in the lives of mortal beings, or even noticed their existence. To the minds of the people at that time, this sort of teaching was comfortable and safe; recent religious wars had been very bloody and seemingly needless, so the idea of having one god who basically did nothing and asked nothing in return seemed pretty good. Other religions were brought into the Assembly as aspects of The One, and eventually assimilated. The gods that were once worshiped were re-imagined, over generations and hundreds of years of constant teaching, into the Saints-
mortals who had made some great achievement in life, and were noticed by The One. This notice, according to the Assembly, resulted in the Saint’s conversion from a mortal to a higher being, able to bestow gifts on mortals who followed in his or her footsteps. So there are still divine spellcasters, but they apparently get their powers from saints, not gods. In game rule terms, each saint has power over one domain-so a cleric must choose two saints to revere as his/her patron saints.
The Assembly is not very strict about doctrine or alignment. Basically, it considers everyone a member, regardless of race, class, country of origin, alignment, or even individual choice. The Assembly asks only three things of its Followers: participate in the weekly Convocation, contribute a portion of your income to the Assembly coffers, and obey the will of the Assembly. Disobedience means a visit from an inquisitor.
Besides these three tenets, and such social obligations as marriages, funerals, etc., the Assembly only takes two things seriously. The first is the accumulation of wealth and power. That is its primary reason for existence. The second is the dead. The dead are to stay dead. Undead are an abomination to the Assembly, primarily because they are a bureaucratic nightmare. Strangely enough, those raised by Raise Dead, Resurrection, or other resurrection spells are considered undead, so these spells are not allowed to be practiced by clerics of the Assembly. When a resurrection is suspected being imminent, the inquisitors have very gruesome means of preventing them.