In this campaign I'll be using the Gods and much of the mythology from a book called "The Book of the Righteous" published by Green Ronin.  This book provides a lot of information on a pantheon of Gods and the myths surrounding that pantheon.  I have made some changes to the mythology presented however to make it fit better into the campaign.

The Mythology presented is characterized by a universe created by a mysterious creator god called the Nameless One.  The Nameless One created the elemental planes, the prime material plane, and the first god, Kador. After these initial creations the Nameless One disappeared from the universe; perhaps to go off and create other universes.

The pantheon is universal, meaning all races and societies pretty much share the same gods, whether they know it or not. There may be schisms within or between churches about the best way serve a particular god or about a gods true nature, however.  Powerful devils, demons and celestials can also grant mortals divine powers and are sometimes considered minor gods in there own right.  Examples of this is are two servants of Urian[God of the air and sky] Alimus and Faro, who are respectively responsible for dragging the sun and moon across the sky; they each occasionally have churches dedicated solely to them.  If you have an idea for a cleric that does not fit well with any of the established gods it may be possible to invent a minor god that fits the bill.

Another important aspect of this pantheon is that there are many non-evil gods that are commonly worshiped and only one true god that is evil.  This evil god is Kador, the firstborn and most powerful of the gods who fell from grace long ago.  Powerful demons and devils can attract worshipers, but are not considered true gods.  In general the open worship of evil gods is not permitted in civilized societies.