The deities form a loose Pantheon. A multitude of deities rule the various aspects of mortal existence, variously cooperating with and competing with each other in administering the affairs of the universe.
Each deity has a portfolio and is responsible for advancing that portfolio in the mortal world and in the divine.
Individuals - both clerics and laity - generally follow one deity above all
others as their patron deity.
Not everybody has a patron deity, though most people show at least some degree of devotion to some of the gods.
There is no penalty for not choosing a patron deity. Most people are assured of finding a home in the Outer Planes after death. Their souls simply go to the plane corresponding to their alignment.
Those with a patron deity find a home on the plane that is home to their patron deity after their death.
There is believed to be infinite divine power available for deities. There are a few very powerful deities and a large number of local or less powerful deities. Some of these deities share portfolios, and it is common for lesser deities to focus on specific domains of the more powerful deities.
The nature of divinity is not known. It is believed that it can be earned, imparted, surrendered, and possibly stolen. In some cases it is said to be innate. The Greater Deities are said to have come from innate divinity.
The power of deities depends some on the number of followers that they have. Deities typically only rise in power by increasing the number of followers they have. Some deities, particularly some of the evil ones, rose to their power levels by destroying other deities and assuming their divinity before they could rejuvenate.
It is not clear whether mortals can kill deities or if they can be killed at
all. Some Greater or Intermediate deities are said to rejuvenate themselves
if destroyed but this is not believed to occur with lesser deities. As such
it may be possible to kill or destroy lesser deities though it is unlikely that
any of the more powerful deities can be destroyed.