Galactic 4th Edition
As cultures and belief structures intertwined through the ages, so too did the religions of the various galactic species until there was one unified church: The Pan-galactic Astral Church. Both major and minor deities were successfully integrated into a pantheistic model, some gods combining into one due to uncanny similarities in domains and influences; for example, how Bahamut is both a platinum dragon and an old man who prefers the company of small birds. (I want to incorporate older versions of D&D gods as well as gods from different campaigns. For example, perhaps Obad-Hai was Melora’s father, or she is a shapeshifter, sometimes taking the form of a man to fool people.)
There are still plenty of purists who hold true to their ancestors’ beliefs. Many Uldrin still feel that Correlon is still the “One True God”.
A smaller group of people agree that divine creatures exist other than their own god, but do not raise them to god-hood. They are inferior, yet still divine and of a higher power than angels.
The Gahb Collective believe that Bane is the true driving force behind existence, but acknowledge the presence of enemy gods attempting to usurp his power.
(for lack of a better term)
Though not quite atheists, the Deniers are people who admit to creatures that exist on another level as they do, but do not worship them as gods. Sure, they may ask for help on occasion, but not out of worship or as a prayer, but as a kind gesture, kin to an Ant asking a Man to offer them a crumb of bread.
Atheism, Agnosticism, Apatheism, etc…
There is plenty of doubt and denial in the galaxy. With the growth of sciences comes the need to rationalize, which can lead to thinking of religion as unrealistic or silly (not to say this is the belief of all people who fall in the above categories).
However, keep in mind that this is a Science Fantasy campaign. The gods have a very real role in the galaxy (divine power source, people!), ergo people who fall into this category will be rare. It is up to these characters to rationalize and determine their own opinions as situations arise.