The world of TDDC has a pantheon of 11 deities, but different cultures have different names for them and even slightly different symbols (see table below). Most people practice a Greco-Roman style polytheism of praying to different gods for different things, to the point that most priests perform rites for muliple deities.
List of deities and domains (replace with table of names - it's in one of the extras)
Larethal (elven)/Lakmaal (Kua) - weather and harvests.
Sirius - protection and justice
Marduk - battle and heroism
Muradin (dwarvern)/Ytaru (Elven)- creativity and renewel
Dialiah - nature and love
Delvash - greed, hatred and tyranny
Blibaal - slaughter, storms and the depths
Amarra - heaven and dreams
Asmodueus - hell and nightmares
Ioun - magic and knowledge
Vecna - secrets, lies and the undead
Mortal forms
Back in the early days of the world, Deities used to incarnate among the mortals. This still happens on occasion, such as Delvash's time in Korstraad, but it is much less frequent. When a god incarnates, they must choose the amount of their divine power that they bring with them. The more power a mortal form has, the more damage the deity takes if the mortal form is slain (natural deaths are fine for this purpose). Also, as long as the god is in their mortal form, they lose most of their knowledge, as well as their divine senses (infomration gleaned from the astral sea), massively limiting their ability to improvise on their plans. They can, however, create omens for their mortal selves.
Spirits
The TDDC setting also has animistic spirits, varying in power from the repentent sould of a warlord protecting an entire nation to a mouse spirit with the powers of ... a mouse. Some are anchored to a specific location or object, some can roam freely. Some are nigh invulverable, others can be beaten up to the point that they are forced to retreat to the astral plane.
Spirits differ from gods not only in terms of power (spirits are much weaker), but also in terms of the dual nature of gods: gods have both a personality and a domain. Within their sphere of influence, the domain is omniscient but the personality is not. For example, Delvash's domain is constantly pushing people to be greedy (other gods push them in other directions). It might not do so if it would benefit Delvash (e.g. tempt somebody to retun to help others rather than escape with an artifact which could harm him), but the personality would not gain knowledge of this, even if it were searching for the artifact.
Sanctums
Each god has a physical sanctum somewhere in one of the planes. Mortals can use them to communicate directly with them, or even temporarily kill them.