The Gods

[TheFred]

"Deities are not to be trifled with... they trifle back."

-- Baldur's Gate

This is a game chock-full of gods, including both the default PHB pantheon and those from real-life mythology (particularly Greek/Roman, but also Norse, Egyptian, etc). Gods from elsewhere, such as the Forgotten Realms, could also get thrown in, particularly if a player wishes to use one of them.

There are some general principles to bear in mind about the gods:

On Geography: This world has something of a notion of "regional deities". Thus, Talos might rule in the south, but the Northern God of Thunder is clearly Thor... despite the fact that thunder is ruled by the King of the Greek Gods Zeus. Having the gods tied in some way to different regions gives a reason for that, and also ties in with Greco-Roman religious ideas a bit. It may be that in a different area, the same god is known by a different name (and even appears to have different characteristics), or it could be that there are simply many gods any they only really have sway in the areas where they are worshipped.

On Alignment: Alignment is a D&D mechanic as much as anything, but will likely be a bit woollier in this game. Remember that gods are gods and mortals are mortals, and even the ostensibly Good-aligned gods may not actually care that much about individual humans (possibly excepting actual gods of goodness or the like). Likewise, the more Evil-aligned gods are more likely to be seen almost as forces of nature; does Poseidon send the earthquake because he hates you, or is he more an anthropomorphic personification of the earthquake itself? Some gods will still be crueller than others and so forth, but it will be less "black and white" and more "don't get involved" (think "Orange and Blue morality").
NOTE: I have removed most alignment-based domains from the gods. Let's say that a Cleric of any deity can pick one if it matches both their and their deity's alignment and is a big part of their character.

On interactions with mortals: To the gods, the games they play with mortals are just that - games, of thousands of pawns moving across a great cosmic chessboard. The gods see much and hold great power, but little of this is ever shared with their followers. The gods are not there to look after mortals; they must fend for themselves, and any aid given is rarely done so freely. Even if one god does favour a particular follower, another may easily undo what was done, or grant as much assistance to an enemy.

Of course, this does not mean that the gods never interfere. They do - a lot, in fact. Capricious and unpredictable by their very natures, however, they do so as suits themselves. To the gods, mortals are but pawns, no more significant than ants are to you or me.