ok how about this there are 12 Greater Gods, these are the 12 that created the world. they would have generalized concepts, like the sea, earth, sky or nature.
then the next batch of gods the Lesser Gods came along. whether they are the offspring of the Greater Gods, ascended mortals, or from something else they are full powered gods. they each have a more focused area of influence. example the gods of sea and nature had a child, this new god has dominion over the weather.