Just wondering if any modules, novels, sourcebooks, or other "official" source has ever stated any connection between night hags (which are outsiders) and other varieties of hag (which are monstrous humanoids). Anyone got anything on the topic?
The Ecology of the Greenhag, in Dragon 116 (?), is the source you're looking for. It proposes the theory that night hags mate with mortals to give birth to greenhags, which in turn mate with giants and ogres to turn out the annis. That does, of course, leave out where sea hags and all those other nifty new ones (the bheur, etc.) come from...
IMC I have The Nighthag (there is only one) be a minor demi-goddess who is the supposed ancestress of all other hags (and called upon by them in certain rituals).
I thought there were some vague hints in the 3.5 monster manual about this, but maybe I'm remembering it from somewhere else. Wasn't there an article on night hags in the October Dragon? Maybe that's what I'm thinking of...
I seem to remember an article "The Ecology of the Greenhag" that said that... greenhags were the offspring of night hags and mortals... and annis hags were the offspring of greenhags and ogres...