As the lore says,there are 7 sentient races in Divine Divinity:

#1 humans
#2 elves
#3 dwarves
#4 orcs
#5 lizardmen
#6 imps
+1 mages (which are like bhaalspawn-descendants of all races)

The trolls are just trolling, or what? They are demons? Gods? Space-aliens? Visitors from the future? Product of natural evolution?

They actually explain that somewhere in the game - perhaps prior to the wastelands. If I remember completely, only the six races are included because they are the major ones and are more intelligent. I guess dem dar trolls are just too dumb, :)

It is just pushed on the side with that.

The question still stands, as later we also learn, that there is an 8th species: demons,created by the God of Chaos (the same place they explain how the First Age/First Banish of Chaos ended).
This further marks that each and every species was created by its own god. Which begs the question, where did trolls and hawkmen come from? Whichgod is responsible for them?
Or maybe all this is a lie. The gods never existed,aside obviously Chaos.

If you play Beyond Divinity, you'll find there is at least one more race with their creator god. There may even be another in Original Sin II (haven't played it yet but that is the impression I get). I don't know the answer but I asked the question on the Larian site - hopefully an answer will be forthcoming.

Which one, and which god? And isn't Beyond Divinity playing on anentirely different plane?

Btw, I don't like asking the developers. Their answer - if the answer is not in the product already - will be definite. I like theoryzing. Like maybe trolls are byproduct of that earth-god (what is a lesser god? or made up by the Stalker?). Or maybe the Good Gods are actualy fiction like modern-scholars-of-the-game claim.

Of course I'll look up their forum now that you DID ask...

Nothing as of a few minutes ago. Most people there are on the Original Sin II section - older games sections are nearly abandoned.