Well we know very few things but of the information we have we know that they're mutated Dark Trolls and that Elune had a hand in mutating them using the Well of Eternity. (I am right correct?)
However there are many blanks to be filled in but let's all discuss how you all think what happened. What do you think happened when they were in the transition from Troll to Elf?
Since we have no canon evidence of how it all went down it's just going to be wishful thinking now.