Did Larian by any chance say something about making the Duergar a playable subrace of the dwarven race? I'm asking because I was just creating a cleric, when I saw that you could play as a cleric of Laduguer, their main deity (and if I recall the lore correctly he is solely worshipped by them), which seemed odd to me. There are also already Duergar in the game (even on the surface), so the only thing they would have to add are race specific lines. It would be awesome, because they add a pretty interesting flavour to the dwarven race.
