Voadam
Legend
The why is actually the thing that connects GDQ together, it is something that can be uncovered inBut IIRC, we wanted to find out why they were raiding. Mind you, I was a player, not the GM, so I didn't read the module, but I don't recall there ever being a real explanation for their acts beyond "they're evil and that's what they do." Which, as I said, is not something we find realistic. If there was an explanation--maybe it was in a later module--we either didn't learn it or it was (IMO) so uninspired that I've forgotten. This was in the Before Times, so my memory of it is pretty sketchy.
G3 Hall of the Fire Giant King, they are doing this on orders from Eclavdra of the drow which leads to the D series of modules.