But isn't it a big thing that you can't just portal in the underdark because the Faerzress radiation interfers with the destination? Drow cities are often in areas of high radiation to take advantage of this, enemies can't just portal in.
I have been wondering about the distances too. Either a lot of Drow walked a long way, or the Mindflayers were putting on a commutor service with the Nautiloid.
