You'll certainly get your fill with this one. I've glanced through the intro and it is very much Underdark . The writers went back and read the 'original trilogy' of the Dark Elf series featuring Drizzt Do'Urden. Then they recruited R. A. Salvatore to help them write the rest. So, yeah, lots of Underdark. There is even a world map that has the overland realm overlaid with what lies below, including a depth scale. Two things of note: 1) The Princes of the Apocalypse campaign is in its final throes. The next few sessions will show the elemental forces ramping up their efforts as the Dessarin Alliance gets continually closer to the Nodes. Things will happen pretty quickly going forward. 2) I don't want to start one thing without finishing the first. This was something I continually did wrong in the Faerun campaign. DM ADD I suppose. So I don't want to get too excited about the Rage of Demons campaign before the Princes of the Apocalypse has finished. Having said that, I want to bring up a point since we're talking about the next campaign to some extent. I spend $120 a year on Roll20 to create the cool immersion that is Dynamic Lighting. ($9.99 a month subscription). So I have a hard time justifying further expense on maps. I've never asked for money in the past (except that one time; thanks Shawn, James and Zamp for that), but I would gladly take donations of subscriptions and convert that expense into new map packs. At ~$4.99 per map pack that's two maps per month subscription. I only bring this up because all of my maps are above-ground but there are some very nice packs dealing with the Underdark that I could use for the new campaign. I'm not looking for anything at this moment; like I said I'm still focused on finishing the Princes campaign. But it's something I've always been too proud to ask for in the past but now seems like a good time to bring it up.