Demand Modifiers for Underground Cities *SPOILER ALERT*

I’m starting my campaign with B4 The Lost City, and am building the underground city of the Cynidiceans as a market. I was wondering if you had any advice on what, if any, climate modifiers to use.

I'd go with:

2,0001+ years; No Water Source; Desert; Hills

That would yield, e.g.:
Grains +3 +1 + 0 = +4

Glassware: -1 + -1/2 + -1/2 = -2

Monster Parts: +1 + - 1/2 + 0 = - 1/2

Spices: +1 + 0 + 1/2 = 1 1/2

And so on



Thanks for responding Alex. Did you go with the Desert climate type because that is the climate on the surface, or becuase you think that’s what best emulates an Underdark-style cavern-so-large-you-can-build-a-city-in-it?

I ask because using this module introduces a potentially campaign-shaping choice: hang out just long enough to gather enough strength to hexcrawl back to civilization through the desert, or stay and help the Cynidiceans. If the PCs fixate enough on the city below, this could easily turn into an underdark campaign.

I picked desert because that was the climate above.

If you want to do an "underdark" campaign, you'd probably have to create a set of domain modifiers specifically for the underdark. Unfortunately, there have been no historical underdarks from which I can draw examples of what their trading patterns might be. Probably what you could do (for gameplay's sake) is figure out the demand modifiers of the nearby regions on the surface, and then make them dramatically different. That way the underdark to surface trade routes will be highly profitable and the exchange of goods will be exotic.

Heh. Yeah, I guess the lack of real-world models would be a problem.

If the PCs decide to go that route, I intend to cheat by making most of the region below the surface region I’ve already built a Pellucidar-style dinosaur-infested lost world jungle in a giant cavern that I can use normal terrain for. I’m designing some underground hexcrawl terrain types to connect it with the surface, which is fairly simple as far as movement and getting lost and encounter chances go. I broke it down into 3 basic terrain types:

Caverns - vast open areas like the aforementioned jungle. They get subdivided based on what’s on the ground: water (underground lakes and seas), bare rock, volcanic areas, mushroom forest, or surface terrain like the jungle.

Labyrinths - hexes full of twisting passages and rooms, whether natural or constructed or, most likely, a combination of the two. It’s assumed they are pretty diverse, so they don’t get subdivided, except maybe into volcanic yes/no. Super high chance of getting lost.

“Deepways” - long tunnels that lead more or less straight from one hexside to another, or branch to lead to several hexsides. Deepways are divided into roadways (underground roads, usually constructed by giants), waterways (underground rivers), passageways (what’s left after a waterway dries up), and lava tubes (volcanic).

I figure the age, water source, and elevation demand modifiers would translate directly. For climate, I’ll run with bare rock, volcanic, and mushroom forest, basing the first two on desert and the last on one of the forests, maybe taiga. Or taiga plus swamp…

Anyway, it’s totally doable, and I love the idea of purposely setting things up to make trade with the surface interesting. Thanks!