Tiefling said:
Why do so many huge cities exist and how do the inhabitants get enough food?
Well, first of all, huge cities exist in
Urbis because there is a very big incentive for rulers to have them - the so-called
Nexus Towers.
These are large magical constructs that draw on the life energy of everyone who lives nearby (how much life energy depends on how greedy the rulers are - the settings range from "barely noticeable" to "death camp"...) and convert it into magical energies, which can be used to either create magic items, or cast epic-level spells - with the aid of Nexus Towers, even non-epic spellcasters can do it! You can find the exact mechanics
here.
So the more people you have within a confined area (the range of a Nexus Tower), the more magical energy you get. So naturally, most rulers will try to cram as many people as possible into their cities.
So, how do all those teeming masses get fed? Well, farming isn't done by small farms run by families of serfs anymore - instead, most crops are planted on huge plantations tended to by armies of migrant workers, and the plantation owners are always seeking ways of maximizing their harvests. Casting epic-size plant growth spells (powered by Nexus Towers...) is pretty much the standard. All that yields crop yields that are pretty much comparable to modern ones.
The remaining problem is transportation - the food not only has to be created, it has to get to all those starving masses as well. Well, it is easy (and comparably cheap!) to hire a couple of thousands of people to dig a new canal or two where nature didn't place a convenient river, or built a new railway (rails tend to be pulled by teams of quadrupedal stone golems)...
The city-states of
Urbis are a constant drain on the surrounding areas - they consume food, raw materials, and even people. But competent rulers (and any others don't survive for long in their jobs) can keep the whole system going.
All in all, I think this creates a quite different setting than what you may be used to from the Forgotten Realms, Greyhawk, or Dragonlance...
