For a DnD campaign, I'm designing a setting with steampunkish tech level, as well as magic used to explain tech accomplishments not possible with real world physics. Almost all settlements in this world are "moving cities", powered by extensive clockwork mechanisms, that gain the majority of their resources through either moving to a new area and harvesting the wood/coal/etc that can be naturally found there, or through stealing resources from other, smaller, cities.
My question for you all is: What sort of population numbers would be reasonable for the Large and Medium cities of the world?
For context, the world will contain the following city sizes:
- Large city - primarily fully predatory, taking resources from medium sized and small cities. Constantly in motion.
- Medium cities - some economies and resource acquisition from trade with other cities or harvest of the surrounding areas, but also predication on smaller cities.
- Small city - primarily gain resources through harvesting from the natural resources around them. These are probably going to be no more than 100 people.
- Sedentary settlement - extremely small, less than 10 people. Primarily hiding from the cities to avoid being preyed on, but rarely trading with some of the cities.
I'm attempting to set this up roughly like a food ecosystem web, except with cities rather than animals. Additionally, leaders of large cities have an agreement to attempt to preserve this system, so "harvest" of resources from prey cities is done in a way that doesn't completely cripple that city. Catch and release, basically.
Any help you all can give me would be vastly appreciated, thank you!
I am drawing inspiration from the Mortal Engines book and movie setting, if this helps explain what I mean by "moving city".
(Edit: I'm relatively new to Stack Exchange, if I've messed up any other rules or norms for the community please let me know and I'll edit to fix)