In my world, humanoid races are an afterthought added by the gods only after they'd spent millennia treating the world as their personal canvas, designing it however they found most interesting. This resulted in an extreme and hostile environment, with large forbidding mountains, deep impenetrable forests, and wildly tumultuous rivers. Furthermore, the exceedingly fertile ecosystems have larger trophic chains than on Earth, resulting in a proliferation of large animals, including many predators and magical beasts– monsters, in short.
To be specific, in this world it is difficult to travel, colonize new areas, expand settled areas, and maintain current holdings due to:
- Hostile ecological elements, such as large animals
- Natural barriers, such as mountains and forests
- Difficult-to-tame environments, such as forests with high regrowth rates
My question is this: in such a dangerous and difficult-to-navigate world, where would civilization be located and how would it be distributed? I assume it would have a stronger focus on navigable waterways than our world, but I'm trying to figure out the scale and population distribution of nations. Would there be tiny, isolated city-states? Could thinly-spread dense population centers become a larger nation despite the difficulty of travel? Or would a world such as I have described not deter human expansion at all, to the degree that humanoids have settled a significant portion of the world's arable land?
Civilization has been developing for several millennia and is currently in the late Middle Ages, technologically and culturally. Magic is present, but should not be a significant factor in any answers.