Why don't the monsters simply eat the people?
I was reading Pikliz Dungeon's most recent post and thinking about one of the contradictions of the Jewelsea that I haven't yet resolved - why does a world full of states and empires have a wilderness full of monsters? Why hasn't one destroyed the other?
The Monster Age
One of the reasons so little is known about the old empire is the complete collapse of civilization following its fall. Monsters roamed the world, breaking, burning, and butchering all they could. Societies only rose again once people learned techniques to repel the monsters. Two primary means ward the peoples of the Jewelsea against the malign forces that still hide in the dark places of the world. Neither are unfailingly effective, but they do enough that to most people, monsters are something present in scary stories for children rather than an ever-present threat.
Ritual
Rituals direct the natural forces of the world in ways that benefit the ritualist. Most pertinent here are the rituals that reinforce the boundaries of a settlement, creating a sort of barrier that monsters hesitate to cross. The more elaborate and permanent the boundary, the harder it is for a monster to pass. Some rituals are so elaborate as to involve inscriptions stamped into every brick in a wall.
Charms
Amulets, talismans, and other forms of charm are made to not only hide people from the notice of monsters but also to guide them away from places of danger. They act as effective wards against minor curses and rituals like the evil eye as well. They are more effective the longer they have been in someone's possession—they are most often given to a child before they learn to walk. Their protection is slow to build and slow to fade. Because it is not easy to turn on and off, these forms of protection are not very useful to those who seek to find treasure in ruins and the wilderness which is often surrounded by monsters. Those protected by charms will find that dungeons are hidden from them as much as they are from monsters.