Far from the eyes of the modern world, there exists a realm that has only been hinted at in our myths and legends. The world beneath the streets is full of life and magic, unseen by the world above. The Underworld (as it has been termed by its citizens) is divided into various Domains, each ruled by a Lord. Like the kingdoms of old, the Domains of the Underworld forge alliances, trade in goods and services…and, at times, make war upon each other. The Lords each rule their domain as they see fit: some are benign, others are despotic. A key to survival in these tunnels and caverns is awareness of the mood and temper of each particular Domains ruler…in some cases, it can mean the difference between life and death.
The denizens of these underground Domains are made up of several Breeds. A Breed is a grouping somewhat akin to a species or a race, but usually cast in a wider net. Some, like the elusive Mole People, are a true race unto themselves. Others, like the Homeless, are as widely varied as the different species of flowers that blossom in the World Above. Some Breeds like the Junkmen are born of magic and not natural at all.
The people of the Underworld, in all their Breeds, organize themselves by profession. These professions, known as the Guilds, are, perhaps even more than the rule of the Domains, responsible for carving out a sense of order in the chaos of magic and survival that is the World Below. Every Domain respects the rule of the Guilds, regardless of the whims of the individual Lord. The traditions maintained by the guilds, similar in structure to the guilds of Europe’s renaissance, allow for a rule of law that maintains the status quo, and allows the secret of the Underworld to be kept from the mortal world. Traders are the only Guild who travel Above. Bravos are the only Guild who trade in violence. Mendicants tend to the health of the people. Navigators get you where you need to go. The guilds all have their roles, and those roles are sacrosanct. It is the order of things, and all but a dangerous few obey.
Outside the Domains, the Underworld is wild. Great beast lurk through dark tunnels, ready to devour the unwary. In caverns deeper than any Upworlder has ever traveled; there are lost cities, built by inhuman hands. The Radiance manifests itself in wondrous and unexpected ways. There are villains, and there are heroes. This is the World Below. The is Underworld.