Before the great glaciers covered the northern world for the last time, there was an age of legends now forgotten in the modern world. Cities of barbaric splendor and monstrous survivors from prehuman times were scattered across the great isles of the north like a handful of gems strewn from a dead thief’s hand. This was the land of Thule, savage and spectacular, a world of wonders and terrors. And it lives now only in the darkest depths of prehistory and half-remembered glimmers of myth.

Thule is a world in which legendary places and creatures exist and magic, dark and mysterious, holds power over a young and superstitious humankind. This is the time of Atlantis and Lemuria, of serpent-men and savage beasts, of star-demons and sorcery.

If you’ve ever read a Conan story, if you’ve ever watched a movie about lost worlds or sword-and-sandals adventure, you know what Thule is already. But just in case you haven’t, here are seven simple truths about this forgotten age of adventure.

Thule Is Barbaric

Humans and demihumans are young races. Nomadic hunters roam the wide world, following the great herds and eking out hard lives in the unspoiled wilds. Warlike hill-tribes guard their territory with grim fury and raid those weaker than themselves. Even the cities are barely civilized; in most realms power lies in the hand of whatever chieftain, warlord, or king who was strong enough to seize the throne, and these despots reign only as long as they remain stronger than their rivals.

The Wilderness Is Savage and Spectacular

Leave the city or the safety of your tribe’s camp, and you’re taking your life in your hands. The jungles are teeming with bloodthirsty beasts and venomous perils. This is the age of ferocious beasts—dire wolves, saber-tooth tigers, spotted lions, giant ground sloths, and ill-tempered mammoths. These deadly creatures roam a world of misty forests, icebound mountains, and endless plains. Thule’s vast wilds teem with life, and most of it wants to kill you.

Nomads and savage tribes learn the hard way how to survive in their brutal homelands. For civilized people, the wilderness is a deadly obstacle indeed. There are few roads between cities, and those are often plagued by raiders or outlaws.

Cities Are Wicked Places

If you think you might be safe and comfortable behind city walls, think again. The city-states are dens of greed, thievery, and callousness. Civilization is young and untested, representing a thin veneer over this brutal and violent age. Consequently most cities are fatally flawed, built on injustice or immorality. Each of Thule’s city-states embodies its own special brand of wickedness: hedonism, slavery, tyranny, avarice, cruelty, demon-worship, and more. The barbarians of the wilderness may be violent, but they at least are free of the corruption and injustice that steep the very stones of most cities.

The World Is Mysterious

Given the daunting terrain, ferocious beasts, and bloodthirsty savages lurking in the wilderness, Thule remains largely unexplored. Even nomads stake out their hunting grounds and rarely venture far from the lands they are familiar with. Most people don’t know what lies more than a few days’ travel from their homes. Anything could be lost in the jungles and ice of the wilderness: abandoned cities, the strongholds of inhuman powers, foul temples, degenerate tribes, or hidden lands ruled by obscene monstrosities.

Magic Is a Secret Man Was Not Meant to Know

In Thule, magic is rare. In a city of thousands, there might be only a handful of mages schooled in the arcane arts, and each of those individuals is widely feared and whispered about by his or her fellow citizens. The reason for this is simple: arcane magic is not a human invention. The various schools and spells of magic were learned (or stolen) from prehuman teachers, most highly inimical to humankind and related races. Students of the arcane study unwholesome lore and bargain with perilous powers indeed.

Divine magic is just as uncommon, a secret jealously guarded by priests who choose only the most promising young acolytes to be initiated into the deeper mysteries of the gods. The gods are fickle and inscrutable creatures, prone to ignore those in need of their aid or punish suddenly when offended. Worse yet, priests form a powerful and corrupt caste in many city-states, and use their powers for their own gain. It is a dangerous thing to attract a god’s attention, even a relatively benign one; they tend to use their servants poorly, and their enemies even worse.

Ancient Evils Threaten to Destroy Humankind

The reign of man is new and fragile; older races such as serpent-men, beast-men, giants, and rakshasas still lurk in many places. Human tribes and cities that stumble into contact with these ancient dangers are often destroyed, enslaved, or corrupted in horrific ways. While the Great Old Ones no longer walk the Earth, their servants are everywhere. Degenerate tribes sacrifice captives to Tsathoggua or Ithaqua on fearsome stone altars in the wilderness, while depraved cults worshiping Hastur or Cthulhu infest many cities. Worse yet, humans are not the only slaves of these star-spawned powers—alien horrors such as moon-beasts, mi-go, deep ones, and worse infest the places where the Great Old Ones once held sway.

Thule Is a World of Adventurers, Not Heroes

High morals are a luxury most people cannot afford; true heroes are few and far between. The typical adventurer is a thief, mercenary, sellsword, or freebooter—an opportunist on the lookout for a prize worth risking everything for. Adventurers strive to win rich treasures and climb to the heights of power. Any good they happen to do along the way is more or less accidental, although it is certainly true that many freebooters have a rough sense of honor and act to protect the weak when they absolutely have to.

Because Thule is home to many mercenaries and wanderers, it’s not unusual for rumors of significant discoveries to attract the interest of more than a few rivals, or outright villains. Adventurers can expect to cross swords with scheming sorcerers, greedy thieves, and brutish mercenaries who share many of their interests and motivations. At least these thugs and villains are driven by human appetites—there are many dire perils in Thule that are not remotely human. In the face of threats such as these, even the most coldly calculating sellsword or reckless freebooter might be forced to play the hero.