Centerra is my oldest campaign setting. I've been wandering its weird hills for almost a decade now. In that time, a lot of places have gone through a lot of revisions.
There was a weird little island in the south that I just labeled Carcosa as sort of a placeholder identity. Because I already knew what Carcosa was: it was dangerous, at the very edge of the map, and with a strange culture that wanted to kill me. But then Geoffrey McKinney's Carcosa was released and I bought it and read it and it was excellent and then Carcosa meant something different.
Because of that, I couldn't just leave the little island named Carcosa. Geoffrey will probably never knowof his spooky assholery that compelled me to remodel my Carcosa at a distance. But sometime between when I rotated my map 180 degrees (why're the cold places always to the north?) and the 11th and 12th drafts of my globe (I've redrawn that map a lot), the ambiguous little island of Carcosa became the much more specific island of Charcorra.
The streets are made from black clay, hard-packed and crisscrossed with ruts. Most buildings have monotonous facades, all carved from the same dark brown fungal wood. The forest of giant mushrooms on the island is quite sparse, and most of the buildings are older. There are no sewers, and the streets are awash in dung and sour filth.
That is most of what is known of the city, since it is a closed community. Outsiders are forbidden from landing on the island, and are killed on sight if they ever set foot outside of a tiny zone in the harbor district.
It's fairly obvious when you aren't from around there.
Although they live on the very fringe of it, the Charcorrans are darklanders, and like all darklanders, their skin is a mix of olive, grey, and green. Their eyes are brown, grey, or golden. Their teeth are black with lacquer (unless they are too poor to afford even this paltry cosmetic). Their spines are prominent through their skin. They average a good 6" taller than the other races of man (most of it in the torso) and their blood is black and extremely salty. Dreadlocks are nearly universal.
Like many darklanders, the Charcorrans are infected with a powerful sense of superiority. Even the harbor whores will tell sailors of their inferiority when they think their listeners are asleep.
In Charcorra, there is a warrior caste that artificially lengthens their arms with a mixture of sorcery and mechanical mutilation during childhood (mostly the latter). They believe that having a few inches of extra reach is an advantage on the battlefield, and they may be right. However, it does give their knights a very gangly look: dreadlocks whirling above their platemail as they thrust their toothy spear into the melee, that sort of thing.
They import metals, lumber, warfish oil, and especially leather. They export dyes, spices, a fortified wine called pittry (black as ink, but delicious), ceramics, and weapons. Let's talk about those last two categories for a second.
Rosenglass is enchanted glass (normally a light pink) that can be easily manipulated magically to alter the color and opacity, and is much sought after rich people who want to appear rich (rosenglass is quite expensive). Chargale is a ceramic that is strong enough to scratch steel, and is often made into bladed weapons. However, cheap chargale is quite brittle, and the strongest chargale weapons are the ones that have spent the most years in a fire (like a wine). If a Charcorran says that he has a seven-year sword, it means that it was baked for seven continuous years in a kiln, so his sword is much better than yours. After the ceramic has cooled, subsequent heatings do nothing for the strength of the material. Crysmere is not made in Charcorra, but is rather imported from somewhere deeper in the darklands. It is another form of durable crystal that is baked similar to chargale, although a bit softer. Unlike chargale, however, crysmere can be used to template spells, similar to a wand or staff, and many wizard's swords are made from it. Sotlatl is a poisonous metal, viper green and perpetually toxic. There are several other types of poisonous alloys, but none so famous as sotlatl.
In Charcorran culture, bonjuka are weapons that are used to kill animals and honorless criminals; they may not be used on anything else. Kreya are weapons that are used to kill enemy warriors and other intelligent combatants. Most Charcorran warriors carry at least one weapon of each type.
There are finer subdivisions of weapon. An infidel-killing spear is subtly different from a slave-killing spear, which is likewise different from a king-killing spear (perhaps a few more teeth along the saw edge and a crossbar that has been shifted a few inches). These distinctions are lost on outsiders. These intentions aren't strict, but any Charcorran worth the name will do their best to equip themselves with the appropriate weapon, and wartime killcounts are worthless unless performed with the right weapon. Charcorrans love their killcounts.
There are even women-killing knives (more of a hand sickle, really). You know you are in bad part of town when several men in the room wear baby-killing hammers on their belts (in case they need to kill a baby tonight, and want to make sure it counts).
Charcorrans are famous practitioners of mariculture. Their island is ringed with private ocean-ranches, vast tracts of shallow sea netted off. The owners of these marine farms are often found nearby, on huge, sprawling floating platforms (ranch houses, to continue the analogy). Although they love to eat salmon, eel, and dolphin, they are most famous for sangrayl, which is a 15'-long, free-swimming, herbivorous sea slug. (There are larger, carnivorous sea-slugs in the northern seas. Most southern sailors, given the choice, would choose shark's teeth over the slug's radulas.) The sangrayl ranches use so many nets, weights, floats, and buoys that most have been built over generations.
One last source of food: spindle pigs, a dog-sized sort of water strider than spends its entire life at sea. They are used for meat, companionship, and as "sheepdogs" for the herds of sangrayl. You know -you're sailing too close to Charcorra when an angry marine rancher pulls his raft up (pulled by big ol' sea worms, although you won't see them) along side your ship, and angrily demands that you pay him for trespassing on his sea-slug ranch. Scattered in the water around his boat are his spindle pigs, baring their fangs and making threat-chirps.
There is a resin called kreesh that is poisonous when it is smoked. Or at least, its poisonous when southerners smoke it. It causes a subtle numbness, followed by extreme weakness, followed by unconsciousness, followed by death unless you are given clean air to breath. Despite this, or perhaps because of it, Charcorrans smoke kreesh all the time. Perhaps they have some natural immunity to it, or are exposed to enough of it that they avoid the worst effects of it. But if you meet a Charcorran smoking kleesh, don't accept his offer to share any. If you are lucky, your knees will wobble, you'll fall over, you'll be laughed at, and that'll be the end of it.
Charcorran wizards can be easily recognized by the huge breathing apparatuses that some of them wear, like reverse gas masks. They'll have tiny smokepots strapped to their bellies, or to their backs (giving them the look of a hunchback). Speaking through sooty respirators, they'll cast their spells in between puffs of poisonous kreesh, although most suspect that they supplement it with tantigar (which always makes southerners nervous).
Charcorrans (and presumably all darklanders) worship vast pantheons of horrible gods. This is probably the biggest reason why they'll never be accepted by the "civilized" cities of the Great Continent. Their gods are always baroque, overwrought things with complicated cosmologies, tangled (and sometimes cyclical) genealogies, and no shortage of fanged orifices. You may see a Charcorran burning a stillborn calf to honor Malcarna, Who Dwells In Shells and Bleeds Black Pitch, but you'll never see a Charcorran cleric casting healing spells. In fact, Charcorrans are amazed/aghast that anyone dares to trade worship with the gods for petty miracles, like some cheap merchant. Gods are horrible things that must be appeased with blood. They take, and give nothing in return, and this is as it should be.