The Winding Serpent
By James Wyatt
In the midst of the Serpent Hills, astride the upper reaches of a small river that feeds the Serpent's Tail Stream, the petrified body of a gigantic serpent lies mostly buried in the ground. One coil of the creature's immense corpse forms an arch over the stream, while its head and tail protrude from the rocky ground some 500 feet apart.
A portal near Hlondeth leads to the mouth of the petrified serpent, which yawns about 50 feet above the ground. The natural inclination of most travelers through the portal is to get out of the mouth as quickly as possible; in fact, the yuan-ti have placed a coil of rope in the mouth, firmly attached to one of the serpent's petrified teeth, to encourage unwanted visitors to follow that instinct. When the yuan-ti use this portal, however, they use a secret door they've built in the back of the mouth that leads into the narrow passages inside the serpent. The secret door is fairly well hidden, requiring a Search check (DC 25) to find it. Because the door is stone, a dwarf's stonecunning bonus applies to this Search check.
Maps of the petrified serpent are located in the Map-a-Week archive.
Near the head of the petrified serpent, but some 50 feet underground, some enterprising gnomes (perhaps the same ones who dug the famous Dungeon of Swords) long ago established a small mine complex. Now long abandoned by its original owners, this mine serves as a way station for the yuan-ti who use these portals. These yuan-ti have extended the mines to connect to their extensive network of tunnels crisscrossing the Serpent Hills and the surrounding area.
The yuan-ti of the Serpent Hills rule a loose kingdom of reptilian creatures, in a tenuous alliance with a number of spirit nagas and dark nagas. The bulk of this kingdom's population are ophidians, a lesser race of serpent people. Shortly after the fall of ancient Netheril, this Kingdom of the Snakes became a mighty force in the Heartlands, with its capital temple-city in the western end of the Forest of Wyrms. Founded on ancient Netherese ruins, the rulers of this temple-city (called the Shrine of Cowled Serpents) used Netherese artifacts to help them dominate the region for over a century, until a coalition of human wizards from nearby kingdoms banded together to put down the threat they represented. Their capital was destroyed and the yuan-ti forced to flee the Forest of Wyrms, most of them taking up residence in the Serpent Hills.
A village called Serpent's Cowl (population 795) now stands on the ruins of this ancient yuan-ti capital, much to the chagrin of the yuan-ti. They would like nothing better than to slaughter the villagers and reclaim the ruins, reestablishing the ancient capital of their degenerate kingdom and the Netherese artifacts that still lie within the ruins. Some older residents of Serpent's Cowl believe they have a sacred duty to watch the area lest the yuan-ti return. They grow nervous about the increasing presence of ophidians dealing with the merchants at Boareskyr Bridge, apparently hoping to purchase any Netherese artifacts unearthed from nearby ruins. They also fear the rising numbers of snakes and snakelike creatures within the Forest of Wyrms.
However, the brave defenders of Serpent's Cowl remain completely unaware of the true threat to their city, which has little to do with ophidian traders or mutant serpents. The yuan-ti of the Serpent Hills have recently developed a technique for infecting humans with a tiny portion of their corrupted essence, creating a new type of servitor -- the tainted one. While pureblood yuan-ti look mostly human, tainted ones are indistinguishable from humans and serve as incredibly effective spies among the population of Serpent's Cowl -- as well as Boareskyr Bridge, Soubar, Thiel, Scornubel, and Baldur's Gate.
The yuan-ti also use another highly effective tool in their plots against the humans of the Western Heartlands: an additional portal located in the tail end of the petrified serpent, in the observatory atop the Sorcerer's Tower. The portal, shaped like a skull and occupying most of the southwest wall, stands about 9 feet tall. This variable portal functions differently depending on which of two keys is held by the creature activating it. If the creature carries a disembodied skull (as the form of the portal would seem to suggest to the unknowing), the portal connects to a remote region of the Barrens of Doom and Despair, an Outer Plane that is home to some of Faerûn's most evil deities (including Bane, Beshaba, Hoar, Loviatar, and Talona). Should the activating creature carry a live snake (or a snake and a skull), the portal functions as the yuan-ti intend, opening into the bowels of Zstulkk Ssarmn's private residence in Skullport.