Dwellers of the Forbidden City

The adventure begins when the player characters hear reports of bandits waylaying and attacking caravans in a jungle region. Most of the ambushed merchants and guards have been killed, but the few who have returned alive tell fantastic stories about deformed plants and deadly beasts in the jungle. The stolen goods taken from the caravans provide an impetus for the characters to enter the jungles in search of this lost treasure.

After a long and perilous journey, the player characters encounter some friendly native people and are invited to stay in their village. The characters learn from the village's chief about the dangers of creatures called the yuan-ti and their servants, the tasloi, and that these creatures recently kidnapped the chief's son, taking him into the jungle. The chief and village shaman tell the player characters about a "forbidden city" in the jungle which they believe houses the ghosts of the enemies they have killed, and they supply the characters with guides to show the party the way to this forbidden city.

The adventuring environment in this module allows for both action and intrigue. The player characters can recruit allies from the various power groups and factions within the city, namely the bugbears, mongrelmen, and bullywugs, or else help pit these factions against each other for their own benefit.

Dwellers of the Forbidden City was first used in Dungeons & Dragons tournament play at the Origins Game Fair in 1980.^[2][3][4] The module was published in 1981 by TSR for the first edition of the Advanced Dungeons & Dragons rules, and consisted of a 32-page booklet with an outer folder.^[2] The module was written by David "Zeb" Cook, with cover art by Erol Otus and interior art by James Holloway, Jim Roslof, Harry Quinn, and Stephen D. Sullivan.

Dwellers of the Forbidden City is the first of the mostly unrelated and unconnected Intermediate series (I-series) of modules designed for characters at between 4th and 8th levels. The module was originally intended to bear the code S4,^[5] but the code was reassigned to Lost Caverns of Tsojcanth before Dwellers was published. As published, the adventure bears the code I1. It was one of the first adventures written by Cook, and he attributed TSR hiring him after he submitted an early version of the module.^[2] Cook would become the lead designer for the second edition of the AD&D rules, which debuted in 1989, and years later, he became the lead designer on the City of Villains MMORPG.

The adventure was instrumental in introducing the yuan-ti as a new species of antagonists.^[3] Much like the drow from the Queen of the Spiders Series, the yuan-ti have been featured in a number of 1st, 2nd and 3rd Edition books for the D&D game, and are one of the few species that Wizards of the Coast did not keep open for the Open Game License.^[6] The yuan-ti have also been expanded from their introduction in this module to other game worlds, in particular the Forgotten Realms campaign setting.^[7][8] Other new monsters introduced to the game through this module include the aboleth, mongrelman, tasloi, and yellow musk creeper.^[9]

The module was set in the World of Greyhawk campaign setting, and was later used to add detail to the continent of Hepmonaland in Greyhawk supplements.^[10] In the Greyhawk accessory The Scarlet Brotherhood, by Sean K. Reynolds, the Forbidden City was named Xuxulieto, and the mountains wherein it lies are called the Xaro Mountains.