A degenerate and cannibalistic race that worship strange gods. They are noted to have been living in southeast Asia in the 1920's, having migrated from Tibet, their homeland. Apparently they follow an ancient legend about migrating toward the rising sun, which has caused speculation that they may have one time lived as far as Europe. A Basque legend of "dark dwarves that left their home in the Pyrenees at the command of their priests" supports that theory.

Some Tcho-Tcho have actually integrated themselves into modern society, masquerading as just another harmless ethnic group. The Tcho-Tcho are cannibalistic criminals devoted to the worship of the Great Old Ones and to have received funding and weapons by the CIA-owned campaign of support to anti-Vietnamese ethnic groups in Indochina during the early 70s, via Tiger Transit, an Air America-style front company.

A delicacy of their cannibalistic cuisine, which they secretly dole out to unsuspecting diners at their "ethnic restaurants", is a dish called bak bon dzhow. This dish is composed of human ganglia mashed into a thick paste and is usually served in accompaniment to other "white pork" (human flesh) based dishes. Bak bon dzhow means, literally, human ganglia paste in their blasphemous native tongue, though inquisitive outsiders are always told that the translation is "White Pork Sauce". Non-Tcho-Tchos who partake of it dream of lustily partaking in a vile cannibal feast the next time they sleep.

Encountered in Mission 15: The Gates of Delirium, Mission 19: The Fortress, Mission 20: An Outbreak of Alchemy.