The Greyfaces were the workers looking after the gas supply in Darujhistan. They dressed anonymously in hooded grey robes, walking the streets like silent spectres and lighting the city's gas-lamps with long-poled sparkers as evening fell.
At least one of the districts of Darujhistan had been supplied with gas from around 260 BS onwards. There had been the occasional fire, with flames reaching hundreds of meters into the sky, but the Greyfaces had held on.
They were called Grayfaces in the American edition of Gardens of the Moon.