Qui-zi was the city the Tukharistanis gave to the human families they brought in to produce silk for them. It was said to be a paradise, but one that imprisoned its inhabitants: No human or none of the mixed-bloods that emerged over the years, was allowed to leave the city.
It was this city that the Scourge of Qui-zi apparently burned to the ground, at the order of the Nahids he served as afshin, during the Zaydi al Qahtani rebellion. The Nahids had given this brutal order to prevent much greater atrocities.