Greyhawk
Fiends in the Horned Lands
Fiends have great influence here. As noted, many of the population believe that the Hierarchs, who they believe still survive in Molag, are fiends themselves, and they are used to fiends acting as messengers for the Hierarchs. Thus, priests of Iuz often need to have fiends on hand to control and command the population and the indigenous troops of the Horned Lands. The priests must therefore tread extremely carefully, for they must indulge the demands of the fiends while not arousing the ire of Iuz himself. In addition, as noted, there are many fiend-ruled estates in the eastern lands, given over to fiends serving Pazrael who administer them as they wish.
Carl Sargent. Greyhawk Adventures, Iuz the Evil, 1993