Orlanth, as the God of Freedom, finds slavery objectionable. His temples and Rune Masters are prohibited from owning slaves (Lightbringers p. 23).
As a result, that means the Prince of Sartar, the tribal kings and clan chieftains, and the temples, tribes and clans as entities, do not have slaves. It does not stop cults other than Orlanth from doing so, but does mean that slavery is going to be disfavoured by the most socially powerful cult in the Kingdom. As a result, the percentage of society that is unfree in Sartar and Heortland is among the lowest in Glorantha.
