Dawn of the World: The Ancient Dragonflight
Vos is a very large mixed city at the end of the Vostin Canyon, a canyon home to another city, a Dwarven city. The reason the PCs have stopped here is because this is the only city availible to all races on the continent.
Many things are able to be bought here, and this is the main adventuring hub for the PCs.
Vos is in the center of Naggaroth.
Saul is the main employer of all folk and the guide to newcomers in the city of Vos.