From PathfinderWiki

Vash-vatom is a centuries-old title for venture-captains of Nexus House, the Pathfinder lodge located in Quantium, Nex.[1][2]

There are reportedly three who bear the title "vash-vatom", and all are powerful spellcasters. Like any other venture-captain they are responsible for sending Pathfinders on assignments into the city, country, world, and beyond.[3]

Known vash-vatoms