Shadows of a Fallen World
Zaros is a silent and mysterious drow summoner. Zaros serves Itu’mostharug as Master of Chains, meaning his responsibility is to guard the Hourglasses.
He led Orin Katar’s assault on the Grey Gauntlet’s keep and is responsible for the murder of the guild master Amen Jorde.
He disappears immediately hereafter without a trace.
Simon Goodchild explains to the Heroes that Zaros is a drow mercenary who lives somewhere in the Old World on the Material Plane.
Morgost Hun’ett explains that Zaros is now a member of the Nightbringers, and that Orin Katar’s assault was a favor owned to him and his organisation, making the Nightbringers responsible for it.