The masquers are the elite spies of the Thousand Eyes— exceptional changelings trained in the arts of subterfuge and observation. A masquer seldom carries weapons and never initiates combat. Her job is to infiltrate, observe, and report, allowing others to do the messy work. Those who encounter a masquer rarely know it, but any foreigner who spends time in a bastion is observed by one.
Masquers always take changeling rogue substitution levels (Races of Eberron 122). They also wear psionic shiftweave outfits (Sharn: City of Towers 170), which are universal items based on metacreativity.