Imperial Masters were the eyes and ears of the Emperor. They were an organization of Gnomes who were his secret intelligence services. The Imperial Masters were headed by the Grand Master of the Empire, a position of considerable power and influence.
The Gnomish Imperial Masters were all recognized by their pointed wizard-like hats and ornate robes. Each grade was represented by a color and arising up the ranks was something that Imperial Masters did by demonstrating loyalty and effectiveness in maintaining internal security. They were there to keep eyes on the officials of the Empire, and make sure that they were loyal to the Emperor and if any disloyalty was found, the Emperor himself would be notified and likely so would the Sunstar Elite Guard.