A supremely powerful Witness, usually fixed in location and requiring more power to operate. They allow the user to see random events instead of what the user knows like a Minor Witness. Known Master Witnesses include:
The stone known by the Sithi as Rhao iye-Sama'an (Earth Drake's Eye) underneath Sesuad'ra has the ability to turn Minor Witnesses temporarly into Master Witnesses. Scince all of the great Sithi cities had a Master Witness there should be unnamed ones for the cities of Da'ai Chikiza, Enki-e-Shao'saye, Kementari and Tumet'ai.