I was escorted along lifts and enclosed tracks by two guards of the Council’s own select security, designated by sleek black and red armor. Through translucent walls, I saw unfamiliar automatons speeding along their own tracks and tubeways; some were decorated in the most alarming insectoid carapaces. But more surprising still were the numerous embodied and heavily armored ancillas. I had heard of Warrior-Servants utilizing such during battle and for other special tasks, but we encountered hundreds spaced throughout the ship, floating in serene quiescence, in apparent low-power mode, their blue, red, or green sensors dimly aglow. They will come alive in an emergency. They can replace human commanders, if necessary. They are a vital portion of the Council metarchy—the overall network of ancillas that support the Council. But compared to a metarch-level ancilla, these are mere toys.
Bear, Greg (2011-01-04). Halo: Cryptum: Book One of the Forerunner Saga (Halo: the Forerunner Saga) (p. 256). Macmillan. Kindle Edition.