Forerunners of all rates wear body-assist armor through much of their lives. The armor protects us both physically and medically. In emergencies, it can suspend a Forerunner until rescue, and even provide nourishment for a time. It allows mature Forerunners to connect to the Domain, from which all Forerunner knowledge can flow. Armor is one of the main reasons that Forerunners live so long. It can also act as friend and advisor. I consulted with my ancilla, the armor’s disembodied intelligence and memory—a small bluish figure in the back of my thoughts.

Halo: Cryptum Ch 1