Domain

The Domain was a vast information network used by the Forerunners. It contained the ancestral records and all knowledge of the Forerunner civilization. The Domain was apparently not located within normal space-time, or tied to any particular location or system, as mature Forerunners were able to connect to the Domain through their personal armor anywhere, regardless of distance. The Domain was also central in major Council proceedings, such as a political trial. Among other things, it was used by the judges to store archival and accounting material, assess precedent, and to verify witnesses' testimonies. Contender-class ancillas such as 05-032 Mendicant Bias were connected to the Domain upon their activation.

There was a mysterious quality to the Domain; its exact nature or origin remains largely nebulous. Sometimes, the records contained within the Domain changed for an unknown reason. The changes were regarded as sacred, and were never reversed or corrected. However, due to these anomalies, the Domain was not commonly used as means of communication; messages could be inexplicably altered on the way. The Domain appears to be somehow related to a Forerunner's subconscious; according to an ancilla, Forerunner scholars theorized that the dreams of early Forerunners accessed the "ground" that the Domain is built upon. The Didact mentioned that that the Domain sometimes had a "broken-mirror aspect", making it appear as if one's experience of visiting the Domain was the product of their own mind.

Further adding to its mystical nature is that in some cases, the use of an armor's interface was not even necessary to contact the Domain; when Bornstellar Makes Eternal Lasting approached Janjur Qom, the Domain opened to him for a brief instant; at first he described the experience as "deep" and "appropriately shapeless", but it soon took form, shaping into a coherent whole around his consciousness. Through this experience, Bornstellar felt the essences of everyone who had ever visited the Domain reach out to him, urging him to preserve the history of the Forerunners which would soon come to an end. When the Didact confronted his main opponent, Forthencho, the Lord of Admirals after the final battle for Charum Hakkor, he mentioned that "But to all of us there is a time like this, when the Domain seeks to confirm our essences, and for you, that time is now", possibly referring to Forthencho's impending death.

During the Forerunner-Flood war circa 100,000 BCE, the Domain had become inaccessible for all Forerunners. This was apparently the work of the rampant AI Mendicant Bias, who had exhausted the entire Domain in its search for the truth about the Precursors' plan.

Trivia
The Domain serves as the fictional basis for the terminals in Halo 4.

List of appearances

 * Halo: Cryptum
 * Halo: Combat Evolved Anniversary
 * Terminals
 * Halo: Primordium
 * Halo 4