Abaddon

The Organon was a rumored Precursor artifact of incredible power, believed by some Forerunners to be able to activate all Precursor artifacts. It was considered to be the most sought-after Precursor artifact by Forerunner archaeologists.

In approximately 100,000 BCE, Bornstellar Makes Eternal Lasting sought the artifact on both Edom and Erde-Tyrene using a pair of human guides to lead him to its presumed resting place in the Djamonkin Crater. Instead he found the Cryptum of the Didact, who outright denied the Organon's existence.

Years later, the Flood revealed to the Librarian that the Organon was actually the Domain, which was a Precursor consciousness embedded within their ancient structures. Its takeover by the Flood allowed them to use Precursor artifacts as weapons, and so gain an edge over the Forerunners.

List of appearances

 * Halo: Cryptum
 * Halo: Silentium