The Watcher

The Watcher is an ancient Precursor entity that observes and catalogs the history of the Milky Way and Andromeda galaxies.

Pre-Forerunner-Precursor War
Prior to the Forerunner's rebellion against the Precursors, The Watcher was tasked with compiling a record of all of history. With it's new assignment, The Watcher left the Milky Way galaxy and settled within the Triangulum Galaxy with several other Precursor scribes. Through remote, yet still-active access to the Domain, they were able to maintain the ability to watch over history as it unfolded.

Forerunner-Precursor War and Isolation
When violence erupted as the Forerunners began their warpath against the Precursors, numerous scribes from The Watcher's catalogue returned to the Milky Way galaxy in a vain attempt to persuade the Forerunners to end the war. Following the conclusion of the war, only three scribes, including The Watcher, remained within the catalogue.

As the centuries progressed, The Watcher's fellow scribes slowly drifted away, leaving one-by-one to travel the cosmos aimlessly. As it grow closer to total isolation, The Watcher refused to end it's assignment to catalog all of history.

Firing of the Halo Array
When the Halo Array was fired, The Watcher was far outside of the Array's reach, but was not separated from it's effects. With the Domain having been severely damaged, The Watcher was no longer able to use it to observe and catalog history. Seeing the preservation of the Domain as neccessary, The Watcher traveled back to the Milky Way galaxy to repair it, but was beaten to it by Growth-Through-Trial-of-Change and the Iso-Didact. Having already arrived in the galaxy, The Watcher saw fit to observe history far more closely, and also began to compile the catalog of history within the Catalogue in Triangulum instead of the Domain to preserve it in the event of the Domain's destruction.

Post-Firing
50,000 years prior to the Common Era, The Watcher's physical form had deteriorated significantly to an extreme point. The Watcher would infuse his consciousness, memory and personality into a Knowledge Engine within the Triangulum catalogue. The Watcher did not fully abandon it's body, instead placing it into stasis until a time in which it had repaired itself enough to become viable.

It was at this time that The Watcher came into accidental contact with the ancient S'southi, who began to worship it as a god within the S'southi pantheon.

The Watcher continued to catalog history, avoiding contact with all civilisations and remaining in solitude. During the S'southi invasion of the galaxy, The Watcher permanently fled back to the Triangulum Galaxy, believing that the S'southi would win and destroy all life within the Milky Way.