Auditor

Vigilant-Watch-Over-Realms-Unknown, better known by their title of The Auditor, was an official in the Forerunner ecumene.

Flood invasion
In approximately 97,745 BCE, the Auditor received a report from the Prelate detailing what would later prove to be the first Flood invasion of the Milky Way since the human-Forerunner wars 9,000 years earlier.

Composition into Adjutant Revendicate
The Auditor would later go through a long series of events they would later describe as "a long story and not one that need to be told now", ultimately being subject to composition and conversion into the, Adjutant Revendicate - who would act as one of the administrators of Installation 07. Upon hearing of the Auditor's fate and reduction to the role of monitor, the Invariant Bias would express shock.

Trivia
"Auditor" is defined as a person who in charge of evaluating or assessing something. This reflects his task, seemingly geared toward monitoring suspicious phenomena across the ecumene and further reporting them to the appropriate authorities.

List of appearances

 * Halo: Evolutions
 * Soma the Painter