Unidentified ancilla (Shield World 0459)

"Security barrier breached. High order infection detected. Unidentified alien intrusion detected. Initiating stage three defense protocols."

- The ancilla as the enters the Shield World

This unidentified ancilla was a Forerunner ancilla stationed on Shield 0459. It is unclear whether the ancilla was in charge of the whole shield world or just the installation's entry tunnels and the cleansing ring systems lining them.

Human-Covenant War
On February 23, 2531, when scanning the surface of Shield 0459, the accidentally initiated an automated docking mechanism and was subsequently pulled into one of the portals on the surface that led into the interior of the shield world. As the ship made its way through the tunnel, the ancilla detected a "high order" Flood infection, as well as intrusion by humans, though the ancilla did not recognize the latter. The AI initiated "Stage 3 Defense Protocols", which included activating Sentinels, Super Sentinels, and cleansing rings to clear away the Flood and the "unknown alien intrusion". It was most likely destroyed when the shield world was obliterated by a supernova caused by Spirit of Fire's crew.

This ancilla's voice did not resemble those of most other known Forerunner AIs, with the exception of Mendicant Bias. While ancillas like the monitors have more natural-sounding voices, this construct spoke in a robotic monotone. It may have been a Forerunner counterpart to a human "dumb" AI, as it did not recognize the humans on its installation as Reclaimers, instead referring to them as "unknown aliens".

List of appearances

 * Halo Wars
 * Halo: Smoke and Shadow