Araqiel

Araqiel was a UNSC "smart" AI assigned to Colonel James Ackerson.

As Ackerson's private AI, Araqiel was tasked to spy on Dr. Catherine Halsey and her research. His avatar is that of an elongated skull with long, demon-like horns, fire-filled eyes and jagged teeth. His voice is a low bestial growl or rumble containing a trace or crackle of far-off thunder.

He was left at CASTLE Base in 2552 during the Battle of Reach. He threatened Dr. Halsey and Kalmiya, Dr. Halsey's personal AI, accusing them of treason, after he attempted to stop her from breaking protocol and military law by accessing Ackerson's private data files. He even went so far as to threaten to fill Halsey's office with fatal levels of narcozine gas or to pressurize her office and cause pulmonary edema (the flooding of the lungs via the inability of the heart to remove fluids, effectively causing the victim to drown). Dr. Halsey responded by activating the fail-safe in his Riemann matrix, effectively destroying him by sending a concentrated UV Burst to burn it out.

Trivia

 * His name and avatar were based on Arakiel, a fallen angel described in the Book of Enoch in the Apocrypha.
 * In Dr. Halsey's personal journal, there is an entry in which Halsey talks about being monitored by an ONI AI is accompanied by an image composed of vertical lines. These lines appear to create an image of a fanged skull with long curling horns. It almost certainly is an image of Araqiel.

List of appearances

 * Halo: The Fall of Reach
 * Halo: First Strike
 * Halo: Glasslands