Araqiel

Araquiel was an AI assigned to Colonel James Ackerson.

As Ackerson's private A.I., Araquiel was tasked to spy on Dr. Catherine Halsey and her research. His appearance 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 laser beam to burn it out.

Trivia

 * His name and avatar was based on those of Arakiel, a fallen angel described in the Book of Enoch in the Bible.
 * The override used to destroy him greatly unsettled Kalmiya who confronted Dr. Halsey about it. The same method was later used on Kalmiya as well.