Office of Naval Intelligence

The Office of Naval Intelligence, acronym ONI (pronounced as /oʊni/), is the intelligence service branch of the UNSC Navy. Its formal name is the UNSC Military Intelligence Division.

Introduction
The Office of Naval Intelligence is a division of the UNSC Navy that is responsible for counter-espionage and propaganda.

Although it is under the jurisdiction of the Navy, ONI appears to report directly to HIGHCOM. It is responsible for intelligence matters across the UNSC. As such, ONI employs members of other military branches, and even civilians, to complete the Division's shadowy work.

Many of its functions and subdivisions, like the Beta-5 Division and the SPARTAN-III Program, are enigmatic, and its personnel are regarded as mysteries by mainstream naval officers. ONI personnel, especially officers, are often referred to as "spooks". Agents appear to enjoy significant latitude in the discharge of their duties, often violating moral boundaries or acquiring vast amounts of UNSC resources to achieve their ends.

Operations
The Office of Naval Intelligence often operates independently of other UNSC branches. At times it contravenes the law and UNSC protocol to complete top-secret missions. It appears to have an unusually large amount of military equipment for an intelligence service, and has a strong fleet presence. The Office of Naval Intelligence possesses a destroyer-sized prowler-class starship, the, which is used as a command vessel and a secure conference location. ONI also maintains the UNSC's Prowler fleet, a major source of Covenant deployment intelligence, under the auspices of the UNSC Prowler Corps. ONI also manages field intelligence with units such as ONI Recon 111 liaising with mainstream UNSC military units.

Intra-ONI dynamics are often strained with intense competition amongst its own personnel. Agents operate under heavy scrutiny with mistakes often leading to demotion or termination of employment.

Section Zero
The most secretive section, Section Zero's existence is not general knowledge outside ONI. Details of its role and operations are limited. Based on the records of an AI named Melissa, it is thought to be ONI Internal Affairs, charged with rooting out and eliminating illegal programs. It is very discreet in its work. The true nature and activities of Section Zero are highly classified and unknown outside the ONI command hierarchy. Zero is, essentially, an internal investigations division that polices other ONI activities.

This section has gained notoriety as the section that keeps and maintains sealed SPARTAN-I Program file archives, including Avery Johnson's. As Internal Affairs it enforces the rules and ensures standards are met. It is authorized to use lethal force in the course of its operations.

Section I
Section One is the main branch of ONI and the branch most often utilized by the UNSC. Information released by Section I includes evacuation notices for colony worlds and Covenant force deployments.

Section II
The propaganda branch of ONI. It handles communication between colonies to reduce the spread of rumors and information that would damage morale. It was responsible for releasing details of the SPARTAN-II program to the public to boost morale throughout the UNSC. Once information about the Spartans was released to the public, Section II had to maintain the Spartans' near-mythical status within the military by listing those killed in action as MIA. It was believed that news of Spartan deaths would cripple the UNSC's already-flagging morale.

Section III
The top-secret projects division of ONI. It is responsible for the SPARTAN-II project, the NOVA project, the MJOLNIR Program, and many other "black ops". Though a few of Section III's programs are well known and celebrated for their success, the Marines and top brass of the UNSC treat most with contempt. This is especially true of the Spartans, who are regarded as "freaks" by some Humans. Beta-5 Division is the sub-cell of Section III that operates the SPARTAN-III project. The Spartan-III project was kept secret from the vast majority of Section III. This is not particularly unusual as Section III is a large division with numerous sub-cells. The division and compartmentalization is to ensure secrecy and security.

UNSC Prowler Corps
The ONI branch that handles the Prowlers and its electronic intelligence gathering.

ONI Signal Corps
The Signal Corps is tasked with broadcasting radio signals in order to confuse Covenant Fleet and troop movements, diverting attention from UNSC Colonies that are evacuating.

ONI Ships

 * STARS
 * - Retired
 * UNSC Prowler- Flagship
 * - Retired
 * Stealth Cruiser
 * ONI PRO-49776
 * ONI PRO-49776

Reach

 * CASTLE Base
 * ONI Medical Facility
 * HIGHCOM Armory Omega
 * Sword Base
 * Olympic Tower (ONI HQ)

Onyx

 * Zone 67
 * Camp Currahee

Earth

 * Chawla Base
 * HIGHCOM Facility Bravo-6
 * B5D
 * Alpha Site

Arcadia

 * Unknown ONI facility

ONI Units

 * ONI Recon 111

Trivia

 * The Office of Naval Intelligence is a real life existing organization within the U.S. Navy that was established in 1882. It is also the oldest intelligence agency, thus the most senior of the United States' military and intelligence community, similar to the fictitious department.


 * ONI's motto, "Semper Vigilans", is also the motto of the United States Civil Air Patrol. The phrase is Latin for "Always vigilant."
 * ONI's pre-Halo 3: ODST insignia features the all-seeing eye, a nod to ONI's line of work.
 * "Oni" is also the name of one of Bungie's previous games, which predates Halo: Combat Evolved. It is also the name of an ogre-like creature from Japanese mythology which is known to deceive and devour its prey.
 * The ONI insignia can be used as a multiplayer emblem in Halo 3: ODST.
 * In both games an ONI base is featured (Halo 3: ODST and Halo: Reach), both are slated to be destroyed to prevent sensitive data from falling into Covenant hands. ONI Alpha Site on Earth was destroyed by ODST Trooper Mickey. The facility on Reach was never shown as being destroyed, however the artifact chamber below was.