Office of Naval Intelligence

Summary
The Office of Naval Intelligence (or ONI) is the main source of intelligence for the UNSC. ONI is divided into "Sections" as follows.


 * Section 1 is the main intelligence used by the UNSC. Covenant ship movements and force deployment, evacuation notices for colonies, and much more are all released by Section 1. Minimal intra-UNSC security.


 * Section 2 is the propaganda branch of ONI. They handle communication to and from colonies to reduce the level of rumors and information that would cripple morale. They were responsible for going public with the SPARTAN-II program. Even after the release of this information to the public, the SPARTANs were still viewed as near-mythological figures. Most marines and ODSTs didn't believe they even existed until they saw them for themselves. Because of the low morale among the colonies, the SPARTANs are always listed as Missing-In-Action instead of Killed-In-Action upon death. This gives the illusion that SPARTANs can not and do not die. Higher-than-average intra-UNSC security.


 * Section 3 is the top-secret projects division. They are responsible for the SPARTAN-II project, the NOVA project, and many other "black op" programs. The secrets possessed by ONI are the key to Earth's continued survival, for the Covenant cannot be beaten with military forces alone. Though a few of Section 3's programs are well known for their success, most of them are disdained by the Marines and brass of the UNSC, especially the SPARTANs, who are generally regarded as "freaks". Extreme intra-UNSC security.


 * Section Zero is the most secretive section of ONI. Almost no one knows exactly what they do, let alone know it even exists. From the records of an AI named Melissa, though, it is thought to be ONI internal affairs, charged with rooting out and eliminating illegal programs.

Trivia

 * ONI may be included in Halo because of a previous Bungie game called Oni.