SPARTAN-B312 (Earth-4001)

Lieutenant SPARTAN-B312 was a Spartan-III supersoldier attached to Special Warfare Group Three of the UNSC Army. During the Fall of Reach in summer 2552, he served as a member of NOBLE Team under the call sign "Noble Six". Although unknown to most of the UNSC military and humanity in general due to the classified nature of his operations, Dr. Catherine Halsey stated that B312 shared a "hyper-lethal" rating with only one other Spartan and served just as essential a role in securing humanity's victory in the Human-Covenant War.

Because his file was heavily redacted by the Office of Naval Intelligence, much of SPARTAN-B312's early life is unknown. The Spartan was originally a Beta Company candidate whose performance so impressed his superiors that he (along with a small number of his peers, designated "cat 2") was reassigned immediately after training before the inevitable bloodbath of Operation: TORPEDO. As one of the few remaining contemporary Spartan-IIIs, B312 was repurposed as a counter-terrorist operator, performing black operations. After several years of being fielded against Insurrectionists, B312 was transferred from his ONI handlers to Spartan NOBLE Team, where took the deceased Thom-A293's place as "Noble Six". B312's transfer to NOBLE came immediately at the start of the Fall of Reach, placing the Spartan in a new territory of teamwork against the Covenant.

Though initially viewed with resentment by some of his teammates, Six's skills eventually proved themselves as the fight for Reach began failing and NOBLE Team took losses. On August 30, Six delivered a fragment of the A.I. Cortana to the UNSC Pillar of Autumn in the hope that the data she carried could defeat the Covenant. With the aid of his team, Noble Six delivered the A.I. intact, but chose to remain behind to secure the Autumn's escape from the Covenant. Though the Spartan was killed hours later, his sacrifice allowed humanity to discover the Halo Array, ultimately bringing about the dissolution of the Covenant and the end of the war.

History
The history of SPARTAN-B312 is the same as his mainstream counterpart.

Personality & Traits
SPARTAN-B312 was regarded as a skilled assassin and "... more of a hyper-lethal vector than a soldier," evidenced by his heavily redacted personnel file. Noble Six had a tendency to "go solo" during missions, much to the dismay of his superiors. Despite having an obscure past, highly potent skills, and a reserved, "lone wolf" personality, 312 showed care and compassion for his fellow humans; he often undertook life-threatening actions to assist soldiers, civilians, and the other members of NOBLE Team. Although Six became fairly close to the other members of NOBLE Team, he shared a great deal of camaraderie with Jorge, and the two soon became friends. This inspired Jorge to give his life in Noble Six's place, and may have, among Noble's other sacrifices, inspired Six to do the same when allowing the Autumn to escape. Six's bond with Jorge is noted by the fact that Jorge gave Six his dog tags before sacrificing himself and Emile later refused them when Six offered up the dog tags, telling Six that Jorge chose to give them to Six so Six should keep them. Dr. Halsey and Cortana considered him to be of equal ability and trustworthiness to the Master Chief himself, despite the doctor's initial distaste for the Spartan-IIIs.

Armor
During the defense of SWORD Base on July 26, 2552, SPARTAN-B312 wore a standard Mark V [B] suit and helmet. At some point after joining NOBLE Team the Spartan requested a RECON-class helmet. Although this request was granted, whether he received the helmet before his death is unclear.

Trivia

 * In the Video Games Awards trailer, Jorge-052 remarks "Didn't think anyone survived Pegasi, sir" upon seeing Noble Six for the first time, in reference to Operation: TORPEDO, a mission on Pegasi Delta which led to Beta Company's near-total annihilation. This line is not present in the final game, as it was later established that SPARTAN-B312 did not take part in the operation, having been taken out of Beta Company directly after training.
 * In the February 2010 issue of GameInformer, Noble Six's birthday is claimed to be January 30, 2530. This is likely an error, however, due to the fact that Bungie.net's profile for Six lacks a birthdate and that it is the same birthdate as Kat.