Leon-011

Like the other SPARTAN-IIs, Leon-011 was abducted at age six and conscripted into the SPARTAN-II program in 2517. He later survived the augmentation procedures in 2525. Along with Robert-025 and August-099, Leon formed the Spartan-II fast reaction unit Omega Team, which was created primarily for asset denial operations.

Omega Team is typically deployed with the goal of breaking the enemy's hold long enough in order to reinforce local defenses and buy time for a UNSC response. During the Human-Covenant War, Omega Team was deployed to several colony worlds threatened by the Covenant, assisting in emergency evacuation efforts and enacting classified last-stand protocols. The team proved highly proficient at the denial of critical resources, data, and even personnel to the Covenant by any means necessary, which sometimes required the deployment of weapons of mass destruction.

At some point in 2527, Omega Team may have been deployed against Insurrectionist forces in an operation on Hellas against insurgent forces employing the use of Rumbledrugs.

Omega Team worked closely with Jerome-092, Alice-130, and Douglas-042 of Red Team, including during the defense of Arcadia when it was attacked in 2531. They were separated when the UNSC Spirit of Fire departed the system to chase retreating Covenant forces. During the Arcadia Campaign, Leon worked alongside August-099, Robert-025, Kai-125, Riz-028, and Vannak-134, before the latter three were split off to form an independent Silver Team. The full six-member roster of Omega was temporarily reformed and deployed to an unknown operation on Hellas.

In the late stages of the Human-Covenant War, or the earliest years of the post-war era, Omega Team was involved in the testing of numerous "Breach" development iterations on the MJOLNIR Mark VI platform. These field tests were successful, and saw improvements folded into later GEN2 and GEN3 productions.

Decades after Red Team's last encounter with them, Commander Jerome-092 discerned that Omega Team had survived the war based on UNSC records recovered from the Henry Lamb Research Outpost. In 2560, the team was deployed to Arcadia once again, this time with goal of observing a deal between Adam Andrews—the CEO of Optican—and Kig-Yar working for Nor Fel. After a successful handoff between the two parties amid Forerunner ruins, August eliminated a trio of Kig-Yar with her M99A2S3 Stanchion, the signal for Leon-011 and Robert-025 to move. While Leon rushed for the Kig-Yar's Phantom, Robert positioned himself to neutralize any escapees from the craft with his machine gun turret. Leon leaped through the dropship's rear gravity lift and ignited his energy sword to eliminate the pilot and any others still aboard. When he confirmed the dropship was clear, Robert got to work securing the Kig-Yar's would-be prize: the focus cannon of a R'awuw-pattern Scarab. After checking the Phantom's cargo manifest, Leon confirmed that the aliens had delivered a shipment of rumbledrugs to Andrews, exclaiming that it had been a while since he had seen the drugs while sending the data to his team's HUDs. With the Scarab's cannon secure, the manifest confirmed, and their objective complete, Omega Team left the area.

Leon-011 specializes in and is equipped for close-quarters combat. At some point, he began using a custom Domotos-pattern energy sword. Additionally, circa the end of the Human-Covenant War, Leon participated in field tests while wearing MJOLNIR Mark VI with the Breach Scout helmet attachments, UA/GRT78 chest armor, and UA/WAYLAND shoulder armor. As of 2560, he wears Mark IV MJOLNIR armor with a Valiant helmet incorporating the CNM(5)/BNR/TYPHON-X attachment. He also wears TAC/THORNBLADE left shoulder (which includes an experimental, wickedly sharp combat knife), an IMA/GARITA/OMEGA right shoulder, and an UA/RINGECK chestpiece. Robert's left forearm includes the TAC/FIRMBLUR TRIPLET attachment while his kneepads are the UA/ULLOP variant. He sports a TAC/SBER-X DISPENSER attached to his left leg.

The MA5C Individual Combat Weapon System, abbreviated MA5C ICWS and commonly known as the MA5C assault rifle, is a standard-issue service rifle for the UNSC Marine Corps and the Navy.

The M7/Caseless Submachine Gun (M7/SMG) is a personal defense weapon developed and manufactured by Misriah Armory.

The M90 Close Assault Weapon System (CAWS), also known as the M90 Close Assault Shotgun, M90 assault shotgun, or simply the M90, is a pump-action shotgun in service with UNSC.

The United Nations Space Command (UNSC) is the military, exploratory, and scientific agency of the Unified Earth Government (UEG) and has acted as the emergency governing body of the human race.

The Sangheili, or "Elites" as they are known by humans, served as the military leaders of the Covenant. The Sangheili are the only race within the Covenant permitted to build and command starships within the Covenant, though the crews are always composed of a mix of races. The Jiralhanae, or "Brutes" as they are known by humans, were the most recent addition to the Covenant, and served as soldiers and bodyguards within the Covenant military. The Lekgolo are a race of worm-like creatures that can combine to form large, intelligent assemblages called Mgalekgolo, known by humans as "Hunters". Clad in nearly impenetrable armor and armed with their trademark Assault Cannon, they served as the Covenant's heaviest ground troops. Hailing from Balaho, the Unggoy, or "Grunts" as they are known by humans, were the most common and low-ranking caste of the Covenant. They breathe methane gas, and thus must wear a large tank on their back full of methane to survive on other planets. The Kig-Yar, or "Jackals" or "Skirmishers" as they are known by humans, were the scouts and marksmen of the Covenant military due to their superior senses.

The D77-TC Pelican, commonly known as the Pelican, is an extremely versatile space-to-ground capable craft used by the United Nations Space Command, as well as being marketed toward law enforcement, security, corporate and civilian markets.] In its role as a tactical aerospace lifter, the Pelican is mainly for the pickup and transportation of personnel, vehicles and equipment, though some variants are capable of serving in the role of a gunship.

The Human-Covenant War was instigated by the High Prophets of the Covenant following a discovery which led them to believe that humans were directly related to the Forerunners, contradicting their ancient religion. Seeking to keep various political and religious orders intact, the High Prophets declared a holy war of genocide against the human species, and the discovery of their relation to the Forerunners was kept a secret. With superior firepower, numbers and technology, the Covenant would repeatedly overpower the UNSC across hundreds of human-inhabited worlds, including the heavily defended strongholds of Reach and Earth. Humanity would win only scattered and costly victories.