Mark-G313

Mark-G313 is a SPARTAN-III supersoldier of Gamma Company. Originally assigned to Team Saber as a marksman, he served as part of Blue Team following the Battle of Onyx until Operation: JOVIAN WHISTLE in July 2553, when he was reassigned to an Office of Naval Intelligence Ferret Team led by Veta Lopis along with fellow Gamma Spartans Ash-G099 and Olivia-G291, with Mark serving as the team's security specialist.

Conscription
Mark was orphaned at a young age by the Covenant and was conscripted into the Gamma Company of the SPARTAN-III program at age six. Once on Onyx, he and the other Spartan candidates were trained by LCDR Kurt Ambrose, SCPO Franklin Mendez, as well as the surviving Beta Company members, PO2 Lucy-B091 and PO2 Tom-B292 at Camp Currahee.

Zone 67
Mark was assigned to Team Saber, under the command of Ash-G099. When the human forces on Onyx came under attack by Sentinels, the teams were still vying for top honors. Team Saber went dangerously close to Zone 67 to avoid the other teams. The team spied what they assumed at the time to be a new kind of Covenant drone due to its energy shields and anti-gravity technology it possessed. They decided to investigate and the Sentinels engaged. Mark remained with the team as they tried to figure out the weak spots of the drones. He and the rest of the team hurled rocks at the drones and to their surprise, the drone's shields did not activate. The Sentinel chased Ash into a hole and Mark and the rest of the team pummeled the drone with huge rocks, destroying it.

A general decision was made and the Team moved to the armory to get heavier armaments. Team Saber met up with Commander Ambrose, Chief Mendez, as well as PO2 Tom and Lucy and they spent several days fighting the Sentinels using guerrilla tactics. Mark and the team later met up with PO2 Kelly-087 and Dr. Catherine Halsey and were subsequently engaged by a pair of Sentinels. After the skirmish, Mark and the rest of the Spartans took Dr. Halsey and Kelly to a bombed-out bunker where Halsey revealed the origin of the Sentinels and what to do next.

Team Katana
After the team destroyed the two Sentinels and the overwatch position at Camp Currahee, they moved back to Zone 67. After making their way through an excavated Forerunner city, they discovered Onyx's map room, where they learned that Onyx was an artificial construct, as well as pinpointing the location of Team Katana. Before recovering Team Katana, however, AI Endless Summer sent them on a mission in a Sentinel manufacturing facility to make sure no more Sentinels were produced. Mark and Team Saber played a key role in destroying the factory, using its teleportation grid to their advantage. Later, they moved out to discover Team Katana and found them in slipspace field pods. However, the Covenant knew the location of the two teams and were advancing towards their position with four legions of Sangheili, Mgalekgolo, and other soldiers, as well as armored vehicles.

End of the battle
The humans fell back to a portal which led to Onyx's interior shield world, located within a massive room in Onyx's core, where they soon found themselves surrounded by the Covenant. Mark and the other Spartans formed a loose half-circle "killzone" around the portal and picked off targets at close and long range. They managed to defend the entrance to the shield, although it had come at some serious losses. William-043, Dante-G188, and Holly-G003 had already been killed by the advancing Covenant army. Due to little time left, Commander Ambrose ordered Team Saber through the portal before it closed. Soon after, Dr. Halsey and the surviving Spartans entered the portal. On the other side of the rift, Mark awaited Kurt's arrival, but he never came, having given life by detonating a pair of FENRIS nuclear warheads to prevent the Covenant from following them.

Shield world
"Welcome to Blue, Spartans. We're going to make a great team."

- PO2 Kelly-087

Once Mark, Dr. Halsey, and the other Spartans were safely inside the Dyson sphere that lay beyond the portal, they made gravestones for Kurt Ambrose, William-043, Dante-G188, and Holly-G003. After the ceremony, Mark and the other Spartan-IIIs were reassigned to Blue Team by Lieutenant, Junior Grade Frederic-104 and Petty Officer, Second Class Kelly-087.

Mark and the other survivors then proceeded to explore the vast construct, soon establishing base camp in a Forerunner structure. A group of Huragok, discovered by Lucy-B091, eventually helped them bring the sphere out of its slipspace bubble into normal space, and an ONI team was dispatched to retrieve them. The few days the survivors had stayed inside the slipspace bubble turned out to equal over three months in normal space-time, and as such they returned to normal space in February 2553. Mark and the others were taken to Earth aboard the for a debriefing in HIGHCOM Facility Bravo-6 in Sydney.

Following their recovery from the shield world, Mark and the other survivors of Team Saber continued to serve with Blue Team on a number of missions.

Gao
In May 2553, Blue Team was attached to ONI's 717th Xeno-Materials Exploitation Battalion deployed to the Outer Colony of Gao to search for a Forerunner ancilla, Intrepid Eye, that had been detected on the planet by the battalion's Commander Murtag Nelson. The UNSC's presence on the planet was largely undesired by the traditionally independent Gao. For over a month, the UNSC attempted to capture the ancilla, who, in turn, regularly harassed the 717th with her Aggressor Sentinels. Additionally, upon learning of the UNSC's intentions, Intrepid Eye began covertly murdering Gao citizens in the Montero Cave System in an effort to create discord between the Gaos and the UNSC. The Gao Ministry of Protection dispatched Special Inspector Veta Lopis to find the murderer and Nelson had members of Blue Team aid her in her efforts to allow the UNSC to return searching for the ancilla without the Gaos' interference. Lopis was initially convinced that the murderer was one of the Spartans, with her suspicions eventually focusing on Mark in particular due to his often standoffish and ruthless behavior.

On July 4, 2553, Blue Team escorted Veta Lopis and her team to Crime Scene India within the Montero Cave System to study a recently-discovered victim. From there, Mark, Ash, Olivia, and Fred accompanied Lopis and her partner Cirilo to the last known location of Major Ira Halal and Private Hayes, both of whom turned out to have been murdered. The Gao investigators decided to follow a trail of an unidentified fluid—in fact belonging to the wounded Huragok Roams Alone—deeper into the caves, with the Spartans coming along. As they reached a large cavern, after nearly a twelve hours' descent, Intrepid Eye attacked the humans with her last four remaining Sentinels. Though the Spartans were able to destroy the Sentinels, Cirilo was killed and Olivia was seriously wounded. Ordering the others to stay put and leaving Mark in charge, Fred left to investigate a nearby pit in hopes of finding the Forerunner base they were looking for. While waiting for Fred, the Spartans and Lopis were approached by Roams Alone, a Lifeworker Huragok who began to heal Olivia's wounds. Fred eventually returned and decided that the party should take the Huragok with them, return to the surface and report to Commander Nelson.

Olivia had lost her "Smoothers"—drugs that controlled the Gammas' altered brain chemistry—during the fighting, meaning that the young Spartans would run out of them on the way out. Mark volunteered to take only one of the remaining five Smoother injections, leaving two doses each for Ash and Olivia, and took point as the group began their nearly one and a half day's climb toward the surface. As the group approached Crime Scene India, Mark continued to scout ahead, encountering and stealthily killing Jiralhanae of the Keepers of the One Freedom in the process; while the party was in the caves, the Keepers had landed on Gao, intending to take Intrepid Eye for themselves. At one point Mark lost contact with the rest of the group, seemingly beginning to unravel mentally due to his lack of Smoothers. At Crime Scene India, however, he saved Lopis from an attacking Jiralhanae, though he would continue to scout ahead on his own as the party continued toward the surface.

After another twelve hours, the group eventually reached the Gallery of the Inverted Forest where Fred managed to capture Intrepid Eye's inspection drone shell with a scramble grenade. The group surfaced at the embattled village of Wendosa and proceeded to reinforce the 717th, which had fallen under attack by the Keepers. During the ensuing battle, Mark encountered Marine Sergeant Nguyen and, believing him to be an enemy infiltrator due to his paranoid state caused by his Smoother deprivation, Mark took the sergeant hostage and held a combat knife to his throat. However, Fred was able to convince Mark to release the Marine, who informed Fred that he was to return to the Montero Vitality Center with the ancilla. The group fought their way through Wendosa and Fred boarded a Falcon, but the craft was shot down and crashed in the jungle several kilometers away.

With the battle in Wendosa turning to the UNSC's favor, Mark and the others reunited with the rest of Blue Team, who soon decided to make their way to the Falcon's crash site before the Keepers could reach it. With access to Smoothers again, the Gammas' mental condition was stabilized. After a series of sniper battles along the Briones Ridge, the group arrived at the crash site. With the eventual help of Alpha Company, they fended off the Keepers and recovered Fred as well as the ancilla. The Spartans were brought to the Montero Vitality Center to recover, although Mark would soon go on patrol with the rest of Blue Team while Ash and Olivia stayed in the Vitality Center.

Meanwhile, the newly-elected President of Gao Arlo Casille sent Gao Republic's military to forcefully remove the UNSC from the planet. Determined to prevent the Forerunner support base from falling into the hands of Gao's insurgent government, Blue Team embarked to destroy the facility with a HAVOK tactical nuclear weapon, while the rest of the 717th evacuated from the planet. Pursued by Wyverns carrying Gao battle-jumpers, Blue Team and Lopis traveled in Warthogs to the Well of Echoes, below which the Forerunner support base was located. At the Well of Echoes, the team boarded the Owl Silent Claw, with Rear Admiral Serin Osman waiting onboard. Mark was charged with dropping the HAVOK into the Well of Echoes and successfully did so, destroying the Forerunner base.

With Intrepid Eye successfully captured, the UNSC left Gao. Fearing that Gamma Company's illegal brain mutations would cause a crippling public relations scandal were they to be discovered, Osman had Mark, Ash, and Olivia officially marked as killed in action and transferred to a classified ONI Ferret field operative team of which she gave command of to Lopis.

ONI career
In the following months, Mark, Ash, Olivia, and Veta Lopis underwent a training regimen to mold them into elite ONI operatives, with Mark being assigned as the Ferret Team's security specialist. While the Gammas were exceptionally quick to learn the new skills, their military background meant they would often instinctively fall back to lethal force in life-or-death situations. During this time, they visited multiple colonies, rarely staying in one place for long; at one point they were stationed on Jastolo, where Mark listened to a BuzzCast by investigative reporter Spencer Hume, who blamed Spartans for a devastating incident on Tanuab III. Adamant that the incident was instead caused by a meteor impact, Mark considered Hume a "shit-flinger" who was merely attempting to smear the Spartans' name.

Neos Atlantis
"Osman"

- Mark

On October 14, 2553, the Ferret Team participated in a training exercise against Oscar Squad at UNSC Recreational Facility 6055-NA-A on Neos Atlantis. Disguised as junior ODST lieutenants, Mark and Ash posed as rookie ONI agents in the facility's officers' club as part of a ploy to deceive Oscar Squad. However, an unexpected complication occurred when Olivia was drugged by an unidentified man—in fact the reporter Spencer Hume, who attempted to coax her into revealing classified information about the Spartans. Lopis ordered Mark to arrest the man while Ash created a distraction and Veta escorted Olivia back to the Halsey Suite, which the team was using as their base of operations. While hauling the subject out of the club, Mark was attacked by a woman who managed to wound him with a knife. By his own account, Mark intended to use Hume as a shield and struck him in the chest when he resisted, which unexpectedly killed Hume. At this point Ash arrived, prompting the attacker to flee.

Mark and Ash decided to dispose of Hume's body through an airlock and returned to the Halsey Suite afterward. Before they could explain the incident to Lopis, Admiral Osman arrived, accompanied by Oscar Squad's Commander Svenson, who had witnessed Mark and Ash carrying a body and demanded an explanation. Though Mark intended to reveal to Osman what had happened, Lopis ordered him to remain quiet and maintained that her team had done nothing wrong. The admiral then left the suite, giving the Ferret Team two hours to resolve the situation. The team soon discovered Hume's identity as well as that of Mark's assailant—a former ONI operative named Ota Gallo, now working for the private security company Dark Moon Enterprises. Attempting to recover Hume's belongings, now in the Ferret Team's possession, Gallo and two of her henchmen stormed the Halsey Suite soon after. After a brief firefight, the Ferrets managed to defeat the attackers, with Gallo being blown apart by her own grenade.

Immediately after the attack, Admiral Osman returned to the suite with an armed escort. After the admiral claimed Hume's personal effects, she asked Lopis what had really happened to Hume. Lopis lied that Gallo killed Hume after the reporter was planning to name her as his source. Obviously incredulous yet seemingly accepting the explanation as being sufficiently believable, Osman sarcastically asked Mark to affirm Lopis' story, which he did without hesitation.

Personality and traits
Mark-G313 has a remarkable ability to handle stress, only becoming more composed under increased pressure. He has a wry, morbid sense of humor and is generally more aloof and detached than his peers. He is also quite ruthless, tending to favor lethal action as a solution to most problems. However, he is also very protective of his teammates, sometimes to their annoyance; during the incident on Neos Atlantis, for example, he was convinced he alone should take the blame for his mistake, failing to realize the entire team would face the consequences if he revealed to Admiral Osman what had become of Spencer Hume.

An exceptionally competent Spartan, Mark is particularly noted for his marksmanship abilities for which he is nicknamed "The Mark" by his fellow Spartans. Although he is proficient with sniper rifles, Ash considered him even more skilled with an assault rifle in a free-for-all scenario with an abundance of targets. He is also highly skilled in stealth and close-quarters combat, a fact noted by Fred-104 after Mark had stealthily killed numerous Jiralhanae during the crisis on Gao.

By November 2552 Mark kept his head shaved.

List of appearances

 * Halo: Ghosts of Onyx
 * Halo: Glasslands
 * Halo: Last Light
 * Halo Mythos
 * Halo: Fractures
 * A Necessary Truth