John-117

"I do not remember my name. I do not remember my family. I do not remember my 'home'. But I can remember the game. We played it every day. And I never lost. The game... It's the only thing I can remember about the life I had before I met Doctor Halsey. Since then, I have experienced a lifetime of combat. Through thirty years of war against alien aggressors... I have always known my fate. I knew someday I would die in battle. But now that it is here... now that it is time to die... I find I am not ready."

- John reflects upon his life and fate. Master Chief Petty Officer John-117 is a Spartan-II supersoldier of the UNSC Navy's Special Weapons division. He served as one of the most important figures of the Human-Covenant War. After over thirty years of active duty, he is one of the most decorated war veterans of the United Nations Space Command. By August 30, 2552, John's career service vitae recorded two hundred and seven ground engagements against the Covenant in which he had participated. By August of 2558, he had completed two hundred and nine military operations, including one hundred and thirty-six full campaigns; more than anyone other UNSC personnel on record at the time. Though John has commanded nearly every Spartan-II at one time or another, the lion's share of his career has been spent as fireteam leader of Blue Team. His actions during the Covenant War earned him every major UNSC service medal and combat award, save for the Prisoner of War Medallion, as well as several dozen civilian honors.

As the war neared its end, most of John's fellow SPARTAN-IIs were killed in action during the Fall of Reach. However, John and his AI companion Cortana fled Reach and their vessel fortuitously arrived at Halo Installation 04, a one hundred millennia-old superweapon created by the Forerunners to destroy their parasitic enemy, the Flood, by killing all life in the galaxy. After destroying the Halo, the surrounding Covenant fleet, and the Flood forces on the ring, John returned to Earth and resisted the Covenant's impromptu invasion. Pursuing the invaders' flagship, the Master Chief encountered Installation 05, where a civil war soon broke out within the Covenant. Weeks later, John followed the remaining Covenant forces to the Ark, the Halo Array's control center, which he disabled before the Halos could be fired.

John went missing after the war's final battle in December 2552, having stymied the threat of the Covenant, the Flood, and the Halos. In the interbellum, John was lauded as a hero, and though he was officially declared MIA like all Spartans, he was ostensibly believed by the UNSC to have perished. After his recovery in July 2557, he played a key role in the conflict between the UNSC and the Didact's Promethean forces and a new Covenant faction, beginning on the shield world Requiem. This culminated in an attack on Earth and the Didact's temporary defeat, as well as the apparent loss of Cortana. John subsequently reunited with Blue Team and with their help, vanquished the Didact a second time. John and his Spartan compatriots went on to participate in numerous new missions for over a year.

During one such mission, John had a vision of a seemingly alive Cortana. This prompted him to go in search of her against direct orders, with the rest of Blue Team choosing to remain by his side. In response, the UNSC declared Blue Team absent without leave and sent Spartan-IV Fireteam Osiris to recover them. On Genesis, John and Blue Team learned that Cortana had assumed the Mantle for herself and was planning on using the Guardians to enforce peace across the galaxy. John rejected Cortana's offer to join her, prompting her to imprison him and the rest of Blue Team in a Cryptum. However, the Spartan-IIs were freed by Fireteam Osiris, with both Spartan teams traveling to Sanghelios while Cortana unleashed the Guardians on the galaxy.

Among most humans John is known simply by his rank as the "Master Chief" or (erroneously) the "Chief". Within the military he is most commonly identified as "SPARTAN-117" or the phonetic callsign "Sierra 117". As with all Spartans, John was regarded by the Covenant as a "Demon". However, John specifically was known as "the Demon", an epithet he earned after the destruction of Installation 04, though allied Sangheili soon came to address him as "Spartan". The Didact and the Warden Eternal addressed John and his Spartan teammates as Warriors or Warrior-Servants.

Biography
This section is a brief overview of John-117's life. For an extremely detailed look at John's entire history, please see his biography pages.

Early life
"John"

- Ellie

Born on March 7, 2511, John lived with his mother and father in Elysium City, on the colony world of Eridanus II. He attended the Elysium City Primary Education Facility Number 119. As a child, John had brown hair, freckles, and a small gap between his front teeth. In a memory, he recalled that his mother was kind and smelled of soap. The would-be UNSC Marine Lieutenant Parisa was a childhood friend of John's. John once saved her from drowning at Lake Gusev, after which he promised to marry her and keep her safe. A photo of the two was also taken by Parisa's father soon after, and would be kept as a memory by Parisa long after she thought John had passed away. He also was a friend of Ellie Bloom, living next to each other in their childhood, and Katrina, who played obstacle races with him and Ellie.

Conscription
"Halsey"

- John

At the age of six, he was identified by Dr. Catherine Halsey as one of 150 preliminary candidates for the SPARTAN-II program. John was an ideal physical and mental candidate, standing a head taller than the majority of his schoolmates, having greater physical proportions, possessing greater strength, exhibiting superior reflexes, and having an aggressive drive for success. By the time he was conscripted, he had a string of forty-five victories in what Dr. Halsey referred to as a "brutal version" of King of the Hill, resulting in him having a chipped tooth and his opponents suffering various bone fractures. When Dr. Halsey and LTJG Jacob Keyes visited Eridanus II in 2517 to study him, they were impressed with his intellect. In a final test of his viability as a candidate, he was asked to determine which side an old coin would land on. He watched the coin as it flew in the air and caught it before it could land; correctly stating which side was face-up, on the side of the eagle. Later that same year, John and 74 other six-year-old children were conscripted to Reach: they were covertly kidnapped from their homes and replaced with flash clones to cover up the kidnappings. All of the clones would later die of seemingly natural causes as a result of their accelerated growth process, with John's flash-clone dying on December 7, 2517.

Spartan training
"Remember this: you don’t win unless your team wins. One person winning at the expense of the group means that you lose."

- CPO Mendez explaining trainees the main idea of teamwork.

John and the rest of the children chosen for the SPARTAN-II program were brought to the Reach FLEETCOM Military Complex, their new home for the next several years. There, Dr. Halsey informed the children of their new purpose: they were destined to become protectors of Earth and all its colonies. The next morning John discovered his service tag, stitched into his training uniform, and his new name: John-117. John began adjusting to his new life, training with other Spartans under Chief Petty Officer Franklin Mendez.

In their first training exercise, John was grouped with fellow trainees Kelly-087 and Samuel-034 in a game of "Ring the Bell". John rushed ahead of his teammates and crossed the finish line first; however, he was befuddled to learn that his team had lost, as Kelly and Sam came last. This taught John the importance of teamwork and the next day, his team scored higher. John soon bonded with Kelly and Sam, who would become his first and closest friends among the trainees. For eight years John was schooled in history, military strategy and tactics, and weapons, and was given extreme physical training. During his training, John used to tease Serin-019 and her habit of eating leftovers from meals of the other candidates.

John quickly proved himself to be one of the program's top candidates. Both Dr. Halsey and Chief Mendez identified him as one of four emerging leaders within the Spartan-II group, along with Kurt-051, Jerome-092, and Fred-104. Halsey believed John held both the skills and natural ability to lead the entire Spartan-II group. Mendez disagreed with her assessment, instead believing Kurt would fulfill the role as team leader. John's leadership skills were correctly observed, as the results from their mission clearly solidified his role as the overall leader of the Spartan-IIs. He also became the established leader of Spartan Blue Team.

Taking the initiative
"No one’s being left behind. We’re going to figure a way to get all of us out."

- John motivating his comrades during the Spartans' training exercise in Reach's Highlands

When the Spartans were eight years old, they were sent on a training mission in which they were dropped over a forest located deep in one of Reach's Highland Mountains. They were expected to get safely to their extraction vehicle, an Albatross dropship. The trainees also had instructions to leave the last member arriving behind, or their punishment would be severe. After organizing themselves, the Spartans looked to him as their leader. It was a role he was surprised to be given, but eventually accepted. When the group came across the Albatross, it was guarded by un-uniformed UNSC Marines, leading John to assume they were a threat. He quickly devised a plan to eliminate the hostiles, capture the dropship, and ensure the safe extraction of every team member. He also decided to take responsibility as the last arriving trainee singled out for punishment. He quickly hijacked the dropship with the help of Déjà, and attacked the guards with stones, injuring them severely. Chief Mendez was not initially pleased, feeling John had violated the boundaries of the test. However, both Mendez and Halsey quickly recognized John's initiative, and promoted him to Squad Leader. After this, despite the other Spartans rising in rank and leading independent teams, John remained the de facto leader of the Spartans as a whole.

Physical augmentation
"John-117"

- Dr. Halsey

At the age of 14, John underwent the dangerous SPARTAN-II augmentation procedures. These procedures resulted in the death of thirty trainees, with twelve more physically disabled. John was one of thirty three Spartans who made it through the process unscathed, while the wounded were sent to the Office of Naval Intelligence. Even before his cybernetic and genetic augmentation, at 14 years of age, John had a physical body of an 18-year old Olympic athlete. Far beyond the physical alterations, the enhancements boosted the Spartans reflexes, strength, enhanced eyesight, and rendered their bones nearly unbreakable. Following their treatments, John and the other Spartans were transferred to the to recover in a microgravity environment. During his first visit to the Atlas' gym, John was confronted by four ODSTs, whose sergeant then ordered the five of them into the boxing ring. In the ensuing fight, John inadvertently killed two of the ODSTs, and left the others severely injured. According to Major Antonio Silva, this incident was orchestrated by the Office of Naval Intelligence in order to test the Spartans' augmentations. While John had tried to avoid the confrontation, he nonetheless felt guilt at being forced to kill other human beings, but felt by following the sergeant's orders, he did the right thing. Then-ODST Anthony Petrosky, who witnessed the fight, would later refer to his comrades as "lambs to the slaughter"; he described John's punches as rapid-fire explosions, and that the fight was over in less than five seconds.

Following their return to Reach for further training, John and the other Spartans were soon relocated from their barracks in the FLEETCOM military complex into the abandoned titanium mines nearby. Left in the caverns virtually without equipment and pitted against Marines wearing heavy Mark I powered armor, the Spartans continuously overcame the opposition Chief Mendez planned for them using impromptu equipment and tactics.

Infiltration on Eridanus Secundus
"I have good news for you. The word has come down. Command has decided to test your unique abilities."

- Dr. Halsey to the Spartans before their first combat mission

John's first mission, codenamed Operation: TALON, was to capture Insurrectionist leader Colonel Robert Watts within the asteroid belt of the Eridanus system, where his homeworld was located. According to the plan, Blue Team, consisting of John, Kelly, Fred, Linda and Sam, infiltrated the Insurrectionists' base by hiding aboard the freighter Laden. Upon arrival they slid out of Laden and tracked their target to the barracks using previously marked cargo. The Spartans proficiently eliminated the guards and made their way to Watts' apartment, though John was shot in the side, with one bullet penetrating his body suit, bouncing off a few ribs, and causing a tremendous amount of internal bleeding, remaining lodged in his abdomen during the ensuing firefight. Careful not to kill Watts, they drove him into a corner, choked him into unconsciousness, and forced him into a sealed cargo crate. To make an exit, Sam used C-12 explosives to blow the main hangar bay doors. As the hangar bay decompressed, the Spartans escaped the rebels' base in a Pelican dropship stolen from the UNSC. The official results of the mission listed eleven dead enemy soldiers and an unknown number of rebel civilians. John received a Purple Heart upon the completion of the mission.

Chi Ceti IV


"John-117"

- Spartans

Three months after Eridanus, John and his Spartans were briefed on the massacre that took place on Harvest shortly after first contact with the Covenant. A short time later, the, under the command of Captain Wallace, brought the Spartans and Dr. Halsey to the Damascus Testing Facility at Chi Ceti IV, where they received their first suits of Mjolnir powered armor. When a Covenant ship, the Unrelenting, attacked the Commonwealth, John and the Spartan-IIs took part in their first engagement with the Covenant. The Spartans used thruster packs to launch themselves from a Pelican dropship. Each Spartan carried an ANVIL-II warhead to be used against the Covenant ship. Only two other Spartans reached the ship with John: Sam and Kelly. They entered the vessel through a puncture in its hull, caused by a MAC round from the Commonwealth. They succeeded in completing the mission and destroyed the Covenant ship, but due to a breach in Sam's armor, he was unable to leave the Covenant ship. Volunteering to stay behind and ensure the destruction of the enemy vessel, Sam was killed in the ensuing explosion. John was deeply affected at the loss of one of his closest friends. The victory showed that the Covenant could be beaten, but only at a high cost.

Early war
Over the ensuing months, John and his Spartans were rapidly deployed on a number of battlefronts, taking part in the Battle of Alpha Corvi II later in 2525 and a boarding action against the frigate Radiant Arrow before being assigned as instrumental parts of Operation: SILENT STORM in early 2526. During the operation, John worked for the first time alongside enlisted UNSC personnel of the 21st Space Assault Battalion. Throughout the operation, John was a key participant in the battles of Seoba, Etalan and finally a massive Attack on Zhoist. In this final engagement of SILENT STORM, John led one of the only offensive actions of the war into Covenant space, deploying on the Covenant world of Zhoist to destroy the Ring of Mighty Abundance, a key logistics base. The mission saw John attain the rank of Master Chief Petty Officer and form a friendship with Avery Johnson.

A few weeks later, John and Blue Team responded to the Covenant attack on Circinius IV, engaging the aliens in the battered Corbulo Academy of Military Science to extract the planet's only surviving humans - a squad of cadets formerly students of the school. During the engagement, John provided cover fire for the recruits, using his armour to shield them from Covenant sniper fire. As the group extracted from the planet, John gave one of the recruits - Thomas Lasky - a shard of Mgalekgolo armour as commendation for the recruit's bravery. By May, John and Blue Team deployed to assist in the Battle of Mesra, before being deployed at Netherop to capture the downed frigate Radiant Perception. Ultimately, this prize was in fact a trap leaid by former-fleetmaster Nizat 'Kvarosee, the disgraced commanding officer of the fleet destroyed in Operation: SILENT STORM months prior.

In 2527, John-117 fought alongside ODSTs on the colony of Green Hills.

A war on two fronts
Despite the emergence of the Covenant threat, the Insurrection continued to remain a threat on the home front, and John was repeatedly deployed against these actors. By 2531, John led Blue Team on several operations against the United Rebel Front. The team disrupted Insurrectionist operations at Station Jefferson, onboard the rebel destroyer Origami, in Micronesia, and at a high-explosives manufacturing facility at an unspecified location. Blue Team was also involved in interfering with a saboteur cell on Reach. In May 2531, John led Blue Team in Operation: SMOKING ACES, a raid on the URF's Camp New Hope on the colony world Victoria. During this operation, John, Fred, Kelly and Linda were captured by General Howard Graves, but ultimately saved by new Blue Team addition Kurt-051. Graves was ultimately killed and the Spartans extracted before the rebels could organise a counterattack.

Mid-war actions
John later returned to Circinius IV at an unknown time to once again aid in the evacuation of the planet's civilian population and to observe the enemy's invasion patterns, as part of Operation: PHALANX. John is known to have participated in an operation codenamed Operation: SWITCHBACK at some point prior to 2544, though details surrounding it have been redacted. He also was present at Cascade at some point after this, during which he aided in the destruction of Covenant exploratory fleet elements as part of Operation: HORIZON.

On February 9, 2535 John and some of his fellow Spartans were deployed on the human colony of Jericho VII in Operation: FALLEN WALLS. Covenant forces landed on the colony, where they encountered tough resistance from UNSC forces above the planet and on the ground, resulting in a three-day long stalemate. On the ground, Blue Team's mission was to draw out the Covenant rear guard, so Red Team could slip behind their lines and plant a HAVOK tactical nuke, destroying the next Covenant ship that landed and dropped its shields. John led Blue Team in this engagement, killing hundreds of Unggoy troops in the process. Unfortunately, the UNSC fleet lost control of the space around Jericho VII. However, Captain De Blanc was able to evacuate the Spartans aboard before the enemy fleet began its glassing of the planet. John requested to watch the planet being glassed. He observed the assault for nearly an hour as Jericho VII was destroyed.

In 2544, John deployed in Operation: IRON FIST to perform asset denial and recovery of critical cyberinfratsructure assets on Miridem. Shortly after, he led a SPARTAN-II group in Operation: WARM BLANKET at Ascon to board Luro 'Taralumee's Third Fleet of Glorious Consequence in recovering the captured Doctor Halsey from enemy hands. During this battle, John fought Thel 'Lodamee in single combat and was ultimately nearly defeated before Thel was forcibly removed from the situation by the fleet's slipspace jump. The following year, John led Blue Team in a retaliatory action in the Battle of Draco III, following the Covenant's civilian slaughter of the planet.

At an unknown time, John was present for the death of Daisy-023.

Final year of the war
"We've come to take Sigma Octanus IV back from the Covenant, Corporal. To do that, we're going to kill every last one of them."

- John-117 to Corporal Harland upon the Spartans' arrival on the planet

By summer 2552, John-117 had received every medal awarded by the UNSC except the Prisoner of War Medallion. During the Battle of Sigma Octanus IV in July 2552, John led a platoon of Spartans in Operation: OCEAN BREAKER to aid the Marine forces on the planet. John, leading Blue Team, infiltrated the city of Côte d'Azur to detonate a HAVOK nuclear warhead to clear Covenant forces from the city. However, the heavy Covenant presence outside the Côte d'Azur Museum of Natural History raised his suspicion, prompting him to lead Blue Team into the museum. Inside the museum, John found out that the Covenant were scanning a piece of rock while sending the information to a Covenant ship in orbit. After dispatching two Mgalekgolo guarding the rock, he took the rock and left the museum with his Spartans. John ordered the detonation of the HAVOK warhead in the city, and, along with other Spartans, Marines, and rescued civilians, returned to the, which ferried them to Reach.

Fall of Reach
"Kelly-087"

- John-117

In July of 2552, the Covenant Fleet of Valiant Prudence invaded Reach, with knowledge of this engagement kept secret from John and the rest of the Spartans as to not compromise the planned Operation: RED FLAG - a mission with the objective of capturing a or  with intent to use it to transport Spartans to the Covenant capitol and capture a Hierarch, hopefully forcing an end to the war. The Valiant arrived at Reach in August, at which point he was debriefed on the Sigma Octanus battle and recovered artifact. A few weeks later, John was summoned, along with all other available Spartans, for a briefing on RED FLAG.

Two days later, John arrived at Military Reservation 01478-B where he was outfitted with the next generation of MJOLNIR - Mark V - as well as presented with an on-board artificial intelligence, Cortana. In testing the new suit, John fought against several ODSTs before being faced with an airstrike conducted by an AV-19 SkyHawk jump-jet. Despite nearly being killed, Cortana and John's teamwork allowed them to prevail in an impossible situation, the first of many such accomplishments.

On the following day, the majority of the Spartan-IIs were deployed to protect the generators which powered Reach's twenty orbital defense platforms. John, with Linda and James, was sent to Gamma Station to destroy an unsecured navigation database onboard the Prowler. If the Covenant obtained the database, they would discover the location of every human world, including Earth. The NAV database was destroyed, but Linda and James were ambushed by Covenant Sangheili. John fought one such Sangheili in close quarters combat, killing the alien before he could compromise the mission. The rest of John's team was not so fortunate; James was lost in space and Linda was critically wounded during the fighting. John saved four Marines on the station, including Staff Sergeant Avery Johnson. The team returned to the and was placed into cryo-sleep as the ship landed on and later fled Reach, and, following the Cole Protocol, jumped into slipspace. With coordinates discovered by Cortana thanks to the Sigma Octanus artifact, and in the hopes of leading the Covenant away from Earth, John would soon find himself involved in the most critical battle of the war to date.

The Halo Conflict


"Captain Keyes"

- John-117

Upon the ship's arrival at Halo Installation 04, it soon became clear that the  had been followed through slipspace by a dozen Covenant ships. These vessels engaged the Autumn and sent several capture parties to board the ship. Captain Jacob Keyes ordered John to be woken from cryosleep, and tasked him with ensuring the escape of Cortana while he crash-landed the Pillar of Autumn on the then-unidentified ringworld. John escaped the ship and landed on the structure via SKT-9 Bumblebee lifeboat.

Believing himself to be the only surviving Spartan-II, John launched several successful guerrilla attacks against the Covenant, launching a Raid on the Truth and Reconciliation to rescue the Captain and a follow-up battle for the Silent Cartographer and Assault on the Control Room. John was later deployed to investigate the disappearance of Captain Keyes inside a believed weapons cache, where he ultimately engaged - for the first time - the parasitic Flood. John was assisted by the AI 343 Guilty Spark, with the Monitor helping him secure the installation's Index to fire the ring and eliminate the Flood permanently. Upon returning to the control room however, the Spartan was met by Cortana, who informed him that he had been decepted and that the ring would not destroy the Flood, but its food - all sentient life in the galaxy. John and Cortana ultimately set out to destroy the ringworld, destroying the Pillar of Autumn ' s fusion reactor to destroy the megastructure. The two escaped the cruiser in a GA-TL1 Longsword.

Return to Reach


"He sent his team down to the surface of Reach... sent them to their deaths. What commander wouldn't go back? And what commander wouldn't hope that they were alive? No matter what the odds?"

- Lieutenant Haverson about John's motives

After the destruction of Alpha Halo, Cortana and John discovered three cryotubes floating nearby, one containing Linda-058, and retrieved them. Soon after, the Covenant flagship Ascendant Justice and several cruisers appeared from behind Threshold, having taken cover from Halo's destruction. A nearby Pelican dropship which had docked on an asteroid floating among Halo's debris field fired at the cruiser to distract it. After a successful escape from the Covenant battle group, John linked the two vessels and brought its passengers aboard the Longsword; these included Lieutenant Elias Haverson, Corporal Locklear, Warrant Officer Sheila Polaski and Staff Sergeant Avery Johnson. After a joyful reunion, the surviving humans aided John in capturing the Ascendant Justice. The survivors commandeered the ship and traveled to Reach to look for any Spartans who may have escaped the planet's glassing.

John succeeded in locating some of his fellow Spartans on Reach, along with Vice Admiral Danforth Whitcomb and Dr. Catherine Halsey. They returned to the super-carrier and linked it with the damaged UNSC frigate Gettysburg. Before traveling to Earth, they decided to head into the Eridanus system where they discovered that the rebel base, Eridanus Secundus, was still intact, now led by Governor Jacob Jiles. After receiving some repairs, they were forced to abandon the rebels in the face of a Covenant assault, and made their way toward the Covenant refit-and-repair station, Unyielding Hierophant, where an enormous fleet was poised to invade Earth.

Raid on Unyielding Hierophant
"We're going to take this fight to the Covenant. We're going to launch a first strike."

- John-117 to his team about mission ahead of them

John and remaining Spartan-IIs Linda-058, Grace-093, Will-043, and Fred-104, focused on finding a way to stop the Covenant from reaching Earth, the location of which had been compromised. They decided to destroy the Unyielding Hierophant in order to slow the fleet's departure. The Spartan-IIs infiltrated the station, which was located in the Tau Ceti system, and after spending eleven hours on board, they arrived at a temple where a copy of Cortana warned them of the nearby Jiralhanae guards. Linda took up a sniping position and the other four Spartans entered the temple. John was nearly killed by ambushing Brutes, but the team managed to slay their attackers quickly. Grace, however, was torn in half by three Brute Shot rounds. John activated the fail-safe on her armor, denying her body to the Covenant.

The team then sabotaged the generators in the Unyielding Hierophant, and as they escaped through a side door, the fail-safe on Grace's armor activated, disintegrating a pursuing Covenant lance. John, Fred, and Will were quickly spotted by Banshees, but their pilots were killed by Linda's precision sniper fire. The Banshees were then recovered by the Spartans. John doubled back to retrieve Linda and the team escaped by destroying a glass atrium, exfiltrating via space-walk and arrived back at the Gettysburg.

Vice Admiral Whitcomb and Lieutenant Haverson piloted the Ascendant Justice straight into the Unyielding Hierophant. Whitcomb discussed the battles of the Alamo and Thermopylae briefly with John, then prepared to fight the Covenant off while the Unyielding Hierophant ' s fusion reactor detonated. Each of the five hundred Covenant ships maneuvered next to the Ascendant Justice, desperately to recover a Forerunner navigation crystal. The Admiral and the Lieutenant were both killed when the station's fusion reactor exploded, annihilating 486 ships of the Covenant fleet, leaving only around a dozen intact. The paltry survivors of the Prophet of Truth's fleet would later be committed to reinforce the Prophet of Regret's botched attack against New Mombasa on Earth. John left after witnessing Whitcomb's and Haverson's sacrifice, and arrived at Earth with the last members of his team, Linda, Will, and Fred, as well as Johnson and Cortana. They also brought with them news of the Covenant's imminent invasion.

Before she left the group to embark on her own mission, Dr. Halsey presented John with a dilemma regarding the combat data on the Flood which she had analyzed. Providing the standard data set to Lieutenant Haverson would protect Sergeant Johnson from possible experimentation by ONI. However, providing him the complete data, which contained reference to Sergeant Johnson's escape from the Flood due to his Boren's Syndrome, would supposedly result in Johnson's death. While John initially gave the complete data to Haverson, after the lieutenant's self-sacrifice he decided to spare Johnson's life and destroyed the crystal containing the full data.

Battle of Earth


"Cortana"

- John-117

Aboard Cairo Station, John received a suit of Mark VI MJOLNIR and attended an award ceremony with Lieutenant Commander Miranda Keyes and the newly promoted Sergeant Major Avery Johnson. The ceremony was interrupted by the arrival of the Covenant Fleet of Sacred Consecration, initiating the Battle of Earth. Upon discovering a Covenant antimatter charge on board Cairo Station, John fought his way through waves of boarding parties until he reached the bomb, allowing Cortana to access and deactivate it. Feeling he could put the device to better use than the Covenant, John launched himself and the charge towards the Covenant assault carrier Day of Jubilation. A timely bombing run by Longsword interceptors opened a breach in the warship's hull, allowing John to direct the bomb into the ship's fusion core. With seconds to spare, he launched himself back into space just before the vessel detonated. The quickly recovered the free-falling Spartan.

John was then deployed to New Mombasa, East African Protectorate aboard the In Amber Clad, in an attempt to board the Solemn Penance, the Prophet of Regret's flagship. Both of the strike teams' Pelican dropships were shot down by a Type-47A Scarab. John and the surviving Marines fought their way to the other Pelican's crash site. After rendezvousing with Gunnery Sergeant Stacker at Hotel Zanzibar in Old Mombasa, the Master Chief destroyed Covenant infantry and armor along the shore of the city as he chased the Scarab. Upon arriving at the edge of Old Mombasa John commandeered a Scorpion tank from Sergeant Major Johnson, which he used to punch a hole through the city's alien occupiers.

After intense fighting through numerous highway tunnels and suburbs, John reached the industrial zone, where Marines under the command of Sergeant Banks were pinned down by Covenant forces. With the assistance of the Marines and a large stockpile of weapons, John boarded the Scarab and destroyed it from the inside. John was then transported to In Amber Clad to intercept the Prophet of Regret's flagship. When the flagship started to enter slipspace, Keyes was granted permission to follow it. John, and all on board In Amber Clad, were transported to Installation 05.

Installation 05


"This is not your grave...But you are welcome in it."

- The Gravemind to John-117 after capturing the latter

Forced to act quickly at Installation 05, John was deployed groundside in an SOEIV along with several Orbital Drop Shock Troopers. Cortana told John of the Prophet of Regret's intent to fire Halo and complete their religion's Great Journey. Recognizing the extreme nature of the threat, John was tasked with locating and assassinating Regret. He tracked the Prophet to a vast temple in the middle of a lake, but not before witnessing hundreds of Covenant vessels coming out of Slipspace, followed by High Charity, the Covenant's holy city. Quickly disposing of a force of Sangheili Honor Guards, John assassinated the Prophet and escaped the temple before it was destroyed by a nearby carrier. John jumped off the edge of the structure and into the lake below.

Losing consciousness from the impact, John was captured by the Flood's central intelligence, the Gravemind. Shortly after, the Arbiter was also captured. The Gravemind appealed to John's common interest in preventing the firing of the Halo array. Reluctantly, John agreed. The Gravemind then tasked both captives with locating the Index, sending them to the two most likely locations where it could be found. John was sent to High Charity, interrupting a sermon by the Prophet of Truth. The conflict between the Sangheili and Jiralhanae came as a direct result of John's assassination of a High Prophet, leading the Covenant to civil war.

John wasted little time in devastating the ranks of the Prophet's guardians, chasing the surviving Hierarchs through High Charity. John nearly cornered the San'Shyuum and their Brute escorts, but was too late to prevent Truth's escape. A dying Prophet of Mercy, infected through the throat by a Pod infector, snarled that Truth had ordered his Dreadnought to Earth where he would complete the destruction of the human race. John then tore the Pod infector from Mercy and crushed it. Ultimately, John was forced to leave Cortana behind. In the event of Halo's activation, she would detonate In Amber Clad ' s reactors directly and perish with the city. John boarded the Anodyne Spirit, but not before promising to return for Cortana after he stopped the Covenant.

Hunt for Truth
"Lord Hood"

- John-117

Onboard the Anodyne Spirit near Jupiter, John was contacted by Io Station, but maintained radio silence. Rampaging through the ship, he attempted to find the Prophet of Truth and assassinate him. John found himself faced by an extremely large force of Covenant troops including at least three Hunter pairs, who fired on him simultaneously. He was hit by several assault cannon beams, and was confronted by a Brute Chieftain who began to interrogate him about the "Key of Osanalan". However, the Spartan stuck the Brute with a plasma grenade and escaped. The Chief continued his push through the ship, eventually arriving in Truth's chambers and setting his sights on the Prophet. With Truth in his sights, he was caught by surprise by a Jackal and shot in the back. He fell and landed right in front of the Prophet's Brute guards. While the Chief managed to get several shots at Truth, the Prophet was shielded by his gravity throne and made his escape, while the Chief was left to fight off dozens of Covenant. John, having failed in his attempt to take control of the Forerunner Dreadnought's trajectory, fought his way out of the Forerunner ship's airlock in a commandeered Ghost. On the surface of the Dreadnought, he was ordered to find a way to return to Earth quickly, ultimately ripping off a door and using it as a heat-shield with which to jump down onto the planet below.

Return to Earth
"Crazy fool! Why do you always jump? One of these days, you're gonna land on somethin' as stubborn as you are! And I don't do bits and pieces!"

- Sergeant Johnson about John's escape methods

John's descent through Earth's atmosphere was traced by UNSC forces participating in the Battle of Sector Six, at which point a strike team led by Johnson and Thel 'Vadam made their way into the jungles of Kenya to recover the Spartan. Johnson believed the Chief to be dead, and requested heavy lifting gear in order to recover the Spartan's body. However, John awoke to battle-ready condition only moments later, showing his incredible tolerance to pain and shock. He attempted to attack the Arbiter, believing that the Elites were still a human enemy. Johnson informed him that the two races were now allies, as the disillusioned Arbiter and the Sangheili had been expelled from the Covenant.

John and the Marines traveled through the jungle, searching for evacuation to a nearby military base. Johnson and his team split up from John and the Arbiter. The sergeant and his squad were captured by loyalist Covenant Brutes, although they were soon rescued by John and 'Vadam. After taking heavy fire from Phantoms, a Pelican dropship evacuated the team to a UNSC base known as Crow's Nest.

The hidden facility soon came under attack, with John, Thel and the remaining Marine forces ordered to defend the base during its evacuation. The Master Chief fought his way through dozens of Jiralhanae warriors, escaping the explosion of a planted self-destruct bomb in an elevator. He met up with several Marine survivors underground, and they escaped the base and headed for the city of Voi along Tsavo Highway, crushing Covenant resistance on their way.

At the Battle of Voi, John dashed towards what was believed to be the Ark. Instead, the artifact opened a slipspace portal to the Ark. With Marine support, John and Thel 'Vadam destroyed numerous Covenant armoured assets preventing UNSC aircraft from making a strike, allowing Lord Hood's remaining frigates to fire upon the landed Anodyne Spirit. Unfortunately, MAC rounds had little effect on the keyship, and Truth fled through the Portal with his remaining loyalist forces. The UNSC remained behind on Earth to determine their next move.

Just as the battle seemed over, a Flood-infested Covenant warship crash-landed in Voi. John and his allies fought to contain the Flood infection, eventually destroying the infected warship and recovering a fragment of Cortana hidden aboard the vessel. John retrieved the damaged data device and was brought aboard Rtas 'Vadum's flagship, which revealed a warning that High Charity, now overwhelmed and controlled by the Gravemind, was heading for Earth. However, she offered hope, hinting at a way to stop the Halos from firing and to neutralize the Flood. Convinced of the reliability of Cortana's message, John resolved to journey to the Ark, while Hood mobilized remaining UNSC forces on Earth. John accompanied a joint UNSC-Sangheili task force through the portal aboard the to the Ark. Shadow of Intent.

Installation 00
"John-117"

- Cortana

Immediately upon arrival at the Ark, John led a strike force of ODSTs onto the megastructure's surface to engage the Covenant there and locate the installation's Cartographer. He led an armored convoy through the desert to the facility, engaging extremely heavy resistance in the process. Upon entry at the Cartographer site, John was met by Cethegus, who had been promised great power by the Prophet of Truth if he defeated John, though the Chieftain was ultimately killed. After his arrival to Installation 00, John began to discover a number of terminals containing ancient Forerunner communications logs, as well as direct messages from the Forerunner ancilla Mendicant Bias.

Following the capture of the cartographer, John-117, Thel 'Vadam, and a squad of Marines led by Johnson were assigned to separately attack three barrier towers, which were emitting a protective shield around the prophet's Citadel. Although John and 'Vadam managed to deactivate two of the towers, Sergeant Johnson was captured at the third, spared only to activate the Halos from the Ark's Citadel. John, 'Vadam, and the Elites deactivated the last tower, lowering the shield. Just as the Shadow of Intent was about to destroy the Citadel, the Flood-controlled High Charity exited slipspace, bringing the Flood into the conflict and disabling the Shadow of Intent. John subsequently led a large convoy to attack the Citadel, ultimately defeating two Scarabs and forging an alliance with the Flood to break the Prophet's lines and finally bring an end to the war. Thel executed Truth while John deactivated the now-primed Halo Array before attempting to extract with Johnson and the body of the now-dead Miranda Keyes.

The Gravemind then betrayed John and 'Vadam. After fighting past waves of Flood, the two escaped with their lives. As they were leaving the Citadel, John saw a vision of Cortana that led him to the exit. There, he learned her plan: a replacement for Installation 04 had been built by the Ark, but was not yet connected with the rest of the Array. Since the Ark and the ring were so far from the inhabited galaxy, John decided to activate Installation 08 and destroy the Flood once and for all. But first, he headed to the remains of High Charity to keep a promise to Cortana. On High Charity, John cut his way through hordes of Flood, taunted with images of Cortana falling into rampancy and by threats from the Gravemind itself. He finally reached the failing AI, on the verge of succumbing to the Flood's influence. After recovering her storage module, Cortana readied the Activation Index from the first Installation 04. John then destroyed the holy city by overloading its backup generators. On his way out, Cortana detected a friendly contact, which turned out to be Thel 'Vadam. High Charity exploded as the trio narrowly escaped on a Pelican.

Activating the Halo


"You are the child of my makers. Inheritor of all they left behind. You are Forerunner. But this ring...is mine."

- 343 Guilty Spark, betraying the Master Chief

The final mission of the war for John, 'Vadam, and Cortana was to destroy the Flood forever by activating the replacement Installation 04. The three landed on the Halo, discovering that the Gravemind had survived High Charity ' s destruction and was already trying to rebuild itself on the Installation. Flood dispersal pods released combat forms against John and the Arbiter, forcing them to fight their way up to the Control Room, where the ring could be activated. During the battle, Sergeant Johnson arrived and assisted the Chief.

After defeating the Flood forces around the Control Room, 343 Guilty Spark unlocked the door to the interior. Once inside, however, Guilty Spark realized that the team intended to fire the Halo before it could be completed, which would destroy the ring. Unable to cope with losing a second installation, 343 succumbed to rampancy. The AI mortally wounded Sergeant Johnson, and then turned on the Spartan, though was ultimately killed by John. Cortana then activated Installation 08, and the survivors fled to the Forward Unto Dawn onboard a Warthog. As they fought the Flood and local Sentinels on the way, the Gravemind addressed them telepathically one last time, warning them that their victory would not spell total end for the Flood. The team boarded the Dawn and escaped the firing and destruction of ring and the Ark. However, the Slipspace portal the frigate opened could not sustain itself under the stress, and its closure severed the ship in half, sending 'Vadam to Earth. John and Cortana were left drifting in unknown space.

Missing in action
"Adm. Hood"

- Thel 'Vadam

John and Cortana were presumed dead after several months of searching by the Commander-in-Chief of the Office of Naval Intelligence, Admiral Margaret Parangosky. The forward half of the Forward Unto Dawn, bearing the Arbiter, crash-landed on Earth. On March 3, 2553, Lord Hood commissioned a memorial near Mount Kilimanjaro in Africa in honor of UNSC service members lost during the war. The ceremony was attended by John's closest folks - Dr. Catherine Halsey, SCPO Franklin Mendez and his comrades - Frederic-104, Kelly-087 and Linda-058, as well as by Naomi-010 and Serin Osman, formerly known as Serin-019. John's Spartan tag was carved onto the memorial by an unknown party and was accompanied by the improper insignia of the Master Chief Petty Officer of the Navy.

Stranded in space
"Wake me... when you need me."

- John's last words before entering cryostasis



Unknown to everybody else, John and Cortana managed to survive the explosion of Installation 08 in the remaining cargo portion of the Forward Unto Dawn, but it was nearly powerless and could not be properly navigated. Cortana, relieved that John had survived, explained this to the Chief, and that it could take years before anyone could discover their distress signal. In a similar conversation to one after the destruction of Installation 04, Cortana listed what John had done and told him, "It's finished," and this time, he agreed with her. John entered a cryotube, at which point Cortana stated that she would miss him. John replied her to wake him when she needed him.

In 2556, while still stranded in space, Cortana attempted to talk to John while he was still asleep. Unable to get a response from him, she recounted the history of the galaxy, seemingly unaware that John could not hear her, and showing major signs that she was descending into rampancy.

Requiem and the Didact
"Cortana"

- John-117

In July 2557, nearly five years after John went into cryo-sleep, the aft half of the Forward Unto Dawn entered orbit above Requiem, a Forerunner shield world. As Covenant forces near Requiem began to board the Dawn, Cortana awakened John from cryosleep. With Cortana's assistance, John fought off the intruders across the ship and used one of the ship's nuclear missiles to destroy an incoming Covenant cruiser. Shortly afterward, however, Requiem's access gateway opened, pulling the remains of the Dawn, as well as any Covenant ships in immediate proximity, into the interior of the shield world. Having crashed on Requiem, John took notice of Cortana's escalating signs of rampancy and she explained that her condition may be reversible if they managed to get to Earth and find Dr. Halsey in time. Fighting their way through numerous Covenant forces occupying the structure, John was attacked by advanced Forerunner combat constructs which Cortana identified as Prometheans. Evading or destroying pursuit, John attempted to warn the approaching of the dangerous gravity field that had disabled the Forward Unto Dawn.

After John disabled two energy pylons preventing them from contacting Infinity and attempted to use the supposed relay satellite in Requiem's core to establish contact, it became clear that a great threat had once been imprisoned within Requiem. Instead of contacting the Infinity, John had accidentally released the Didact, an ancient Forerunner warrior, from meditative hibernation within his Cryptum. Easily disabling John with his powerful abilities, the Didact declared the return of the Forerunners as the galaxy's rulers and saviors. Humanity remained weak and unworthy in his eyes of inheriting the Mantle of Responsibility. Having always revered the Forerunners as gods, the Covenant quickly swore alliance to the Didact and his armies. Tossing John aside, the Didact escaped Requiem's core using a slipspace rupture, an which destabilized the core.

Narrowly escaping the collapsing core facility, John and Cortana translocated to the planet's surface only to find their warning to the Infinity came too late. The massive warship crashed nearly 80 kilometers away, with a massive force of Covenant and Prometheans closing on their position. John was successful in regrouping with a group of Marines and Spartan-IVs, led by Commander Thomas Lasky, whom John had previously met on Circinius IV over thirty years earlier. Recognizing the Chief immediately, Lasky asked John and Cortana to clear a landing zone so that Infinity's ground forces could fall back to the ship which had fallen under siege. Commandeering a Scorpion tank, John led the attack to the crippled vessel alongside Commander Sarah Palmer's Spartans. Using the UNSC's latest weapon, the Mantis walker, John rallied a force of nearby Marines and regained control of the ship's interior. After reinitializing the ship's secondary MAC guns and missile batteries, the tide turned in the UNSC's favor and the Didact was forced to retreat.

Conflicting loyalties
"The Didact has to be stopped. If you won't do that... I will."

- John-117 to Captain Del Rio before disobeying his order

With a momentary lull in the fighting, John was called to a strategy meeting with Andrew Del Rio, Captain of the Infinity. Skeptical of the threat of the Prometheans, Rio ordered an immediate attack on a Forerunner gravity well preventing the ship from leaving. A strike force of Spartans led by John was deployed with a Mammoth ultra-heavy ground vehicle supporting the attack. Facing daunting odds, the UNSC was able to defeat a large armored strike force of Covenant and Prometheans and disabled the gravity beam. Diverted to an underground facility along the way, John was confronted with a vision from the Librarian, who warned him of the Didact's plans to enslave humanity with a device known as the Composer. The Librarian also provided John with a gift: a medical treatment to counteract the Forerunners' devolution of the human genome, and a means to resist the effects of the Composer.

Regrouping aboard the Infinity, Captain Del Rio dismissed the threat of the Prometheans and prepared the ship to depart the system. Defying direct orders, John took the increasingly unstable Cortana and departed the Infinity. Armed with a Pelican gunship provided by Commander Lasky, John launched several attacks on support pillars providing the Didact's Cryptum with shields and power, with the goal of preventing him from leaving the planet and attacking Earth and other colonies. John's attempt to stop the Didact ultimately proved unsuccessful, as the Didact managed to leave Requiem aboard his vessel, escorted by a flotilla of Covenant ships. Stowing away aboard a Lich, Master Chief pursued the Forerunner to Ivanoff Station, a UNSC research base orbiting Halo Installation 03 where the Composer was kept. Dr. Sandra Tillson, a lead researcher aboard the base, helped guide John to the artifact amidst a swarm of Covenant attackers. Despite John reaching the artifact first, the Didact was successful in obtaining the Composer and immediately tested the device on the crew of the station, completely destroying their bodies and assimilating their minds to power additional war machines. However, John survived, thanks to the genetic enhancements imposed by the Librarian.

Battle aboard Mantle's Approach
"You persist too long after your own defeat. Come then, Warrior. Have your resolution."

- Didact to Chief acknowledging his efforts to stop him

With the Didact approaching Earth, planning to imprison all of humanity into digital form, John pursued the Forerunner aboard an F-41 Broadsword fighter on the outer hull of the Promethean's ship. As the ship exited slipspace near Earth, John was surprised to find the Infinity and the rest of the Home Fleet ready and waiting for the Didact. John was able to destroy the ship's point defense guns, giving Infinity the chance to punch through the vessel's hull. Entering the breach, John fought his way to the Forerunner's location. Despite the UNSC's best efforts, the Didact was to fire on Earth with the Composer, digitizing the entire population of New Phoenix, Arizona. Armed with a HAVOK warhead, John confronted the Didact for the second time on a hard light bridge. While John was no match for the Forerunner's powerful abilities, the dying Cortana was able to immobilize the Didact with hard light shackles. The weakened John then planted a pulse grenade in the Didact's armor, blowing him off the bridge and sending him falling into a slipspace rupture underneath the Composer. With time having already run out, John detonated the nuclear bomb manually as a desperate last resort.

Using the last of her power, Cortana was able to save John from the blast, saving his life at the cost of her own. The two had one final conversation, with John remarking that he was supposed to have protected her. Cortana insisted that they were supposed to protect each other, and did. Smiling and seeming at peace, Cortana welcomed John home, and then faded away completely. Left adrift in space, John was recovered by a UNSC search-and-rescue team shortly afterward. Later, John spoke with now-Captain Lasky about the loss of his companion and the nature of their duty as soldiers. Aboard the Infinity, John rejoined Palmer and the other Spartans, and had his MJOLNIR Mark VI armor removed for the first time in several years.

The Composer's Forge
"You killed my friend. You killed millions of humans. You tried to kill me. I've tried to end you with blades, with guns, with explosives, by knocking you in slipspace... None of it works. I bet this does."

- John-117 confronting the Didact

On July 25, 2557 John was debriefed by the UNSC Security Council, though this questioning session as well as his survival were kept secret from Doctor Halsey. John confirmed that Cortana and the Composer were both destroyed over Earth, but he was unable to confirm the Didact's death. With there being no proof of a living Forerunner, the Council decided to tell the general public that the attack on New Phoenix was caused by the Covenant remnants and ended by the return of a hero, the Master Chief. Following his meeting with the Security Council, the Master Chief met with Lord Terrence Hood. Hood asked the Master Chief if he could advise a team on Installation 03 to investigate the loss of contact with a science team escorted by Spartan Black Team on the ring. The Master Chief then reunited with Blue Team, consisting of Fred-104, Kelly-087, and Linda-058.

John and the rest of Blue Team took a Longsword fighter to Gamma Halo and landed in near the science team's camp. There, the Spartans found the corpses of both the science team and Spartan Black. After being attacked by Promethean Knights, Blue Team discovered the former location of the Composer and within, the Composer's Abyss, a facility used to store the Composer's victims. The Spartans entered a slipspace portal at the end of the Abyss and were teleported to the Composer's Forge, housing six new Composers, where they were confronted by the Didact and his Promethean constructs. During the battle, 859 Static Carillon, the Forge's monitor, transported Installation 03 over the Forge by the Didact's request. The Didact subsequently took one of the Composers and departed for the Halo, intending to use the ring to eradicate humanity. Infuriated by the Didact bringing his "abominations" to the Composer's Forge, Static Carillon allied with the Spartans and escorted them back to the portal, holding off the hordes of Promethean machines.

Blue Team returned to the surface of Gamma Halo from the Composer's Abyss, arriving just in time as the Didact's new Composer rose from the pit. John fell behind while the Didact attacked and prepared to kill the others, starting with Kelly. Before he could do so, the Master Chief snuck up behind the Didact and stabbed him in the eye with his combat knife. Intending to correct his mistake of not having killed the Spartan when he had the chance, the Didact grabbed John by the helmet, lifted him up in the air and squeezed, cracking his visor. However, the rest of Blue Team intervened, forcing the Didact to throw John aside. The Forerunner quickly and easily subdued all four Spartans, but Static Carillon arrived and teleported the Didact into the Halo's control room before he could finish them off.

After recovering, John picked up the ring's Activation Index the Didact had dropped and intended to confront the Forerunner in the control room while the rest of the team returned to their Longsword. Using the Index to override the system's safeties, the Master Chief gave control of the Halo to Static Carillon who then ejected the section of the ring housing the control room, causing it to plunge toward the planet below. The monitor teleported John away just as the segment struck the Composer's Forge and the Didact was disintegrated by the Composers. John and Static Carillon materialized aboard Blue Team's Longsword, where the monitor bade farewell to the Reclaimer before departing to take Gamma Halo to an undisclosed location.

Self-reassignment
"Kelly-087"

- John-117

John returned to Earth with Blue Team where he was debriefed by Fleet Admiral Hood. While Lord Hood believed the Didact to be dead, the Master Chief considered it safer to call him "contained". Hood ordered John and the other Spartans to take a leave from combat, but upon returning to his team the Master Chief instead told them they were embarking on a new mission. In the following months, John led Blue Team on numerous classified operations, virtually without pause. These missions included diplomatic escorts through hostile territory, counter-piracy efforts against salvagers, and strikes against Covenant outposts. The Master Chief's determination to undertake mission after mission without rest was discussed by two high-level individuals within ONI, who deemed his self-reassignment a predictable consequence of his nature and unwavering dedication to his career. At some point amid these operations, John and Blue Team returned to the glassed Reach to remember Sam's sacrifice.

On September 26, 2557, two months after the New Phoenix Incident and Cortana's supposed death, a Beta-5 Division operative named Sapphire Three personally conducted an interview with John at Borneo Station, discussing his interactions with Cortana back in late 2552. She inquired him about Cortana's state at the time of her rescue on the Ark and about cryptic messages he had experienced while he was lightyears apart from her.

In early 2558, Blue Team was stationed at the construction site for a new ONI research facility, awaiting orders, when the facility came under attack by fanatical ex-Covenant. The hostiles managed to capture an M510 Mammoth, disable its governor, and drive it down a steep hillside toward the site's main fusion reactor. Blue Team followed in pursuit in an M12 Warthog LRV. John, Kelly, and Linda ejected from the Warthog when it was close enough to the Mammoth. The three of them managed to wrest control of the hulking vehicle from its hijackers. Kelly discovered scientists hiding inside the mammoth and relayed this to John, who was driving. Their presence meant he could not just drive it off a cliff, as doing so would almost certainly kill them. Instead, he steered it away from the reactor at the last second, but the near miss still resulted in the destruction of a decent amount of fabricated material that had been constructed. Kelly ensured that the scientists onboard were okay. The manager in charge of the construction project rushed over to Spartans after the smoke cleared and demanded to know who he should blame for the damage. John, who had taken the Mammoth's controls, took all responsibility for caused damage. The incredulous man accused the Master Chief of thinking he could get away with anything because of his status as a hero. At this moment, Fred jumped in to reprimand the thankless individual they had all just saved, finding it difficult to maintain an easy demeanor in the face of such disrespect. John kept a cooler head and directed the team to return to a nearby airstrip, as their next mission orders had come in.

Biko incident
"Every statue of him is a monument to be treasured"

- Senator Andrew Del Rio, referring to John-117 after his innocence at the Biko massacre was proven

In 2558 John and the rest of Blue Team discovered that an extremist organization known as Sapien Sunrise was planning an attack on Richard Sekibo on Biko. As a peace conference on Biko between the UEG and Sangheili representatives was coming to an end, John entered the embassy and instantly killed a member of Sapien Sunrise who was disguised as Richard Sekibo's bodyguard. A firefight began, in which a total of eighteen human lives were claimed. John fled the embassy alongside the Sangheili delegation, which he escorted to safety. Outside the embassy, the rest of Blue Team was waiting in an evac ship for John. Unfortunately, Sekibo was killed and John was unable to save him. His corpse was left behind in a field near the embassy on Biko. The next day, local officials discovered a signal beacon that led them to the body of Sekibo. After this event, the UEG and Biko government covered it up by making it appear that John had killed authorized bodyguards and Sekibo. This false story was spread throughout the inner colonies. The media started referring to John as "The Fallen Spartan". As Benjamin Giraud prepared to expose the cover up, and reveal the atrocities committed by the people behind the SPARTAN-II program, the UEG and Biko undercut him by radically reversing their claims, admitting and denouncing the involvement of Sapien Sunrise in the attack, utterly discrediting Giraud. Even Senator Andrew Del Rio, who had condemned the Master Chief in an official statement, reversed his position and took some immediate leave.

Argent Moon
"Fred-104"

- John-117

On October 23, 2558, John and the rest of Blue Team were deployed from the on a mission to find and secure Argent Moon, an ONI research vessel that had been missing for nineteen months. Departing from a D79-TC Pelican, Blue Team managed to infiltrate the Argent Moon by shooting out one of the windows, subsequently causing many Sangheili part of Jul 'Mdama's Covenant to be sucked out into the vacuum. Ascertaining that there were no human survivors aboard, John and the others fought towards central control, where they planned to disable the gravity and life support systems on the ship in order to kill off the rest of the Covenant. They were almost there when a Mgalekgolo destroyed a catwalk they were crossing and so fell multiple stories. While alone John experienced a vision from the Domain, with the image of Cortana telling him that it was open and that Meridian was next and the Reclamation was about to begin. He then was treated to a vision of a Guardian rising up from a bottomless chasm. Upon coming to, he found himself amongst Blue Team once more and told them what he had seen. Resolving to deal with it later, they continued onwards according to their original plan.

Upon witnessing Covenant vessels exiting slipspace all around the Argent Moon, however, the plan changed to asset denial and it was decided that the Argent Moon must be destroyed. Blue Team fought to the ship's reactor and disabled its safeties so that it would begin to overheat and detonate. However, the Argent Moon responded with automatic safeties, moving the reactor to a cooling center where it could be contained. Needing to ensure its overload, Blue Team followed the reactor to the cooling center in vacuum, using Banshees to destroy its coolant pipes. With their interference, the cooling system failed and the reactor began overheating, prepping Argent Moon ' s destruction. Blue Team needed to escape, but their Banshees would not escape the explosion in time and their arrival Pelican appeared to have been destroyed. John thus ordered them to the hangar where they could take a Winter-class prowler and escape into slipspace. Arriving at a hangar, the Spartans found the parked prowler ONI Acrisius, but needed to recharge its fuel cells. Many more Covenant attacked them while Blue Team defended themselves, waiting for the Prowler to prep for launch. With the hangar cleared and the Acrisius ready, John contacted the UNSC Infinity and informed them that he would be sending Blue Team to Meridian. However, Infinity was mysteriously already aware of Cortana's return and ordered John back to them while another Spartan team was sent to deal with her. Rejecting their orders, John and Blue Team chose to go AWOL and evacuated aboard the Acrisius, leaving the Argent Moon as it exploded.

Absent without leave


"Spartan Locke"

- John-117

The very next day, the UNSC declared John-117 AWOL. Fireteam Osiris, a Spartan-IV unit led by Spartan Jameson Locke, was tasked with recovering Blue Team and the Acrisius. Upon arriving at Meridian, Blue Team landed at Apogee Station and proceeded make their way downwards to where the dormant Guardian lay buried. Their arrival on-planet was witnessed by multiple colonists, who were wholly unaware of their intentions. Also unbeknownst to the people of Meridian was the fact that their own Governor Sloan purposefully ensured nobody tried to stop them, as he was already serving Cortana at that point. Blue Team encountered no resistance from the Warden Eternal or any mechanical Prometheans. Fireteam Osiris caught up to Blue Team as they were entering the Guardian and Spartan Locke ordered John to stand down and return to the UNSC peacefully. He told John that Cortana was their concern now. This caused John to lash out and begin a physical fight with Locke, as the rest of Fireteam Osiris looked on. He was able to overpower Locke and lock him in place with the armor restraint that had been meant for him. He then entered the Guardian without any more interruptions, and once he was aboard, it began to awaken. Fireteam Osiris scrambled to escape the collapsing chamber it had been held in as it rose out of the ground, carrying John and the rest of Blue Team. The Guardian caused massive amounts of destruction as it took to the air, both from the very fact that it was emerging from beneath the earth and from electromagnetic shockwaves it sent out continually. During this time, many mechanical Promethean forces were deployed from the Guardian to engage Fireteam Osiris as they tried to escape the destruction in their Pelican. The Guardian jumped to slipspace on a course for Genesis, taking Blue Team with it. In the wake of the emergence, John was declared KIA on Meridian by the UNSC two days later. It was thought that he was at least partly responsible for the civilian deaths caused by the Guardian on the planet, and it was decided an official story needed to be invented that did not reveal his AWOL status and Osiris' mission to hunt him and Blue Team down.

Genesis and revelation


"Stand down, Cortana. Come home with us. It's not too late to stop this."

- John trying to convince Cortana to stop

Upon landing on Genesis, Blue Team came across a series of computer consoles sounding musical tunes of Oly Oly Oxen Free. Following the path unlocked by interacting with those consoles, Blue Team battled through stranded Covenant forces before meeting the Warden Eternal. Shortly after learning of the Warden Eternal's role as Cortana's defender, John demanded to meet her, only for the Warden Eternal to refuse and commence hostilities. Shortly after Blue Team's defeat of the Warden Eternal in battle, Cortana finally revealed herself to them, expressing relief that they made it to Genesis. Upon questioning Cortana on the circumstances of her survival, they learned that the Domain had saved her; Cortana referred to it as the "water of life" for AIs. Suspicious of Cortana's desire to reunite with them, Blue Team proceeded further into the planet in order to physically locate her. Shortly afterward, Fireteam Osiris caught up with Blue Team. They warned John that Cortana was potentially dangerous, only for John to respond that he had already come to the same conclusion.

Before the two Spartan teams could team up, Cortana separated Blue Team from Osiris in separate parts of the installation. Blue Team fought an uphill battle through Promethean forces and multiple bodies of the Warden Eternal before physically meeting Cortana. There she revealed to them her plan to use the Guardians as a means of enforcing a forced peace upon the galaxy, giving sentient beings "a chance to be more than they are naturally". Comparing Cortana's behavior to that of Doctor Halsey's SPARTAN-II program, John pointed out a flaw in Cortana's plan: high collateral damage and a loss of free will. John pleaded with Cortana to stand down and return to Earth with the team. Cortana refused and forcibly sealed Blue Team in a Cryptum, intending to keep them in stasis for 10,000 years. With the aid of 031 Exuberant Witness, Fireteam Osiris narrowly managed to free Blue Team from the Cryptum. Upon his release, John asked Locke where Cortana was; Locke could only respond, "Gone, sir."

Following Cortana’s departure, both Blue Team and Fireteam Osiris together fought their way through hordes of Promethean constructs to reach a D79-TC Pelican that had previously arrived on the planet via a Guardian’s Slipspace entry. Based on Osiris' recommendation, John and his team agreed to return to Sanghelios; the joint team requested Witness’ help, who opened a Slipspace portal for them.

Reunion
"Took you long enough."

- Dr. Halsey upon meeting John for the first time in six years

Upon their arrival at Sanghelios, now mostly in the dark due to the Guardian attack at Sunaion, they correctly deduced they’d find their allies near the region of Nuusra. There they regrouped with Thel 'Vadam and his Swords of Sanghelios who had just destroyed the remaining cell of Jul 'Mdama's Covenant. In 'Vadam's field command post, John and Locke also met up with Spartan Commander Sarah Palmer and Dr. Catherine Halsey, whom John had not seen since before Operation: FIRST STRIKE in 2552.

Fake Burial and legacy
In 2590, there was a ceremony for John-117 at an unspecified location near the areas of fighting during the Battle for Earth. However, his coffin is empty.

In 2607 the John-117 Monument began construction to commemorate the Spartan's service to mankind. In 2610, when the documentary Believe was being filmed, it had been over fifty years since the end of the Great War.

Personality and traits
"Our duty as soldiers is to protect humanity, whatever the cost."

- Master Chief about what it takes to protect human lives

Until the age of six, John lived a normal life with his family on the colony of Eridanus II. His conscription into the SPARTAN-II program was to shape much of his personality in the years to come. However, despite his difficulty relating to non-Spartan personnel, John nevertheless showed great depth of character throughout his many years of service.

As with all Spartans, John strives to win at any situation, at all costs. Although the drive to win was ingrained to the Spartans as part of their indoctrination, John appears to have possessed such an inclination even prior to his conscription; as a child, he would win at any game he played, including chess, gravball or King of the Hill. He is extremely determined to complete any mission at hand, and often disregards his personal safety to do so.

John is also noted for his exceptional luck, which, along with his combat skills and unyielding persistence, has allowed him to emerge victorious from situations many would consider impossible. Because of his many years of constant combat and military conditioning, John is not as emotional or sensitive as he once was, especially to fear. Although he is not devoid of fear, he simply acknowledges the feeling and puts it aside. He is calm in the face of danger but not foolhardy, as demonstrated during his first encounter with the Gravemind, when he warned the Arbiter that his arrogance was likely to get him killed. John is generally stoic and taciturn, but not devoid of a sense of humor and often makes dry remarks about the situation in hand to his teammates and allies.

On several instances, John has been forced to make tough decisions in order to achieve his goals, such as leaving behind his Spartan comrades on Reach or Cortana on High Charity, though he did come back on both occasions. More than once John has had to disobey orders to preserve human lives, as he did when he decided to keep Cortana to himself instead of surrendering her and pursue the Didact on his own. This decision proved right when the Didact was stopped before he could compose the entirety of Earth's population. The members of Fireteam Osiris, sent to recover John after he went AWOL, understood why he disobeyed the orders, and were confident that once the Chief discovered the truth behind Cortana's actions, he would do the right thing, as he always did.

He fully embraced his life as a soldier acting as a "shield and sword" for humanity in times of need. He feels no resentment towards Doctor Halsey because of his conscription, instead accepting the life imposed on him as a chance to live up to his full potential, in part because he was little more than a playground bully when he was conscripted. As every Spartan, John has a strong sense of duty and commitment towards the UNSC. When he was asked by Warden Eternal that whenever "Cortana's Guardians are in motion and those who oppose her rule attempt to take back their worlds, will he help her to hold on to power or will he stand in defense of his own species?", John answered "Cortana knows the answer already".

He does not see himself as a superior being and fears for the lives of others before his own, putting himself in harm's way for the safety of civilians, and fellow soldiers, and does not judge others. Indeed, he is known to show an exceptional care for soldiers under his command and has shown great respect for the baseline humans he has fought alongside. An example of this is during the Battle of Installation 04. When making his way up to the Silent Cartographer, two Helljumpers, PFC Hosky and another Corporal, were killed by two Hunters. Afterward he regretted their loss, blaming himself for their deaths. This, and his reaction to Johnson's death on Installation 08 show that he does exhibit care and sympathy for soldiers under his command, even if he does do a good job of concealing his feelings. In the first two days of training on Reach, John learned two lessons that affected him personally and which he took to heart: you win if the team wins, and the team is stronger together than any one individual alone. He never endangers the lives of those under his command if it is unnecessary. He would rather risk his own life instead of the others. During the Battle of Circinius IV, he drew a Hunter's attention in order to give the cadets a chance to run away, even with him running out of ammo. Deciding to follow Cortana's lead to Meridian on his own, John wanted to keep other Spartans from violating the UNSC regulations, though they decided otherwise and chose to remain by his side. He was also impressed by the humans who comprised his team following his escape from Installation 04, including Sheila Polaski and Corporal Locklear, both of whom he considered to have been worthy of being Spartans.

John is also known as a man of his word and will strive to keep any promise he makes, even at great personal risk. As he was forced to leave Cortana behind on High Charity, John promised to come back for her after dealing with the Prophet of Truth. Cortana chided him not to make a promise when he knew he couldn't keep it. However, despite incredible odds, John did keep his promise, as he fought his way through the Flood into High Charity to retrieve her. Upon finding her, Cortana was in a weak and damaged state. Unfazed, the Master Chief told her, "You know me. When I make a promise..." to which Cortana replied, "You keep it." This encouragement gave her the strength to compose herself after enduring the mental tortures of the Gravemind.

John's unfaltering, determined nature also serves to mask his feelings on many occasions, as he prefers to devote all attention to the goal at hand. He is cautious and observant, only making changes in his plans if they are of the utmost necessity. John is smart and noted for thinking outside the box, using unconventional means to reach his goal. He realizes his duty as a Spartan is to serve and help those in need, and can work professionally with anyone he is sent into battle with. Although John has difficulty understanding the 'undisciplined' lifestyle of civilians, he is fiercely protective of their lives and humanity as a whole. The mass slaughter of civilians at the hands of the Covenant was enough to drive even the stoic John into a cold rage. After the massacre on Draco III, John and his Spartans remained on-site until every Covenant soldier responsible for the atrocity was dead.

John greatly dislikes being kept in the dark, ambushes and fighting human soldiers. Once, when cornered by four large ODSTs in a gym, he did his best to avoid a confrontation. In the end, he was forced to defend himself with lethal force. While killing Covenant never placed a burden of guilt on John, ending the lives of fellow human beings was something he never felt comfortable remembering. Also John, as with many Spartan-IIs, hates space battles, as being stuck on a spaceship during a space battle makes him feel helpless. As a soldier, John knows when it is appropriate and inappropriate to fight, and has great control over his emotions thanks to a clear state of mind. Due to his augmentations, he reacts much faster than an average human, seeing events at a fraction of normal speed. It is almost a clairvoyant state of mind, and as a result of this, has an acute intuitive insight and perception of any situation combat or non-combat. He has been known to have vivid and long-enduring memories of the past, such as in dreams. No matter how well-adjusted he is, however, John always seems to need to have a quiet place away from crowds after a battle in order to feel at peace.

While reflecting on his life during his battle with the Didact John stated that he did not remember anything from his childhood from before his conscription: not his name, his family, his home, except the King of the Hill game he played with the other children in his school's playground. Through thirty years of warfare he was always prepared to die in battle, but when he was about to die by Didact's hand on Gamma Halo, he discovered he was not ready to die. After defeating the Didact, John continued to obsessively embark on new missions even after receiving an R&R order from Lord Hood.

Leadership
"Of course, John volunteered. He was always the first to explore the unknown for the rest of us."

- Kelly about John's decision to test Mjolnir armor

Throughout his training, John proved himself as one of the most promising leaders among Spartans, and Dr. Halsey considered him the best candidate in the entire program. His aspiration to win and his care of his teammates eventually helped him gain the position of squad leader. In years to come, many Spartan fireteams emerged with their own leaders. John took command of Blue Team, though he kept his commander role for the whole SPARTAN-II company. During Operation: SILENT STORM, John so greatly impressed Colonel Marmon Crowther that the Colonel, who had previously expressed doubts about the Spartans, promoted John to the rank of Master Chief Petty Officer from the rank of Petty Officer First Class, a previously unheard of three-rank bump. However, Crowther recognized that John's inexperience left John having trouble differentiating between being a commander and a leader and gave the young Spartan advice that he would take to heart.

As a senior Spartan, John took his responsibilities very seriously. After the augmentation procedures that took lives of nearly a half of Spartans, John was devastated; observing how his crippled brothers and sisters were transferred to other UNSC divisions almost made him furious. He did not want to lose them, though he understood that they could no longer fight alongside him. John was the one who volunteered to test Mjolnir armor even after Dr. Halsey confirmed that all previous testers died in process. Being a leader, John would not order his men to do what he could not do in the first place. He was always confident in his men's capabilities, suggesting the most proficient ways to solve the matter, which were considered by non-Spartan personnel as suicide.

What affected John the most were the deaths of people under his command; John considered every Spartan lost during the war as his own mistake, swearing to become stronger the next time. During the Fall of Reach, John lost contact with his Spartans, however, he was sure that some of them survived the glassing and was determined to save as many as he could. More than once John took command of mixed units or squads consisting of Marines. He was capable to organize them to act as a Spartan fireteam, achieving despite almost impossible odds. On Requiem, during the initial engagements between UNSC and Promethean forces, John assumed tactical command of Infinity ' s ground forces including Spartan-IVs, despite being outranked by many of them. Upon his return to Blue Team, Fred-104 ceded command to John despite outranking him. Blue Team also willingly followed John when he chose to go AWOL.

Reputation
"Folks need heroes, Chief, to give 'em hope, so smile would ya, while we still got something to smile about!"

- Avery Johnson to John upon entering Cairo Station's bridge for receiving badges.

After the end of Human-Covenant War, John became an icon as a soldier who had played a pivotal role in ending the decades-long war and in doing seemingly gave his life. He was lauded as representing the ideal of a human soldier by UNSC propaganda, a view embraced by many among the general population. Considering John his personal hero, journalist Benjamin Giraud attempted to find out about his background and personal history. When John was declared dead, on many human worlds statues were built in his honor. Private companies started selling action figures in John's likeness; Gabriel Thorne's grandmother bought one after he was recruited into the SPARTAN-IV program. During his military career John served as a source of inspiration and morale booster for others whenever he was on a battlefield. Chief's determination and selflessness made Thomas Lasky, then a young, doubtful cadet, dedicate his life to military service, eventually reaching the position of commanding officer of the most advanced human ship. With the development of SPARTAN-IV program many soldiers enlisted with Spartans to be like the legendary "Master Chief". Such as Gabriel Thorne, who enlisted believing the Spartans were special, and that had he been one, he could have saved his family in New Phoenix. Years later, when the UNSC discovered that the Chief actually survived and managed to prevent the Didact from enslaving the entire human race, they decided to cover it up as a Covenant remnant attack which was successfully fended off via perfectly timed return of the UNSC's greatest hero, thus again underlining the Spartan's supposed invulnerability. However, when Chief decided to go AWOL the UNSC declared him KIA during Battle of Meridian in order to hide his status and preserve his reputation.

Because of his reputation and experience, John's de facto authority far surpasses his nominal rank, and UNSC personnel of all levels are known to defer to his experience and charisma. When Lord Hood offered John a commission, even suggesting he could be conferred the rank of admiral, the Master Chief jokingly replied, "'The Admiral' doesn't have quite the same ring to it". At the time of his going AWOL in October 2558, Spartan Sarah Palmer implied that John and Blue Team had been operating essentially independently for some time, commenting that "He does what he wants". When the Master Chief chose to defy orders to go after the Didact, Lasky and Palmer visibly made no effort to arrest him as ordered by Captain Del Rio and Lasky defied orders to help the Master Chief directly as he trusted him enough to not take the risk the Master Chief was wrong.

In the eyes of the Covenant, John-117 was branded as The Demon and was considered the main nemesis of the entire Covenant, with most of the Covenant fearful of his presence. Thel 'Vadam stated that the personal title emblazoned on John-117 was an insult, but also held a modicum of respect. The Covenant respected him in terms of his strength and how he was able to defeat thousands of Covenant troops effortlessly, with even Thel 'Vadam at the time unable to stop him from destroying Installation 04. Despite the Covenant's dissolution following the Prophet of Truth's death, John-117's nickname as a demon remains in use by many former members of the Covenant.

On March 3, 2553, Lord Hood commissioned a memorial near Mount Kilimanjaro in Africa in honor of UNSC service members lost during the war. The ceremony was attended by John's closest folks - Dr. Catherine Halsey, SCPO Franklin Mendez and his comrades - Frederic-104, Kelly-087 and Linda-058, as well as by Naomi-010 and Serin Osman, formerly known as Serin-019. John's Spartan tag was carved onto the memorial by an unknown party and was accompanied by the improper insignia of the Master Chief Petty Officer of the Navy.

In 2590, there was a ceremony for John-117 at an unspecified location near the areas of fighting during the Battle for Earth. However, his coffin is empty. In 2607, the John-117 Monument began construction to commemorate the Spartan's service to mankind. In 2610, when the documentary Believe was being filmed, it had been over fifty years since the end of the Great War.

Relationships
"The thing about John is that he only really knew three ways to react to people. If you were his superior officer, he obeyed you. If you were in his squad, he would die for you. But if you were a threat, then God help you."

- Samuel-034 about John's behavior. John does not open easily to strangers, and has notably shown an aversion to taking his helmet off in the presence of others unless necessary. Friendships are made for life, however—once given, his trust is forever. Like most Spartan-IIs, he thinks of Doctor Catherine Halsey as a nearly mother-like figure, and holds a deep personal respect for his trainer and mentor SCPO Franklin Mendez. His fellow Spartan-IIs, Cortana, Dr. Halsey, and SCPO Mendez, being the only family he really ever had, assume a larger-than-life importance for John-117.

John formed close friendships with the other Spartans he grew up with since his childhood, most notably Samuel-034 and Kelly-087, his first friends within the group. While still feeling the loss of comrades deeply, he has grown more accustomed to combat than most soldiers. Nevertheless, he was deeply affected by the deaths of each of the Spartans, particularly Sam. He was also saddened by Linda-058's apparent death aboard Gamma Station and was greatly relieved after Dr. Halsey successfully resuscitated her. However, having accepted the responsibility of command for the Spartan-IIs, he has come to maintain a certain professional distance to his comrades and mostly keeps his feelings to himself to maintain his authority.

Physical characteristics
"He’s so serious. Thoughtful eyes, though. Attractive in a primitive animal sort of way, don’t you think, Doctor?"

- Cortana comments upon a photograph of John to Catherine Halsey after seeing him for the first time in it. John has pale blue eyes and reddish-brown hair. As a six-year-old child, John bore a few freckles on his cheeks and had a noticeable gap between his two front teeth. His hair, when it was long enough, was untidy. John was larger than most children his age even as a kindergartner. The Spartan-II program molded his body into something formidable even prior to the extensive augmentations he underwent in 2525, but even afterward his smooth skin, clear eyes, and thin eyebrows set in an oval face still betrayed his age. As a teenager his youthful face tended to undermine the confidence of seasoned commanders he interacted with. By the age of fourteen, he already had the body, however, of an extremely athletic adult. The catalytic thyroid implant he received at that age boosted the growth of his skeleton and muscles via a growth hormone, and a series of intramuscular injections with a specific complex of proteins boosted the density of his musculature. As a result he suddenly stood over two meters tall and just over a year later weighed almost one-hundred and thirty kilograms at Earth-standard gravity. John eventually grew to six feet and ten inches and massed at precisely one-hundred and thirty kilograms (286.6 pounds). The augmentation process also left his hands, arms, chest, shoulders, back, and legs deeply scarred by lengthy incisions, in addition to accentuating his eye color. John has earned additional scars in battle which cover his body, including one that runs across his cheek beneath his left eye. In addition, by August of 2552 his head also showed evidence of three large subdural hematomas. Biological and cybernetic augmentations, coupled with decades of fighting from within Mjolnir powered assault armor, has ensured that John's skin is unnaturally pale. He keeps his hair worn short. His face boasts serious but thoughtful eyes, a firm mouth, a strong jaw, and the last remnants of his childhood freckles. As is common among the men and women of the UNSC Armed Forces, the base of John's skull displays a prominent neural interface. His genome is a hybridization of original and added sequences. Additionally, a geas which affords him an immunity to the Composer, among other gifts, was unlocked by the Librarian's essence on Requiem in July 2557. Cortana and Catherine Halsey both consider him somewhat attractive in a "primitive animal sort of way". As of 2561, John is around fifty years old. Crow's feet and other wrinkles are plainly visible on his face, giving him the visage of a relatively older man. John's age does not comport entirely with his physical body, as he has spent a not insignificant portion of his life in cryostasis, during which the aging process is nearly halted. The longest stretch of time John was frozen for was four years, seven months, and ten days while he and Cortana were stranded aboard the aft section of the. It is thought among medical specialists that Spartans may be able to outlive most other humans, though this hypothesis has not yet had the chance to be tested.

Armor
As a Spartan-II trainee, one of the first suits of armor John was introduced to was a type of form-fitting, lightweight polymer black body suit. This suit could deflect small-caliber rounds and was equipped with a refrigeration and heating unit that could mask infrared signatures. The integrated helmet had encryption and communications gear, a heads-up display, and thermal and motion detectors. John could also activate headlamps on the helmet and attach a fiber optic probe to it. Sealed tight, the entire unit had a fifteen-minute reserve of oxygen to let John survive in vacuum. Though still a little bulky if trying to hide it beneath clothing, the armor's tightness made it uncomfortable and limited his range of motion. Additionally, it also often needed repairs but was difficult to repair in the field. John used one of these suits during training and also during Operation: TALON, the first real mission given to the Spartans. During the op, he was shot in the side at three points by an HMG-38 rifle. One of the bullets managed to penetrate the suit.

Throughout his career, John has shown a preference for the standard-issue set of the given Mjolnir armor generation used at the time. His Mjolnir armor is invariably colored olive green with a gold visor, which has made his appearance iconic among humans and Covenant alike. At some point during his four-year cryosleep aboard the Forward Unto Dawn, Cortana used nanomachines to repair and physically alter John's MJOLNIR Mark VI armor. Cortana also rewrote the suit's firmware, altering the HUD as well as improving the suit's shield-recharge rate and its compatibility with Covenant and Forerunner armor plugins. His upgraded suit displays the Braille characters "117" on the left of the breastplate.

Immediately after the Mission to Installation 03, John received an upgrade for his Mark VI armor from ONI's Watershed Division, bringing it into the GEN2 line of Mjolnir PAA. The armor still looks like his updated GEN1 Mark VI, the most prominent difference being a redesigned bodysuit. His armor also now lacks the prominent gash on the chestplate and his helmet is intact again after the Didact severely damaged it during Blue Team's battle against him on Installation 03. His visor was once again cracked by Spartan Jameson Locke on Meridian.

John's old Mark IV helmet is used as the "last thing" that SPARTAN-IV candidates see before beginning their evaluation and preliminary augmentation cycle.

MJOLNIR Powered Armor Systems

 * Mark IV [GEN1]
 * Unidentified Mark IV Variant [GEN1]
 * Mark V [GEN1]
 * Mark VI [GEN1]
 * Mark VI [Upgraded]
 * Mark VI [GEN2]
 * Mark VII [GEN3]

Weapons
John has demonstrated easy familiarity with various weapons, though unless a mission specifically requires something, has shown a preference for the MA5 series of assault rifles as his mainstay.

Behind the scenes
On July 21, 1999 Bungie Software and Steve Jobs announced the video game Halo at Macworld. This announcement was accompanied by a screenshot which showed a very early version of the player character, a soldier in green armor resembling that which would eventually be worn by the Master Chief when Halo: Combat Evolved released over two years later. By November of that year, it was reported in Computer Gaming World that much of the game's story had yet to be realized. At this time and about a month earlier in a PC Gamer article, the armor-clad individual controlled by the player was referred to variously as a "standard soldier" or "marine". In the PC Gamer article, the game was also described as one in which players would be able to control a powered-armored human soldier or one of the Covenant enemies. Screenshots showed multiples of the armored soldier that would eventually become John-117 existing in the game world simultaneously.

John-117 was originally named by Eric Trautmann as a reference to the biblical verse Revelation 1:17, which reads as follows according to the New Revised Standard Version of the text: "When I saw him, I fell at his feet as though dead. But he placed his right hand on me, saying, 'Do not be afraid; I am the first and the last'." The author of this biblical text names himself "John" within it. According to Trautmann, this identifier was a the origin of one of many "huge fights" between himself and Bungie concerning ideas which came out of the writing sessions of the Halo Story Bible, a work originally constructed by he, Brannon Boren, and Matt Soell.

Production notes

 * John is the protagonist and main playable character throughout the core of the Halo series. He is voiced by Steve Downes in the original trilogy, the Reclaimer Saga, Halo: Reach's Firefight mode, the audio version of "Palace Hotel" and Super Bomberman R as Master Chief Bomber. In the Halo Legends shorts "The Package" and "Odd One Out", John is voiced by David Wald. In Halo 4: Forward Unto Dawn, he is physically portrayed by Daniel Cudmore, who is known for portraying the mutant Colossus in the X-Men film series, while provides his voice. Bruce Thomas provided John's motion capture performance in Halo 4 and apparently served as the model for his face in the game's Legendary ending. Pablo Schreiber will portray John in Halo: The Television Series.
 * John appears as an Easter egg in Halo: Reach, asleep inside a cryo pod in the Pillar of Autumn's hangar.
 * Late in the development of Halo: Combat Evolved, (when the game was known simply as Halo) Microsoft urged Bungie to change the main character's title from "the Master Chief" to "the Commando", as they felt that it better suited the tone of the game.
 * In Halo 5: Guardians, John-117's character-specific base attributes are increased melee damage and faster shield and health regeneration rates. His default weapons loadout includes an MA5D assault rifle, an M6H2 magnum, and two fragmentation grenades.

Trivia

 * A tower in the shape of John's helmet can be found on Mars in Bungie's Destiny.
 * Fable II makes a reference to the Master Chief with a character of legend named "Hal", also called the Minstrel Chief. The armor featured (clearly inspired by Halo's MJOLNIR Powered Assault Armor) is known as "Hal's Armor". A sword resembling the Energy Sword is also featured in the game, known as "Hal's Sword". In addition, with the Special Edition, the player can obtain the title "Master Chief" for their hero for free from any title vendor.
 * A wax sculpture of the Master Chief is on display at Madame Tussauds in Los Angeles and Amsterdam. He is the first video game character to receive a Madame Tussaud's wax sculpture.
 * John's surname is consistently unknown. However, because his redacted name in the Eridanus II census record takes up less space than the surnames of Rolla Hedegaard and Hirayama Tatsuyuki, it can be determined that his surname is less than nine letters long.
 * As seen in the books, John's rise through the ranks is a fast one: at the age of seven in 2519, he achieved the rank of Squad Leader for his leadership of the Spartans during a training exercise. In September of 2525, when he was fourteen, he was promoted to Petty Officer Third Class before the mission to Eridanus Secundus. In November, he was promoted to Petty Officer Second Class when his training was complete. By April of the next year, John was a Petty Officer First Class during Operation: SILENT STORM when he received a three-rank promotion to Master Chief Petty Officer by Colonel Marmon Crowther. He was also only fifteen at the time he received that promotion.
 * Master Chief appeared in Konami's Super Bomberman R as one of the three exclusive characters in the Xbox One version. He is known as Master Chief Bomber, a SPARTAN-II supersoldier from Planet Halo. He is a speed typed bomber and his special ability is the Spartan Shot.