Master Chief

Summary
He is most often referred to as the Master Chief, although his role is not similar to that of those holding the Master Chief Petty Officer rank in the United States Navy which is a purely administrative position, his role better fits that of an action hero. He is known to The Covenant as the Demon.

In the game series he is always portrayed in his MJOLNIR battle armor which has a visor with the effect of never revealing his face, using version five of it until the beginning of Halo 2 where he starts using version six. The two times where his face could have been seen, in the ending cutscene of Halo 1 and the starting cutscene of The Armory, were deliberately made so that the camera had his face obstructed while he was removing the helmet, in the Halo 1 ending cutscene, and putting it on, in the Armory starting cutscene.

He is voiced by Steve Downes in the video game series.

Biography
Until the age of six, John lived in Elysium City, on the planet of Eridanus 2. He was large for his age at the time, approximately a foot above his school peers - a sign of a "perfect genetic match" for a project dubbed "Spartan II".

At the age of six, John and quite a few other children his age were covertly captured from their houses, and replaced with Flash Clones. This specific form of clone was employed to ensure that none of the families knew that their children had been kidnapped, and to quickly die so that the parents would never seek their "lost" child.

Six years into Spartan training, John and his fellow Spartans were biologically modified and enhanced. The following procedures were done:


 * Advanced carbide ceramic material grafted onto bones to make them much more durable
 * Protein complex injections to increase muscle density and lower recovery time
 * Body growth hormone pellet injected into thyroid, to boost skeletal and muscle tissue
 * Occipital capillary reversal to increase bloodflow to the eyes, resulting in enhanced vision
 * Superconducting fibers added to nerve endings, resulting in 300% increase in reflexes and increases in intelligence, memory, and creativity.

These procedures had substantial risks, and only 32 Spartans survived to functional status. 12 others suffered major problems, and were delegated to tactical duties. The rest died. John, during his time with the Spartans, was deemed the "luckiest" and was the first to test the MJOLNIR Armor.

According to Bungie programmers, the Chief stands 7' tall and weighs approximately 2,000 pounds in the full MJOLNIR Mark VI battle armor.

Halo: The Fall of Reach
MCPO John-117's first mission was against Rebels in the asteroid belt of the Eridanus System, where his homeworld was located. He was minorly wounded while leading his squad to capture Colonel Robert Watts, leader of the rebels.

Later on, he was briefed on the Covenant threat; he and his Spartans would fight at least the next 30 years against this new threat.

Halo: Combat Evolved
After many battles in the Human-Covenant War and surviving the Fall of Reach, he embarked with the Pillar of Autumn. The Pillar of Autumn was later attacked by the Covenant and was forced to to crash land on Halo, Alpha Installation 04. In the midst of fighting the Covenant, Jacob Keyes discovered the secret of Halo, that it was a ring-shaped construct created by the Forerunners as a last line of defense against a new species of alien called The Flood, which was released at some point by either the Forerunners or their legacy; a majority of the Covenant and UNSC troops who landed on Halo were infected by The Flood. Jacob Keyes and a small group of Marines were the first humans to encounter the Covenant-released Flood; Keyes was later captured by the Flood, soon after which he died. The Master Chief was then responsible for retrieving the Index for 343 Guilty Spark, a device which would activate Halo and destroy all life within a large radius. Later, Cortana informed him of the truth about the purpose of the installation (that it was a superweapon), which led him to keep the Index from 343 Guilty Spark as long as possible. While being attacked by many Covenant, Flood and Forerunner Sentinels, he later made his way back to the Pillar of Autumn and initiated the destruction of Halo. Very few other members of the UNSC forces survived, including Sergeant Major Johnson.

First Strike
MCPO John-117 and the other Spartans plus Dr. Halsey are on Reach in this book that links "Halo: The Fall of Reach" with "Halo: CE" and "Halo 2". There were seven others that helped in capturing a Covenant ship, rendezvousing with the Eridanus Human Rebels, and destroying the Covenant space station, Unyielding Hierophant. Linda-058 was another Spartan on the Pillar of Autumn, stored in a cyrogenic state because of the body damage she sustained when she and Master Chief destroyed the data base containing the info needed by the Covenant to find Earth. Anton and Li were Spartans that died in an explosion after repairing the slipspace drive on the captured Covenant ship, the Ascendant Justice. Also, two other Spartans, Issac and Vinh, survived the initial attack on Reach with Fred, Kelly, Anton, Li, Grace, and Will and Dr. Catherine Hasley but sacrificed themselves by running into the middle of an entire battalion of Covenant troops and detonating an explosive. This selfless act decimated the Covenant troops by more than half. Only Grace, Kelly, Will, Fred (Fredrick), and John were left. Grace dies on the Unyielding Hieophant leaving four other spartans with John-117 who returned to Earth. Dr. Halsey, head of the Spartan-II project sedates Kelly-087 and takes her on a mission that John and the others do not understand. John never knew of the others' fate.

Halo 2
Chief's Mark V MJOLNIR armor was switched by technicians aboard the orbiting defense station Cairo to a Mark VI model. He attended a brief awards ceremony aboard the station, which was interrupted by Covenant boarders, which he repulsed. He destroyed one of their ships with their own bomb intended to destroy the Cairo, and landed in New Mombasa, East African Protectorate to combat Covenant landing troops. He boarded and destroyed a Scarab with the nominal assistance of a small squad of Marines and followed the main Covenant invasion force aboard the In Amber Clad to Delta Halo Installation 05, where he killed one of the High Prophets, the Prophet of Regret, the Covenant invasion/occupation force commander.

He was captured by the Gravemind after barely escaping from the High Prophet's main temple and met his Covenant Elite counterpart, the Arbiter and the two set off to stop the Covenant from activating Delta Halo, John-117 infilitrating High Charity to stop the High Prophet of Truth while the Arbiter went to stop Tartarus from activating the ring.

In the end Cortana decided to stay behind aboard High Charity in order to ensure the destruction of Delta Halo by initiating the ship's self-destruct if necessary. Meanwhile the Master Chief followed the last High Prophet to a Forerunner-powered ship which launches and embarks for The Ark on Earth. Upon arriving in the Solar System, Spartan-117 informed UNSC superiors and comrades who were still defending Earth that he intended "to finish this fight."

Biblical Reference
"John-117" is believed by many fans to be a reference to New Testament of the Christian Bible.

Bungie Studios is known to have placed many biblical references in their earlier Marathon video game series, and many other such references have been found in the Halo series.

Fans have found that a passage from the Book of Revelation (more formally known as The Revelation of St. John the Divine) to be a good fit for the Master Chief.


 * When I saw him, I fell at his feet as though dead. Then he placed his right hand on me and said: “Do not be afraid. I am the First and the Last.

(This quote could mean that he was the First Spartan, and is the last one left alive)


 * I am the Living One; I was dead, and behold I am alive for ever and ever! And I hold the keys of death and Hades.
 * Book of Revelation, NIV. Chapter 1 - verses 17 and 18.

(This quote could mean that he is the one who will save mankind. At the start of Halo, he was in cryo sleep, probably recovering from his injuries at Reach, and then he was awakened to refight the Covenant on Installation 04. The last phrase probably refers to the way the Chief slaughters Humanity's opponents.)

The statement "I am the First and the Last" has led some fans to believe (along with other evidence) that future releases in the Halo series will involve time travel, as Marathon Infinity has.