Master Chief Petty Officer John-117, more commonly known as the Master Chief, is a SPARTAN-II commando of the UNSC Special Warfare Command. He is the main protagonist and the main character in Halo SPV3.

Overview & Background


John was born in 2511 and lived with his mother and father in Elysium city on the colony world of Eridanus II.

Dr. Catherine Halsey identified John as an ideal physical and mental candidate for the 150-strong preliminary pool of the SPARTAN-II Program when he was six: he stood a head taller than the majority of his schoolmates, had greater physical proportions, and possessed greater strength, superior reflexes, and an aggressive drive for success. When Dr. Halsey and Lieutenant Jacob Keyes visited Eridanus II in 2517 to study him, they were impressed with his intellect and luck.

At the age of fourteen, John underwent the dangerous SPARTAN-II augmentation procedures. These procedures killed 30 and physically disabled 12 of the Spartan trainees. John was one of 33 Spartans who survived the process unscathed, while the rest who could still operate were moved to positions in the Office of Naval Intelligence. At only fourteen years old, John was said to have the body of an eighteen-year old Olympic athlete; the augmentation process hastened their reflexes, increased their strength, enhanced their eyesight, and rendered their bones nearly unbreakable.

In 2525, John would later find the Covenant, resulting in losing his best friend Sam in the process. Sam's death would remind John that the Covenant can be defeated but at the cost of many lives.

In the year of 2552, John-117 meets his brand new Artificial Intelligence, Cortana, who was created by none other than Dr. Catherine Halsey. During the Fall of Reach, John-117 fought along side Blue Team for the last time with James-005 and Linda-058. James was later lost in space while Linda was critically wounded. John had rescued 4 marines, in which one of them was Staff Sergeant Avery Johnson, leading them to the Pillar of Autumn.

Eventually, the Pillar of Autumn would make a blind jump towards slipspace and arrives at the ring world known as Installation 04. John-117 is later awakened from cryo-sleep, and is ordered by Captain Jacob Keyes to head towards the ship's bridge. Due to the Pillar of Autumn taking more damage from nearby Covenant ships, John-117's next objective is to protect Cortana from the enemy and escape on a Bumblebee pod. After landing on the captivating ring world known as Halo. After reuniting with several marines who are being attacked by Covenant infantry, Cortana manages to decrypt Covenant Data, uncovering the capture of Keyes, who was being held prisoner on the Covenant Cruiser, the Truth and Reconciliation. Throughout the rescue on the Covenant ship, Captain Keyes orders John-117 and Cortana to locate the Map Room of Halo. After eliminating many Covenant forces, John-117 reaches the Control Room of Halo; however, upon being inserted, Cortana discovers that there is something horrible buried underneath Halo. Cortana desperately tells the Master Chief to find Captain Jacob Keyes before it is too late.

John-117 is taken to a swamp where Captain Keyes made his last transmission over 12 hours ago. The Spartan notices hoards of Covenant troops running away from an underground facility. Upon reaching the lowest level, John-117 discovers that the Captain's squad has been infected by the Flood, a deadly parasitic foe. John-117 fights his away out of the swamp with Marine survivors and meets 343 Guilty Spark, the monitor of Installation 04. This new "ally" later teleports the Chief towards the Library, a place that contains the key in order to activate Halo, the Index. Returning the Control Room, Cortana tells the Master Chief the truth about Halo. Discovering that ring does not destroy the flood, but its food, which includes the whole galaxy, John-117 refuses to turn on the rings, resulting in 343 Guilty Spark betraying the Spartan. Cortana suggests that the Chief disrupts Halo's pulse generators in case if the Monitor finds another way to activate the rings. In order to destroy Halo, the duo needed to locate Captain Keyes's neural implants to activate the self-destruct codes for the Pillar of Autumn. Returning to the Truth and Reconciliation, John-117 fights through endless hoards of Flood and Covenant forces, but is too late to save Captain Keyes, who has met his demise at the hands of the Flood. After retrieving the neural implants, John-117 escapes on a Banshee and locates the Pillar of Autumn, but is followed by Covenant Special Operations, the Flood, and 343 Guilty Spark's Sentinels. As soon as the two reached the Bridge and activated the countdown, 343 Guilty Spark stops the self-destruct sequence. However, John-117 plans to head towards the Engineering room to damage the Autumn's fusion reactors. After the objective was finished, John-117 manages to locate a Warthog and drives towards Echo-419's evac site. Unfortunately, Echo-419 is shot down by Banshees, forcing the Master Chief to find another escape plan. With no time left at all, John-117 reaches a Longsword in the Hanger Bay, and successfully manages to escape the destruction of Halo. After getting away from the destruction, John-117 asks Cortana if anyone else survive, in which she replied there were only "dust and echoes." When Cortana claimed that it was all over, the Spartan only replies, "No, I think we're just getting started."


Throughout gameplay, John-117 never speaks, until a cutscene is triggered. His personality in the series is not shown, which makes him a blank state character for the player. However, in the novels, his personality is explored deeper.

John-117 was known to be a very determined person at such a young age, he demonstrated complete perseverance and resilience during his training in the SPARTAN-II program. Spartans are known to be fearless from the perspective of others; however, John is not immune to being afraid, but never shows any of it. John-117 strives to protect humanity and the life of his UNSC comrades with such a large amount of courage.

Developer Information



  • In Halo SPV3, his armor resembles more of the Mjolnir Mark IV instead of the Mark V. This is most noticeable through the helmet and shoulder differences.
  • As of SPV3.2, John-117 is no longer the sole playable character. Thel 'Vadamee, the Arbiter from Halo 2, 3 and 5, is the player character in The Commander and The Commander: Evolved, as is May-017 in the Lumoria campaign.
    • John-117 is the only playable character who never speaks during gameplay, only in cutscenes.



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