The Hero's Journey: the Chief

The Hero's Journey Pt. 2

Now this is a story all about how
My life got flipped, turned upside down
And I'd like to take a minute, just sit down Montana
I'll tell you how I became the Chief of Cortana.

The Call to Adventure
At the ripe young age of six, Master Chief had qualities that were designated as "ideal" for a super soldier, one who would be an unstoppable killing machine. In other words, a Spartan. However, due to the often unethical treatment and harsh environments that the trainees went through (with a casualty ratio of over 50%) and in order to maintain secrecy, these kids designated as "ideal" would be stolen from their parents with a clone taking over as them and quickly dying of natural causes.
Refusing the Call
As you can imagine, John did not take too kindly to being kidnapped for a Spartan project. It took many men to subdue him, with many broken hands and fingers sustained in the process.
Supernatural Aid
After years of training and physical and mental enhancements, Master Petty Officer John-117 completed over two hundred missions, most notably combating an alien race known as the Covenant. However, with the Covenant slowly and surely wiping out each human colony one-by-one and then glassing them, the UNSC (United Nations Space Command) designated John-117 with an intelligent AI, one who could assist him no matter the circumstances, Cortana. He also soon adopted a new moniker: Master Chief.
The Crossing of the First Threshold
Trying to escape the Covenant fleet, the ship The Pillar of Autumn and its escape pods crash land on a mysterious planet as "Halo". There Master Chief explores the planet, and discovers that it is really not a planet, but a device created by an ancient alien race known as the Forerunners to wipe out all sentient life in the galaxy as a last-ditch effort to prevent another alien race known simply as "the Flood" from consuming all life in the galaxy.
The Road of Trials
In Halo: Combat Evolved, the alien race known as the Flood have been released on the planet Halo. Knowing that destroying Halo is the only way of stopping them, but that detonating Halo would also wipe out all sentient life in the galaxy, Master Chief and Cortana decide to blow up The Pillar of Autumn, as the blast would destroy Halo but also prevent it from detonating completely. Along the way, they fight against continual Covenant and Flood troops before they are able to detonate The Pillar of Autumn while also escaping a safe distance from the blast radius. In Halo 2, Master Chief is assigned to help fight back against a Covenant invasion of Earth, and in the process discovers that there are actually nine "Halo" rings, and they can all be remotely activated on an ancient Forerunner structure known as "the Ark". In Halo 3, Master Chief follows a Covenant force to "the Ark", and discovers that a new Halo ring is being built to replace the one destroyed in Combat Evolved. Master Chief is able to stop the Covenant from activating the Ark completely. Instead, John-117 has the Ark detonate both itself and the new Halo ring, thereby preventing all Flood from infecting the galaxy while also saving the galaxy from certain annihilation. However, as he is trying to escape, the force of the detonation disrupts the ship from slip-space travel, meaning Master Chief is stuck with half a ship as it slowly floats towards a distant planet.
The Ultimate Boon
Master Chief is able to stop the Covenant from invading Earth and is also able to stop the Flood from infecting the entire galaxy. He also prevented the entire galaxy of being wiped out by activation of the Halo rings.  In his own words, he "finished the fight."