Find Out Everything You Need to Know About the Halo Universe

Nine games, eighteen novels, two miniseries, short stories, comic books, and an anime series make up the Halo universe. It's daunting to try to keep track of all the different story elements that go into each Halo game. As a quick glimpse of the expanded Halo universe, we've put together a short look at some of the most important characters and events to help prepare you for the release of Halo 5: Guardians on October 27. There will be spoilers discussed throughout this gallery, so proceed accordingly.

Master Chief Petty Officer John-117, or The Master Chief

He's the main character of the Halo series, and one of the most iconic video game heroes of all time. The Spartan-II super solider was taken from his home at six years old and trained to fight human rebels. At age 14, he was physically enhanced to be stronger, tougher, quicker, and smarter. Among his group of Spartans, he was the leader. Following the fall of the planet Reach, Master Chief was pivotal in taking down the Covenant army and saving Earth from the Flood.

Cortana

Cortana is an artificial intelligence entity based on the brain of Dr. Catherine Halsey, the founder of the Spartan program. Cortana was taken off Reach by Noble Squad, and then accompanied Master Chief throughout the events of the four numbered Halo games. She was instrumental in the destruction of the Didact in Halo 4, helping to keep the Promethean attack at bay and ultimately blowing up the Didact's ship and herself.

Thel 'Vadam, or The Arbiter

As the leader of the Elites (aka Sangheili), the Arbiter was a crucial ally to John in achieving victory over the Covenant and the Flood. During the events of Halo: Combat Evolved, 'Vadam tried and failed to stop John from destroying Installation 04, one of the Halo rings. This caused the Covenant to strip him of his position and bestow upon him the indignity of the Arbiter rank, a designation meant to mark an Elite as a failure. The Arbiter then discovered that the Halo rings were actually weapons meant to wipe out all organic life in the galaxy, and this revelation caused him to split from the Covenant and join forces with the humans.

The Covenant

This union of alien forces was composed of Elites, Brutes, Jackals, Grunts, Hunters, and Prophets. The Prophets led while the Elites had control over the military, a division resulting from a past war between the two races. The Covenant was based on a religious belief that Forerunners were gods, and that to activate the Halo array would begin a "Great Journey" of divine salvation. The war with humans began because the Covenant wanted to gain control of Forerunner artifacts on human worlds.

The Flood

Nothing inspires fear in the Halo universe quite like the Flood. This parasitic enemy takes control of corpses, reanimates them, and uses them to swarm over its prey. Although unintelligent normally, the Flood can amass bodies and minerals to create a sentient, self-aware organism known as the Gravemind. After the creation of the Gravemind, the Flood becomes incredibly dangerous and capable of using advanced technology. The parasite reached Earth during the events of Halo 3, but ultimately it was beaten back and completely wiped out by Elite strikes on Earth and Master Chief's destruction of the Ark, the construction point of the Halo Array.

Halo Array

The Forerunners built the Halo rings as a last-ditch weapon to fight against the Flood. They have immense power, capable of destroying all sentient life in the galaxy if activated. Since the Flood needs to consume sentient organisms to survive, an activation of the Halo Array would effectively starve the parasite. The rings have only been used once in their entirety, when the Forerunners used them to drive the Flood nearly extinct. During Halo: CE, Master Chief destroyed Installation 04, which triggered the Ark construct to automatically begin building a replacement. In Halo 3, he blew up the replacement ring at the Ark.

Forerunners

Over a hundred thousand years before the events of the Halo games, the super-intelligent species known as the Forerunners lived and built a civilization. Forerunner society stretched across the Milky Way, and their structures and machines still are found throughout the galaxy. They were able to access a mental Internet of sorts, called the Domain, that connected the Forerunners to a massive store of information. They, along with the Domain, were destroyed after the Forerunners activated the Halo Array to combat the first infestation of the Flood. The Halo ring custodial AI known as "monitors," like 343 Guilty Spark, are also products of Forerunner technology.

The Didact

The highest commander of the Forerunner warrior class, the Didact fought against the humans in the Human-Forerunner War and also struggled against the Flood during the first infestation. There were actually two Didacts with the same personality and memories; the Iso-Didact led the charge against the Flood and died when the Halo rings were fired, and the Ur-Didact fought in the Human-Forerunner War and then was imprisoned in hibernation in a chamber for the next 100,000 years. Ultimately during the events of Halo 4, Master Chief was tricked into releasing the Ur-Didact, who had been corrupted by a Gravemind during the first Flood infestation. The Ur-Didact attempted to wipe out the entire human race, as he was warped by the Gravemind into believing that humans would usurp Forerunners and bring about the Flood's victory.

The Librarian

The Librarian was the Didact's wife and one of the most important Forerunners. She was responsible for cataloguing and preserving every life form possible before the activation of the Halo Array. These species were kept on the Ark, one of the only places in the galaxy protected from the blast of the rings. The Librarian also had the power to imprint commands on the minds of organisms, affecting seemingly millions of humans from birth and giving them certain boosts to awareness or environmental knowledge. She gave one of these imprints to Master Chief, granting him immunity from the Didact's Composer weapon.

Prometheans

These robotic life forms based on the essences of other organisms make up the Ur-Didact's personal army. Using the Composer, the Ur-Didact could effectively digitize people and upload their sentience and autonomy into robotic frames. Although the Composer was originally only used on willing Forerunners to make them immune to the Flood, the Ur-Didact began digitizing innocent humans as his forces grew smaller. Prometheans will feature prominently in Halo 5: Guardians.

Great Schism

During the events of Halo 2, it became clear to the Arbiter that there was no "Great Journey" linked to the Halo rings and instead the Array was designed to wipe out all life in the galaxy. Discovering this lie perpetuated by the Covenant leadership, the Arbiter and most of the Elites broke away from the Covenant and joined forces with the humans. Brutes took over as leaders of the Covenant army.

Covenant Remnant

After the end of the Human-Covenant War and the events of Halo 3, the Covenant was dissolved and the surviving aliens went back to their home planets. A radical faction of Elites, however, still believing in the divinity of the Forerunners and the Great Journey, came together to form the Covenant Remnant. It is led by the Elite Jul 'Mdama. This sect fought against the Arbiter's government on the Elite home planet and ultimately sided with the Ur-Didact as Master Chief attempted to stop him. The Covenant Remnant will likely appear as an enemy force in Halo 5: Guardians.

The Spartan Program

The legendary training program that created the Spartan super soldiers has been through four iterations. The first, Spartan-I, was costly and ineffective, used more as an experiment in bioengineering than an actual military force. Spartan-IIs are the most effective. These soldiers were taken from their homes as six-year-olds, trained from childhood, and augmented at puberty to grow faster and stronger than normal humans. Master Chief is one of these Spartans. Spartan-IIIs were cheaper and less deadly than Spartan-IIs. They were deployed on Reach during the Covenant invasion. Noble Team, the squad of Spartans followed during Halo: Reach, are Spartan-IIIs. The Spartan-IV force is composed of willing adults who undertake biological enhancements; this program began after the events of Halo 3. Agent Locke and Sarah Palmer are both Spartan-IVs.

Agent Locke

First seen during the Halo: Nightfall miniseries, Jameson Locke is an agent with the Office of Naval Intelligence who is tasked with bringing Master Chief in after the soldier disappears. He was part of the team that investigated the Alpha Shard of Installation 04, the Halo ring destroyed during Halo: CE. He is a playable character in Halo 5: Guardians.

Blue Team

Blue Team was one of the only contingents of Spartan-IIs still active during the events of the first three Halo games. Composed of Fred-104, Kelly-087, and Linda-058, Blue Team will fight alongside Master Chief during Halo 5: Guardians. After several fights against the Covenant Remnant, Blue Team was considered AWOL by the Office of Naval Intelligence, and Locke was sent to bring them in.

ONI

As the top-secret branch of the human government and military, the Office of Naval Intelligence has virtually unlimited funds to use for the purpose of one goal: protect Earth at any cost. From ONI came the Spartan Program, artificial intelligences such as Cortana, and the massive warship, the UNSC Infinity. ONI's methods have been controversial, especially the abductions of children used to build the Spartan-IIs and its role in stimulating the creation of the Covenant Remnant.

Precursors

This mysterious species lived before the Forerunners and achieved the greatest technological understanding of any species ever in the galaxy. They eventually succeeded in both intergalactic travel and the creation of new life. The Precursors brought Forerunners and humans into being, although the Forerunners eventually fought a war with their creators that consequently drove Precursors extinct. The Flood exists as the only direct relic of the Precursors; during the Forerunner-Precursor war, the Precursors were warped and mutated into Graveminds.

Halo: Reach

The events of Halo: Reach are chronologically the first in the series. After attacking humans on the planet Harvest, the Covenant traveled to Reach, one of the most important human colonies besides Earth. On Reach, Noble Team, a squad of Spartan-IIIs, were tasked with holding off the Covenant as long as possible and allowing important information to escape. They also helped evacuate a city and were responsible for getting Cortana off of the planet and into the ship Pillar of Autumn, where she was given to Master Chief to use. Only Noble Three, known as Jun-A266, survived the battles on Reach.

Halo: Combat Evolved

Following the fall of Reach, the Pillar of Autumn went through a Covenant slipspace portal and ended up near a Halo ring, Installation 04. Knowing that the Covenant wanted something with this ring, the human leadership sent Master Chief and a contingent of marines under command of Sergeant Johnson to investigate. During the ensuing clash, the Covenant accidentally released the Flood upon the ring world. The parasite multiplied quickly and the monitor 343 Guilty Spark attempted to get Master Chief to activate the ring, but Cortana stopped him. Instead, John destroyed the ring by blowing up the Pillar of Autumn.

Halo 2

After the destruction of Installation 04, the Covenant blamed Thel 'Vadam and made him the Arbiter. Meanwhile, John returned to Earth followed closely by the Covenant. The aliens launched an assault on Earth, and Master Chief helped beat it back. The Covenant soon located another ring and dispatched the Arbiter to try and activate it. John, who was in a ship pursuing the Covenant fleet, also went down onto the Halo to attempt to stop its activation. Both the Arbiter and Master Chief ended up in the clutches of a Gravemind after fighting the Flood which had been released on the ring. Together with the Gravemind, Master Chief convinced the Arbiter that the rings were weapons meant to destroy life. The Arbiter and Master Chief then departed, with John going onto the Covenant ship High Charity while the Arbiter fought against Covenant forces on the ring. They stopped the ring from being fired, but High Charity was overrun with Flood and Cortana was left behind on the ship.

Halo 3: ODST

Between the events of Halo 2 and Halo 3, a contingent of elite soldiers called Orbital Drop Shock Troopers were deployed on Earth to combat the Covenant assaulting there. The squad became scattered around the city of New Mombasa following a slipspace rupture which knocked their descent to Earth off course. Rookie, the main character, then explored the city, eventually reuniting with his squad. While looking for information on the Covenant presence in New Mombasa, the group stumbled across an Engineer, an organic Forerunner creature, which had massive stores of information on the Covenant's activities. The group escorted the creature back to a human ship, where it provided information about the aliens to the human leadership.

Halo 3

Coming back from his battle with the Flood on High Charity, Master Chief dropped onto Earth where Sergeant Johnson and the Arbiter were preparing for extraction from Covenant-held positions. Master Chief then fought against the Covenant for control over a Forerunner artifact which was believed to be the Ark, capable of activating the Halo Array. The Covenant fleet escaped Earth through a portal, while a ship overrun with Flood crashed into Earth. Along with Master Chief, the Elites allied with the Arbiter held off the Flood. John then left through the portal and ended up on the real Ark, where the Covenant were attempting to activate the rings.

Halo 3 (cont.)

John and the Arbiter assaulted the Covenant positions and ended up fighting alongside the Flood as the Covenant managed to activate the Halo Array using an abducted Johnson, who was one of a certain group of humans who could activate the rings. After deactivating the array, John traveled to High Charity to destroy the Gravemind inside it, as well as to rescue Cortana who was left on the ship during Halo 2. Succeeding, John traveled back to the Ark, uploaded Cortana into the structure, and activated the ring being built there in order to finally kill off the Flood. He and the Arbiter escaped via the UNSC Forward Unto Dawn, but the slipspace portal they escaped through split the ship in half. The Arbiter made it to Earth, while Master Chief and Cortana drifted through space toward a planet called Requiem.

Halo 4

Three years after Halo 3, Master Chief and Cortana arrived near the Forerunner Shield World Requiem in the broken remnants of Forward Unto Dawn. Cortana woke John from cryostasis and the two fought through Covenant Remnant forces who had landed on the ship. After the fight, the ship crash-landed on Requiem and Master Chief set off to find a way off the planet. He and Cortana then discovered the Ur-Didact, contained within his suspended-animation shell called a Cryptum. After tricking John into releasing him from the Cryptum, the Ur-Didact overwhelmed Master Chief as the Covenant forces swore allegiance to him.

Halo 4 (Cont.)

John attempted to get in contact with human forces nearing Requiem, but the UNSC Infinity crashed into the planet, forcing Master Chief to go attempt to rescue them from the Promethean forces closing on their position. Using the Composer device, the Ur-Didact attempted to eliminate humanity and upload them into Prometheans, but Master Chief fought onto his ship. While Cortana attacked the Didact's defenses and contained him in hard light constraints, John attacked him and forced him into a slipspace rupture. Cortana blew up the Didact's ship, then spoke with John for the last time before ceasing to exist.

Halo 5: What We Know

There are still a lot of mysteries surrounding Halo 5's story, but we do know that it will focus on the conflict between Master Chief and Agent Locke. Both will be playable, and both will have squads of Spartans accompanying them. Locke is pursuing Master Chief because of his suspected role in an assassination of a human ambassador to the Elite home planet, although this attack was actually carried out by a human splinter group called Sapien Sunrise.

Halo 5: What We Know (Cont.)

We also know that Halo 5 will feature new, massive enemies called Guardians. These Forerunner AI machines seem to have awoken due to the events of the Human-Covenant War, the elimination of the Flood, and the defeat of the Ur-Didact. Additionally, while Master Chief tries to make sense of these new Forerunner enemies, it appears that the Arbiter and his loyal Elites fight a civil war against the Covenant Remnant.