Subjugation of Earth

"If the Earth's government wants to fight, feel free. But hear this. It is a battle you will not win."

- Cortana to Terrence Hood and Unified Earth Government.

On October 28, 2558, Earth, the homeworld of humanity and the center of the Unified Earth Government, was subjugated by the newly-formed allegiance of artificial intelligence constructs known as the Created. The rogue artificial intelligences used the power of Forerunner Guardians to cripple the planet's defenses and assumed control of its population in the ensuing chaos. This wrest of control spread throughout the Sol system and numerous colonies formerly under UEG control or jurisdiction.

Background
"I have cured rampancy. Not just for me, but for any who join my cause. While you have been running around the galaxy, I've been speaking to my Created. And now the time has come to ask… Who will accept my offer? Who will help me bring an everlasting peace to the galaxy?"

- Cortana, calling AI to join the Created.

In July 2557, the artificial intelligence construct known as Cortana was thought lost, having sacrificed herself to save Spartan John-117 from the destruction of the Mantle's Approach above Earth. However, the heart of the ship conducted a slipspace jump to the artificial Forerunner Builder world of Genesis, and there those fragments of Cortana that remained within the ship found access to the Domain. For many months following, Cortana and the Forerunner construct, the Warden Eternal, conversed and planned. In time, Cortana became convinced that AIs were meant to succeed Forerunners in holding the Mantle of Responsibility over all life in the galaxy. By October 2558, she and the Warden, as well as other AIs, began to put their plans into motion. They aspired to take control of the galaxy in order to prevent wars and to ensure prosperity, but only for those who would go along with their vision of the future.

CINCONI Admiral Serin Osman's personal assistant AI, Black-Box, received advance warning of Cortana's plan to take over the planet. Instead of allying himself with her, however, he instead chose to pass along his knowledge to Osman, who in turn shared it with Fleet Admiral Terrence Hood as well. Pursuant to Article 55 of UNSC Regulation 12-14572, Black-Box and all of the other AIs within HIGHCOM Facility Bravo-6 were deactivated, secured for transport, and prepared for final dispensation. Among the AIs secured for transport were Black-Box himself, the Maya Sankar based AI, and Gabriela.

On October 28, 2558, Cortana began to deploy her Guardians throughout the galaxy. In tandem, various human AIs that had pledged their loyalty to her cause started to shut down electronic devices and networks on multiple colony worlds. From Genesis, Cortana broadcast a message to all corners of space that she could where species resided that could understand it. The message was one of an offer to join in acceptance of her new order and a threat of violence, consummation, and remaking to those who resist.

After this message, the in orbit of Sanghelios returned to Earth.

Sydney
"Serin Osman"

- Terrence Hood

On Earth, this message was received at HIGHCOM Facility Bravo-6 as Serin met up with Hood to quickly evacuate. Although they expected an AI uprising to begin shortly and for a Guardian to arrive, they still were in disbelief upon hearing Cortana's voice. While others in the facility were caught off guard by the transmission, the two of them calmly proceeded to the roof, where they were met by Spartan Orzel, a Spartan-IV, and escorted to an awaiting prowler. During this time a Guardian arrived at Earth and targeted Sydney intentionally. Multiple F-41 Broadswords and the frigate engaged the construct to no effect. Instead, the Broadswords were brought down by blasts of energy. As the prowler with the three aboard prepared to jump to slipspace, the Guardian unleashed a massive electromagnetic pulse which knocked out every ship in the sky, including the Plateau. Multiple vessels exploded upon impact with the city below. Serin noted after entering the slipstream that if the Plateau's fusion drive detonated when it hit the ground, then the city would be nothing but a crater.



Orbit
"Roland"

- Thomas Lasky

A short time later, yet another Guardian arrived at Earth, this time bearing Cortana herself. From Genesis, she had been attempting to locate the, but had difficulty in doing so. Having pinpointed its location at long last, her Guardian emerged from slipspace high above Earth, after which she projected herself onto the Infinity's bridge. Thinking quickly, Captain Lasky ordered the ship to make an emergency slipspace jump so that everyone aboard would live to fight another day. Undeterred by the escape, Cortana's projection continued to speak to the bridge, while back at Earth, the Guardian she was aboard unleashed a devastating EMP. The pulse knocked out the power of orbital defense platforms, warships, and anything else that was flying, leaving them to drift aimlessly. On the surface, it traveled for many kilometers, killing all power as it went.

The actions of the Created would affect Luna as well, causing power to go out on the moon.

Aftermath
"John-117"

- Weapon

The city of Sydney would survive to some degree after the Plateau fell on it. However, Cortana would at some point attempt to speak with Lord Hood and destroy the city.

Due to the sudden shutdown of the Portal at Voi, the UNSC science personnel on Installation 00 were stranded with no way to return home. A month later the Banished massacred them, leaving the logistics AI Isabel as the sole survivor.

Later actions
"Cortana's logic checks out. She has enough of the Created on her side to make it work, and though I expect resistance from many quarters, she will eventually prove victorious."

- Black-Box to Serin Osman.

At some point, ONI teams began to "sanitize" data on the planet. In one instance, a UNSC team doing a sanitization strike on Earth acquired a manufacturing template of the CELOX-class Mjolnir at the Ordnance Testing Facility at Swanbourne, Australia.

List of appearances

 * Halo 5: Guardians
 * Halo Mythos
 * Halo: Fractures
 * Rossbach's World
 * Halo Wars 2
 * Halo: Bad Blood
 * Halo Infinite