Mars

"The wind wiped away our footprints. When the storm had passed, we found something shining beneath the sand..."

- Grimoire description

Mars is the fourth planet in the Sol System, and the third largest terrestrial planet. Since the Collapse, much of Mars has returned to the desolation that came before the Traveler. Like the rest of the planets in the system, the red planet is littered with ruins from the Golden Age. It is home to Rasputin. It is also a living consciousness, and one of the Nine. Mars was one of four destinations that was Taken by the Witness at the end of Season of Arrivals. However, it mysteriously returned in The Witch Queen.

Overview
A harsh and deadly environment, Mars is now a desert world frequently plagued by dust storms. The Cabal forces have a presence on the planet in the form of their Exclusion Zone, as do the Vex, who are at odds with the Cabal. An indelible sign of the Cabal presence on Mars is the moon of Phobos, which has had its orbit dramatically altered by Cabal planetary engineering; it now fills a significant part of the sky. Even more disturbing is the discovery of large "planet-cracking" munitions among the Cabal's already devastating arms. There is some degree of conflict as humanity tries to reclaim its former glory.

The Ancient Past
Long before the evolution of humanity, Mars and the other planets of the Sol System served as gravitational foci for interstellar streams of dark matter particles. When life evolved elsewhere in the System, the movements of lifeforms created perturbations in these looping streams, which caused the dark matter loops to "awaken" into consciousness. These nascent consciousnesses would one day become known to Humanity as the Nine.

Golden Age
With the coming of the Traveler, rain washed over Mars, and it was here that humans first encountered the spherical entity. Once, populating Mars had been nothing more than a dream for humanity, but after its terraforming, a thriving metropolis named Freehold came to dominate the skyline - a bastion of human life in the red dunes. The Clovis Bray corporation had a major presence in Freehold, in addition to setting up their own private facilities, such as one in the Hellas Basin which acted as a tourist attraction and a site for research into Exo and Warmind technology, as well as the location for the core of the Warmind Rasputin.

The Collapse
With the coming of the Darkness, nearly all of Freehold was "swept away" and the sand claimed what remained. Today, Freehold lies buried beneath a mountain of sand, and its once-soaring skyscrapers are only visible.

City Age
Mars would be subject to incursions from multiple alien races, being the Cabal, the Vex, and the Hive. The former two would find each other at odds in an attrition war in Meridian Bay, the area surrounding Freehold, with the Cabal vying to mine resources and study the Vex artifacts and structures in the area, which include the massive gate to the Black Garden. A Hive sect known as the Grasp of Nokris would attempt to invade the Hellas Basin, only to be frozen in ice by Rasputin's defensive SIBERIAN ENTROPY protocol for the years to come.

Red War
When the Red Legion arrived in Sol, breaking the Cabal-Vex stalemate in Meridian Bay was one of its priorities. The Vex are hard-pressed and have lost multiple gates, including the Black Garden gate. The whole of Meridian Bay is now under total Red Legion control.

With the awakening of the Traveler at the end of the Red War, the ice caps on Mars began to thaw, extending to the iced-over Hellas Basin. This would also thaw the invading Grasp of Nokris, prompting Rasputin's newly-awakened core intelligence to deorbit Warsats as a defensive measure, inadvertently attracting a defeated Red Legion looking to scavenge technology to strike back at the Guardians who denied their victory.

Arrival of the Pyramids
Two years later, a Pyramid would arrive on Mars, mirroring one of its counterparts which arrived on Io a month earlier. There was recently a signal that was coming from a device in the Clovis Bray Facility, Guardians went to investigate to find an individual's journal whose name is Helsom, Ana describes him as a Xenoarchaeologist who believed in possible contact with extrasolar species and humanity, she contemplated on if he ever found what he was looking for, he remained on Mars since the Collapse happened.

Several months after the arrival of the Black Fleet, they caused the planet along with Io, Titan, and Mercury to mysteriously disappear, just as the Traveler healed itself. Mars' two moons Phobos and Deimos, however, survived and orbit the maw of the void planet.

Shortly after the disappearances, Emperor Calus attempted to speak to the unknown entity behind the gravitational anomaly of Darkness left where Mars used to be. He experimented with Scorn and the Crown of Sorrow aboard a carrier to ultimately succeed, with Calus disappearing afterwards.

Return from Darkness
Over a year after its disappearance, Mars would be returned with temporal rifts to Golden Age Mars. Baffled by Mars' return, Ikora Rey along with her Hidden set up The Enclave in Agrisector 24-A, Freehold due to the appearance of the Relic, a mysterious structure left behind by the Black Fleet.

Not long after their investigation into the Relic, the Cabal of Caiatl's Imperial Cabal of the Cabal Ascendancy began constructing outposts and cannons around the Martian Cradle, wishing to retake Mars as Cabal territory. Although Ikora Rey and Eris Morn were concerned, they realised that the Cabal were not aiming at them, but instead aiming at Savathûn's ship, The Lure. The Guardian would then arrive at the scene and would be instructed by Ikora and Eris to investigate further since they are pinned down. The Guardian was then engaged by Cabal forces and boarded Savathûn's ship by shooting themselves out of a nearby Cabal cannon.

The Guardian explored the depths of the ship, finding Hive forces of the Lucent Brood, a relic made from Pyramid tech and Hive with new powers. After investigating further, the Guardian was tossed off the ship, landing on the Martian surface and eventually travelled to Ikora for debriefing.

While the Imperial Cabal/Vanguard alliance was battling the Lucent Hive, Cabal Deserters set up a base of operations in The Barrens, with the backing of Emperor Calus, and began broadcasting anti-Imperial propaganda. The area was stormed by the Guardians multiple times to shut down the transmission.

Rebuilding the Warmind
Months later, Vanguard forces would return to Mars to obtain Rasputin Submind data from the Braytech Futurescape, which is stuck in a time tear. The Guardians would clash with Hive and Taken forces of Xivu Arath's Horde, who occupied the complex and deactivated or subverted its defenses. The Fireteam confronts their leader, Darkblade Kelgorath, Risen from Bones, and slays him in a fierce battle, though his Ascendant status saves him from final death. Many more retrieval operations like this would be launched and continue to be conducted.

Around the same time, the Ares Spire, a Golden Age Seraph Complex, powered on for the first time since the collapse. Osiris instructs a team of guardians to investigate the facilty, finding Sol Divisive Vex intent on harvesting its data. The guardians fight through the Vex, destroying their leading Axis Minds Akelous, the Siren's Current and Persys, Primordial Ruin, and retrieve critical data about extrasolar colonies. Ana would later lead a fireteam consisting of Cogburn, Earp and Moss-2 into the complex to fully clear it, retrieving any further data as well as Tex Mechanica armor and weapon schematics.

Locations

 * Athabasca
 * Clovis Bray Special Projects
 * Meltdown
 * Eos Chasma
 * Firebase Delphi
 * Meridian Bay
 * Bastion
 * Campus Martius
 * The Timekeeper
 * Freehold
 * Blind Watch
 * The Hollows
 * Dust Palace
 * Overwatch
 * The Cortex
 * The Buried City
 * Freehold Station
 * Tharsis Junction
 * Skyline
 * The Drift
 * Rubicon Wastes
 * Iron Line
 * The Legion's Keep
 * Trenchworks
 * Scablands
 * Firebase Rubicon
 * The Barrens
 * Valley of the Kings
 * Giants' Pass
 * Cerberus Vae III
 * Black Garden
 * Pantheon
 * The Lost Oasis
 * Crossroads
 * Upper Stratosphere
 * Retribution
 * Hellas Basin
 * New Arcadia
 * Arcadia Circle
 * Glacial Drift
 * Dynamo Approach
 * Olympus Descent
 * Penumbral Depths
 * Ma'adim Subterrane
 * BrayTech Futurescape
 * Alton Dynamo
 * Hellas View
 * Aurora Reach
 * Mindlab: Rasputin
 * Submind Vault
 * Mindlab: Charlemagne
 * Core Terminus
 * Warmind Facility Hellas
 * Solitude
 * The Enclave
 * Relic
 * Agrisector 24-A, Freehold
 * The Lure
 * Ishtar Chronoscopic Analysis
 * Ares Spire
 * Reactor Firewall
 * Pillory-0 Cell Stack
 * Seraph Reactor Core

Trivia

 * Acording to the description of the Long Tomorrow 9G chestpiece, Mars was once ruled by the Awoken.

List of appearances

 * The Law Of The Jungle
 * Destiny
 * The Taken King
 * Rise of Iron
 * Destiny 2
 * Warmind
 * Forsaken
 * ''Black Armory
 * Joker's Wild
 * Season of Opulence
 * Shadowkeep
 * Season of Dawn
 * Season of the Worthy
 * Season of Arrivals
 * The Witch Queen
 * Season of the Risen
 * Season of the Seraph