The first long-distance warheads were launched in the year 2295. But the world was tittering on the brink of destruction much earlier than that.

Humanity had reached the pinnacle of their scientific advancements; nuclear-powered devices that fitted in the palm of the hand, cures for every known ailment, self-sustaining food sources that could feed the entire population; science-fiction was no longer a madman’s fever dream. But it was these maddening, reckless advancements that had driven the Earth towards its expiration. Oxygen levels were critically low, UV rays scorched the earth dry, and global temperatures had reached well above tolerable levels for most life to flourish.

In the wake of the planet's dying throes, plants and trees turned to dust, animals perished by the hundreds of millions. Half of Earth's surface was swallowed by the rising tides, while what land remained faced a constant barrage of natural disasters.

As with all tragedies, humanity had known of this coming future well before the inevitable. But in a twist of fate none could have foreseen, man turned against his neighbor for his own survival. Instead of harnessing the collective brilliance of the human race to search for a solution together, countries slaughtered each other for a foothold on the rapidly shrinking land. Weaker nations were forced to band together to fend off stronger ones, while centuries-old alliances were betrayed overnight.

The Last War known to humanity continued for a total of fifteen long years, and ended only with a stalemate between the last two super-nations remaining on the planet.

The first nation was an amalgamation of Earth’s most technologically advanced countries before the War broke out. These nations saw themselves as the architects of the fate of humanity, and came together with the common goal of elevating the human genome – to push humanity into a new era – so that humanity may survive and flourish on a new, harsher Earth.

They called themselves, “Eternal Heaven.”

In the ashes of the fifteen-year war, Eternal Heaven found herself facing against a superpower unlike anything else that existed in Earth's history. This nation, made up of a handful of small but wealthy countries scattered around the world, did not believe in Eternal Heaven’s goal of remaining on the dying planet. And so, in the interest of self-preservation and the future of mankind, they joined under one banner and turned their sights to distant planets, and eventually other dimensions, for humanity’s new home.

They were called the “Proprietors of Arcadia”.

Both sides wanted the technology and resources the other had. Neither could find a way to co-exist. These two remaining halves of the world ending up fighting for domination of Earth – and the future of mankind – for the next twenty years, before everything was ended by a single cataclysmic event.

The first prototype of Arcadia's interdimensional gate was built in the year 2331.

Their victory was a short-lived one, however, because it was at the same time that Eternal Heaven also had her first technological breakthrough: A plasma-nuclear energy source the size of a pebble, which fused together will form a near-indestructible battery capable of powering a space station, or a small city, uninterrupted for 24 hours without needing to be recharged.

It was known as the "Master Core".

In the next six years, Eternal Heaven would go on developing nanobot technology that surpassed the impossible. Under Heaven's brilliance, cold and unfeeling machines were able to function, repair, and adapt themselves to even the most inhospitable conditions on the planet. A simple sheet of metal, with the help of a mass of swarming nanobots within it, was able to slice through a concrete pillar without damage to itself.

Then in the year 2340, the next milestone was achieved - the birth of the “Synapse-Mother-System."

This was a central uplink and command system for Artificial Intelligence, created with the sole purpose of governing and harnessing the terrifying power of machines that could think and learn on their own. While A.I. had existed long before, even before the War, it was only until the S-M-S was put in place that the true power of A.I. was finally deemed safe enough to be unleashed upon the world.

With a centralized command center, any A.I.-controlled machine was able to communicate, share information, and come to a shared – and individual – conclusion on the problem at hand, with the System’s commands still reigning supreme above all else. In other words, what the System dictated, the machines did, though the methods to achieve the order were able to be debated.

Lastly, to ensure nothing ever tempered with the S-M-S, human or otherwise, the entire system was built on the Moon under extreme secrecy, and shortly after the System was established, all those who worked on it disappeared, taking its secrets into the void.

It took two more years for all the pieces to be put together, but in 2342, the Mark I God Giers were finally created.

It was a massacre.

Nothing the Proprietors of Arcadia had in their arsenal came close to stopping these hyper-intelligent, self-learning monsters. Even an MKV Hyperion Spider Tank – the most heavily armored weapon Arcadia had at the time - could not so much as hinder a single God Gier's advances.

Deeper and deeper these demons marched into Arcadian territory, soaking the earth with Arcadian blood. It took Eternal Heaven just half a year to secure over 65% of the entire Earth’s land.

But the Proprietors of Arcadia were never focused on the fight in the first place; they never cared about winning the war, they only wanted to buy enough time so that they could escape it. During the thirty-four years Heaven spent creating their killing machines, Arcadia pioneered teleportation, alternative energy, wormholes, and even space-time manipulation in their quest to make their interdimensional gate work. It was not a quick process though, as even when the mechanical monsters came tearing down their strongholds, Arcadia’s goal of finding a new home was still far from realized.

And so it was, in the year 2344, the remaining forces of the Proprietors of Arcadia found themselves holed up in their last stronghold, built inside a dormant volcano. All seemed to be lost. But as fate would have it, it was in this stronghold that the first prototype of the gate was made, and it was with this gate that the Proprietors made their world-changing breakthrough.

The gate had a response. It worked.

Ecstatic, the scientists in the Arcadian base named the portal "Pandora’s Gate", and rejoiced as Humanity now finally had a second chance. After so much sacrifice and blood, they had found the hope that was sealed within the mythical box.

But the scientists didn’t have time to run all the tests; the screams of their comrades were already echoing down the long hallways. They turned to the Gate, these men and women with whom the last hopes of humanity will either flourish or die, and came to a decision. The Gate, its stern black beams standing stoic in the face of the approaching chaos, was ready. The readings were clear. All systems were performing at full capacity. There wasn’t any more time for additional tests, but none more were needed. Besides, if the androids did strike down the doors, the moment they saw the light of the Gate, even they, cold and unfeeling as they were, would understand the importance of this discovery, and stop their senseless madness.

The final command was given. They had one chance. They took it. They had to.

And so it was, on December 12th, 2344, Pandora’s Gate was opened for the first time. That day was forever remembered as the day humanity took its first steps into a new future, and the day the world, and everything mankind thought they knew about it, was changed irreversibly.

It was the day the Earth ended.

It was the day, of the Horizontal Reset.