Earth in the year 3219 was prosperous unlike the earth of the early 2000s. Humanity was now a truly united race. Technology had greatly improved, and was still improving at breakneck speed.
All these started after World War III, the war that started because of power hungry nation leaders who wanted to be sovereigns, nation leaders who just couldn't bear the sight of their enemies anymore; by religious fanatics who wanted to kill everyone else that didn't believe in their god; and those who just wanted to show of their military arsenal.
As if this wasn't enough trouble, Global warming, which some people thought wasn't a thing, came like icing on a cake, or rather like piss on a turd, and caused natural disasters like hurricanes, earthquakes and volcanic eruptions. What'd ya say? I guess Mother Nature was pissed.
Soon after that, the Ozone layer started disappearing like how a kid erased his wrong homework. Then like a cherry on that cake, some dude created an almost perfect AI that was capable of a lot of stuff and that just made things a whole lot crazier. Thankfully, robots didn't take over the world. But just like the saying goes 'there's always light at the end of the tunnel', there truly was light. It all ended, and just like some other dude said 'the greater the suffering, the greater the peace'. Indeed he was right; the suffering caused the whole of humanity to unite.
No one really knew what caused the war to stop, and caused humans to unite against the true disasters which were global warming and other stuffs. Some said someone finally became the sovereign of earth, some said AI took over humanity and were leading humans towards its best calculated path, some said humans discovered the garden of Eden, ate of the fruit of wisdom and grew a brain, some said it was a divine emissary that descended to Earth and settled the war, while some outright said God came down himself.
The rumors just kept on getting more and more outrageous, but the important part was that it ended, and humanity improved by leaps and bounds to what it was in the year 3219. Thank God for that.
However, when everyone thought that things would only keep getting better and better, the 'Invasion' swept everyone off their feet.
It came as sudden as death, as painful as a kick in the crotch, and as terrifying as a sadist with a Djinn bottle.
This Invasion was the intrusion of Earth by dozens of foreign beastlike lifeforms from another world.
The Beasts were three times the size of elephants and ten times more ferocious than injured tigers. They only knew how to kill and eat (maybe sleep). The only thing they feared was the stronger fellow beasts, as no animal on Earth seemed to threaten them.
They ran rampant with the only thought in their brains (if they had any) being that if you aren't stronger than me, then you're prey, purely survival of the fittest.
Humans took swift and decisive actions with their armies, guns and missiles, but those all proved futile because even the strongest of their Laser guns could only pierce their skin, the strongest of Nuclear Bombs could only mildly injure the beasts even if they were caught in the epicenter of the blast. Fortunately this only applied to the three strongest of all the beasts who seemed to be the beast's leaders.
The only sliver of hope humans had left was the Atomic Bomb. So, after much calculation and waiting for a perfect chance, humans used their great intelligence to catch one of the three beasts off guard, and killed it with an Atomic bomb. But the joy of success turned into despair when the two remaining beasts fled into sea, even though one them clearly looked to be a land beast. It was like a dagger was placed at humanity's throat.
The fact they ran wasn't the scary part, the scary part was that they possessed intelligence. Not enough to rival humans, but enough, enough to make it so that they never showed up in the open again. This led to the comparatively less powerful, but just as vicious, beasts to run rampant.
Humans were helpless. Not because they couldn't kill them, but because the planet couldn't handle anymore Atomic Bomb detonations. But like the wise man who knew to quit while he was still ahead, humans resorted to Plan B, which was to abandon earth and live on the Moon, just kidding, rather, humans fled to planet Mars, which was barely inhabitable even with the already high level of technology.
But just as in all times of necessity, humans made do with what they had. The pressure of the fear of death, of being homeless, of running out of food and space caused humans to speed up the existing projects that were in place to make Mars more inhabitable. This caused the already growing level of technology to further soar.
Plants were imported from earth to facilitate food production and recycling of the Carbon dioxide released by humans. After that was established, humans imported from earth animals of different breeds to ensure continuity in case of any accidents.
With time, humans created an artificial self-sustaining biosphere around planet Mars that even without providing equilibrium between animals and plants, all life forms would survive because AI machines regulated it through deliberate chemical reactions which will either fix oxygen into the atmosphere, or remove through processes like carbonization (or by simply asking humans to breathe faster...again, I'm just kidding).
These series of events known as the 'Invasion' lasted for about a year, and it gave humans a wake-up call. It caused them to further develop their weaponry, armory and other artillery.
High Tech Body Suits possessing high defense and offense, and even capable of space travel were designed and created after much effort. This as a result gave humans the ability to kill some of the beasts while leaving others to die of old age or of a simple yet surprising incompatibility of the beasts with Earth's atmosphere (this death due to incompatibility left humans flabbergasted at its discovery).
However, even after killing practically all the beasts, and waiting all this time, the remaining two top beasts never showed themselves to the world again, and all efforts to find them proved futile. Later on, probably due to humans missing home, or due to the hunting of the corpses and young ones of the beasts, or to bait the beasts into coming out, or due to their confidence in their weaponry as a result of their continuous breakthroughs in the level of technology, or the hope that the top beasts died of old age, or maybe their greed for the now free land, or curiosity of what will happen, or maybe just plain stupidity and some other reasons I can't figure out, some humans returned to and reinhabitated Earth, and began happily living there.
After some thorough investigation, news concerning the reason for the start of the 'Invasion' was released. It turned out that some scientist (whose origins were hidden probably for the fear of humans massacring the persons entire bloodline) experimented during their good-willed project of creating teleportation portals (which would revolutionize transportation as man knows it) that instead of opening a teleportation portal from one teleportation node to another teleportation node, they should try to open a portal to a random and unspecified node in space, and that will therefore enable them to explore the great unknown (God knows whose stupid idea that was).
It was like blindly stepping into a random vehicle during rush hour and opening your eyes only after the vehicle had stopped (exhilarating, isn't it?). But that was them only considering the best case scenario, as none of them expected something as terrifying as these beasts to come to our world before they got the chance to explore the other side.
However, World War III, the Invasion, and all these events were all history. In 3391, Teleportation portals had come to replace Subway stations of the past. These portals could be seen in every big city on Earth and even on Mars. Although it was banned at first because some humans didn't want the 'harbinger of the Invasion' anywhere close to their Plan B, it was later accepted after much politics and reassurance from the teleportation portal creators, and breakthroughs in weaponry technology. Or maybe it was simply because humans just couldn't bear to see others teleport from one place to another while they couldn't. Electromagnetic rail subways were still in use, probably because of those who still fear the portals or because it is simply cheaper.
Teleportation portals were remade in such a way that it would be absolutely impossible to teleport to an unspecified destination, 'just as impossible as cooking noodles without a pot' said the creators.
Hackers, sadists, suicidal psychos and adventurers all tried to find loopholes but failed. They said it had something to do with the portals make-up. But all of that was not of great concern because Lei Shi was currently in a tight spot, literally.