40 years have passed since the First Advent, beings of god-like power descended onto the world, that day marked a tragedy responsible for far more human deaths in history.
These beings were referred to as "Aether" by the military, but of course were called plenty of things by many people all around the world.
1 Yr After Advent
The creatures fought each other as well as military forces, which mobilized to suppress them. Most population centers were destroyed, leaving the military and remnants of civilization to survive or perish.
2.5 yr After Advent
Most military is destroyed in battle, Government shelters become overrun, and people survive by fleeing to places where it is more under control. The remaining military engages in guerrilla warfare and has slightly advanced their tactics towards fighting these monsters.
5 Yr After Advent
The government discovered the reason they have been having so much trouble subduing these creatures with brute force is that, in combat, every single one of them, even weaklings emit a strange foreign energy that repels all things without it. They name this strange force 'Aegis.' however they still have no idea how to get around it or even measure how it functions, with the only method to defeat the monsters being by killing them while they are asleep.
10 Yr After Advent
Humans start undergoing an evolution, strangely, once their goal is set in their mind, they enter a trance-like state and undergo a trial of sorts. Once returned, they become the Awakened, far more powerful than any modern weapon, except for nuclear missiles; they also possess their own Aegis Field. And have the ability to kill the monsters of the Advent even while their field is still active.
15 Yr After Advent
The world is finally rocking toward stability… almost; however, the human awakened are too unorganized, and the worst is yet to come. Many awakened fall into another trance, some never return with both their bodies and mind seemingly disappearing to entirely different dimension.
16 Yr After Advent
The monsters coming through into the surface world are far stronger than before; the awakened are no longer able to combat them. It seems as though the end times are upon the world. However, in the central continent, a group of awakened has formed an organized group and is slowly gathering manpower to search for the cause of all this.
They are joined by the returned, a new level of awakened that is far stronger, helping further fortify their status as the leading power of humanity.
Year 17 AA
The strongest creature recorded appeared clocking in at an 8.8 on the Aegis Scale when it was later measured. It is known as the Angel of Death, as it was directly responsible for the most deaths of any Aether, as it mercilessly and effectively targeted the largest population centers one by one and was nearly indestructible through its Aegis.
Year 18 AA
The western continent, as well as the northern frozen continent, has fallen; however, the Inquisition had built a total of three cities during this time, defying all odds and keeping the entire central continent safe. They also rediscovered the ancient technology of the Aegis scale, which finally allowed them to read the danger of the monsters, giving groups valuable knowledge to at least know when to face a foe or run from an unbeatable monster.
Year 19 AA
The Republic of Babel was founded by the Inquisition, which also finished construction of yet another city, and the other governments of the world were systematically wiped out by the angel of death and other "continent destroyer" class seven monstrosities.
As for the angel of death, it was never destroyed. It killed billions, and then simply disappeared. The military had failed every attempt to stop it, the last one being the sacrifice of the entire southern continent, which had been reduced to a burning, radioactive ruin by the detonation of a truly ridiculous amount of nuclear bombs.
Year 20 AA and onwards
After the disappearance of the angel of death, a spark of hope was lit under the people of the Republic of Babel; they mostly battled for their lives every day, but it was becoming a routine, however this was all shattered with the appearance of an abomination.
This creature clocked in at 7.5 on the Aegis scale, far weaker than the angel of death; this being sure looked like the end of Humanity.
That being said, the humans were undeterred, the strongest and most capable army was formed, and the construction of the fifth city sped up for everyone who remained.
10000 awakened, 100 of the returned, and the seven heroes who had formed the inquisition in the first place all formed the cohort that would fight this scourge.
The seven heroes had apparently all achieved a level of power that could rival a beast at the peak of the sixth level of the aegis scale, which was far ahead of anything a regular returned could do.
The battle commenced, tearing across the sea between the eastern and central continents, and when it was all said and done, they had bought enough time for the completion of the central city.
All the cities had a tower at the center of them and were built in the way shown in the ancient technology the group had found long ago.
They formed a sigil of protection of the ninth level.
Yes, even if the angel of death were to reappear, he would not be able to get through the barrier.
However, the cohort had not been victorious.
The heroes had died in the battle against the monster, the awakened had been slaughtered to a score, and the returned were fewer than a handful.
But they would be immortalized through the mechanized army built by the new leader of the Republic of Babel.
Life from this point on would be peaceful. Inside the barrier, there were only low-level monsters, and it was extraordinarily rare for one to get inside a city.
The real danger was people, both in the literal sense and in the sense that if they failed their materialization, they would allow a monster into the real world.
Onwards
As such, the laws were put into place that education would mostly focus on the history of the Advent, as well as how to get through the Materialization into an awakened, and the world you would have to return from to become one of the returned.
There were many discoveries after, and the strongest returned had conquered another stage of the strange nine-layered world, however that is as far as anyone has gotten as of yet. Despite many attempts to continue rising up through the layers, they had all failed.
This caused many groups and factions to bloom inside the five cities of the Republic of Babel.
The simple awakened humans reside mostly in the safest first and second cities.
The evangelical saints reside in the fifth city.
The Inquisition has a strong presence throughout all the cities.
And the fiends who draw power from the forces of evil reside in the shadows of the fourth city.
Aside from these main groups, there are dozens of small cults and groups that each have their own agendas in this new world where belief turns into reality; even these groups are dangerous.
Because of this, the venerable leader of the Republic of Babel has enforced a strict curfew and other laws cracking down on any miscreants that would dare defy him with his monstrous iron legion.