20 years ago, abruptly, this world's common sense was defied and defiled.

Like the coming of a storm, the idea of history being a chain of events linked by cause and effect was shaken to its core.

The human ability to separate the fantastic from the real and foresee the future, however loosely, was suddenly lost.

Our world, in which one could argue lunacy against predictions so far removed from the established order, suffered immensely once history saw itself completely derail.

Removed as it was from everything Earth had seen before, it remained true that at the very least, one event could be blamed for this.

Later called "The First Contact", unbeknownst to humanity at the time, our world's logical path had been crushed by a simple message from an unknown woman's soft and collected voice.

The words heard throughout the world...

As if their senses were shared, every single mind stopped to listen and focus on what was told to them.

Nowadays... There isn't one person alive who doesn't know the words by heart...

 [Congratulations, people of Earth.

I, Catherine, Goddess of the Red Night, have kindly chosen to bless your planet.

Rejoice, as you may now claim your Gifts.

Your planet shall be exposed to its true nature.

You are to be accepted amongst many others.

Revel, and celebrate. Pray, and struggle.

As I have chosen you...

Prove to me your worth.]

On a smaller scale, such a thing would certainly be attributed to mass hysteria, yet...

When the entire world's population, from the most influential of politicians to the most average of kids... Even those with disabilities, the deaf, the detached... From countries with completely different languages or writing systems...

When all of them recalled the same words...

No excuses could be made.

Humanity understood. It knew.

This was not something that had happened before.

It was not the result of any one human's actions.

However, as chilling and difficult as this seemingly simple realization might have been, understanding what those words meant was much more challenging than accepting them.

Soon after... People discovered access to their Gifts, proving the truthfulness of the woman's words.

The laziest man could turn into an athlete.

With seemingly magical means, by waving their hands while they emitted a weak glow, some found themselves capable of healing others' injuries.

From basic improvements to supernatural and unexplainable abilities, cases were popping up everywhere.

These miracles... They made many feel blessed.

However, humanity cannot trust what it cannot comprehend.

We had no choice but to accept what had become of our reality, so many searched for explanations fitting the reality we used to know.

The most widely spread theory framed Catherine as a being from a more scientifically advanced civilization.

Her abilities, and the ones she gave to humanity, were not magic, but a result of science beyond our comprehension.

Unfortunately, popular as it may have been, and influential as it might continue to be, common sense no longer dictated reality.

People who were quick to embrace what the world had become were intrigued by something much more critical.

They pointed out the similarities to some games.

By accessing their Gifts, they could see their own status.

Things like their mana, their magic power, strength, speed...

Even their levels.

These are all staples of the RPG genre and were well understood by many.

However... All of them, but especially the last one...

Their best-known game application was related to something we had yet to see.

Combat.

Weirdly, contrary to the implications, no monsters had appeared anywhere.

No other races. Or labyrinths and dungeons to be explored...

That was our reality.

For a brief time...

The answer to the questions we still had could be found in Catherine's words.

The self-proclaimed Goddess, dubious as such a claim might have been, had spoken about changes in both humanity and the world.

We were already acquainted with what had become humanity's reality, but the world's...

It was much more subtle at first.

Gates.

They had no particular characteristics apart from an arguably large size for modern standards.

They possessed an old and simple design. Due to them seemingly having been made out of wood and stone, they looked medieval, and thanks to initially being few in number, it took a while for the general public to notice their existence.

And yet... Around the world, these structures started to appear everywhere.

They had a random nature.

Sometimes, they would appear in odd, but acceptable places, such as forests or cave mines.

Almost as if something had been planned to be built there and was abandoned, or if they were the sole remains and ruins of something that once existed.

But it didn't take long for them to appear in more unusual places.

Inexcusable places.

At the time, there were a bunch of pranks circulating. Chaos thrives in chaos...

A gate floating in the middle of a busy street without any cables attached to it or anything else, while undoubtedly strange, considering the state of the world at the time and everything that was happening, almost could be acceptable.

But more of them kept appearing... Floating in the middle of the air.

Reports appeared of gates in completely uninhabited locations where most humans would have a hard time surviving, much less building.

The scale was undeniably too big. Even with abilities, no prankster had come even close to something of this magnitude.

I can only imagine how people felt while this happened, but it is often said that... A foreboding feeling lingered in the air.

Without anyone being able to resist it, fate bore its fangs against humanity again a month after the gates had first appeared.

Suddenly, almost as if arbitrarily, they opened their doors in a day that became forever known as "The First Reminder".

The connection with the First Contact was obvious, but also...

As the name implies, it was to be a reminder of a stain in our history.

Whether or not we accepted it... Whether or not we could explain it...

The fact remained.

Humanity found the opponents it had been searching for.

When the gates opened, monsters stormed out of them in waves.

From the people using their new powers for good to the people who had been abusing them...

Humanity fought... Struggled.

But it was too late. No matter how much they had tried to abuse their power, not a single person had developed them enough with the time they had.

To this day, it's impossible to know exactly how many lives were lost during The First Reminder.

While we survived, we later discovered that this was a periodic event we would have to deal with for... Perhaps for our entire future on the planet.

There were only two methods to guarantee that one of the Gates wouldn't open and unleash all the monsters inside it.

The first was to reduce the number of monsters inside. As long as they were not overpopulated, the normal monsters couldn't leave and wreak havoc in our world.

The second method was a little harder. We had to kill a "Boss", a stronger monster who resided in a special room within the Gate.

The conditions are still unknown, but sometimes, these monsters can leave their rooms and seem capable of traversing the insides of a Gate freely. They are even able to ascend or descend floors or invade our world without needing a Rampage.

All we know is that a Boss cannot be left alone for too long...

Because of how the Gates seem to imprison the monsters inside for a while, their interior became known as "Dungeons", and throughout the years, it's unfortunately estimated that the Dungeons have claimed more lives than the First Reminder.

The Lesser Dungeons, later dubbed "Easy Dungeons", had Rampages happen about once a month with a slight variation depending on their "Dungeon Level".

As for more difficult Dungeons... They seemed to have a longer wait period between Rampages.

Thanks to these inconsistencies, different time frames, and the appearance of new Gates, almost every day after The First Reminder, smaller, but equally tragic moments marked our history.

However... Humanity fought back with all it had.

The monsters from the Easy Dungeons, ferocious as they might be, weren't much stronger than the average man.

They found that their odds of winning against someone prepared, with a weapon in their hands, were quite small.

We were caught off guard, but humanity was not that weak.

We had no way of resisting the first time, but we were the species that dominated all others in this world.

Once we knew we were in a fight, we made sure the invaders would understand who rules this planet.

For the weak monsters that could be killed by fists alone, even without the use of special abilities, firearms spelled doom.

It was the first time humanity collectively had an opponent, but we proved ourselves.

The armed forces and the people, together, took back the world... For the most part.

Although many places are still dangerous and challenging...

Mountains and islands, inaccessible places such as underground caves or the bottom of the oceans... Even the sky is not an exception...

To this day, in many places, Rampages still occur.

Our fight is continuous.

There are cities still lost to us.

Underwater monsters attacking make maritime trading incredibly expensive.

Away from cities, it's not rare to see stray monsters roaming around.

We have not yet won. The Dungeons and the monsters have not been defeated.

We only learned how to survive.

And even that took us a while to figure out...

The first plan was to use the armed forces to raid and hunt the monsters inside, but this didn't work.

There were too many Gates, their locations were completely random, making it too expensive and impractical to contain every single one like this.

Not to mention... Firearms were only effective against monsters below a certain level.

We had no choice but to adapt to fight the stronger ones...

Emboldened by their own fight for survival, the memory of lost ones, or a desire to prove themselves, the common folk took it into their own hands.

The government tried to argue for our protection, but they couldn't prohibit access and guard every Dungeon, so inevitably, a new job appeared.

Adventurers started risking their lives to enter the Dungeons... To hunt the monsters and uncover the mysteries about them.

Although... It would be unfair of me to say that the government only wanted to protect us when they first tried to monopolize the Dungeons.

It was quickly discovered that monsters, when killed, had a chance to leave something behind.

There was quite a variety, but most commonly, weapons or small stones.

The stones in particular had an interesting quality to them.

They could be used as an alternative energy method.

Questioned about why they tried to prohibit people from entering the Dungeons when the adventurer system was working well to prevent more Rampages, the government responded by striking a deal to buy the "Monster Cores", as the stones were later called, from the adventurers.

Not only that, other goods found in the Dungeons, such as minerals and crystals, also became items the government was willing to buy since they all had value as research material.

Thus, offices were set up to facilitate trading materials obtained inside the Dungeons.

This led to a surge in people becoming adventurers, and in turn, a problem started due to the exodus of the workforce from almost every other job.

Eventually, supply surpassed demand, and the government also made it less profitable for adventurers so that things could return to a sense of normalcy.

Still, even considering such efforts, the world was barely recognizable.

There also weren't any clues as to what could change next.

All we had was the knowledge that our existence could, in a moment, change completely.

The only certainty was uncertainty now that reality and fantasy were closer than ever.

As for me...

I wasn't part of that story.

I was born 18 years ago.

This fantasy-like reality was the only one I experienced. It was my common sense.

And it was the stage on which my story began.