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

Like 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 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 one event led to 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 they were being told.

Now... 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 they cannot comprehend.

We had no choice but to accept what had become of our reality, so, many tried to explain it.

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 what we knew.

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.

All staples of the RPG genre, and 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.

However, contrary to their expectations, 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 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 design. Medieval-looking.

Due to their low initial number, it took a while for the general public to notice.

But 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.

As if something had been planned to be built there, or if they were ruins of something that once existed.

However... 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.

So a gate floating in the middle of a busy street, with no cables attached or anything else, while strange, considering everything that was happening, was almost acceptable.

But more of them appeared. Floating in the middle of the air.

Reports of gates in completely uninhabited locations...

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

I can only imagine how they felt, but it is often said that... They had the foreboding feeling that something was going to happen again.

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

Suddenly, they were open.

That day became known as "The First Reminder"

An obvious reference to the First Contact, but also...

A stain in our history.

But most importantly, as the name implies, a reminder.

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

The fact remained.

Humanity now had an opponent.

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 that was our first mistake.

No matter how much they had tried to abuse their powers, no one had prepared enough to fight for their lives against the monsters.

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

Worse yet... Although we survived, we later discovered this was a periodic event.

Named "Rampage", there were two methods that guaranteed a gate wouldn't open and unleash all the monsters inside.

The first method was to reduce the number of monsters inside. By doing so, the gate doesn't overpopulate, and the normal monsters inside aren't able to leave and wreak havoc in our world.

The second method involves killing a "Boss"... A stronger monster who resides in a special room within the Gate.

These monsters can sometimes leave their room and enter our world without causing a Rampage.

The conditions for this are still unknown for the most part, but if left alone for long enough, it is bound to happen.

Because of such conditions, the areas inside the gates became known as "Dungeons", and throughout the years, it is estimated that they have claimed more lives than the First Reminder.

Lesser Dungeons, later known as "Easy Dungeons", had Rampages about once a month, with slight variation depending on the "Dungeon Level".

More difficult Dungeons had a longer wait period but also posed a more difficult challenge.

Because some inconsistency existed with their grace periods, every day after the First Reminder new Gates opened, causing smaller, but still tremendous tragedy.

However... Humanity was able to fight back.

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

Against them, a man equipped with a weapon was not only able to defend himself, but also kill it.

Humanity wasn't that weak.

We were caught off-guard.

We couldn't resist the first time.

But once we knew we were in a fight, we pushed back.

For weak monsters that could be killed by fists alone without the use of special abilities, firearms proved themselves a worthy equivalent.

With the combined efforts of the people and the armed forces, humanity managed to regain control of the world for the most part.

However, challenges could still be found in many places.

The Dungeon Gates appeared in places like mountains, islands, or the bottom of the sea.

Even the sky was no exception.

Nor underground caves in inaccessible locations...

To this day, in many of these places, rampages still occur.

There are cities still lost to us.

The oceans remain a problem due to underwater monster attacks making maritime trading incredibly expensive.

Away from cities, you can often find a monster roaming around.

We never truly defeated the Dungeons.

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, and it was expensive and impractical to contain every single one like this.

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

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 chose to respond 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, in a single year, the world was barely recognized after these events.

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.