Chapter 1 : ▼ The Purpose of Entering the Dungeon
Originally, I was supposed to die.
For someone like me, who could toil endlessly yet reap no rewards, the only thing I had to offer was this insignificant life of mine.
In this world, no matter how hard I tried, I was surrounded by talents I could never surpass.
When an insurmountable wall loomed before me—one that effort alone could not overcome—what was I to do?
No matter how much I struggled or persevered, a person without wings could never take flight.
If the pinnacle was so distant it seemed beyond reach, what could I possibly do?
Could I keep pushing forward, unrelenting and undeterred?
Could I live with pride and defiance in my heart?
No, I couldn’t. Because I… was a failure.
I was a "failure" with a mere 5 in magical power.
From a young age, people called me by that humiliating label instead of my name, and over time, I came to accept that I truly was a failure.
For a child like me to believe there was no bright future ahead—it wasn’t surprising, was it?
To me, a world where magical power determined everything was simply common sense.
The magical power one was born with could never grow.
A world where victory or defeat was decided the moment you were born.
Two years before I came into existence—twenty years ago, to be exact—something happened that turned this world upside down.
The sky let out a sudden, piercing scream, and with a sharp, resounding crack, a rift tore open in the air.
From that rift, enormous jewel-like boxes fell into our world.
Giant gemstone chests—ruby, emerald, sapphire—each shimmering with vivid, radiant hues.
These boxes rained down onto the earth in droves, like a torrential storm.
Now known as "Cubes," these massive containers brought about a drastic transformation in the world.
Each was a dazzling, house-sized cube, sparkling like a gemstone. The moment someone touched one of those vibrant boxes, they would be sucked inside as if swallowed whole.
Within every cube lay a vast, otherworldly labyrinth.
These became known as "Dungeons."
And waiting inside were grotesque monsters hellbent on slaughtering humanity.
They were called "Magical Beasts."
The beasts poured out of the dungeons, attacking humans and driving them toward annihilation.
The human race, once thriving on this planet, unleashed chemical weapons in desperation—but they were powerless against the magical armor of the beasts, suffering defeat after defeat with no hope of resistance.
As the people of the world felt the sting of racial defeat and the looming threat of extinction, something changed.
Humanity awakened. The species evolved.
To stand against the magically evolved beasts, humans gained a miraculous power of their own.
And that power had but one name:
"Magical Power."
Magical power brought evolution to humanity, enabling them to overcome the beasts and fundamentally altering the way this world functioned.
In this world, the magical power one was born with created an unbridgeable gap in ability—an absolute disparity in talent.
A single individual’s strength could even shift the balance of power across the globe.
And I was born into such a world.
Classified as the lowest of the low—unranked—with my magical power measured at a pitiful "5" on the scale.
A failure who hadn’t evolved.
At this point, I should have given up on everything.
But I couldn’t—not when the lives of my precious family were at stake.
So I made up my mind and took that step forward.
With a resolve to sacrifice my life if necessary, I entered that unknown dungeon.
Perhaps it was that very determination that granted me this power.
Perhaps there was some meaning behind it—
Something that turned my once-gray existence into one illuminated by these shining golden eyes.
"Haa… haa… Help! Save me!!"
I was being attacked by a massive ogre.
A grotesque magical beast had suddenly invaded the junior high school campus during class, slaughtering countless students.
Friends, acquaintances, even the school bully—no one was spared.
Everyone was killed. Every single person, far stronger than I ever was.
The school building was splattered with blood, the screams of students mingling with the roars of grotesque monsters echoing back and forth.
I was being hunted by that ogre.
I thought I was done for, curling up and sobbing in despair.
There was no way I could fend off that massive club—it was about to crush me to death.
A look of hopelessness on my face, my legs frozen and unable to move.
Just as death loomed before me and I shut my eyes in terror, she appeared.
She looked about my age.
Maybe a high schooler, clad in a black uniform, her stunning silver hair cascading down in stark contrast—a beauty unlike anything typically Japanese, gleaming brilliantly.
Was she a foreigner? She was so striking, like a sculpture carved from ice, captivating even in a situation like this.
And yet, she was incredibly strong.
This high school girl held a schoolbag in her right hand, while her empty left hand casually swept to the side.
In an instant, a silver light flashed, and within mere seconds, every last ogre was cut down.
The magical beasts didn’t stand a chance—they couldn’t even resist. I couldn’t even process what had happened before they all lay dead on the ground.
“Are you okay?”
Instinctively, I grasped the hand she extended toward me—a moment I knew I’d never forget for the rest of my life.
That icy, serene expression paired with the surprising warmth of her palm.
She was beautiful, like an ice statue.
Perhaps I began to admire her.
This unreachable girl, as if she belonged in the heavens.
I idolized her—S-rank Awakened “Reina Silverfield”—a figure who stood among the strongest in a world far beyond my grasp.
Me, the unranked, the weakest in the world.
◇ Years later. I , Ash Tenchi, eighteen years old, the year of high school graduation.
I, Ash Tenchi, was scavenging corpses in a labyrinth.
Though it resembled a cave, the walls were clearly man-made, a maze illuminated faintly by the dim glow of torches.
I carried a massive pack nearly as heavy as myself, my hands stained with green blood, searching for bodies.
“…Alright, got it.”
I sliced open a corpse’s abdomen with my knife, retrieving a stone about two centimeters wide.
Wiping the faintly glowing blue-white stone clean with a cloth, I tucked it into my bag.
Looking up, I spotted another body.
It was an ugly green goblin with a long nose and pointed ears. I crouched down, preparing to cut into its belly, when someone shouted at me.
“Hey! Hurry it up, you useless trash! The only thing you’re good for is handling corpses, and you can’t even do that right?!”
“S-Sorry! I’ll be right there!”
One of the guys up ahead yelled “trash” at me, and my body flinched in fear as I hurriedly extracted the stone from the corpse.
These stones, taken from magical beasts, were called Mana Stones—valuable enough to trade for money, so they had to be collected.
After gathering all the Mana Stones from the bodies, I rushed to catch up with the group ahead.
“Hey, trash, tea.”
“N-No problem! Just a sec.”
The moment I rejoined the group with all the Mana Stones, an arrogant man immediately dumped chores on me.
It was always like this. Since all I could handle were odd jobs, I had no choice but to comply.
“H-Here you go, Sato-sen—!?”
I poured tea into a paper cup and handed it to Sato, the team leader.
He took it—and promptly splashed it in my face.
I shut my eyes as the cold tea drenched my face and clothes. Good thing it was summer.
“Hahaha! Did that wake you up a bit?”
“Haha, h-hey, don’t do that~”
I forced a laugh, slipping my clenched fist behind my back to hide it.
Then I poured another cup of tea for Sato, acting as if nothing had happened.
“Sato-bro! How about we take today’s earnings and grab some drinks tonight?”
One of the team members mimed drinking toward Sato.
They were my high school classmates.
Underage, technically. But this lawless bunch of delinquents had been smoking and drinking since high school—whether they were adults now hardly mattered anymore.
“Sounds good! Let’s get moving then!”
The four of them, including Sato, stood up with grins.
I didn’t even get a moment to sit and catch my breath before I had to hoist all their gear and the loot, trailing after them.
With no combat ability or magical power, I—someone with “less than 10 Mana, an Old Human”—was stuck with nothing but grunt work.
After pressing forward for a while, we reached a large door.
The door bore a menacing emblem glowing with an eerie purple light, signaling that the boss ruling this dungeon lay beyond.
Sato and the others opened it without a shred of hesitation.
Once everyone stepped inside, the door slowly creaked shut, sealing us in.
Inside stood an unusually massive goblin.
A Hobgoblin—a creature novices were bound to face.
The battle between the ogre and Sato’s crew began. No, it could hardly be called a battle.
Because it was just too…
“Take this! Die!!”
“Hahaha! Pathetic!”
It was a massacre.
The four of them didn’t even break a sweat as they pummeled the Hobgoblin.
They toyed with and slaughtered a beast they could easily overpower with their strength.
According to the Dungeon Association’s difficulty ratings, this was an E-rank dungeon—the weakest tier.
Based on their Mana levels, they were D-rank Raiders, with Sato even boasting a C-rank status.
In terms of raw power, the boss here was no match for them.
The boss went down in no time, and I retrieved the Mana Stone from its corpse.
With that, this dungeon would enter a dormant state, preventing a dungeon collapse.
That was our job. Dungeons had to be periodically cleared of monsters and their bosses defeated.
If left unchecked, the beasts would spill out into the world beyond.
That phenomenon was known as a Dungeon Break.
“Another easy win this time.”
“For real. Almost a hundred thousand yen for this—dungeon raiding’s such a cash cow.”
Sato and the others slung their swords over their shoulders, chuckling about their victory.
After waiting in place for a moment, a glow of light enveloped our bodies.
“Oh, they’re here to pick us up.”
It was the signal that the raid was complete. My vision suddenly darkened.
My body felt as though it were floating in midair, and when I opened my eyes again, walls resembling a shimmering blue water surface enclosed us from all sides.
These sapphire-like, beautiful walls surrounded us—a cube ten meters tall and wide.
The walls of the cube slowly tilted outward, lowering to the ground and releasing us back into the familiar cityscape.
Passersby spared us only a fleeting glance—such a sight was commonplace—before their eyes returned to their phones.
In a bustling metropolis like Tokyo, people rarely paid much attention to others.
“Phew… We hit this month’s raid quota. That’s a relief…”
I murmured quietly, watching as the fallen walls merged with the ground.
This was the Cube—a square box that served as both the entrance to the dungeon and the exit we were teleported to after defeating the boss.
To enter, you simply touched the outer wall of the Cube, and it would pull you into the dungeon.
To leave, you either had to touch the same Cube at the entrance or defeat the boss.
When a dungeon entered its dormant state, the walls would collapse flat like this, but in its active state, it retained the shape of a box.
At that moment, someone clapped a heavy hand on my shoulder.
“Trash, we’re leaving the report to you. Split the earnings like usual and don’t forget to transfer the money.”
Sato and the others waved lazily over their shoulders, abandoning me—their teammate—and walking off.
“G-Got it!”
I gave a forced smile and waved back.
In this team, hauling gear and handling chores were my responsibilities.
They’d been kind enough to take in someone like me—an unranked nobody, not even an Awakened— so I should probably be grateful.
After all, they let me join their crew. I had no right to complain.
I stared at Sato’s retreating figure, convincing myself of this.
Then I noticed him pointing at me and laughing.
The others joined in, pointing and mocking me too.
I lowered my head, bitterness welling up inside me as I clenched my fists.
But I quickly took a deep breath, exhaling the pent-up anger with it.
“Phew… Alright. Time to head home, then deal with the Mana Stones. At least this month’s raid goal is done.”
I started walking home.
On the way, I spotted a green Cube—a dungeon in its active state.
“Oh, the dormancy period’s over here too. A green Cube… B-rank, huh. No way I’d ever set foot in there in my lifetime…”
Twenty years ago, when the Cubes fell from the sky, humanity awakened alongside them.
This phenomenon, known as Awakening, triggered a racial evolution in humans, granting them the miraculous power called Mana.
When I entered elementary school, I underwent the government-mandated Mana assessment.
All my friends around me were D-rank, some even A-rank, while I alone was something rare in the opposite sense—unranked.
At just seven years old, my life was already branded a failure.
An unchangeable gap in talent, a Mana deficit that no amount of effort could overcome.
As a kid who idolized the cool, dashing Raiders, my young heart sank into despair.
“…Damn it!”
The memory soured my mood to the core.
For no reason at all, I broke into a run, racing back home.
If I didn’t, I feared my thoughts would spiral into an even darker place.
I reached a rickety, rundown apartment building and opened the door to one of the units.
This was my home.
“I’m back.”
“Oh! You’re home… cough… Welcome back, Onii-chan. Good work out there.”
“Nagi! Why aren’t you resting in bed?!”
I dropped my stuff at the entrance and rushed to support my little sister, who was leaning against the wall in her pajamas.
She’d come out to greet me with a bright smile when I got home, and while that warmed my heart, her flushed face looked feverish.
“It’s fine. I feel pretty good today. Look, I can move…”
Our home was a cramped, six-tatami-mat room in this dilapidated apartment.
Just the two of us—my sister and me—lived here.
Our parents had lost their lives long ago in a Dungeon Break.
Back then, dungeon-raiding strategies like we have now hadn’t been established, and the world was like a living hell. Things like that happened everywhere.
“Is that so? You can stand…?”
“Piece of cake… S-see! Ah!”
I caught Nagi as she stumbled.
Her body was so light and fragile, as if it might snap at any moment.
“Hehe… Thanks.”
Nagi, who was supposed to start junior high this year, was utterly adorable.
She was my treasure, my reason for living, my beloved little sister… but she was gravely ill.
When the Cubes appeared in this world, they brought with them a pandemic—an incurable disease called “Amyotrophic Mana Sclerosis,” or AMS for short.
Its symptoms closely resembled those of ALS, which is where the name came from.
It was now considered the most terrifying disease in the world.
The illness itself wasn’t directly fatal.
After humanity evolved through Mana, even muscle movement came to rely on it.
Mana couldn’t be replenished from external sources—it would gradually deplete, affecting the muscles until, aside from involuntary organs, no voluntary muscle could move anymore.
Though modern medical equipment could sustain life, the body would be completely immobilized.
And yet—
“Here we go! Up you go—!”
As long as a shred of life remained, consciousness wouldn’t fade.
“Eek! S-Stop it!”
I lifted Nagi into my arms.
Even unranked, I was a high schooler—picking up my junior high-aged sister was easy.
Especially since Nagi… was so light. So very… light.
“How’s that? Fun, right?”
“Geez… Thanks, Onii-chan.”
Nagi, slightly embarrassed as I held her, gave me a frail, flickering smile.
Seeing that smile filled me with indescribable joy.
But I couldn’t do anything meaningful for her.
My beloved sister was battling a horrific disease—one so terrible that many who contracted it chose to end their own lives—and I was powerless to help.
AMS: fully conscious, yet trapped in an immobile body.
Locked inside yourself for decades until death—what a horrifying fate. I couldn’t even imagine it.
“…Onii-chan?”
“Ah, ahh! Must’ve gotten some dust in my eyes, haha.”
How embarrassing.
Nagi and I relied on each other.
I found a sense of belonging and a reason to keep going through her, while she couldn’t do anything without me.
For someone like me—unwanted, with nowhere to belong—perhaps this was all I had left.
Even so…
“I love you the most, Nagi.”
“Onii-chan… I’m already in junior high, you know. That’s too embarrassing.”
My feelings were absolutely genuine.
I helped Nagi into her wheelchair and took her to the doctor.
At least in this moment, I wanted her to live freely.
Her medical visits were barely covered by the insurance system available only to those who’d earned national certification and registered as dungeon Raiders.
Since it was a life-or-death profession, the government provided substantial support.
If I weren’t a Raider, I’d be unable to afford the exorbitant medical fees and forced to decide whether to continue Nagi’s AMS treatment.
With only a high school diploma, regular part-time jobs or work couldn’t possibly cover the costs of AMS care.
This disease, rampant across the world, strained national budgets and wasn’t covered by standard insurance.
If I didn’t become a Raider, I—a penniless nobody—would have to sign the papers to let Nagi die.
Sign away her treatment.
I’d never do that.
So no matter how much I despised it, I couldn’t leave Sato’s team.
I handled all the grunt work for a pittance of a reward.
Even if it was a drop in the bucket, I couldn’t demand more.
All I needed was the achievement of raiding dungeons.
The government mandated at least one dungeon raid per month—a performance requirement I had to meet.
The only lunatics willing to let a combat-useless unranked like me join their team were Sato and his crew.
Even knowing they just wanted a convenient errand boy or punching bag, I had to swallow my pride and keep them happy.
If I endured, surely happiness would come someday.
But reality never hesitated to crush us.
“You don’t need to come with us anymore. Our team doesn’t need you.”
“Huh?”
After taking Nagi to the hospital and converting the dungeon loot into cash, I headed to Sato’s place.
Though it was raining, I figured I’d better deliver today’s earnings quickly to avoid angering him, so I went straight to the house where they hung out.
It happened at the doorstep.
“You’re a burden and no help at all, so you’re out. It’s everyone’s decision.”
“W-Wait a second! D-Did I do something wrong? If I messed up, I’ll apologize! Please don’t abandon me!”
I dropped to my knees in front of Sato, begging and apologizing.
Had I done something to upset him?
I tossed my umbrella aside, frantically pleading in the rain without understanding why.
“You’re unranked, aren’t you? All you can do is chores, and we want to aim higher. Bottom line—we don’t need a useless piece of trash anymore.”
He threw out the irrefutable, unchangeable fact of my lack of rank.
“N-No way! Please! I’ll do anything! All the chores, I’ll—Guh!”
I clung to Sato’s leg, and he kicked me off with a casual swing.
It wasn’t a hard kick, but the difference between a C-rank and an unranked was stark. A light tap from him sent me flying backward, the impact nearly knocking me out.
“P-Please, my sister… If I can’t raid dungeons… She’s sick, please, I’ll do anything…”
Blood sprayed from my mouth as I crawled on the ground, sobbing and clutching at Sato’s pants, begging him.
The rain-soaked asphalt was a muddy mess, and I was filthy, yet I kept pleading desperately.
“You’re disgusting! Don’t touch me!”
“Urgh!”
A kick to my jaw sent me sprawling face-down.
My dizzy mind faded, Sato’s voice growing distant.
In my blurring consciousness, the last words I heard were:
“Weaklings like you can just die on the roadside for all I care. Oh, right, your sister’s got AMS—she won’t die that easily, haha!”
Those were words I could never forgive.
Sato turned his back on me and went inside.
I lay there, still sobbing on the ground.
My mud-streaked face was a mix of rain, tears, and blood as I wailed like a child.
Unforgivable.
Not just Sato, who cursed my sister to die.
Not just this world that offered no help to the weak like us.
But above all, my own powerlessness.
Couldn’t I even protect my one and only sister?
If I failed to meet the monthly dungeon raid quota, my Raider status would be revoked—no medical care, no treatment.
If it came to that, Nagi—who always endured her pain silently, forcing a smile so I wouldn’t worry—would eventually succumb to Mana depletion and die.
“AAAAHHH!!!”
The frustration was unbearable, but this wasn’t something effort alone could fix.
I pounded the asphalt over and over.
Even as blood oozed from my hands, I kept striking, as if apologizing to Nagi through the pain.
My cries vanished into the rain. That day, I was cast out of the team.
~ Three weeks after being expelled from Sato’s crew.
Since then, I’d tried everything to join another team, but no one was recruiting an unranked.
The reason was simple: Raiders typically started at E-rank at the bare minimum.
An unranked was barely different from a Mana-less human, and a normal person couldn’t possibly fight grotesque monsters.
“…I’ll do anything—carry luggage, whatever it takes. Is there any way to find a team?”
“I’m very sorry, but for an unranked Raider… there are currently zero openings. There are teams recruiting for E-rank dungeons, but…”
The Japan Dungeon Association, Tokyo Branch—the global organization managing dungeons worldwide.
I stood in the grand lobby of their Japanese headquarters, pleading with the receptionist.
All around me were fellow Raiders—some exchanging Mana Stones for cash, others accepting missions to tackle Cubes on the brink of a Dungeon Break.
“…Alright. Thank you.”
For days, I’d lingered in this lobby, searching for a team willing to take me.
However, few Raiders operated primarily in low-tier E-rank dungeons, and even those teams had no spare slots.
As expected, I hit wall after wall.
But I couldn’t blame anyone for this.
Everyone was risking their lives to raid—no one had the luxury of taking in a hindrance out of shallow kindness.
I trudged out of the Dungeon Association alone, my steps heavy.
“Damn it!”
That night, in a dark room, I cursed to myself.
Despite all my searching, I couldn’t find a team, and the Association wouldn’t bend the rules just because I had a sick sister.
The deadline was closing in, and between the uncertainty of my future and sleep deprivation, my frustration boiled over.
“Onii-chan?”
Nagi woke up, hearing my voice.
“Ah, sorry…”
“Onii-chan… You need to rest, okay?”
Nagi said, eyeing the dark circles under my eyes.
These past few days, I’d been running around nonstop, too anxious to settle down and rest.
“…How could I rest? Who do you think I’m doing all this for?”
My irritation made my words sharp.
Why did I say that?
Shut up—Nagi didn’t do anything wrong. Stop it.
I knew it in my head, but I couldn’t control my emotions.
“What if you fall and get hurt again? Go back to bed…”
“B-But…”
“Stop it. Go to sleep…”
“Onii-chan, I… Normally, Onii-chan…”
“All you can do is sleep, so go to sleep already!!”
The moment the words slipped out, a jolt ran through me.
That was the worst thing I could’ve said. No matter how frustrated I was, I shouldn’t have let that escape my mouth.
I didn’t mean to say it.
“S-Sorry. Thank you… for always taking care of me… I was just scared and wanted you to stay with me… I’m sorry.”
Nagi stammered before hurriedly pulling the blanket over herself.
“I love you the most, Onii-chan. Good night.”
Then she fell silent, and I missed my chance to apologize.
“…What am I even doing…”
I smacked my own head, resolving to apologize to Nagi in the morning.
~ The next morning.
“Good morning, Nagi… About yesterday…”
“Onii-chan… huff, huff… Good… morning…”
“Nagi!”
When I approached Nagi’s bed to apologize that morning, she was visibly weaker.
Her breathing seemed labored, her lungs struggling, her body unresponsive.
I scooped her up immediately, but her body was unbelievably cold.
“Nagi! Are you okay!?”
“It’s scary… Onii-chan, I’m so scared…”
“I’m taking you to the hospital right now!”
I hoisted her onto my back and rushed out without even locking the door.
Her limp body had no strength, and all I could hear from behind me was faint breathing.
My pounding heartbeat wasn’t from exhaustion—it was the ominous dread swirling in my mind.
Nagi was currently in the second stage of Amyotrophic Mana Sclerosis.
Her mobility was limited, but she could still breathe on her own and walk short distances, so hospitalization wasn’t necessary.
But if her condition worsened—
“Hold on! Nagi, we’re almost there! You’ll be fine! I’ll stay with you—you’ll be okay!”
She’d never open her eyes again.
Not until the moment of death—no, not even after death.
I prayed to a god I didn’t even believe in, casting aside exhaustion as I sprinted to the hospital.
The National Raider Specialty Hospital.
A top-tier facility in Japan, dedicated to treating Raiders’ injuries and aftereffects, as well as caring for their families or survivors.
It was one of the government’s policies to encourage more people to become Raiders.
Gasping for breath, I carried Nagi on my back and begged the receptionist for help.
A doctor arrived immediately.
He was a bespectacled man in his thirties, clad in a white coat—a serious-looking yet gentle physician who genuinely cared for his patients: Dr. Ijuin.
“Doctor! Nagi, she—”
“Ash… Bring her this way, quickly.”
The doctor led us to a room, and I laid Nagi down on the bed.
He began his examination while I stepped outside, clasping my hands against my forehead, eyes shut in prayer.
My legs were trembling.
A few minutes later, the door opened, and Dr. Ijuin stepped out.
He said the words I dreaded most.
“Doctor!”
“Ash, I don’t know how to say this… Her condition has progressed to Stage Three. She’ll need to be hospitalized and kept alive through intubation… It’s all been arranged, so there’s no immediate worry, but… I’m afraid it’s likely already…”
“H-How could this happen!?”
Stage Three was practically a death sentence.
No matter how much effort she put in, her body would be as if bound tight—breathing would be a struggle.
She wouldn’t even have the strength to open her eyes, quietly trapped within herself.
“Doctor! Isn’t there—Isn’t there something we can do!?”
“…I’m sorry. There’s no treatment for this disease yet. Mana still holds too many mysteries… Modern medicine is powerless. All we can do is prolong her life. Her ears should still work, so at least she can hear your voice…”
I knew that.
I knew all of it, but I still begged the doctor for another way.
The answer, though, remained the same.
Ijuin-san bowed his head in apology and left.
Soon after, specialized medical equipment was brought in and attached to Nagi.
I stayed by her side, holding her hand.
Her hand was so cold, as if no blood flowed through it.
But her eyes were still open.
She looked at me, fighting to keep them from closing.
“Nagi…”
Just yesterday, she’d been able to smile. I hadn’t noticed her symptoms had worsened this much.
They say the signs before Stage Three resemble anemia—a persistent inability to stand properly.
Her body would gradually stop moving, feeling like it no longer belonged to her. How terrifying must that process be?
Yet Nagi always wore a smile.
She hid her pain, just so I wouldn’t worry.
Yesterday, she must’ve been terrified.
And yet I’d said those awful things to her. When she said she loved me, I didn’t respond—I didn’t even tell her how I felt.
“Ugh, ugh, Nagi… I’m sorry, I’m so sorry…”
Nagi, barely able to keep her eyes open, looked at me as I gazed back at her.
I couldn’t believe it. I’d never see her smile again.
Millions worldwide suffered from this disease.
Ever since humanity awakened, people had been desperately searching for a cure—maybe one day they’d find it.
Until that day, I wanted to prolong Nagi’s life as much as possible.
To do that, I couldn’t give up my Raider status.
“Nagi… Onii-chan will keep trying. I’ll fight… I’ll save you from this, I swear…”
I wiped away my tears and gripped her cold hand tightly.
Looking straight into her eyes, I made up my mind.
Even if I had to do it alone, I’d raid a dungeon.
Even if I failed, a Raider who died in a dungeon wouldn’t lose their status—instead, their family would receive condolence funds.
So if I died, Nagi should, in theory, still be able to continue her treatment.
I repeated the words I hadn’t said yesterday.
“Nagi… I love you the most—I really, really love you!”
I said it again, squeezing her hand tightly once more.
“I… know…”
With a hoarse voice, Nagi mustered the last of her strength to give me a smile.
She gripped my hand weakly yet firmly before slowly closing her eyes.
That day, I talked to Nagi late into the night.
I knew there’d be no reply, but I kept speaking anyway, then stood up.
“Nagi, Onii-chan will save you. I promise I will.”
My resolve was firm.
“Even if it costs me my life.”
I’d charge forward without hesitation.
◇ At the same time, Shibuya, Tokyo.
“Huh, what’s that thing?”
Right in the middle of Shibuya Crossing.
The green light flashed, and streams of pedestrians crisscrossed the intersection.
One of them pointed at the sky, seemingly noticing something.
Eyes followed the direction of his finger, one by one tilting upward.
A golden, square-shaped object was drifting slowly down from the heavens, gleaming brilliantly.
It was evening, in the height of summer.
The object’s golden glow rivaled the fiery red of the setting sun as it descended toward the ground.
“Huh, is that…”
“A Cube!! Isn’t that a Cube!?”
“A Cube!? A golden one!? I’ve never heard of that color before!”
One after another, pedestrians pulled out their phones to snap pictures.
Known as Cubes, these boxes served as gateways to otherworldly realms.
This one floated down like a leaf, defying gravity with its gentle descent.
People scattered, watching to see where it would land.
The pedestrian signal changed, and car horns blared all around.
Silently and slowly, the Cube touched down in the noisy center, radiating an unprecedented golden brilliance.
~ The next day.
“A golden Cube?”
As I made up my mind and headed to the Dungeon Association, I spotted an emergency recruitment notice posted there.
The notice called for volunteers for the first investigation team to explore the sudden appearance of a golden Cube, with the words “no rank restrictions” written prominently.
“No rank restrictions… Does that mean even an unranked like me can join…? The reward is… one million!?”
I stared at the details below the notice, my eyes glued to the page.
I decided to ask the receptionist what this was all about.
“Yes, that’s correct. Anyone who participates will receive one million yen from the Association.”
“What!? No way! W-Why!?”
“To be honest, we have no idea what’s inside, so we’re forming the first investigation team. But hardly anyone’s willing to join. Since we can’t assess the situation inside or determine the required ranks, people are hesitant to sign up…”
“I see… S-So, even someone unranked like me can join?”
“Yes, no problem. Even if you can’t fight, you can still help carry supplies or assist the team. It might take quite a while, after all.”
“Then what about the monthly raid quota…?”
“Since this is a special Cube, joining the investigation team will count as completing a dungeon raid.”
“I-I’ll join!! Ash Tenchi! Sign me up for the golden Cube!”
I answered without hesitation.
I couldn’t possibly clear an E-rank dungeon on my own—I’d just end up as fodder.
So, even though it might be dangerous, the promise of one million yen and counting grunt work as a raid made this an incredibly appealing offer to me.
“No problem. I’ll register you now. Please provide your Raider certification.”
“Sure.”
I pulled a card from my wallet, similar to a driver’s license.
The rank field read “Unranked,” and it contained my details as a Raider.
The certification also listed my last raid date—three weeks ago, when Sato kicked me out of the team.
“All set. Mr. Ash Tenchi, the start time is this Saturday, August 6th, at 1:00 PM. Please arrive on time. The participation fee will be paid after you return from the dungeon.”
“Got it.”
She handed me a sheet of paper detailing the dungeon raid specifics.
Even though the Cube had appeared just yesterday, their efficiency was impressive.
That said, with an unknown dungeon, no one knew when a Dungeon Break might occur—there was no time to waste.
After completing registration that day, I left the Dungeon Association.
Back at the rundown apartment, I started maintaining my gear.
My only Mana-infused weapon was a waist-length iron sword.
Though it was a cheap, heavily worn blade, it still cost over 100,000 yen.
Issued by the government upon becoming a Raider, it was my sole Mana-imbued sword.
Even someone like me could gain a measure of strength by wielding it, drawing power from the act of swinging it.
I’d become a Raider right after graduating high school and had been using this same sword for the past four months.
In the cramped six-tatami-mat room, I sharpened the iron sword.
In a room lit only by moonlight, with no lights on, I worked alone.
The space was tiny, yet lately it felt strangely spacious.
And so quiet—almost lonely.
~ Saturday, the Day of Destiny.
“Alright.”
I looked at a family photo on my phone—my parents and Nagi.
With a small nod, I strapped the sword to my waist and headed to the meeting point: Shibuya Crossing.
About fifty Raiders had gathered there.
The intersection was cordoned off, the once-bustling road now deserted.
Perhaps to guard against a Dungeon Break, few people passed by.
I checked in at a temporary registration tent, confirming my participation.
“So many people… This is my first time joining such a big team. Are those… foreigners?”
Judging by their gear, some were clearly high-ranking Raiders.
And over there—U.S. military? A group of about ten wore foreign military uniforms.
Everyone looked strong—surely upper-tier Awakened.
And then, there they were.
“Hahaha, one million yen each just for this!”
“Let the pros handle the fighting!”
“Exactly! We’ll just hang back and watch the show.”
Sato and his crew had joined too.
I ducked behind the others, hoping to avoid their gaze.
But Sato’s sharp eyes spotted me almost instantly.
“Hahaha! You’re here too, huh? Couldn’t resist that million yen, you broke bastard?”
“…”
“…Hey! Ignoring me, huh? Watch it, or I’ll kill you!”
I turned my eyes away, silently fuming, and Sato grabbed me by the collar.
He looked ready to punch me on the spot, but with so many Raiders around, he didn’t dare go too far.
Several people turned toward us at the sound of his voice.
“Tch! Asshole.”
Sato shoved me aside and stormed off.
I wasn’t part of their team anymore—I didn’t have to grovel.
Even so, standing up to him made my legs tremble slightly, though it felt satisfying.
At that moment, a man stepped up to the golden Cube.
“Attention, everyone!!”
His shout drew the focus of every Raider present.
He was in his thirties, someone I felt I’d seen before…
Dressed in a suit, he exuded an elite aura.
That suit was likely custom-made from monster materials.
A cool older guy? He gave off a sharp, competent vibe, wearing glasses with a scar over one eye.
“I’m Issei Tanaka! Vice Guildmaster of ‘Avalon’!”
The crowd erupted at his words.
That was Avalon Guild—a name even I recognized as Japan’s top Raider organization.
One of the world’s leading guilds, it was the largest and strongest in Japan, home to a handful of the country’s rare S-rank Awakened—elite individuals who ranked among the best globally.
“Thank you all for volunteering to risk your lives today and enter this unknown dungeon. Our guild has been entrusted by the Japanese government and the Japan Dungeon Association to oversee the investigation and conquest of this golden Cube. I’ve been appointed as the leader of this raid, and I ask for your cooperation. Now, let’s go over some key points!”
For this operation, Tanaka-san would serve as the team leader.
Not only did he have an impressive track record, but he was also an A-rank Raider himself, so no one objected.
He gave a concise rundown of precautions and the battle plan.
However, since the interior was still a mystery, it was mostly an explanation of the chain of command and similar logistics.
The term “chain of command” was likely chosen with the American soldiers in mind.
While Tanaka-san was technically in charge today, the U.S. military seemed to operate under a separate system.
It felt like they were planning some kind of military intervention, though I didn’t really understand the political intricacies.
The briefing finally concluded.
Tanaka-san glanced at his watch, then issued his orders, his voice booming louder than before.
“It’s now 1:15 PM! Is everyone ready!?”
The Raiders responded by raising their weapons in unison.
Led by Tanaka-san and his group, everyone gathered around the Cube.
“Let’s move out!”
With that, the group stepped toward the Cube.
Renowned high-ranking Raiders surrounding it vanished inside one after another.
“Alright! Let’s go!!”
Sato and his crew followed suit, mid-tier Raiders disappearing into the golden Cube.
And then…
“Okay… Here I go.”
I gripped my sword and walked forward slowly.
It was as if I could hear my own heartbeat, growing faster and louder.
Before me stood a box that gleamed like pure gold.
Its golden walls shimmered, rippling like a luminous water surface.
I hesitated, then touched it lightly.
The surface stirred with faint ripples, like a drop falling into water, accompanied by a clear, bell-like chime.
“Hoo… Alright!”
I clenched my fists and stepped forward with determination.
Not knowing what awaited me, I carried a mix of anticipation and unease—
And entered the golden Cube.
…
“Qualification for the Divine Knight Selection Ritual has been met. Current number of participants: 60…”
——.
Chapter 2 Part 1