(Arin's POV)
The world around me had mutated into a sickening sulfur-yellow hell.
It was not the warm yellow of the morning sun promising new hope, but a sickly yellow, thick and deadly. The heavy methane gas mixed with sulfur dioxide, cunningly pumped by Vesper through hidden ventilation ducts, had now filled this cavern completely without leaving any pocket of clean air. The oxygen that should have sustained lungs had now turned into choking poison.
Visibility inside the cave was no more than three meters ahead. Beyond that narrow radius, everything was just blurry silhouettes swallowed by thick chemical fog.
"Ugh... Arin... my chest... it hurts so much..."
Beside me, safely hidden behind a large damp stalagmite, Erika curled up clutching her chest tightly. Her face was beet red like a boiled crab, her eyes watering severely until tears flowed incessantly, and blue veins in her neck bulged tensely as if about to explode out of her skin.
"My head... feels like it's going to shatter into pieces..." moaned Tom beside her. Saliva dripped uncontrollably from the corner of his mouth which was clamped shut holding back pain. His body trembled violently, not from the cave's cold, but from the systemic shock attacking his body suddenly.
They were suffering greatly. Yet ironically, their current suffering was not caused by the poison gas surrounding us, but by the antidote they had just swallowed.
Micro Oxygen Capsules.
The small marble-sized objects they had just swallowed released high-pressure pure oxygen directly inside the oral cavity, then forcibly absorbed into the bloodstream. For laypeople unaccustomed to the Piston Heart breathing method or body modifications like me, the sensation must be like swallowing a smoke grenade exploding inside the throat.
Acute Hyperoxia.
Their blood was suddenly saturated with oxygen in massive amounts. Blood vessels experienced sudden vasoconstriction, causing skull-splitting headaches and torturous burning sensations in the lungs.
But that pain was a cheap price for staying alive.
"Hold on a moment, do not fight it," I whispered calmly, trying to soothe them. My voice sounded slightly different in my own ears, feeling heavier and echoing inside my head. "That pain means you are still breathing. Do not vomit the capsule, or your lungs will be scorched by sulfur in seconds."
I myself stood tall, leaning my back against the cold stone wall. My body, brutally modified by the Grizzly Serum and tortured by Brook's gravity training, absorbed the oxygen surge greedily.
Instead of pain, what I felt was... extraordinary sensory sharpness.
My senses increased drastically. My pupils shrank, catching every dust particle floating in the yellow fog clearly. My ears heard the sound of dripping water in the distance as clearly as a church bell. Even Tom's panicked heartbeat sounded like war drums beating in my ears.
THUMP... THUMP... THUMP...
I glanced at my mechanical watch with its slightly cracked glass.
Fifteen minutes had passed since the explosion closed the cave door.
"Vesper, you are so slow," I mumbled impatiently. "Are you drinking tea while waiting for us to suffocate?"
CRACK.
The sound was faint to ordinary people, but to me, it sounded like a loud explosion amidst the silence.
It was the sound of very unnatural stone friction.
Not from the direction of the main door ruins buried under tons of rock. The sound came from the dark corner of the cave at two o'clock.
"They are coming," I hissed sharply. "Take positions now! Do not make a sound!"
Erika and Tom, despite being in half-dead pain, forced their bodies to move. They crawled deeper behind the rock shadows, holding their breath and moans so as not to be heard by intruders.
I remained standing still like a statue, letting the yellow fog envelop my figure completely.
The stone wall in the corner of the cave vibrated slightly. Then, with a muffled rumble, the center of that wall collapsed inward. It was not a natural collapse. It was Earth Magic: Earth Crumble performed with precision to open a rat path.
A human-sized hole formed in the wall.
From behind the hole, orange light beams from magic torches pierced the fog. Shadowy figures began to emerge one by one, stepping into our kill zone.
One person... two people... five people... until ten people entered.
They wore standard academy light armor coated with sound-dampening cloth. Their faces were tightly covered by Magic Gas Masks. The mask shape resembled an insect snout with two filter tubes on the cheeks, making them look inhuman and terrifying.
That was Karl's 'Cleanup Squad'. Hired lackeys from Class B paid handsomely to ensure this dirty work was finished without witnesses.
They moved casually. Their weapons were drawn but lowered. Their body posture was relaxed, full of misplaced confidence.
"Check this area," one of their voices sounded muffled and metallic from behind the mask. "Make sure the targets are dead. If anyone is still twitching, just slit their throat to be quick. Boss said we have to make a scenario where they killed each other out of panic running out of breath."
"It smells so rotten here," complained another while waving his magic torch left and right. "The methane gas is thick. Impossible for anyone to survive more than ten minutes without a mask."
They spread out forming a fan formation, combing the cave casually. They were looking for corpses, not fighters. They were sure we had become stiff and lifeless lumps of blue meat.
I smiled thinly behind the thick fog. My teeth felt itchy wanting to bite.
They brought fire into a gas cave. So stupid. But fortunately, the methane concentration was not yet high enough for a thermobaric explosion, or we would all have been roasted dead.
I did not draw the Adamantium sword on my back. The sound of drawing the sword would give away my position.
Instead, my hand reached into my cargo pants pocket slowly. My fingers grasped a handful of small red capsule pellets. The remaining stock of Micro Oxygen Grenades.
I took one pellet, weighing it in my hand carefully.
"Let's teach them a little basic physics," I thought.
I stepped out from behind the stone pillar, deliberately making heavy and clear footsteps.
TAP.
The ten gas-masked heads turned simultaneously toward me in shock.
Their eyes widened behind the protective glass seeing me standing tall in the middle of the poison fog. I stood without a mask, without any protection, staring at them with eyes glowing red due to the drug's effect.
"He... he is still alive?!" shouted the squad leader with a panicked voice of disbelief. "That is impossible! Sensors say oxygen is zero!"
"How can he breathe here?!" chimed in another trembling, stepping back.
"Do not ask questions! Kill him! Attack now!"
The three frontmost people immediately charged forward. They raised their weapons, intending to slash my neck.
But I was far faster.
I flicked the capsules with my thumb, using the flicking technique I practiced to throw scalpels.
Zip. Zip. Zip.
The red pellets shot through the fog with high accuracy.
Target: Enemy gas mask glass.
Micro oxygen capsules were designed to explode upon impact or hard collision. Inside, a chemical reaction produced instant gas expansion with hundreds of PSI pressure.
TING.
The first capsule struck right in the center of the frontmost student's mask glass.
POP!
A small explosion occurred. Not fire, but an explosion of compressed pure air pressure. The gas mask glass, designed to withstand physical impact, was not strong enough to withstand zero-distance barometric pressure shock concentrated on one point.
CRASH!
His mask glass shattered into pieces, exploding inward injuring his face.
"ARGHHH!"
The student screamed hysterically. Glass shards pierced his face, but worse was what happened next. His airtight seal was totally broken.
The thick yellow methane and sulfur gas in the room immediately rushed into his mask, inhaled deeply by his shocked lungs.
"Cough! Urgh!"
He dropped his sword, scratching his own neck, coughing violently until vomiting blood.
His two friends were distracted seeing their comrade fall in a horrific way.
TING. TING.
POP! POP!
Two more small explosions were heard in succession. Two more masks shattered apart.
"My mask! My eyes sting!" shouted one of them while covering his face.
Chaos broke out instantly. Their combat formation shattered. They panicked, not because of my attack, but because the air they breathed suddenly betrayed and killed them.
"Hold your breath! Take off the masks now!" shouted their leader, but his voice was swallowed by mass panic.
"Now is my turn," I mumbled softly.
My body shot forward charging into that chaos.
I did not use a sharp weapon; that would leave wound traces difficult to explain in court later. I used my body as a deadly blunt weapon.
My stamina was at its peak thanks to oxygen doping. My muscles were flooded with energy-rich blood.
I emerged from the fog right in front of the fourth student who was trying to take off his cracked mask.
THUD!
My fist struck his solar plexus with accurate surgical precision.
He folded in two instantly, his eyes bulging out, his diaphragm totally paralyzed due to impact shock, then collapsed silently.
I spun fast, my right leg sweeping the floor strongly.
SPLAT.
Two other students trying to approach tripped and fell due to my leg sweep. Before they could get up, I stomped on their wrists holding weapons.
CRACK.
Bones cracked. Weapons released from grips.
"Erika! Shoot their legs now!" I shouted while parrying a dagger attack from the seventh student with my armor-coated arm.
From behind the rock, Erika appeared. Her face was still red and wet with tears of pain, but she raised her staff trembling yet determined.
"Mana Bullet..." Erika's chant sounded weak and stuttering, but her accuracy was deadly.
Thud-thud-thud!
Three blue energy bullets launched, hitting the knees of three students trying to run back to the rat hole.
"ARGHH! My legs! My legs are destroyed!"
They fell prone, clutching their destroyed knees while moaning.
Only one person left. The squad leader.
He stood trembling near the exit hole, holding a short sword with two wobbly hands. His mask was still intact, but his courage was shattered seeing nine comrades incapacitated in less than a minute.
"D-Do not come closer! I... I am from the Baron Valois Family! My father will punish you if you touch me!" he threatened with a shrill terrified voice.
I walked casually toward him, ignoring the empty threat completely. My footsteps echoed terrifyingly on the cave floor.
"Your father is not here to save you," I said coldly. "And the air is getting thinner, isn't it?"
I flicked one last capsule into the air, caught it again, then stared at him sharply.
He looked at the red capsule in my hand with horror, imagining his mask shattering and the gas entering burning his lungs.
"Back off! Stay away from me!" he shouted hysterically, swinging his sword wildly.
I threw the capsule.
He reflexively covered his face with his hands, dropping his fragile defense.
But I threw the capsule at his feet.
POP!
A small explosion near his feet shocked him half to death and he jumped.
Taking advantage of that gap, I moved forward quickly, grabbed his armor collar, and slammed him into the cave wall hard.
BANG!
His head hit the stone. He slumped unconscious instantly. His mask cracked slightly, but he was still breathing.
Silence.
The ten "assassins" were now sprawled on the cave floor. Some fainted from punches, some convulsed from inhaling gas, some moaned holding shattered knees.
I stood amidst the fallen bodies, regulating my breath. White steam came out of my mouth every time I exhaled.
My head turned to the hole in the wall where they entered.
"This must be a rat path," I mumbled softly. "Vesper must have made this so his troops wouldn't be affected by the main explosion up ahead."
I walked closer to Erika and Tom. Tom stared at me with eyes wide open, as if I were a monster more terrifying than the Dungeon itself.
"You... you finished them all..." whispered Tom in disbelief. "Without a sword... only with bare hands..."
"They panicked, Tom. And panic makes people stupid," I answered while helping Erika stand. "Can you walk?"
Erika nodded weakly, though her face still grimaced holding back pain in her chest. "Hurts... but I am okay. Your medicine is crazy, Arin. Tastes like swallowing fire."
"We will discuss side effects later," I said. "Now, we have an important appointment."
I stared at the hole in the wall. Thin yellow smoke began to be sucked out through that hole due to air pressure difference.
"They were kind enough to open the back door for us," I said with a cold smile carved on my lips. "It feels impolite if we do not go out and greet the host waiting out there, right?"
(Vesper's POV - Outside the Warehouse)
Outside the Warehouse, the forest wind blew cool, a stark contrast to the tension poisoning the atmosphere between us.
I stood stiffly beside Karl Benzzi, my eyes fixed on the gold pocket watch in my hand. Its second hand ticked with a rhythm that felt increasingly slow and mentally torturous.
Tick. Tock. Tick. Tock.
"Twenty minutes since the explosion," I reported flatly, trying to hide the anxiety starting to grow in my heart. "And five minutes since the Cleanup Team went inside. They should have come out carrying corpses by now."
Karl paced back and forth restlessly, stomping his feet on the ground roughly. His face was red, his eyes wild with impatience. He was like a spoiled child waiting for a birthday present that never came.
"Why is it taking so long?! How hard is it to behead corpses that already suffocated?!" snapped Karl in frustration, kicking a pebble far into the bushes. "Are they having a party in there?!"
Suddenly, my nose caught an unpleasant smell. A sharp and piercing sulfur smell.
"Sir," I pointed to the gaps in the rubble rocks and the rat hole just opened by the cleanup team on the hillside.
Thin yellow gas began to seep out from the rock cracks. The gas pressure inside the cave was apparently so high it started leaking out. The cave wind carried the gas toward us.
"Cough!" Karl coughed, covering his nose with his expensive sleeve. "Damn! The gas is leaking here! It smells disgusting like rotten eggs!"
I immediately analyzed the situation. "This is dangerous, Sir. The concentration is quite high. If the wind changes direction, we could be poisoned here."
I turned back.
There, Kars Benzzi stood still like a statue. He looked down, his face hidden in the shadow of his hair. On his back, he still carried a large wooden box labeled [RESERVE SUPPLY] with the Benzzi Faction stamp.
"Kars," I called sharply. "Open the box immediately. Take out spare gas masks for me and Master Karl. Do it now."
Kars jolted in surprise, as if just waking from a nightmare. He lifted his face which was very pale like a shroud. Cold sweat flowed profusely on his temples.
He looked at me, then looked at Karl with eyes trembling in fear.
"W-What? Must be now?" asked Kars stuttering, his voice cracking from nervousness.
"Now, Fool! You want me to die poisoned?!" snapped Karl, his eyes bulging angrily. He stepped closer to his brother threateningly. "Open it quickly! What is the use of you carrying it if not used?!"
Kars lowered the box with violently trembling hands. His movements were slow, too slow. He knelt on the ground, his fingers stiff as he tried to open the wooden chest lock.
My eyes narrowed behind my glasses.
Something was strange. Why was he so nervous? It was just an ordinary mask box.
"Hurry up!" urged Karl, impatient. He kicked the side of the box lightly.
Click.
The lock opened.
Kars opened the chest lid slowly, as if he were opening a coffin containing a rotting corpse.
Karl immediately reached inside roughly, wanting to grab a gas mask.
However, his hand stopped frozen in the air.
Karl's face changed drastically. From angry to confused, then to total shock.
"What..."
I stepped forward, craning my neck to see the contents of the box with my own eyes.
Empty.
Inside the large wooden chest, there was no pile of magic gas masks. No antidote potions. No spare oxygen tanks.
There was only a pile of river stones arranged neatly for weight, and a piece of shabby paper on top with rough handwriting:
'Sorry.'
Silence.
The forest wind blew cold, but my blood felt frozen instantly. My calculation... collapsed apart.
"What... is this?" whispered Karl, his voice trembling holding back an explosion of emotion. He stared at the contents of the chest, then stared at his brother with a murderous gaze. "Kars... where are the masks? Where is all the equipment?"
Kars took a step back, his face pale as a walking corpse. He shook his head in panic, tears starting to come out of his eyes.
"I-I do not know! I swear to God! This morning I put them in! I saw it myself!" Kars shouted hysterically, his voice shrill with fear. "Must be... must be someone stole them! There is a thief in the dorm! Someone swapped them when I was careless!"
"STOLE?!" Karl roared loudly, grabbing Kars's shirt collar and lifting him until half-standing. "WHO COULD STEAL FROM OUR WAREHOUSE?! YOU BETRAYED ME?!"
"No! Impossible for me to betray you, Brother! I am your own brother! I am your flesh and blood!" Kars cried hysterically, kneeling hugging Karl's legs tightly. "I know nothing! Please believe me!"
I froze in my place. My brain spun at the speed of light, calculating probabilities. Kars was too stupid and cowardly to commit sabotage this bold alone.
But the fact remained... we were now standing in the middle of a poison gas leak without any protection at all.
Our logistics were destroyed. Backup plan vanished. The Cleanup Team in there had no backup if their masks broke. And we out here were exposed to danger.
"Master Karl," I called, my voice tense for the first time. I tried to remain rational amidst this chaos. "We must retreat now. Without masks, this position is not strategic and dangerous. Gas concentration is increasing. We are exposed to our own poison."
"NO!" Karl pushed Kars until he fell backward to the ground roughly. His brother rolled in the mud crying. "I WILL NOT RETREAT UNTIL I SEE ARIN'S CORPSE! I WILL WAIT HERE UNTIL HE ROTS!"
"But Sir, your lungs—"
THUMP... THUMP...
The sound of heavy and firm footsteps was heard.
Not from the direction of the forest where we came from. But from behind the bushes covering the secret hole, the entry path of the Cleanup Team earlier.
Karl stopped raging. He turned quickly toward the sound.
A crazy wide smile slowly bloomed on his beet-red face.
"Ah! That is them!" exclaimed Karl with a terrifying euphoric tone. "They returned! Finally! They bring good news!"
Karl stepped forward approaching the smoke, spreading his arms as if welcoming a war-winning hero.
"Bring the corpse here! Throw it at my feet! Let me spit on it!"
Yellow smoke billowed out of the secret hole, blown by the wind. A shadow appeared from behind the smoke, penetrating the poison fog casually.
However, as the figure became clearer, the smile on Karl's face began to fade slowly.
It was not a student in full cleanup squad armor.
The figure did not wear a helmet. He did not wear a gas mask.
He wore a white shirt now dirty with gray dust and dried blood stains. His sleeves were rolled up neatly, revealing tense muscles.
He walked upright, relaxed, while patting dust off his shoulder as if just finished an afternoon walk in a beautiful park, not exiting a deadly gas chamber.
His blue eyes, now slightly red and watery due to drug side effects and gas irritation, stared sharply through the smoke. That gaze locked straight on Karl.
It was Arin.
Behind him, Erika walked haltingly holding her magic staff, her face beet red but alive. And Tom Garius walked behind with a tired face but his eyes radiating pure hatred at Karl.
The smile on Karl's face froze completely. His eyes widened to the maximum limit, red veins appeared in the whites. His mouth gaped, but no sound came out. His face, red from anger, now turned chalk white in an instant.
As if he had just seen a ghost rise from the grave in broad daylight.
I too took a step back unconsciously. The notebook in my hand slipped and fell onto the wet ground.
Impossible.
My calculation... was wrong?
Methane gas concentration eighty percent. Exposure time twenty-five minutes. Probability of survival without aids: Zero percent.
Why was he still standing?! Why didn't he die?!
Arin stopped five meters in front of us. He did not look dying. He looked... angry.
He looked at Karl, then glanced at Kars who was still kneeling on the ground. And I swear, by God, I glimpsed a terrifying thin smirk on Kars's face before he put his frightened face back on and looked down.
Arin said nothing.
He just spat to the side, getting rid of the bitter taste in his mouth.
Then, he opened his mouth. A small crushed and dented red capsule shell fell from his lips onto the rocky ground.
Ting.
The small sound of the hard shell hitting the stone sounded like a bomb explosion in my silent ears.
Arin stared at Karl straight on, then his lips curled into a cold smile that made my blood run cold.