"Are you possessed, son?"

  Ronald held out a glass of water while looking suspicious, his tired eyes narrowing as he studied Ethan's still-pale face. The neon light in the break room hummed low, creating swaying shadows on the crusted walls.

  Ethan accepted the glass, sipping the water slowly. It tasted metallic, like the rusted pipes in this building. "Not possessed. Maybe the effect of gas on the fifth floor. Or exhaustion."

  "Gas." Ronald repeated the word in a flat tone. "You think I started working yesterday? Twenty years in this dungeon, I know the smell of gas. What you experienced wasn't gas."

  Ethan was silent. At the corner of his vision, the blue screen still waited faithfully with the same notification. Stench Level: 5/100. The inverted triangle symbol in the corridor. The Arcane Explosion incantation pulsing slowly in his chest. All secrets he had to bury deep.

  "My head is dizzy," he said finally, choosing partial honesty. "Nauseous. And there is a strange sensation in my chest. Like something is gnawing at it."

  Ronald exhaled a long sigh. His prosthetic iron arm creaked as he pulled a chair and sat across from Ethan. "Listen, son. I'm not a doctor. But I know one thing: in this dungeon, if your body starts to feel strange, never just stay quiet. It could be a low-level curse that's beginning to take root."

  "A curse?"

  "Or a mana parasite. Or just a psychological effect from seeing too many corpses." Ronald rubbed his face with his real hand. "Whatever it is, you're resting tonight. Tomorrow is the morning shift on the third floor. Another team needs help. But if you're still dizzy, you stay at headquarters."

  Ethan shook his head. "I can work."

  "Can work, or afraid of getting your pay docked?"

  Both of them fell silent. Then, for the first time that night, the corner of Ethan's mouth lifted slightly. "Both."

  Ronald snorted, but behind that snort was a little laughter. "Fine. In that case, you're buying the drinks."

  "My paycheck hasn't come in yet."

  "Put it on credit. I'll pay half later."

  Ethan looked at the old man with a flat expression. "You always find a way to make people feel bad about refusing."

  "Natural talent."

  The Sanitation Headquarters canteen was located on the ground floor, adjacent to the equipment warehouse.

  The twenty-square-meter room was filled with four long tables of rotted wood, one old refrigerator humming louder than the generator, and a cracked glass display case containing instant food. In the corner, a middle-aged man was mopping the floor with slow movements. The night shift was always quiet.

  Ronald ordered two glasses of fermented drink from the automated machine in the corner. The pale yellow liquid flowed into the plastic cups with a splashing sound, leaving a thin froth on the surface. Ethan accepted one cup, smelling its aroma. The smell of alcohol mixed with cheap syrup.

  "Tastes like floor cleaner," he commented after a sip.

  "Have you ever drunk floor cleaner?"

  "Not yet. But if it smells like this, maybe it tastes similar."

  Ronald laughed, a heavy sound that echoed in the empty room. "You're a strange kid, Vance. Six months working here, not once have you asked to transfer teams or complained to the commander. Other cleaners last two months at most."

  "You lasted twenty years."

  "I'm old. No other options." Ronald sipped his drink, his eyes gazing at somewhere outside this room. "Back then, twenty-five years ago, I was a Tier 4 tanker. Part of an expedition team on the 80th floor."

  Ethan raised an eyebrow. Tier 4 on the 80th floor, that was no small achievement. Out there, Tier 4 Rankers were still struggling on floors 20 through 30. The 80th floor was the territory of monsters with Tiers that weren't recorded in any guidebook.

  "My team consisted of five people. A tanker, two DPS, one healer, one support. We went down with the best equipment money could buy, mana-forged armor, elemental weapons, dozens of bottles of healing potions." Ronald stared at his prosthetic arm. "The 80th floor was beautiful. Walls of crystal that reflected light in a spectrum I had never seen on the surface. The monsters there weren't wild beasts, but guardians. They were guarding something."

  "Guarding what?"

  "Never found out. We never reached the core." Ronald drew a long breath. "On the 80th floor, we were ambushed by a swarm. Small monsters the size of rats, but in the thousands. They didn't attack directly, but bit slowly, gnawing at our defenses. As the tanker, my job was to absorb as much damage as possible so the others could retreat."

  He raised his prosthetic arm. "I held out for three hours. Continuously activating [Kinetic Absorption], absorbing every bite, every blow. My team survived. They got out of the dungeon safely. But my arm, the mana that should have flowed throughout my body for regeneration got stuck at the elbow from too much load. The tissue died. Had to be amputated."

  Ethan was silent, letting the story sink in. Outside, the sound of the ventilation machine rumbled faintly.

  "After that, I was demoted. A Tier 4 tanker without a left arm is as valuable as a tanker without armor. No guild would accept me. No team would trust me." Ronald sipped his drink again, more this time. "So I'm here. Carrying the corpses of young people who died from the same mistakes."

  "Why are you telling me this?"

  Ronald looked at him sharply. "Because today, when I found you on the fifth floor, you were holding the Archmage's wrist. Your eyes were blank, but in my eyes there was something. Not fear. Not shock. But awareness. You saw something, Vance."

  Ethan held his breath. In his chest, the Arcane Explosion incantation pulsed faster.

  "I don't know what you saw. Maybe that's your business." Ronald shrugged. "But I know one thing: in this dungeon, people who start 'seeing' things usually don't last long. They're too curious, too bold, and then they die."

  "I'm not bold. I'm just cleaning."

  "Cleaning." Ronald repeated the word in a tone that couldn't be interpreted. "Yes. We're just cleaning. That's a good mantra. Memorize it well."

  He raised his glass. "To the cleaners who are never seen by anyone."

  Ethan raised his glass. "To those who clean without being seen."

  They drank together, and for the first time that night, Ethan felt something warm in his chest. Not an incantation, but something simpler. Connection. A spark of trust still raw, but real.

  The night shift on the third floor began at two in the morning.

  The night cleaning team consisted of only six people. Two of them were Ethan and Ronald, the other four thin young men with tired faces and heavy bags under their eyes. They were seasonal cleaners, kids from The Grime who needed quick money without caring about the risks.

  The third floor of The Infinite Maw was different from the fifth floor. Here, the walls were not black basalt, but white limestone covered in pale green moss. The air was more humid, the aroma of damp earth mixed with something sweet. Perhaps it was the sap of carnivorous plants that had already died. Emergency mana-powered lights were installed every hundred meters, creating circles of dim light in the dark corridors.

  If you spot this narrative on Amazon, know that it has been stolen. Report the violation.

  "Third floor green zone," Ronald murmured while examining the data board in his hand. "Three hours ago a Tier 2 team fought against a Warden Slime swarm. Sixteen corpses, twenty-three monsters dead. Standard cleanup. Collect equipment, neutralize residue, transport to surface."

  "Warden Slime," Ethan repeated, examining the corridor ahead. "Which means there is still a possibility that survivors are hiding in wall crevices."

  "The possibility always exists. But Zero Contact rules: don't touch anything still warm. Let that monster die on its own or adventurers will handle it later."

  Ethan nodded, though his thoughts had already drifted elsewhere. At the corner of his vision, the blue screen was still there, calm, waiting. He was curious. If this system could truly detect "Residual Regret", could he test it here? Among the Tier 2 corpses who had died in vain?

  They began to work. Ethan pulled out his rubber gloves, put on his gas mask, then descended the corridor toward the first area. The bodies lay in chaotic positions, six young adventurer bodies scattered across the floor, remains of Warden Slime dried on the walls in the form of greenish slime. Their equipment was scattered: cheap swords, thin robes, healing potions that had already shattered.

  Ethan knelt beside the first corpse, a young man in his early twenties with a bite wound on his neck. His eyes were open, expression surprised, as though he couldn't believe a Warden Slime could defeat him. The identity card in his pocket read: Lukas Gray, Tier 2 Ranker, Affiliation: Independent.

  Ethan reached for his wrist, pretending to check a pulse that had long since stopped. No vibration. No 10-second replay. Only cold and stiff skin.

  'Maybe Tier 2 isn't strong enough,' he thought. 'Or maybe his regret wasn't deep enough.' He removed the cheap ring from the corpse's finger, placing it in the sample pouch. His movements were efficient, automatic. Six months of training had not been wasted. Behind him, Ronald and the rest of the team were busy with their respective tasks. The sound of sacks being dragged, metal equipment clanking, and occasional quiet curses when they found a corpse that was difficult to lift.

  Ethan moved to the second corpse, third, fourth. None of them produced a reaction. The system in his eyes remained silent, showing no notifications whatsoever. He began to doubt. Maybe yesterday had only been a coincidence. Maybe the effect of touching a Tier 7 Archmage was different.

  Until he arrived at the fifth corpse.

  A thin young man in a worn black robe lay on his side in the corner of the corridor, somewhat separated from the others. Around his neck, a half-torn identity card: Rookie Scout, Name Unreadable. His hand still gripped a short dagger, its tip broken. There were no significant external wounds, but his eyes were peacefully closed, as though he were sleeping.

  Ethan reached for his wrist, and the world stopped.

  A subtle vibration spread from his fingertips, the same as when he had touched Archmage Aldric. The limestone corridor began to fade. The damp smell and slime disappeared. The voices of Ronald and the rest of the team vanished, replaced by a total silence that pressed against his eardrums.

  Light.

  Ethan stood in the same corridor, but in a different condition. The limestone walls were still pristine white, no moss yet, no slime yet. Before him, the thin young man in the black robe stood with his back turned, his body trembling. Around him, three Warden Slimes, round creatures the size of basketballs with glowing red eyes, crawled closer.

  "I should have run the moment I first saw them," the young man whispered, his voice breaking. "But my team is still behind. I'm the scout. My job is to warn them. I have to..."

  He took a step backward, the dagger in his hand raised. The first Slime leaped. The young man dodged, but the second Slime was already waiting on the other side. He was trapped.

  "[Quick Step]," he murmured, his eyes shining with desperation. "I can use [Quick Step] to escape. But my team, they don't know there's a swarm here. If I run, they'll die. If I hold out, I die."

  The third Slime leaped from behind. The young man spun, his dagger thrusting, but the Slime had already latched onto his back, gnawing at his robe.

  "I HAVE TO—"

  Then darkness.

  Ethan was flung back into the real corridor with an impact that made him crash to the floor. His knees struck the limestone, his breath gasping. Before him, the young man's corpse still lay in the same position, calm, peaceful, as though he had never struggled with an impossible choice.

  The blue screen at the corner of his eye flickered.

  [Residual Regret Detected]

  Source: Rookie Scout — Anonymous (Tier 2)

  Final Words: “I should have run the moment I first saw them..."

  Skill Acquired: [Danger Sense] (Tier 2)

  Status: Stable

  Compatibility: 91%```

  [Danger Sense (Tier 2)]

  Effect: Early warning 1 second before physical danger.

  Source: Rookie Scout who died by choosing to hold out for his team.

  Note: High compatibility. No significant side effects.```

  Ethan read the notification with mixed feelings. Rookie Scout. Tier 2. Died because he chose to hold out for a team that might never know of his sacrifice. And now, his ability, [Danger Sense] that he should have used to escape, had become Ethan's.

  In his chest, the degraded Arcane Explosion incantation still pulsed. But this new skill felt different, lighter, more natural, like putting on a glove that had been perfectly formed for his hand.

  "Vance!"

  Ronald's voice broke through his reverie. The old man came running from the end of the corridor, his face tense. "What's wrong with you? I heard the sound of falling."

  Ethan rose, brushing his knees. "Tripped. The floor is slippery."

  Ronald looked at him suspiciously, but didn't argue. "Be careful. There's a lot of Slime residue here. If you slip and fall, you could get hit by acid residue." He extended his hand, helping Ethan up. "You're pale again. Want to rest?"

  "I'm fine."

  "Standard answer." Ronald snorted. "If you pass out again, I won't carry you home. Too heavy."

  "You carry corpses heavier than that every day. I must be lighter."

  Ronald laughed, a rough laugh that echoed in the quiet corridor. "Damn you, Vance." He clapped Ethan on the shoulder, then turned back to his task. "Finish this sector within one hour. The transport team is already waiting on the surface."

  Ethan nodded, watching Ronald's retreating back. Then he returned to the Rookie Scout's corpse, kneeling once more. This time, not to harvest, he had already gotten that, but to do something he had never done before.

  He straightened the young man's robe. Closed his already-shut eyes. And whispered quietly, "You made the right choice. Your team survived because of your warning."

  There was no reply. No system notification. But somehow, the air around him felt a little warmer.

  The work continued.

  Ethan and the team cleaned corridor after corridor, collecting equipment, neutralizing mana residue, transporting corpses to the collection area. A monotonous routine, but this time Ethan did it with a new awareness. Every corpse he touched might hold a story, might hold a skill he could collect.

  But not every corpse yielded regret.

  Of the sixteen Tier 2 adventurer corpses, only three possessed Residual Regret strong enough. That scout was one. The other two: a healer who had failed to heal himself, giving him [Lesser Regeneration] Tier 2, and a swordsman who had hesitated to use his final slash, giving him [Iron Skin] Tier 2. Small skills, low Tier, but for Ethan, who had until now relied only on a weak body and instincts, these were treasure.

  He stored them in the Ledger, feeling a foreign warmth in his chest. Three new skills. Three lives that had ended with regret.

  When the team rested for half an hour, Ethan sat in the corner of the corridor, opening his system screen.

  [THE DUNGEON CLEANER'S LEDGER — STATUS]

  Name: Ethan Vance

  Tier: Novice Sweeper (Tier 2)Grade: E

  [BODY]

  STR: 12

  DEX: 14

  VIT: 11

  [MIND]

  PER: 15

  INT: 10

  WIL: 12

  [CORE]

  STA: 70/100

  CAP: 100

  EXI: 8 (Authority)

  STORED SKILLS:

  1. [Arcane Explosion (Degraded)] — Tier 4 (Source: Archmage Aldric Vane)

  Compatibility: 83% | Stability: Low

  2. [Danger Sense] — Tier 2 (Source: Rookie Scout — Anonymous)

  Compatibility: 91% | Stability: Stable

  3. [Lesser Regeneration] — Tier 2 (Source: Healer — Anonymous)

  Compatibility: 78% | Stability: Stable

  4. [Iron Skin] — Tier 2 (Source: Swordsman — Anonymous)

  Compatibility: 72% | Stability: Stable

  STENCH LEVEL: 5/100

  Effect: Normal — Monsters do not react specially.

  Four. Still far from the hundreds of skills he could collect, but this was a start. And more importantly, he was beginning to understand the pattern. The greater the regret, the stronger the skill harvested. That scout didn't have great skills, but his regret was pure. He died by choosing others. That was why his compatibility was high.

  Ethan drew a long breath, closing the screen. In the corridor, Ronald and the rest of the team had already begun packing up. One more hour until the shift ended.

  Suddenly, a piercing sensation at the back of his head. Not pain, but a warning, as though something was gently pulling at his nerve strings.

  Ethan turned quickly to the left, just in time to see a small shadow crawling in a wall crevice, five meters from his position.

  Warden Slime.

  The creature was smaller than what he had seen in the replay, the size of a soccer ball, with a transparent greenish body and dimly glowing red eyes. It was hiding behind a limestone protrusion, still, waiting. Waiting for careless prey.

  [Danger Sense] was working.

  Ethan didn't panic. He stood slowly, pretending not to see, while reaching for the cleaning spray at his waist. The Slime was still motionless, perhaps still hesitating, perhaps still assessing whether he was worth attacking.

  One step. Two steps. Ethan moved away from the Slime, maintaining a safe distance. Behind him, Ronald was busy writing on the data board, unaware of anything.

  "Ronald," Ethan called quietly, without turning. "Behind you, direction eight o'clock. One small Slime."