(Brain Fermentation Room)
One-Punch Man World.
Z-City Underground – Monster Association Headquarters.
"Move it, you worthless scum! If you make the cadres wait for their meal, we're all dead!"
In the dark, damp corridor, a greasy, overgrown Mutated Cockroach Monster waved its antennae frantically, its screeching voice echoing off the narrow stone walls.
The air was thick with the stench of decay and stagnant water. Flickering fluorescent lights, long overdue for maintenance, cast erratic shadows over five misshapen Monsters struggling to haul a massive, blood-soaked carcass.
These five were the lowest of the low. According to the official threat ratings—Wolf, Tiger, Demon, Dragon, God—they barely registered as Wolf-level. Bottom-feeders. Expendable.
Right now, they were grunt labor, dragging the reeking corpse of some unidentified creature through the tunnels. Thick trails of mucus and blood smeared across the crude brick floor, punctuated by their labored footsteps.
Jack, dragging the rear in his hardened insectile shell, wore a vacant expression. Inside, his mind was screaming.
—One minute I'm eating hotpot, the next I'm here? Transmigrated?
—Not just into any world, but One-Punch Man, where the power scale is completely broken!
—And I wake up as a Wolf-level nobody at the bottom of the Monster Association?
This was a nightmare start. Literally hell mode.
And just when he thought it couldn't get worse, his first assignment was revealed:
Delivering a meal to a Dragon-level cadre. Overgrown Rover.
That's right. The six-eyed black dog from the manga. The one who got punched so hard by Saitama he questioned his entire existence and ended up as a house pet.
In the manga, a shrunken Rover looked almost cute. A little derpy, even.
But what Jack and his unfortunate crew were about to face… was the real deal. A genuine Dragon-level monster. A living weapon capable of leveling a city with a few casual energy blasts.
Forget fighting back. All five of them together wouldn't make a decent snack for that thing.
Rumor had it that most delivery teams never came back.
The food was delivering itself.
Facing the very real, very imminent prospect of becoming a Dragon-level dog's appetizer, Jack had zero interest in bonding with his misfit co-workers. He screamed internally, desperate.
—Where's my cheat?
—System? Anybody?
—HELP!
Maybe the chaotic rules of this world favored desperate transmigrators. Maybe his survival instinct was just that strong. Either way, a pleasant chime suddenly echoed in his mind.
[DING! Extreme threat detected. Survival instinct activated…]
[『No Longer Human System』 binding successful!]
Jack sucked in a sharp breath, barely stifling a shout.
His heart hammered—not with fear, but with electric excitement.
—Holy crap, it worked!
A narrow escape!
[——『No Longer Human System』——]
[Host: Jack]
[Current Race: Monster (Unknown Insectoid Mutation)]
[Threat Level: Wolf (Mid)]
(Note: Threat classifications: Wolf, Tiger, Demon, Dragon, God. Further refined into: Shame, Low, Mid, High, Peak.)
[——Ability List——]
[Innate Abilities: 1]
[1. 「Hard Carapace (N)」 Lv3: A steel-hard shell formed from consuming a Monster Cell.]
[Ability Slots: 5/5]
[Origin Points: 0]
[————E N D————]
A flood of information washed over him, and Jack instantly understood his new power.
The "No Longer Human System."
True to its name, it only awakened after you stopped being human.
Its core function was simple: replicate the supernatural abilities of non-human lifeforms. Store them in ability slots. Upgrade them by consuming "Origin Points."
Ability rarity scaled from low to high:
[N (Normal) – White]
[R (Rare) – Blue]
[SR (Super Rare) – Purple]
[SSR (Superior Super Rare) – Gold]
[UR (Ultra Rare) – Red]
Higher rarity meant higher upgrade costs.
He started with five slots. More would unlock as he grew stronger.
Copied abilities began at Lv1. Reach Lv10, and they would permanently integrate into his being, freeing up the slot and even allowing them to transcend their original limits.
To copy an ability, he needed direct contact with the target.
To upgrade, he needed Origin Points—the condensed life force of living things.
And the system made it clear: it didn't have to be his life force.
Got it.
Kill monsters. Get points. Upgrade infinitely.
Jack slowly looked at his foul-smelling "colleagues" and suddenly found them... oddly charming.
The greasy Cockroach Monster. The scrawny Rooster Monster. The Radiation Fish Monster crackling with faint, itchy energy. The grimy, one-eared Rat Monster.
They might look like a collection of rejects and misfits.
But to Jack, they were walking Origin Points.
"Yo, newbie!"
The greasy Cockroach Monster twisted its head toward Jack, compound eyes glinting with arrogance.
"With that shell, you're one of us insect-types, right?"
"You're on food duty. Got it? Senior's giving you a chance here—don't be ungrateful."
Jack: ?
He glanced down at himself—
A humanoid frame, lean and well-proportioned.
His entire body was sheathed in a black, keratinized exoskeleton studded with vicious spikes. His hands were clad in natural armor, tipped with razor claws. He could sense the dark, curved horns atop his head, like those of a longhorn beetle.
At first glance, it did look like living battle armor—insectoid, formidable.
But...
You want me to walk to my death just because we look alike?
And you're calling that a "senior's opportunity"?
Who do you think you are?
The Cockroach Monster's expression had shifted to something threatening. The other three Monsters nodded along, their dull eyes gleaming with encouragement and barely concealed schadenfreude.
Jack barely registered their ugly faces. His attention was locked on the translucent information panels that had materialized above their heads like NPC tags—
[ Monster: Mutated Cockroach ]
[ Threat Level: Wolf (Low) ]
[ Ability: 「Basic Regeneration (N)」: Accelerates wound healing and energy recovery. Can slowly regenerate lost limbs at the cost of significant life force. ]
[ Monster: Iron Rooster ]
[ Threat Level: Wolf (Shame) ]
[ Abilities: 1. 「Caw (N)」, 2. 「Steel Feathers (N)」… ]
[ Monster: Radiation Fish ]
[ Threat Level: Wolf (Shame) ]
[ Ability: 「Leap (N)」… ]
[ Monster: One-Ear ]
[ Threat Level: Wolf (Shame) ]
[ Ability: 「Sharp Fangs (N)」… ]
The system's detection function. It only worked on those weaker or comparable to him. True powerhouses remained opaque until contact.
Jack: "…"
Hard.
My fists are getting hard.
Guess the saying's true—big tree, plenty of birds. The Monster Association really knew how to gather talent. And idiots.
Of the four, only the Mutated Cockroach's 「Basic Regeneration」 caught his interest. Regeneration abilities were rare.
But—
Wolf-level wasn't all the same.
The system placed Jack at Wolf-level Mid. Not exactly impressive on paper.
Compared to these clowns, though?
Suddenly Wolf-level Mid felt pretty damn good.
"Yare yare daze… What the hell are you barking about?"
The old verbal tic slipped out unconsciously. Jack's dark figure seemed to radiate something—an intangible pressure. His gaze sharpened. Killing intent bled into the air.
Back before transmigrating, he'd spent years on certain video platforms. Watched every genre imaginable: broken knife fights, cooking tutorials, donkey hoof trimming, wilderness survival builds… studied every martial art, every sword style.
Lying at home? His heart mastered them all.
He'd absorbed the strengths of a hundred schools.
Now, reborn as a Monster—physique, speed, strength all amplified beyond human limits—Jack felt…
My fists might not be so dull after all.
Besides. Wolf-level was Wolf-level. And this cockroach ranked lower than him.
What was there to fear?!
"Teme… What did you say?!"
The Mutated Cockroach's greasy antennae quivered violently, face twisting with rage. It was about to lash out—
Suddenly!
An indescribable wave of heat—terrifying, suffocating—surged from the depths of the corridor ahead like an overwhelming tide!
"Guh—!"
"L-Lord… Lord Pochi!"
The Cockroach Monster's fury evaporated instantly, replaced by primal terror. All six legs trembled uncontrollably.
The other three Wolf-level Shame Monsters fared no better. They collapsed, whimpering senselessly.
Boom…!
Boom…!
Boom…!
Heavy footsteps, as if capable of crushing the very crust of the earth, approached from the darkness. Each step sent violent tremors through the ground.
Cracked stones rained from above, clattering against shells and fur.
A suffocating pressure—terrifying, absolute—descended upon the entire space.
Jack and the four other Monsters froze. It felt like an invisible hand had seized their throats, squeezing the air from their lungs.
The distant torchlight at the corridor's end was swallowed by an immense shadow. A moving mountain.
Slowly approaching…
…
…
In the darkness ahead, six points of light ignited. Burning. Blazing.
Like demonic eyes staring up from the abyss.
The mountain of shadow drew closer, and the creature within emerged—
Towering. Ferocious. Monstrous.
Its body was covered in coarse black fur, each strand distinct like steel needles. Six eyes—each burning with hellfire—were embedded in its colossal head, radiating a pressure that could freeze the soul itself.
Monster Association. Dragon-level Cadre.
Overgrown Rover.
Here.
Rover's massive head dipped slightly, six eyes rotating independently, curiously scanning the insect-like delivery Monsters at his feet.
Like someone examining a few moving appetizers.
Suffocation.
No hostility. No roar. No attack.
Just the pure, crushing weight of life-force disparity—enough to turn the very air into solid glue.
The temperature in the corridor plummeted. Bone-deep cold shot up from their tails to their skulls.
The shadow of death descended.
Jack's heart stopped. His mind went blank.
Dog food.
They were about to become dog food.
The next second would decide everything.