A couple dozen centuries ago, the world changed forever.
A meteor shower brought about the descent of mana into Earth, along with strange new elements that caused wildlife to mutate drastically. Scientists, for lack of a better term, called it Evolution. Mother Nature overturned nations in a matter of days. The food chain was completely rearranged, and humanity found itself at the bottom.
Even insects grew to unnatural sizes and began developing bizarre, supernatural abilities.
This era became known as The Dawn of Evos.
During this time, humanity was nearly driven to extinction. But luckily, though they were the last, humans evolved too. Or at least, some of them did.
A portion of the population began awakening supernatural abilities known as Skills, marking them as Espers.
From this point forward, two classifications emerged: Esper Tiers and Skill Ranks.
An Esper's Tier determines their maximum potential, how many skills they can possess, and their level cap.
A Skill's Rank defines its strength, versatility, and difficulty of use.
There are ten known Esper Tiers, with Tier 10 being the weakest and Tier 1 the strongest.
The gap in power between each Tier is vast, to the point that it's said a Tier 9 Esper is a hundred times weaker than a Tier 8, and so on.
Likewise, Skills are ranked from F to SSS, and the difference in power between each rank is just as staggering.
Thanks to these evolutions, humanity was able to push back, rebuilding new cities fortified with massive wall systems and plasma shields to protect against the mutated wildlife.
But even now, those defenses are far from perfect.
Every so often, a powerful beast breaches the walls, and the world is reminded that survival is still a gamble.
…
…
Riven skidded around the corner, nearly colliding with a rusted vending unit advertising "MoodBoost™ Vitamin Sludge." His chest heaved like a broken pump, lungs burning as he finally spotted the gates of Site 9-K, the faded lettering barely visible behind layers of ash and dried ichor.
He was already in uniform — a gray full-body suit with high-vis orange stripes across the chest and thighs, reinforced gloves, and a breathing filter strapped over his jaw. The word CLEANER was stitched over his chest like a badge.
The moment he reached the checkpoint, the retinal scanner beeped.
[Identity Confirmed: RIVEN CAEL — Cleaner Rank: E-]
The metal gate groaned open with a sound like a dying animal, and the full weight of the scene hit him.
Monster corpse harvest sites were always brutal, but today's was particularly bad. Whatever had attacked must've been Class C or higher — the stench of ruptured organs, acidic fluids, and scorched concrete clung to the air like guilt.
Huge chunks of alien flesh lay strewn across the ruined intersection — twitching, steaming, bleeding unnatural colors. Bone fragments the size of car doors jutted from collapsed buildings. Black ichor trickled into storm drains, and scorched claw marks tore through pavement like butter. Cleaner teams were already at work in the distance, some using power tools, others operating mana-thread rigs to lift debris off shattered bodies.
And there were bodies.
Human ones.
At least a dozen zipped in translucent body bags, lined up under a broken awning for collection. Some still smoked faintly from exposure to magical residue. Riven's stomach turned — not from the gore, but from the thought that someday, someone might bag him like that.
"'Bout damn time, Cael."
Riven turned to see Toma, his fellow cleaner and longtime complainer, dragging a dripping organ the size of a motorcycle onto a containment tarp.
"You take a damn scenic route here or what? Wang's been screaming on the comms like someone stole his caffeine pills."
"I ran," Riven wheezed, bracing himself on his knees. "From Midtown."
"Congratulations. You now smell like actual death."
Before Riven could reply, Jin — the third member of their team, broad-shouldered and always chewing on something — waved from a heap of rubble.
"Stop flirting and grab a shovel, Cael! We've got four torsos to dig out and three more tagged for transport. You're on Bag Duty."
Of course he was.
Bag Duty meant dragging corpses out of collapsed structures, double-checking for mana saturation, tagging them for funeral credits, and — worst of all — making sure nothing woke up during the process. Not all monsters died clean. Some twitched back to life hours later.
Still panting, Riven forced his legs forward.
"Just one more month," he whispered to himself. "Just one more month, one more check, and I'll—"
He didn't finish the sentence.
He never did.
Because somewhere deep down, he wasn't sure what he was waiting for anymore.
Riven had barely taken three steps into the blood-soaked zone when a voice — hoarse, furious, and always at max volume — split the air like a thundercrack.
"CAELLLLL!"
Every cleaner on-site froze for half a second like prey animals sensing a predator. A few even winced in sympathy before hunching over their work with double the speed. Riven slowly turned, already regretting his life choices.
Striding across the corpse-strewn battlefield was a walking ulcer of a man, all thick arms and thicker neck, clad in a grease-stained supervisor vest that strained against his stomach. Manager Wang, in all his flustered, vein-throbbing glory. A clipboard was clutched in one hand like a weapon. His radio earpiece dangled uselessly, chewed on the end like he'd tried to swallow it in rage.
"Shift leaders! Triple-time extraction on Sector Three! Fume levels are rising! Where the hell is Team D?! Jin, why is there a mana sac lying open? Bag it before it hatches! And YOU—"
His finger stabbed the air like it was firing a spell.
"YOU! RIVEN!"
Every muscle in Riven's body tensed like he'd just been hit with a paralyze hex.
Wang barrelled toward him, boots squelching through puddles of acidic sludge and half-melted monster sinew. A lesser man would have slipped. Manager Wang didn't slip — the laws of physics were too afraid of being yelled at.
He stopped just shy of Riven's face, spittle already flying.
"Tell me you're joking. Tell me you didn't drag your bony ass onto my site, late, after pulling your usual monthly Houdini act, only to show up winded, half-conscious, and missing your damn wrist monitor!"
Riven blinked. "Wait, my what—?"
Wang reached forward, yanked up Riven's sleeve, and groaned. The band was missing. Probably flew off during his sprint or got left in his laundry basin three days ago.
Wang threw up his hands. "Brilliant. No vitals tracker. No team sync. No hazard detection. You know what happens when one of you gets mana-burned out here without one? I have to file paperwork! And I hate filing paperwork!"
"I—I'll fix it! I swear, I'll—"
Wang's finger jabbed into Riven's chest, right where the CLEANER patch was stitched.
"You're on corpse patrol, east quadrant. We've got a ruptured chitin brute with human casualties inside its chest cavity. I want tags, I want body count, I want contamination scans, and I want it done before I remember I was going to dock your pay!"
Then he turned, already barking new orders into his comm band, stomping off to harass someone else.
Riven stood there in silence, feeling the weight of the day pressing down on him like gravity had turned up a few notches. The smell of burnt hair and acidic bile filled his nose.
"East quadrant," he muttered. "Yay. Chest cavity spelunking."
He tightened his gloves and started walking.
Meanwhile in the chest cavity, something was pulsing within a bundle of flesh attached to the flesh wall.