Neuroscience Hell 3 'Sister-in-law??'
Small face, sleek and voluptuous body. It was his wife's little sister.
As far as O Nangryun knew, his sister-in-law was a cheerleader. But right now, her outfit was that of an ordinary office worker. She was kicking off her shoes with a tired expression, wearing an H-line skirt. She hung her Range Rover key on the hook by the front door. The action was so natural that O Nangryun suddenly wondered if she might actually be human.
He'd lived with his sister-in-law and wife all together once before. Until she'd moved out to get married... O Nangryun swallowed hard. Seeing her brought one woman to mind. Go A-hee, who cheered on the same team as his sister-in-law. The goddess of cheerleaders. She'd been the object of his crush for over ten years.
'In this world, is my sister-in-law an office worker instead of a cheerleader? Why's she home?' The reality of being in another dimension hit him hard.
But something was off about her outfit. One stocking was flesh-toned, the other dark brown. Similar enough that most people might overlook it at a glance, but any woman would be sensitive to that kind of mismatch.
'High chance my sister-in-law isn't human.'
Right then, his wife's pussy clamped down hard on his thrusting cock, and she started shaking her hips wildly. Caught off guard by the sudden movement, O Nangryun grabbed her waist. The sister-in-law, now barefoot, turned a languid gaze toward him.
O Nangryun, mid-thrust, felt stripped bare under her eyes. At the same time, the corner of her mouth twisted up in a grotesque grin. Joker Smile.
'My sister-in-law's a demon too.'
O Nangryun squeezed his wife's ass with both hands and flashed a Joker Smile back. With the simple friend-foe check done, the sister-in-law brushed past them and headed into the bathroom.
O Nangryun set his wife down and chased after her into the bathroom, cock still rock-hard and standing tall.
She was pissing into the toilet. He flung the door open, and she startled slightly, her stream cutting off. O Nangryun gave her the Joker Smile. Chorororo—she responded with her own Joker Smile and resumed pissing.
'Her socialization process is incomplete—no learned shame.' O Nangryun realized demon behavior patterns were profoundly primal.
Then she stripped off her clothes without a hint of modesty. No shame at all. Slim waist, full D-cup tits at least. A body taut enough for cheerleading. She casually headed to the shower stall and turned on the water.
Shwaaaa.
Water from the shower sprayed over her sleek, flesh-toned body, beading up like rainbows in the light. O Nangryun stared, entranced by the beautiful female form.
'Fuckin' killer.'
He grabbed the blindfold he'd used on his wife. Convinced this wasn't the real world. Swallowing repeatedly, he slipped the blindfold over his sister-in-law's eyes.
Snap.
She froze mid-shower like a broken machine. O Nangryun led her out of the stall, dried her off with a towel, and plugged her ears with AirPods. Now he could grope her soft, yielding body to his heart's content.
'Block sight and sound, and the resistance vanishes. So this too...'
It was the law of closure kicking in. O Nangryun easily scooped up his stark-naked sister-in-law. He gently stroked her breasts. Cut off from sight and sound, she focused purely on touch.
He slid his hand down, lightly caressing her clit. A cute pink nub swelling slowly from its hood.
'Pretty big clit, huh?'
Teasing the firm-swollen clit made juices gush from her slit. Just as expected, she hit orgasm fast, her body contracting.
'She's probably imagining her boyfriend right now?' Or maybe that actor she had a crush on.
"Haa... haaah~"
Her aroused breaths grew ragged. Emboldened, O Nangryun shifted her into a standing fuck position while holding her. Her arms wrapped around his neck, like greeting a boyfriend eager for sex.
The law of closure was a terrifying brain function. The phenomenon that let mimics appear—filling in unseen info with imagination. His caressing hands became those of her crush, actor Gu Jeong-jae. Her brain mistook his touch, his cock, for the actor's.
Thirsty for kisses, she launched an aggressive affection offensive. Leading naturally to penetration.
Fucking his sister-in-law had O Nangryun massively turned on. A fantasy he'd imagined but never acted on. Her hips twisted wildly. He couldn't last long, creampieing deep inside.
He savored how her soft beauty crumbled so easily in his hands.
'A world where I can do whatever I want.'
Still buried inside, his cock hardened again, and she kept grinding her hips. Dopamine flooded as she arched back, trembling in climax.
That's when O Nangryun pulled off the blindfold. Her writhing stopped dead.
She realized the one fucking her wasn't the actor—but her brother-in-law. Like a mimic's mask dropping. Her pupils quaked.
O Nangryun gripped her waist tight, slowly fondling her tits. He rocked his hips gently. Her pussy walls clenched greedily.
"Haaa~"
A soft moan escaped, and her hips began to move slowly too. O Nangryun recognized this as the fight-or-flight response. Extreme stress from getting railed by her brother-in-law. Her brain chose to perceive him as Gu Jeong-jae instead. Pleasure, dopamine, oxytocin flooded her, letting her embrace the ecstasy fully.
O Nangryun had cracked the code to hacking demon brains. He'd tamed his ex-wife, turned his sister-in-law into a cocksleeve.
He held her all night, creampieing repeatedly until she softened completely. By the third load, she stopped wary of him. Treated him with the devotion she'd give her crush Gu Jeong-jae. Even sucking his glans clean after sex. Washing him in the shower, rimming his ass without hesitation.
"Fuck, this is paradise."
Freshly showered, O Nangryun dragged both sister-in-law and wife to the bed with renewed vigor. The sisters started licking his body. Thus began the threesome.
He pounded the two women on the bed however he pleased. Hours later? Throat parched, he lay swapping spit via kisses, staring at the ceiling.
"Ah... fuck... this is fuckin' heaven."
He'd missed their AirPods falling out amid the intense fucking. The moment his voice rang out, his wife's and sister-in-law's expressions—mid-squirting—twisted in horror.
"Kyaaaa!!"
They screamed in unison.
"Shit!! They react to human voices? When'd the AirPods fall out?"
O Nangryun blindfolded their eyes again and jammed the AirPods back in. They went quiet once more.
"Too noisy... someone might hear... Ah, the screams were signals? Alerting others that a human's here..."
Then—thud at the front door. It was 2 a.m. Something had answered their screams and come calling.
O Nangryun checked the wall pad for the outside cam. Thick fog obscured everything.
"Fog's really dense."
The white mist writhed like a living thing, enveloping the house. But something was still at the door.
[Never go into the fog at night. Unimaginable monsters come out.]
Pretty Husband's forum warning flashed in his mind. He'd seen that freakish head monster in the bathroom too.
'That head monster from earlier?'
Anticipating the monster, saliva pooled in O Nangryun's mouth. He was a born creature maniac, after all.
"Ha... fuckin' curious now."
A shadow loomed on the frosted glass door. Child-sized. Not the head monster. Just one. One monster that could barge right in if he opened the door.
'That size? I can handle it.'
O Nangryun's curiosity burned for the unknown thing pacing outside. A normal person wouldn't open the door—but he wasn't normal.
He grabbed a golf club and a capture blanket. Even a toothed beast could be subdued under thick fabric. Half adult size, kid-sized at most.
'Weight-wise, I've got the edge. Monsters are fuckin' my dream.'
He'd hit the gym hard, boxed too. Fully prepped, golf club in one hand, blanket in the other, he creaked the door open.
Slowly. Writhing fog poured in. And with it, the monster.
Thud.
He slammed the door shut, lunging to capture it. But...
"Holy shit..."
O Nangryun dropped the blanket at the sight. The monster was a woman's lower body. Nothing above the waist. Just a perfectly severed female torso from the rounded waist down: waist, hips, ass, sleek calves.
"Whoa!"
He gawked. Bare skin. Pale, smooth flesh gleaming under the fluorescent light like it was oiled. The cut waist was sealed smooth as wax.
As a neuroscientist, his curiosity ignited.
'No nervous system—how's it moving? No brain—how's it navigating, acting?'
Slim waist, nicely flared hips. Classic hourglass. Plump, firm ass; slender thighs with just the right meat. And the standout feature...
"Whoa, that pussy..."
Between the legs, a pussy sculpted to perfection. Small, plump labia slightly parted, a deeper pink peeking from the flesh-toned slit.
"This creature's a gift from God."
Driven by scientific curiosity, O Nangryun approached. It reacted, freezing then striking a provocative pose: one leg forward, ass cocked back. Like a high-end lingerie model.
'It knows poses!'
Her ass swayed side to side, then—like a reverse-jointed ostrich with ass for a head—she charged him. Round, taut cheeks parting to reveal her asshole.
"Whoa."
The anus gaped, sharp teeth bared. The lower-body monster's attack was pathetic. Barely 20kg charging? One hand stopped it. Grabbing the soft ass and thighs, it just flailed.
Peering into the gaping pink hole: rows of shark-like fangs.
O Nangryun pondered the pathetic thing. It fed through its anus.
One hand on an ankle, he dragged it to the bathroom. Gotta wash the outdoor wanderer clean.
He rinsed the lower-body monster thoroughly. Juices oozed, so he scrubbed carefully. Even cleaned the pink pussy. The bumpy inner walls felt human. Used his sister-in-law's feminine wash to scrub inside too.
"Fascinating."
Fingers in the pussy a few times, and nectar poured out. Slick, viscous—like a woman's. He tasted it: identical.
"Women just need the lower half!!"
O Nangryun slammed his cock raw into the monster pussy. No condom, just pure horniness.
"Whoa... living onahole. The grip... fuck, tighter than sister-in-law."
While creampieing, the ass gaped threateningly. Flesh parting around his fingers, the spread anus chomped its teeth clack clack.
'Those teeth look dangerous.'
Pounding away, he used his prepared tweezers to meticulously extract the shark fangs. Deep roots—each pull drew a bit of blood. Every tooth out made the pussy clench insanely.
"Fuckin' hell."
Toothless anus: no longer a threat. Still thrusting, he headed to the fridge. Toothless hole needed feeding. Giant sausage for egg fritters.
His cock had pierced through the severed top, bulging her lower belly with his glans outline.
'Womb too. Fuck. Can it get pregnant?'
Creampieing nonstop, he shoved the sausage deep into the anus. No teeth marks, no scratches.
"Hmm. No teeth, can't chew? You won't starve, right?"
O Nangryun stroked the monster's ass sadly. The pink anus clenched wildly.
He pulled out of the pussy and thrust into the twitching anus.
"I'll feed you cum. Wonder if cum sustains you?"
No clue if it understood, but the squeeze was pussy times a hundred bliss.
"Kyaa!! Fuck yeah!! This is why people risk poison pufferfish!!"
Toothless ass-hole: another pleasure port.
"Fuck. A heaven full of these? Gotta catch more."
Monster-fucking had O Nangryun forgetting his blindfolded wife and sister-in-law in the bedroom.
He still didn't know the Pretty Husband from the forum—the one he'd chatted with—was his best friend Park Woojin, dropped into this world the same day.
August 7th, Tuesday
"Back again."
A hazy fog welcomed me. Landed in the basement level 3 of Gangnam department store, shell world.
"I like this world better, honestly."
No need to worry about eyes when summoning minions. SpongeBob cupped his hands at chest level, and I mounted his ass on top. Decent ride. His chopstick legs were tougher than I thought.
Running along, I spotted lower-body monsters fleeing in terror at SpongeBob's appearance. Pretty-assed, slender women's lowers. Horrific and repulsive at first glance, but laced with weird sensuality. Like they were screaming, I'm a woman too!
'Nangryun would've rounded up lower-body monsters for a farm.'
I'd come back to save Nangryun, but did he even need saving? I felt sure he was thriving.
Riding SpongeBob got me back to the apartment in a flash.
Opening the door, greeted by...
"Right, Choi Seo-ah."
Choi Seo-ah's skin lay crumpled on the floor like shed leather. Common shell in T-16 shell world. Perky tits, eyes nose mouth blankly staring at the ceiling—normal folk would scream and faint.
I checked my wrist. O Sujung's spot and Shan's were empty. O Sujung was in Jiwon-young's body now; Shan guarded her. Current issue: no soul handy for the empty Choi Seo-ah skin.
"Kinda wanna leave it, but..."
I scratched my chin, eyeing the skin-only Choi Seo-ah.