Hello! How are you? I hope you're doing wonderfully :]
Can I request you write about Yandere Saitama?
When I read your Yandere Mash writing, it reminded me of him and I'd love to see you write him if you can
Take care!
Idk why but I enjoyed writing this one :]]]
The Hero's New Directive
Yandere!Saitama x Reader
The metallic click of the deadbolt sounded deafening in the cramped, quiet hallway.
Your fingers, slick with sweat, twisted the doorknob. It gave way. Just a fraction of an inch of cool night air slipped through the crack before a heavy, suffocating pressure slammed the door firmly back into its frame.
An oppressive, crushing weight settled onto your shoulders. Right beside your ear, a voice cut through the silence.
"What are you doing?"
You froze, your heart hammering violently against your ribs. Turning your head just a fraction, you looked up. Saitama was standing right behind you. The usual dim-witted, blank expression he wore was completely gone.
You swallowed hard, forcing your racing pulse down, and opted for absolute, unbothered nonchalance.
"Uh, trying to see if the mail came." you lied, letting your hand drop from the knob as you turned around to face him. "But it looks like the slot is empty. Anyway, did you finish the chips?"
The terrifying aura vanished in a microsecond, dissipating so fast it left you dizzy. Saitama blinked, his sharp features melting instantly back into his usual, dopey, egg-like countenance.
"No, there’s still half a bag left." he muttered, scratching the back of his head as he shuffled past you toward the tatami mats. "We should finish them before they get stale."
"Good point."
You walked back into the small living area as if you hadn't just been a hair's breadth away from a panic attack, sinking onto the floor next to him. The television hummed, casting a flickering blue glow over the tiny apartment. You pulled the low table closer, grabbing a handful of chips while a mindless variety show blared in the background.
Within ten minutes, Saitama’s head began to bob. Within fifteen, his eyes were closed, a soft snore escaping his lips as he drifted off to sleep right next to you.
Looking at him now, so relaxed, it was almost easy to forget he was a god-like entity capable of splitting the sky. But as you glanced at the closed front door, the phantom weight of his aura still lingered on your skin, dragging your mind backward into the memory of how your life had devolved into this bizarre nightmare.
--
Before all of this, you didn't even know who Saitama was. You were just a completely ordinary citizen trying to survive the chaotic daily hazards of City Z.
Your brush with the extraordinary had started completely by accident. You had been walking home when a grotesque, towering monster cornered you in an alleyway. You closed your eyes, bracing for the end, only to hear a deafening CRACK followed by a wet, explosive sound. When you opened your eyes, the monster was gone, reduced to a shower of gory rain. You didn't see who did it; you just assumed a high-ranking Hero had passed through.
But your luck ran out a week later. It turned out that specific monster had been carrying a rare, highly volatile bio-engineered pathogen. Because you were the only surviving witness exposed to its residue, you were quietly abducted from your bed—not by villains, but by a rogue, black-ops research division associated with the Hero Association itself.
They locked you in a subterranean laboratory. A twisted, fanatical scientist in a pristine white coat had smiled down at your strapped-down form, preparing a tray of horrifying, oversized needles to dissect how your body was processing the pathogen.
You were seconds away from a gruesome examination when the alarms suddenly blared. A massive underground monster nest chose that exact moment to ambush the facility from beneath. The walls caved in, crushing the scientists and throwing the lab into absolute chaos. Amidst the screaming and crumbling concrete, you managed to break free from your restraints, stumbling blindly through the smoke, heavily bruised, bleeding, and terrified.
That was when the wall to your left exploded into dust.
Through the debris walked a bald man in a ridiculous yellow jumpsuit, followed closely by a blonde cyborg. They had been sent to clear the monster nest, splitting up to cover more ground. The cyborg shot down a parallel hallway, leaving the bald man alone.
He stopped when he saw you, his bored eyes widening slightly at your bloodied, battered state. "You okay?"
But as he moved, a stray piece of falling debris smashed into a highly advanced, experimental machine labeled Project: Aphrodite-9 - a weapon the scientists had been developing to manipulate human brain chemistry and induce absolute, unshakable obsession for psychological warfare. The machine short-circuited, its targeting lens snapping directly onto you and Saitama.
A blinding, pinkish-gold laser beam shot out, piercing through you and striking Saitama dead in the chest.
It didn't hurt physically. The blast didn't even singe his yellow suit. But as the energy washed over him, something fundamental in his eyes shifted. The dull, vacant look he always wore shattered. The laser had cross-wired his dormant, numb emotions, violently locking his brain's reward centers onto the exact image in front of him: you.
Saitama gasped, his chest heaving as a terrifyingly intense light flooded his pupils. Before you could speak, he crossed the room in a blur, wrapping his arms around you. He held you so tightly it almost cracked your ribs, burying his face into your shoulder.
"I'm not letting anything happen to you ever again."
A minute later, Genos came sprinting around the corner, "Sensei! I heard an explosion, are you—"
The cyborg froze, staring in absolute bewilderment at his master.
"Genos," Saitama had ordered, "Find the nearest hospital."
--
A month had passed since that chaotic day. Living with Saitama was undeniably safe, but the weight of his constant, suffocating fixation left you with almost no personal space. You hadn't known him before the accident, but aside from specific personal tasks, he now insisted on following you everywhere.
Genos was acutely aware of your existence. At first, you felt defensive; you knew that strangers shouldn't just barge into someone else's life like this. But you understood his concern. You were fine with it, eventually agreeing to cooperate with Genos in secret. You promised the cyborg that you would help find someone to study, fix, and reverse the device, or build a new machine entirely to return Saitama to normal.
But until that day came, you had to manage his intense possessiveness.
Just yesterday, you had needed to go to the local market for groceries. Wanting a moment of reprieve, you had looked Saitama in the eyes and said, "I'm going out to the market with Genos to get some food. You should stay home and rest."
Saitama had simply blinked, "Oh. Okay. Sure."
But he hadn't stayed home.
The moment you and Genos stepped onto the bustling street, you caught sight of a yellow-and-red blur hovering at a "reasonable" distance behind you.
The trip quickly became an exercise in absurdity. When a pushy street vendor stepped into your path, trying to aggressively wave a coupon in your face, a tiny pebble suddenly ricocheted off the concrete with the force of a bullet, striking the vendor’s shoe and causing him to trip backward into his own stall.
Later, when a distracted shopper almost bumped into your shoulder, the wind pressure inexplicably shifted, blowing the man's hat off and sending him scrambling away in confusion.
Even Genos wasn't immune. At one point, the cyborg reached a hand out to guide you away from a puddle. The moment his fingers brushed your elbow, a small rock whizzed through the air, perfectly striking Genos's wrist joint with a loud CLANG.
Genos had paused, his glowing eyes darting toward a nearby rooftop where a bald head quickly ducked out of sight. The cyborg simply let his hand drop, exhaling a soft whir of exhaust. "Sensei’s tracking parameters are... exceptionally vigilant today."
By the time you both finished gathering all the necessary groceries, you finally made it back to the apartment building. As you walked up the stairs, Genos carried the heavy bags effortlessly, casting a rare, analytical look toward you.
"This excursion was remarkably efficient," Genos admitted, "spending this time with you wasn't bad. You were highly cooperative with the itinerary, which made the task optimal."
You couldn't help it. Genos’s absurdly straightforward way of paying a compliment was deeply endearing. You let out a gentle, soft laugh, shaking your head. "Thanks, Genos. I try my best."
The door to the apartment suddenly swung open before you could even reach for the handle.
Saitama stood in the doorway, already back inside as if he had never left. But his eyes weren't dopey anymore. A dangerous, sharp spark of jealousy flared in his pupils, his gaze locking intensely onto the lingering smile on your face, and then darting to Genos.
He didn't like you laughing at someone else.
--
The low hum of the television faded into the background as the tension in the room thickened. That single spark of jealousy from the market had shifted something inside Saitama. Over the next few days, his behavior mutated from a suffocating, shadow-like clinginess into something far more active.
You didn't know what was firing in his brain, but he began making requests you couldn't easily shrug off. You denied him at first, and to his credit, his baseline habit of listening to you made him back off. But overtime, you couldn't stop him from trying. The boundary lines were blurring, and he was pushing through them with the slow, unstoppable force of a glacier.
It culminated on a rainy afternoon. You were nestled deep inside the warmth of the kotatsu, trying to lose yourself in a book. Saitama had been sitting across from you, staring with a heavy, unblinking intensity that made the hair on your arms stand up.
Suddenly, he crawled forward on his hands and knees, sliding under the heavy blanket until he was right in front of you.
"Give me a kiss."
A kiss? You didn't even have a crush on anybody in your normal life, let alone the terrifyingly overpowered stranger who had essentially hijacked your existence.
"Saitama, no," you said, forcing your voice to stay level as you pressed your back against the wall behind the kotatsu. "We shouldn't do things like that. We're not... we aren't together."
"Why not?" he asked plainly. He tilted his head, his face looming inches from yours. There was no innocence in his expression; it was completely dark, consumed by the artificial obsession pulsing through his veins. "I protect you. Why can't I have that?"
Before you could scramble out from under the table, his hands shot forward.
With terrifying ease, Saitama pinned your wrists down against the tatami mat. He didn't use enough force to break your bones, but the sheer, absolute immobility of his grip was paralyzing. You struggled, throwing your weight side to side, kicking beneath the kotatsu, but it was like trying to move a mountain. He didn't even sway.
He leaned in further, hovering directly over you, casting your face in total shadow. Desperate to avoid his gaze, you squeezed your eyes shut, twisting your head violently to the side.
"Saitama, stop!"
He didn't listen. His lips pressed against yours. Losing your mind to pure survival instinct, you used your one shot. As his mouth moved against yours, you clamped your teeth down, biting his lip as hard as you could.
The metallic tang of blood instantly flooded your mouth. You gasped internally, expecting him to pull away in pain. But Saitama didn't care. The small smear of blood only seemed to heighten the dark intensity pinning you to the floor. He shifted his grip, trapping your hands more securely, and went in for another kiss, completely swallowing your protests.
You felt entirely helpless, trapped beneath a force nature itself couldn't stop, your heart hammering a frantic, desperate rhythm against your ribs.
Click.
The front door slid open, followed by the heavy footsteps of his disciple. "Sensei, I have returned with the component upgrades.."
Genos walked into the living area and froze. His glowing optics scanned the scene: you, pinned flat on the floor beneath the kotatsu, eyes squeezed shut, and Saitama, fiercely hovering over you with a line of blood tracing his lower lip.
A heavy, agonizingly awkward silence descended upon the room.
"I... apologize. I will return when the parameters of your... interaction... have concluded." Genos blurted out and turned on his heel and walked right back out of the apartment, slamming the door shut in sheer embarrassment.
The sudden distraction worked. Saitama finally pulled back, his grip loosening just a fraction as he looked toward the door with an annoyed twitch of his brow.
The moment you were free, a massive wave of relief washed over you, so intense it made your head spin. You scrambled backward into the furthest corner of the room, drawing your knees to your chest, your heart still thudding wildly as you wiped your mouth with the back of your trembling hand.
Saitama just sat there, wiping the blood from his lip with his thumb, staring at you with that same terrifying patience.
--
Thankfully, the suffocating atmosphere broke the next evening when an uninvited guest practically burst through the front door.
Fubuki swept into the apartment in her expensive fur coat, ready to pitch another demand for Saitama to join her faction. Instead, she halted in her tracks, her jaw dropping.
You were at the stove cooking a massive batch of stir-fry, and Saitama was quite literally glued to your side. He was wearing his goofy, blank, egg-faced expression, but his hands were firmly clasped around your waist from behind, chin resting lazily on your shoulder as you tried to chop vegetables.
"Saitama?!" Fubuki stuttered, her usual composed aura shattering into complete bewilderment. "What on earth are you doing? Who is this?!"
"Oh, hi," Saitama muttered, not letting go of you. "We're cooking. Don't bother us."
"I made quite a lot of food," you called out over Saitama's shoulder, desperately clinging to any semblance of normal human interaction. "Would you like to stay for dinner?"
To your surprise, behind her haughty hero persona, Fubuki turned out to be incredibly nice. Once she sat down, she polished off two bowls of rice, complimenting your cooking with genuine warmth. You both actually got along incredibly well, chatting about regular civilian life outside of hero business.
Seeing a glimmer of hope, you leaned in closer to her across the low table. "Actually, Fubuki, I wanted to talk to you about something... Saitama has been acting really strange because of-"
"Hey, don't eat all the pork!" Saitama interrupted loudly, shoving a piece of meat into his mouth. He deliberately nudged a plate between you and Fubuki, physically cutting off your line of sight. He wasn't going to let you tell her a thing.
Fubuki clicked her tongue, "Honestly.. Have some manners! You should learn to give people some space, you bald freak!"
"Hah? Who are you calling a freak? You're the one who barged into my apartment for free food." Saitama bickered back, his face twisting into his classic, comical cartoon irritation.
Watching them argue, a wild idea sparked in your mind. Fubuki was beautiful, powerful, and a prominent figure. Maybe, you thought, if I play matchmaker, I can redirect his obsession onto her instead.
You smiled, leaning forward. "You know, you two actually look really good together. You argue like an old married couple."
The bickering stopped instantly. Fubuki’s face flushed bright red, completely flustered. But Saitama didn't look flustered at all. He turned his head slowly, his cartoonish annoyance vanishing. He looked right through you.
"Don't say stupid things," Saitama said, "I don't care about her. At all."
The absolute finality in his voice crushed your matchmaking plan into dust before it could even begin. He knew exactly what you were trying to do.
--
After a deeply awkward farewell, Fubuki left. You carried the stacked plates to the sink, your hands slightly trembling from the residual adrenaline of his intense gaze. In your distraction, a ceramic plate slipped from your soapy fingers.
SMASH.
It shattered violently against the floorboards. "Ah!" you gasped, immediately kneeling down to pick up the sharp pieces.
"Don't touch it!" Saitama’s voice boomed. In a fraction of a millisecond, he was on the floor beside you, his hands swatting yours away. But in his uncharacteristic rush to keep you away from the glass, he carelessly shoved his hand down into the pile.
A sharp tink echoed. Saitama blinked, looking down at his index finger. A tiny shard of glass had managed to find the perfect angle, pricking his skin. A single, small bead of blood welled up.
"Hold still" you said, scrambling over to the cabinet to grab the first-aid kit. Back at his side, you carefully cradled his enormous hand and wiped away the tiny bead of blood. After dabbing the prick with antiseptic, you smoothed a brightly colored band-aid over it, treating the minuscule wound with all the seriousness of a life-threatening injury.
Saitama watched you the entire time, his expression completely softening.
Before you could pull away, his grip on your hand tightened. He stood up, effortlessly pulling you with him until your back hit the edge of the kitchen sink. He stepped into your space, cornering you completely, trapping you between his sturdy body and the counter.
"Why do you always do that?" he asked, "You always try to push me away. Don't you get it? My whole head is filled with you. Every single thought. It's only you."
"It's because you were hit by a machine, remember? This isn't true love. You aren't yourself."
Saitama leaned in close, his breath brushing your cheek.
"I don't care what it is. Right now, you're what I want. And I'm keeping you."
The air grew impossibly thick, your heart hammering against your ribs as he leaned closer-
Click.
The front door slid open again. Genos walked in, carrying a fresh grocery bag. "Sensei, I realized we forgot the green onions for tomorrow's—"
Genos stopped dead in his tracks.
"I... see." Genos turned right back around, walked out, and closed the door.
You let out a breath you didn't realize you were holding, your shoulders sagging in immense relief as Saitama sighed, completely annoyed by his disciple's timing.
--
Later that night, the hum of the refrigerator was the only sound in the dark apartment. Saitama was dead to the world beside you, his breathing heavy and even.
Bzz.
The sudden vibration of your phone against the tatami mat made your heart leap. You carefully slipped it out from under your pillow, the screen illuminating your face. It was a text from Genos.
Genos: I have bypassed the main research protocols. Dr. Kuseno has successfully constructed a prototype of the reverse-resonance device. It is a test version, but the calculations are optimal. We should deploy it immediately.
You stared at the glowing text, a complex wave of emotion washing over you. You agreed. It was for the best. Saitama needed to return to the way he was, and Genos deserved to get his beloved sensei back. As for you? You’d finally be able to return to your normal life. Granted, looking back, there wasn't much about your old, mundane routine that you particularly cared about. These past weeks had been terrifying, yes, but they had also been strangely full. Still, your conscience won out—you couldn't just sit back and let someone have their entire life artificially devoted to you.
You texted back a single word: Okay.
Forcing your breathing to remain shallow, you faked being asleep. Minutes later, the balcony window slid open. Genos slipped into the room, a sleek, rifle-like machine cradled in his hands. You slowly opened your eyes, giving Genos a tight nod as you glanced at Saitama to ensure he was still sleeping soundly.
Genos raised the device. A faint, low hum vibrated through the air as the barrel began to glow with a pale blue light. The beam was just about to shoot out-
Snap.
In a fraction of a microsecond, Saitama’s eyes flew open.
Before Genos could even pull the trigger, Saitama’s fist moved. He didn't even stand up; he just threw a casual, backhand punch from his position on the floor. The sheer wind pressure from the strike didn't just shatter the machine, it completely tore through the ceiling, blowing the entire roof off the apartment building and scattering the debris into the upper atmosphere. The night sky was suddenly completely visible above you.
"What do you think you're doing?" Saitama growled, sitting up. "Both of you..."
You shook violently from the residual shockwave. You knew, with absolute certainty, that if Saitama had intended to aim that punch directly at Genos instead of just swatting the air around him, the cyborg would be nothing but a pile of melted scrap metal right now.
Before you could utter an apology, Saitama’s hand wrapped firmly around your waist. "We're leaving."
In a blink, the apartment vanished. The sheer speed of his movement left your vision blurry and your lungs gasping for air. When your feet finally touched solid ground, you realized he had carried you to a desolate, abandoned warehouse district on the outskirts.
He set you down but kept his grip tight on your arm. "You want me back to normal so badly?" Saitama asked, his eyes gleaming in the moonlight. "You want to get rid of this? Let me show you what exactly it is you're trying to fight."
Right on cue, a massive, grotesque monster tore through the concrete walls of a nearby building, roaring at the sudden intrusion. It didn't even get a chance to posture.
Saitama didn't look at it. He just threw a single, careless punch.
BOOM.
The creature instantly exploded into a massive shower of gore, the shockwave splitting the clouds above the district in half. It was over in a blink.
Saitama turned his head back to you, his face cast in terrifying shadows. "See? That's what you're going against. The whole world is like this. But as long as I'm like this for you, none of it can touch you."
You swallowed hard, the sheer display of absolute power driving his point home. You did know what he was about. You knew exactly how terrifyingly invincible he was.
"Hey! Hey, mister!" a slurred voice suddenly called out. A drunk businessman, who had apparently been hiding in the alley, stumbled out into the open, clutching a bottle. "Did... did you just kill that thing? Thank you... thank you for saving-"
The man stopped dead in his tracks. Saitama turned his gaze toward him. It wasn't a hero's look. It was the cold, predatory glare of a monster far worse than the one he had just killed. The sheer aura radiating from Saitama made the drunk man choke on his words, drop his bottle, and flee into the night, screaming in pure terror from the gaze alone.
But Saitama had made a fatal mistake. He thought he had destroyed the only threat. He didn't know that you and Genos were already one step ahead.
You hadn't just stood by while Genos brought the machine to the apartment. Genos had given you a compact, emergency secondary trigger—a small, palm-sized cylinder hidden right inside your sleeve.
While Saitama was distracted by the fleeing drunk man, you whipped the device out, pointing it directly at his chest, and slammed the button.
A sharp, concentrated pulse of blue light shot out, hitting Saitama. He gasped, stumbling back a step. Because he was only wearing his flimsy, well-worn pajamas, the explosive force of his earlier punch combined with the energy blast caused the fabric of his shirt to completely tear open, leaving him standing in the cool night air with a tattered rag hanging off his shoulder.
Silence stretched over the desolate lot. You held your breath, your heart hammering. Did it work?
Saitama stood perfectly still for a long moment, staring down at his tattered pajamas. Then, his face suddenly slackened, his eyes losing that terrifying, hyper-focused glow. He rubbed his nose, his shoulders slumping into a deeply familiar, bored posture.
"Achoo!" he sneezed loudly, rubbing his head. "Man... it's freezing out here."
A massive wave of relief washed over you.
"We should... probably get back" you suggested.
"Yeah. Definitely. I think there's a sale on hotpot ingredients tomorrow morning anyway." Saitama muttered, turning around and walking back toward the city.
While walking a few steps behind him, you quickly pulled out your phone and shot a hurried text to Genos: It worked. He's back to normal.
You slipped the phone away, letting out the longest sigh of your life. For the first time, the crushing weight on your chest was gone. You were finally free.
You walked alongside Saitama in the quiet night, completely at ease. Which meant you didn't notice the way his eyes cut sideways to look at you through the dark. And you certainly didn't see the tiny, faint smirk playing at the very corner of his lips.
It was so easy to trick you. You actually thought a little piece of plastic could fix it all.
He let you walk a little closer to him, pretending to be cold, secretly relishing the fact that you weren't trying to run away anymore. Let Genos think the machine worked. As long as you stayed right by his side, he would play whatever part you wanted him to play.
Damn... I'm sweating just reading that....
