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He has a hard time being around you.
It’s not him, though. Yuuji would never think these kinds of thoughts about you, his… his little sister . Sukuna. It has to be Sukuna that’s putting these disgusting thoughts in his head. Yuuji loves you, but… he’s afraid to be around you. The images that run through his mind at the sight of you make him sick, and he doesn’t want to hurt you.
“Nii-chan!” You cheer over the phone. “How is your new school going?”
Even over the phone his stomach drops. Disgusting thoughts of you bubble from the recesses of his brain, from Sukuna, no less. He can even hear that sick fuck’s voice whispering about all the things he wants to do to you.
“Good. It’s– it’s good. Are you taking care of yourself?”
“Of course I am!” Your voice squeaks on the other side. “I just… I miss you, nii-chan.”
Isn’t that sweet, Itadori? Imouto-chan misses us. Let’s visit and rip those little fucking holes–
“I miss you, too!” He says it forcefully to dispel Sukuna’s voice from his mind. “I miss you, but- but it’s so busy right now and I don’t know–”
“What If I came to Tokyo?”
“Wh- what? No, you’re- you’re too little to be riding the train. It’s… it’s dangerous.”
“You were riding the train at my age, Yuuji-nii!” You huff. “Plus, it’s so lonely here since grandpa passed. I need you. I didn’t know you were gonna- gonna leave me behind, too…”
He can hear you begin to cry on the other side of the line. You’re… you’re just a little girl. He knows it’s wrong that he left you all alone, and he wants you with him more than anything. But…
It’s been so long since I’ve had a virgin, a little girl at that. Fuck, I want her so bad. Let me have her, Itadori. Let me let me let me let me.
“Come home, nii-chan.”
*
Yuuji wouldn’t dare tell anyone of Sukuna's urges. He didn’t want anyone to know that Sukuna was that depraved, or perhaps withhold him from behind around children. He… Yuuji didn’t want those things, he’d never do that to anyone ever, but Sukuna…
Why should he be protecting him anyway?
That doesn’t matter now. Yuuji’s on the train back to Sendai, tapping his foot anxiously. Sukuna’s been awfully quiet within his head, which can’t be a good sign. At least Yuuji has a moment to think good thoughts about you.
Perhaps Sukuna is only allowing him.
You’re waiting for him at the station once he arrives, even though he told you not to. Yuuji wants nothing more than to drop his things and come to hug you, lift you up and tell you how much he’s missed you and that he’s sorry. Yet, he holds back. He feels like he can’t be himself around you; it’s physically impossible.
“What are you doing here? There’s lots of dangerous people here!”
“Nii-chan!” You simply smile, spreading your arms out and hugging his waist. “I missed you so much!”
Sukuna doesn’t speak nor inserts an image into his mind. Maybe he’s busy or forgot or just decided that he’ll leave Yuuji alone for the weekend.
You both walk home, and he can only listen as you explain all of the “big girl” stuff you’ve been doing. Yuuji wishes he could tell you everything about jujutsu and even Sukuna, but you’re too little to understand. He’s afraid you’d only be scared, and he doesn’t want you to be afraid of him. He’d rather you hate him than be afraid of him.
“We’re home!” You announce to no one as the two of you arrive back at the family home. Both of you kick off your shoes and he watches you march through the house like you own it… maybe you do. God, you’re just a kid . Yuuji thought he was young, but looking at you…
“Can we play like before?” is the last thing he hears as himself.
*
“Of course we can, little one.”
He straightens up, feeling the black marks manifest on his skin as he takes form. Fear and confusion fill your little girl eyes as you watch Sukuna take over what was once your brother. God, the work he had to do to take total control.
“N- nii-chan?”
“That’s just darling ,” he nearly moans at your voice. “You love nii-chan, don’t you?”
You’re slowly backing away, nodding. “Y- yes.”
“Then let’s play! I’ve learned plenty of new games at school that I want to show you.”
You look scared. He nearly scoffs. Children, they’re smarter than most give them credit for. You know he’s not your nii-san, but god, he certainly wants to be.
“O- okay, nii-san.”
“Good girl!” He smiles, stalking towards you. He feels too big for Itadori’s body, stumbling towards you. “Nii-san’s gonna show you so much. Now, get out of those pesky clothes.”
“My… clothes?”
“Yeah! This game requires no clothes,” he laughs. “Here, I’ll go too.”
You shake as he tears off Itadori’s clothes, revealing more marks and a lot of muscle. The more he reveals, the more sure you are that you picked up the wrong nii-chan from the station.
“Why do you have all those tattoos?”
“Silly,” he hums. “It’s your turn.”
Your lips quiver, but you do as he says. You unclip your overalls, letting them pool at the floor. Then your tiny shirt joins, revealing those developing tits. Sukuna thinks he might like them more than regularly developed breasts.
Or maybe he likes them more because it’s you, and it’s causing poor Itadori so much torment.
“Panties, too.”
You whimper, pulling them down. Sukuna doesn’t remember your age, but you’re old enough to recognize that this is wrong, that nii-chans don’t do this to their little sisters. He’s not sure which he prefers, but he knows he’ll enjoy this.
“Why don’t you show me to your room?”
It’s rather clean, he observes. He’s not sure where the thought comes from, maybe Itadori, but it washes over him. You probably sleep in Itadori’s room.
“How sweet…” he sits down on your miniature bed. “You’re such a big girl, you know that?”
“Really?” You perk up, despite the discomfort that wracks your body. “I- I’ve been cooking and everything, too!”
“Good girl, maybe you can cook something for me after this game…”
His hand reaches for your neck, pinning you down to the plush, pink pillows. You immediately squeak, your throat rumbling beneath his palm. He snickers as you writhe beneath him, tiny hands trying to pry his much, much bigger one off. He’ll have so much fun drilling this into you.
“You’re going to be a good girl, aren’t you?” Sukuna gives you his kindest smile, which is full of teeth and horror. “You’re going to let nii-chan do what he wants? That’s the game!”
“N- n- nii…” you croak. “You’re… not…”
“Yes I am!” His eyes widened, revealing the red glow that he hid so well before. “Now, be good or else I’ll really hurt you.”
It’s easy for him to let his spare hand come down your body. He can feel your heartbeat slamming against your ribcage with every passing second. How fragile the mortal life is, Sukuna doesn’t know what that’s like. You seem like the perfect example of a living, breathing animal.
His clawed finger comes down to your little cunny, which puffs out and brims with heat. He grins, not trying to add any comfort into it this time. He pulls your lips apart, getting a good look at the tiny hole that will satisfy his urges.
“Don’t…” you wheeze. “Don’t, I’m scared.”
“Oh, it’s okay, sweetheart. Nii-chan… he wants to give you a good first time.”
He lets the pad of his finger rub that small nub, watching your cunt spasm at the stimulation. Your chest heaves in fear, and he can feel the mechanism of your heart pumping blood to your lungs, the same lungs that struggle with each breath. He lessens his grip on your neck just a tad. He doesn’t want to kill you. You might be one of the only people he doesn’t truly want to slaughter, but that’s only because he wants to torment you for the rest of your pitiful, little life.
Your legs twitch as he harshly swirls at your clit. He can feel his cock throbbing harder and harder as you begin to dampen beneath his touch. Sukuna even spits on you a bit, trying to coax your arousal. If you’re completely dry, then that wouldn’t be any fun for him…
Maybe a little bit.
“Does that feel good, little one?”
“N- no…” you shake your head. “No. I don’t know. I feel like… I need… I need to go to the bathroom please, nii-san.”
“That’s good!” He stares at your little eyes intently. “That’s what I want.”
“B- b- but–”
“You don’t want to deny your nii-chan what he wants, do you?” He glares at you. “Or else he may never come back to see you again.”
You frown, sobbing as he speeds up his pace. The orgasm is forced on you, not like you know what that is. It just happens. You scream as it all gushes out and shakes you to your core. You don’t know what you just did, and you’re sorry.
“Sorry…”
Instead of becoming angry, nii-chan puts his fingers in your mouth, sucking your essence like it’s the last thing he’ll ever taste. You try to crawl away while he fiends with his fingers, but you only make it to the head of your bed, seeking refuge with your stuffies.
Sukuna follows, easily flipping you over and shoving your face into the mass of plushies. It’s easy for him to pry your legs open and see that sopping, molten hole just begging for something to stretch it out. It’s so tiny and tight… he wants it to bleed.
“Be still.”
He presses the head of his cock in your hole, struggling to fit it in. He supposes he should’ve fingered you, but he’s too needy to stop now. He drives the head in, popping your hole open and the rest is slightly easier from there. You scream in pure pain, but Sukuna only feeds off of it.
Sukuna has been pent up for a thousand years, he can almost cum just like this, but he has some restraint. He pushes himself to the hilt, not without some sobs from you of course. You’re tighter than anything he’s ever felt, like a vice grip on his cock. He’s sure even if Itadori had a smaller length, he’d still be pushing at your little cervix.
“Does it hurt?” He clicks his tongue. “Oh no…”
He grabs you by your hair, pulling your head up and looking at your face. Your eyes bulge from the pain, red and bloodshot. Tears stain your puffy cheeks, and your mouth quivers and continuously spews cries. Sukuna can only grin.
“Dear sister…” he begins to move, albeit with some strain. You’re gripping him so tight he can barely move, resorting to rutting into your body. “Sweet, little thing.”
“Yuu-nii!” You screech. “Please stop! Please! Please!”
“Oh sweetheart…” his eyes roll in his head. “Nii-chan’s not home right now.”
But you already knew that.
You wail, and he begins to move as he pleases. Your cunt secretes wetness in an attempt to save itself, aiding him in fucking you like he wants to. All you can do is cry and cry, and eventually you tire yourself out. You fall into his arms, letting him use you like the little fleshlight you are.
“Nii-chan loves you…” he coos in your ear. “He loves you so dearly, darling, but he doesn’t love you enough to stop me.”
Drooling in his arms, you barely make a sound. Your face stays in a permanent frown, eyes spacing out as he uses you like you were made to be. His eyes continue to roll and cock throb as he reaches his end. Sukuna doesn’t know what would happen if he came inside of you and actually got you pregnant, but he’s sure either it wouldn’t be good.
However, he’s not entirely convinced you’ve hit puberty yet.
It wouldn’t hurt to try, he decided, hammering into your pliable body. You leak and drip all over your bed, all over his cock and his toned thighs. As good as your body feels, Sukuna derives true pleasure from imagining how Itadori will react when he wakes him up.
Sukuna thinks about waking him up right as his body cums, just so he can be the one truly cumming… but that’s something he doesn’t want to give up just yet. A thousand years without sex, and now he has a little toy all to himself. Itadori can wait. He can’t.
“Fuck…” he circles his hips before giving his final thrusts. “I’m going to cum inside of this sloppy, young cunt.”
You don’t respond, perhaps don’t register what he’s saying, but you do groan once he fills you up with all of that hot, virile seed.
“Okay, Itadori… you can wake up now.”
*
His cock is wet and warm.
Slowly, Yuuji’s eyes open. His thighs are painted with blood and cum and god knows what else. His cock begins to soften. When he raises his gaze, he sees the image he feared more than anything.
Your face, buried into the pillow, while you cry. You’re nude, with cum gushing out from between your legs. Your whole body convulses with sobs.
“I- imouto-chan…” he gasps. “I… I’m sorry. Oh my god, nii-chan’s so sorry.”
He reaches for your shoulder. You flinch.
“No more!” You rear your head back and scream at him. “No more! No more!”
His face falls at the way you’re looking at him.
“Look…” his voice cracks. “It’s me. N- nii-chan’s back. That… that wasn’t…”
Stop lying to yourself, Itadori.