Warning, this is a rape story.
It should've been a normal day in Headspace, nothing special, just like every other day before it. Omori was having fun playing with his friends at the playground while Mari sat on a blanket watching them all, ready to give them some nice, delicious food whenever they needed it. For the most part, that was how the day was going. It felt like hours passed whittling the day away doing nothing, but in a way that felt rewarding.
But then, something strange happened, something out of the ordinary, though it didn't start that way.
"Hey, Omori!" Mari called out to him.
The boy looked over at his sister, and waved. Seeing that she wanted him for something, he made his way over to her. "Hello," he said politely.
"I saw you staring at Aubrey~" Mari teased her 'little brother.'
"M-Mari…" the boy said with a blush as he glanced over at the girl moving across the monkey bars.
"You like her, don't you~?" his 'sister' pressed, even leaning forward a little to analyze the growing redness and nervousness on his face.
"I-Is it that obvious?" he asked sheepishly, still watching her as her dress fluttered around.
Mari chuckled. "Of course it is, although I see you staring at Basil a lot too~"
"M-MARI!" the boy cried as he covered his face, now even more embarrassed. "St-stop teasing me!"
"What is it you like about Aubrey?" Mari asked, as cutesy and innocent as she could.
"I'm assuming you aren't going to leave me alone until I tell you?" he asked, peeking at her through his fingers.
Mari scooted over next to Omori and smiled up at him. "Nope! That's what big sisters are for, after all."
He nodded, and sighed. "She's…adorable. So, so adorable." he got out, but even just saying that felt incredibly embarrassing.
"What about her is so cute~?"
"Everything." he said, "Her smile, her voice, just…everything she does."
"Even her hair~?" Mari piped up.
"Of course!"
"You mean her long, black hair~?" Mari continued while, rather unsubtly, running her fingers through her own locks like they were fish swimming through a river.
"Yes." Omori affirmed with a nod. At first, he was confused why Mari was staring at him, before he finally noticed her hands were in her own hair. His blush deepened in response as he found himself looking away from her once again. "U-umm…"
Mari couldn't help but giggle at the sight of his clear humiliation at that moment. "Oh, you're so cute when you're flustered like that, y'know that?"
"Sh-shut up." the boy said weakly. He really didn't mind when Mari teased him, but she certainly couldn't let her know that.
"You're so easy to read, but then again, it's cause you're my brother. Isn't that right, Sunny~?"
Suddenly, it was like everything stopped. The world became quiet, and the boy's eyes widened. He felt like he'd been punched in the gut as he looked at his sister. "Wh-what…did you say?"
Mari slowly stood up and looked down on Omori. "Sunny, my real brother. You two know each other, I know that much~"
"I…I don't…wh-why…" In all of his time in this world, this perfect world, she had never once mentioned…him. Omori felt a gasp run through him as the color in the world almost seemed to fade. The growing silence became heavier. "Heh…ehehehe…v-very funny…M-Mari…please stop."
Mari just giggled. "Come on out Sunny, all it'll cost is your love~"
"S-stop!" Omori cried as he felt something inside him. A…thing inside him that felt like it was crawling under his skin. "Th-this isn't funny!" the boy said desperately. His eyes looked around frantically. All of his friends had stopped moving, and all the color was gone, other than Mari.
Mari gently reached out and tapped her finger against his chest, almost as if to make him focus on how unreal he felt.
The boy felt his flesh itself shifting. He looked down to find himself…glitching. His skin was changing color. He looked up at his sister in fear. "What…did you do…?" He began to cry, "WHAT DID YOU DO?!"
"I just reminded you of who's supposed to be here. Is it so wrong for a girl to want to see her little brother?"
"No…no no no no no no NO NO NO NO NOOOOO!" He cried. His voice changed pitch, up and down, high and low. His body continued changing, feeling like it was stretching. His skin flashed through a rainbow of color. He screamed as everything seemed to fade.
Then everything snapped back at once. Omori vanished, as if he'd never existed. What was left was Sunny, someone who wasn't supposed to be here, who was never meant to be here, was now standing in front of his sister. Panic filled every ounce of his body as he trembled in place. "M-Mari…?" he asked, his voice barely above a whisper. The world around them, the world Sunny had built to feel happy and safe, melted away, leaving them in nothingness.
Mari gave him that warm, welcoming smile that she always gave him. If it weren't for the starless void that extended forever in every direction around them, he would've felt comforted. "Sunny~!" she declared with clear joy. "It's been so long! How's my little brother doing~?"
"M-Mari…what have you done?" Sunny asked as he stared at the darkness surrounding him. The lovely world he'd created…gone.
Mari's face contorted into one of sadness and pain. "C'mon, don't be like that, please? I just wanted to see you again..."
"I…" Sunny wished he could say he wanted to see her too, but all he could think about was, well, her. How she looked the last time he'd seen her.
And Something floating behind her.
"W-we can't…"
"Why not, Sunny?" Mari asked as she stepped up to him. "Just because you killed me doesn't mean we can't see each other. Talk to each other. Touch each other~"
That word startled him. He put his hands on the side of his head as he could feel Something staring at him with that stupid horrific eye. "M-Mari…I'm…I'm so…sorry…"
Mari wrapped him into a hug, pressing his head against her chest as she began to pat his back. "Don't worry Sunny, I know it was an accident. I know lots of things, now that I'm inside of you~"
He could barely focus on what she was saying, but he buried his face into her shoulder as he began to sob uncontrollably. He couldn't stop shaking. He felt so small, like how he'd been when she'd died.
"I know you think about me every day, Sunny. I know it hurts."
"I…I miss you…so much…" he blabbered as he clung to her, fearing she might disappear if he let go.
"I know just how much you miss me, and the parts of me you miss the most~" Mari said with a strange tint as she hugged him even tighter against her chest.
"H-huh…?"
"I know you think of me all the time, even when you touch yourself~" Mari practically purred. "I know you even think of me after I died~ You're a sick little puppy, aren't you, Sunny~? I wonder what Mom would think~"
"I…I didn't…th-that's not…" he tried to plead.
Mari wrenched his arm out from around her and ran her fingers over his skin. Even compared to how fair she was, the pallid flesh pulled tightly over his thin, weak skeleton seemed even ghostlier than her existence was. Despite that, she could still make out the look and texture of a dozen or so scars from his periodic engagements with self-harm, and before his eyes, she pulled his arm up and licked them without breaking her gaze from him.
"M-Mari…" He gasped at her touch. "What…are you doing?"
"I'm giving you what you want, Sunny. What you jerk off to, what you think about, I know all of it. Big sis is here to take care of you~" she told him as she wrapped one leg around one of his and yanked, sending him falling onto his ass. "Because I still love you, even after what you did to me~"
"I…I don't…want…" he said as he frantically shook his head, trying to scoot away.
"Of course you do~" Mari insisted as she got onto her knees and grabbed his ankles, dragging him towards her. "I know you want to be punished, that's why you keep running away. You're too much of a pathetic little boy to kill yourself, so you want to hurt and hurt and hurt until everything goes numb~"
"MARI! STOP!" This was clearly no longer his sister. It couldn't be. She'd never do something like this!
"Take off your clothes, little brother~" Mari insisted as she reached up and grabbed his shorts. "Your big sis is going to make all of your fantasies come true~"
"N-NO!" he screamed. He had to admit, she did often creep into his thoughts while he pleasured himself. He couldn't control it. It had happened before she died, and even after. He'd even had a few fantasies with her in it, ones that were much more voluntary. Even so, to have her now wanting to fulfill one of those fantasies that had always been only that, it filled him with dread.
"It's all part of the fun~!" Mari insisted as she pulled his shorts over his scrawny, pale legs. More scars on his thighs were exposed alongside an involuntary bulge in his underwear. "Remember that one dream you had? The one where Aubrey made you eat her out in front of the entire school~? We could do that one!"
"Wh-why are you saying this stuff?!" he asked. Surely this was a punishment of some kind. He already tortured himself enough in reality, so it made sense that eventually his dreams would turn on him too. He hated that he was aroused, that she could see his bulge, that she was speaking so lewdly. It wasn't his sister, and he couldn't seem to get her to go away.
"Because you need this, Sunny~" Mari insisted as she leered over him. He felt so small underneath her, and with how short and malnourished he was, the body she had developed before he murdered her seemed so much better. Sometimes Sunny would think about having a body just like her's, but he tried not to think about it often. His thoughts were interrupted as she reached up and gently wrapped her long, piano-trained fingers around his neck and gently squeezed.
"Akkk!!" he croaked, mostly in surprise as he reached up and wrapped his hands around her wrists. "Wh-why…"
Mari sat on his lap, grinding her panties against the bulge in his underwear as he grew lightheaded. "I know you think about dying, Sunny. Would you rather have died, instead of me? I think you would, maybe I'll just choke you out right here~! I just want what's best for my little brother~"
"I…" He couldn't deny it. Nearly every day he wished he had been the one to die instead. He deserved it more, not her. She was a better life than his would ever be. He slowly removed his hands from her wrists and allowed her to do as she wished.
Mari kept one hand around his throat as she reached down with her others, and sat up a bit to reach down and pull his underwear down just enough to expose his penis. "Aww, you have such a cute dick, Sunny! Would you rather hear that it's better, or worse, than Hero's? I can do either~"
"N-no!" He gasped. He'd meant for her to kill him, not this! "D-don't look!"
Mari displaced her panties and lowered herself slightly, rubbing her wet folds against the head of his painfully erect cock. "I don't want to just look Sunny, I want to fuck you~ Does it feel nice, being raped by your sister~?"
"NO! I-I DON'T WANT THIS!" He screamed as he attempted to wiggle away, but that only shuffled his cock against her lips further, and unwanted pleasure shot through his entire body because of it.
"Yup! That's what rape is, after all," Mari replied rather flatly before gently sliding him inside of her.
"GAHHH!" he cried as pure pleasure flooded him. His body trembled as it was like nothing he'd ever experienced before. Even though he knew he was dreaming, it felt so real, so tangible. It felt so good, and he hated it.
Mari released his throat, instead placing her hands on his chest to steady herself as she slid up and down on his cock, gently milking it with her pussy while she panted and 'praised' him. "You're such a good little slut, Sunny, you should let everyone fuck you like this, it's the best use you'd ever have~"
"Mari…what…did I do to you…gaaaah!" he moaned. He could've taken better advantage of this. He could've groped her like he fantasized, but it just felt wrong, just like everything else. How had this version of her become so twisted? What had happened? Why was it happening?
He could feel her pace grow faster and harder as she used one hand to continue choking him. "Don't you love me, Sunny? You kill me and now you can't appreciate me going out of my way for you?"
"I—ahhhh—I-I do love you…but not…mmmm…like this…" he said. He could feel pressure building inside him, a familiar one, but one he wished wasn't happening.
"It figures," Mari grunted as she could feel him getting ready to cum. "You can't appreciate your family, you can't appreciate your friends, you couldn't appreciate the violin, you're an ungrateful little fuckdoll!"
"Ahhhh…AHHHHHHH~!" he moaned. She was right. Everything she was saying was right. He couldn't be happy, not when he took what he had for granted, not when he didn't treat his sister and his friends the way they should've been! He deserved this and more!
"Show me how fucking gross you are," Mari insisted as her thin veneer of sisterly love gave way to how Sunny truly felt he needed to be treated. "Finish inside of your sister!"
"AHHHHHHHHHHHH~!!" the boy screamed as he did just that. He came hard inside her, filling her womb almost instantly with his seed, bursting like a dam as his body lurched, trembled, and then collapsed back down. He was left shuddering and panting as cum leaked from her pussy and down his waist.
"Does it feel good, Sunny?" Mari asked her little brother.
"I…I-It…did…" he admitted.
"Of course it did, you know what you deserve," Mari insisted as her skin began growing paler until it looked like his. Her hair became stringy and thin. Her body became starved. "You know what you did to us, to me, to yourself."
Sunny opened his eyes, and they went wide as he saw the transformation taking place before him. "N-no…NO!"
She grabbed his collar as her body tensed up. A low, pained groan came from her voice as the skin stuck to her bone until it began to slink away, exposing muscles and nerves. Her eyes rolled into her head until they popped and the fluids ran between the muscles sticking out of her face like rivers through a valley. Her hair fell from her head and back onto his legs as bone began to poke out from beneath like worms rising from the ground after a rainstorm. After a few more moments for everything else to melt away, Sunny was left with the skeleton of his sister clutching his collar bone while it looked up to the sky.
The last thing he remembered before waking up was when it looked back down, snapped forward, and bit into his right eye.
As soon as he awoke, he shot up, clutching his eye, panting and gasping. He frantically looked around his dark and empty room, trembling. It had felt so real, so terrible, so horrible.
As he collapsed against his bedframe, he found himself trembling uncontrollably. Tears streamed down his cheeks as her words, her face, her body, every sensation flooded into him all over again. His knees met his chest as he curled into a ball and sobbed.
Was that world gone? Was his safe space completely empty forever now? He didn't know. He was scared to find out. All he could do was sit there in the darkness, crying and shaking, until the sun rose.
And even then, Something was still staring at him.