"Please, Bellatrix, my husband—"
Her voice barely a whisper, Narcissa lay prone on the floor of the cellar, wrists bound tightly, surrounded by indomitable darkness.
"Please, Bellatrix, my pathetic drunken waste of a husband—" Bellatrix's tone was mocking, a high-pitched mimicry of her sister's soft plea. "Your husband is nothing, Cissy. Nothing. He has shamed you, shamed your family, in front of the Dark Lord."
Narcissa's soft whimper was swallowed by a loud cackle, echoing into the darkness of the room, reverberating off of the rough hewn stone. The darkness of the room was absolute. She could hear the scrape of boots, the subtle swish of skirts. The sound of her own unsteady heartbeat pounded in her ears. The stone beneath her was cold on her nude frame, and her limbs ached from hours of immobilization.
"But you, little sister, you are a Black."
Narcissa felt a tendril of her sister's dark curls brush against her cheek, felt her breath, her lips hovering mere inches from her face.
"You are of a noble family. You are above that wretch of a man. Above that sniveling boy you bore. They are inconsequential. You need no one, Cissy. No one but your blood."
Narcissa moaned involuntarily as Bellatrix's hands brushed through her fair hair, tenderly at first and then harder, nails raking down her scalp. The bindings at her wrists bit into her skin as she struggled against them, struggled to close the gap between her sister's body and her own. It had been years since she had found herself like this, bound and bruised and helpless to her sister's every whim. It had been years since she'd felt the warmth of her sister's body pressed against her own. But she had not forgotten it. And as Bellatrix moved downwards and curved her tongue expertly around her nipple, teasing and nipping, she felt her body responding in very familiar ways.
"Little Cissy, all grown up," Bellatrix singsonged. "Tell me, love, did Lucius ever tie you up?"
Nails scraped across her stomach now, leaving welts that she could feel even in the darkness. She felt the rough fabric of a bodice brush against her painfully erect nipples as Bellatrix worked her way slowly back up to her face, kissing her hard, catching her bottom lip between her teeth in a way that felt like possession. She tasted blood.
"It's such a shame if he didn't. You've always been such a good girl—"
Narcissa cried out as Bellatrix ran a single finger through the wetness at her core.
"—a very good girl, indeed."
Narcissa whimpered again, her hips bucking up to meet the space where her sister's hand had been only moments before. And then that hand was at her throat, holding her down against the stone floor, thumb curled to press against the pulse point there. Wand light suddenly illuminated the area surrounding them. Bellatrix's eyes, pupils enormous with arousal, seemed almost luminous as they hovered mere inches above hers. She ran the glowing wand tip down the younger woman's cheek tenderly, tracing whorls of light onto the skin at her jawline. Narcissa felt the darkness encroaching on her, blurring her vision. As she struggled to draw a full breath, her eyes focused on her sister's lips, watching her tongue dart out to wet them, watching the shapes they formed as she spoke.
"Your husband thought he owned you. That he, waste of a man that he is, was worthy of you. He thought he was worthy of your body, of your loyalty and love."
Her fingers released their grip on Narcissa's throat, hand moving down to cup her breast, fingers rolling a nipple between them.
"He thought your heart beat only for him. But you're mine, aren't you, Cissy? That's our blood in your veins, pumping through your heart, isn't it? You're wet for me."
There was an almost childlike quality to her voice as she said this. The dark curls and hooded eyes hid a desperate need to know, in that moment, she was everything to someone. A longing to know control, to know absolute power. That she was their world, and that she possessed them entirely.
"Bella, I, I—"
Narcissa's response was little more than a stammer, her throat dry. She licked her lips slowly, eyes downcast, feeling, rather than seeing, Bellatrix's gaze on her body. She squirmed against her restraints. Wand light illuminated her pale skin, and she watched with wonder as her sister outlined delicate patterns of light across her body, following the path with her tongue and teeth. A hot line of desire coursed through her, settling at her core with a throb. She twitched as teeth found a sensitive spot above her hips.
"I'm yours, Bella. You know I always have been."
The smile on Bellatrix's face bore the faintest glimmer of relief before it hardened into a smirk.
"Sweet Cissy. So tender. It's touching, really. The way you offer yourself to me as if you have anything left to give. Poor Lucius, he ever realized what a darling little slut he married, did he? He may have made love to you, helped create weak little Draco, but I made you. Even when you were young, a mere wisp of a girl, you were mine. A part of me, darling, in a way that only sisters can be. "
"Please, Bella—"
Narcissa's voice had taken on an edge of desperation, wetness coating the inside of her thighs as her sister scratched and bit her flesh in ways she knew would leave marks. Those marks, both the leaving of them and the furtive attempts at covering them the next day, had always been a ritual of sorts for the sisters. The lines between shame and pleasure, between possession and freedom, had always been blurred. Narcissa's mind had never completely reconciled with the reality of their situation, but her body trembled beneath her sister's touch. She longed for it, even as she feared it.
"Please."
Bellatrix cackled again at this, her sister's quiet plea.
"Always so polite, Cissy. But tell me, don't you think you could show a little more…enthusiasm?"
With the flick of a wand, Narcissa found herself standing upright, hands unbound and back pressed against the damp wall. She rubbed her wrists, red pressure lines crisscrossing them where the ropes had chafed against her skin. Bellatrix approached the younger woman, her movements almost feline. She motioned with her head towards the ropes piled next to them on the floor.
"Did they pinch?"
"N-No."
"Hmm. Pity."
Narcissa moaned as Bellatrix pressed up against her, body fully flush against hers. The rough stone of the wall scraped against her back. The floor was cold beneath her bare feet. Though both tall, the benefit of boots, chunkily heeled, made Bellatrix just tall enough that Narcissa had to arch her neck to meet her sister's eyes. The predatory glint in them made her flush with want.
"Turn around."
Narcissa turned, nipples erect against the wall. As Bellatrix breathed unevenly into her ear, the wand light went out, plunging them into sudden darkness.
"You always peeked when you weren't supposed to, little sister. Never one for surprises, were you?"
Her response was strangled by a groan as nails tore jagged lines down her back, heat flooding the area. The air smelled of sweat and iron, tinged with desire. Fingers tangled in her hair, pulling her head back. A single finger pressed to her lips. Dutifully, she took it into her mouth, the taste of blood acrid on her tongue. She sucked gently, enjoying the soft, throaty moan that escaped her sister's lips as the finger slipped out of her mouth, clean of blood.
"That's our blood, Cissy. Black blood. Yours and mine is the same. Can you feel it inside of you? Can you feel me inside of you?"
The unexpected slap of a riding crop stung against the back of Narcissa's thigh, making her falter on her feet.
"Tut tut, darling. Having a hard time staying upright, are we? Face me, hands above your head."
She obeyed without thought. Senses heightened by the total lack of light, she smelled her own arousal, mingled with her sister's, filling the room. The cold steel shackles clamping her wrists together and chaining them to the ceiling came as little surprise, but the quick twist of her nipples sent a new gush of wetness flooding between her legs. She felt her sister's presence in front of her. She bit her lip in frustration, arching her body to meet the touch she so desperately desired.
"Oh, Cissy. What would Lucius say if he could see you now? Or Draco?"
She flinched at the names of her husband and son, but her body stayed arched, reaching towards a need that transcended any sense of shame she felt. She felt the stickiness of drying blood on her back, the steady throb between her legs. She knew she must look deranged, body slick with sweat and desire, pupils blown, struggling towards a person that offered the last thing she should desire, but everything she needed at that moment. She longed for that finger to her lips again, that taste of blood. Her blood, as much her sister's as it was her own. Just as she herself was, possessed, autonomy stripped away, a part of Bellatrix. She opened her mouth to speak, to beg, but stopped short as a palm pressed against her clit, sending shocks through her limbs. She lost and regained her footing again, muscles straining against the chains above her head.
"Fuck, Bella—"
Her cool exterior and regal bearing gone, Narcissa found herself panting, mouth agape, writhing against her bindings as her sister traced a lazy pattern of circles around her clit, sliding her hand down to coat her fingers in the slick wetness at her core. The older woman was silent now, her ragged breathing the only other sound in the room.
"Please, Bella. Don't tease. I can't take it."
The fingers that had only a moment before begun to slide ever so slowly into her wet center were withdrawn. There was a swish of skirts, and Narcissa was left with nothing but cool air on her swollen clit. She whimpered. Bellatrix's voice was heavy with danger, her tone threatening in response to her sister's desperate plea.
"Don't tease? How dare you tell me what to do! You are mine, little sister. Mine to do whatever it is I want with. And I will decide what you can and can't take."
Narcissa cried out as the crop bit into the tender flesh of her inner thigh, leaving a bright red mark in its wake. The chains rattled against themselves as she fought them, pulling herself towards the flash of pain, to the place she was sure her sister was standing. Bellatrix has spent years learning her, her body; years digging teeth and nails into every tender space, mapping out every place that made her skin flush hot and made her mind flood with want. She clenched her thighs and shuddered, need overtaking her. Moments later, the shackles released, sending Narcissa tumbling to the floor. She hissed at the sudden roughness of the stone floor on her abused flesh, struggling to get her bearings in the pitch black of the room. She heard again the rustle of fabric, the clunk of heavy boots being tossed aside.
Bellatrix's spoke softly now, breath shallow, voice hitching in her throat.
"You are nothing without me. Nothing. "
And with that, Bellatrix was on her; pinning her wrists above her head, mouth hot and eager on her own, clothing gone and body a warm weight on top of her. Their kisses were hard and hurried, all teeth and tongue and swollen lips. Narcissa's groan turned into a gasp as her sister slid a leg between her own, thigh soon sticky with her arousal. Her hips bucked, body arching towards the lithe frame stretched above her. She felt the brush of stiff nipples against her own, and the warmth of her sister's mouth swallowing her moan.
And then her wrists were free, dark curls brushing once more against her face. Her sister's breath was warm on her neck, lips brushing gently against her ear.
"Tell me what you need, Cissy."