Manaka was completely unable to break away from Ryosuke.
On the surface, she never accepted him, but every night, her body eagerly awaited the knock on her door.
And their encounters weren't confined to her room alone.
With their parents often absent and Marin now attending cram school, Manaka and Ryosuke found themselves increasingly alone at home during summer vacation.
He violated her in the living room.
They had sex in their underwear in the changing room.
In the bathroom, in the hallway—everywhere, they devoured each other's flesh with insatiable hunger.
Even when Takuma embraced her on a date, she felt a painful guilt.
But the moment she returned home and collided with Ryosuke in the entrance hall, both sweaty, all of it ceased to matter.
Takuma loved her, yet she possessed Ryosuke exclusively.
Her summer was filled with an unprecedented thrill, a mix of guilt and superiority.
Things changed in the second semester.
It began when Ryosuke started seeing someone else.
One day, when I returned from school, I found a pair of women's loafers lined up in the entrance hall.
(Huh...?)
They were clearly not Marin's.
Mixed emotions welled up inside me as I tiptoed upstairs. When I entered my room without making a sound, I heard faint, girl-like moans coming from the next room—Ryosuke's room.
Unaware that Manaka had returned home, my stepbrother and his partner continued their endless sex. I couldn't tell for sure from the voices alone, but his partner seemed to be around Ryosuke's age, or possibly older. At first, the voice was cute and innocent, but it gradually lost all restraint, growing wantonly disheveled.
(Shito-kun... I love it, I love it! Please, just like before... one more time... Aahh! Nngh... No, ah, ahnn...)
It was torture.
Right now, she must be being thoroughly loved by Ryosuke's fingers, hands, and lips. Deeply connected.
(...)
I know I don't have the right to be jealous.
"Ryosuke..."
Manaka pressed herself against the wall, her only solace being the way her hands could soothe the ache in her body.
*****
Relaxing in the air-conditioned living room had become our routine with my younger sister.
When we first started living together, Marin treated Ryosuke like an enemy, but now she'd climb onto my lap herself.
"You're such a bad person, Nii-san."
My younger sister-in-law's body was gradually becoming more feminine, but she still rubbed against me without a care. She wore an off-the-shoulder blouse and a short skirt.
Near my right ear, she pouted.
"You used to hold Nee-san so tightly."
I'd never told Marin directly, but she'd naturally figured it out.
"Yeah... When summer vacation started, my younger sister suddenly said she wanted to go to cram school. The perfect opportunity presented itself—so things just... happened naturally."
"You're going to blame this on me? And you still call yourself my 'brother'? What a terrible person you are."
She chuckled mischievously.
"I'm just worried about your future."
"I'm fine. Nii-san will take responsibility for me."
"You can't just decide that for me!"
Sighing, he smoothed her long black hair, and Marin relaxed contentedly, as if basking in the moment.
"Ahh, I'm so happy... being held by such a wonderful brother."
"That sounds awful. I'm not some pervert who'd make advances on my own sister."
"You'd be allowed to, you know?"
Her voice was sweet and provocative. Even an adult would likely fall for her charms if she used her feminine wiles.
"Nee-san looks happy too."
"Really?"
"Trapped between Takuma and Nii-san, writhing in torment... but you look happy."
"You're twisted."
"Indeed. We're all twisted. Even so, at least I—and Nee-san—are happy. I hope Nii-san can find happiness too."
"..."
Both his relationship with his older sister-in-law and his affairs with his lovers (if that's what they could be called) provided Ryosuke with stimulation. Whether he could call it happiness, however, was another matter.
His sexual desires and physical needs were certainly satisfied.
Manaka's mature, sensual body and his lovers' innocent reactions were equally alluring. The rules were simple: tease and devour them at will. Satisfy their desires, and they'd repay him in kind. It was child's play to discern what they wanted, making it all effortless.
Yet, he remained clueless about what he truly desired.
Did he want a family? For instance, if Manaka had wanted to remain his sister, perhaps he could have granted her wish. Did he crave someone he could trust with his heart? For example, if his lovers had sought genuine affection instead of mere stimulation—
(...What a foolish question. That's precisely the problem.)
Ryosuke himself had broken it.
Even though it was what the other person wanted, Ryosuke was the one who made it happen.
I can't become the most important person in someone's life.
That conviction lay deep within his heart.
If that's the case... at least I'll become someone they can't forget. A near-desperate impulse was driving him now.
Alongside the superiority he felt from manipulating others, an overwhelming emptiness spread through him. He would probably never be fulfilled again.
"...So Marin will help me become happy, right?"
It wasn't an expectation, just a resigned question, but Marin answered immediately:
"Of course."
"For Nii-san, I'd do anything. You've made Nee-san and me so happy. I love you, Nii-san— I'll always be your accomplice."
This younger sister was somewhat different from the others, which made her all the more intriguing.
After a period of mutual observation, I've finally begun to understand her recently.
She's just like Ryosuke.
In Marin's case, she's constantly seeking someone to depend on—whether it's her older sister Manaka or her brother-in-law Ryosuke.
Her attachment to the person she depends on is intense. She'll say she "loves" them, but she never says she wants to be "loved" in return.
In a way, perhaps she's reserved, I think, and wince at the irony.
The price Marin demands is for her partner to become happy. If her sister or brother can achieve happiness, she's satisfied.
It's a profoundly hidden truth. Her usual behavior is sadistic, like she's enjoying tormenting her prey. But in reality, she simply wants to serve the other person. Her expression of love is just a little... twisted.
I envy those who know exactly what they want. It's something Ryosuke lacks.
Another difference between us is that Ryosuke hides his true nature from his prey, while Marin reveals hers completely. Yet despite this, our approaches to our targets are strikingly similar.
A younger sister, huh?
Putting it into words made it feel right. Despite being a complete stranger, she feels more like family than my own blood-related father ever did.
How to express affection for a family member? That remains unclear—
"Marin."
I gently brushed aside her long black hair and rested my right hand against her slender cheek.
Her beautiful eyelashes and dark eyes met mine. Though she's still young, her bewitching beauty sends shivers down my spine.
"Yes?"
"You're a wonderful younger sister, Marin."
"Of course—mmph!"
I lightly kissed her thin lips.
"Mmm, Nii... sa... hah... ugh..."
Caught off guard, Marin tensed for just a moment, but then...
"I love you... so much... mmh... ah..."
She closed her eyes in bliss and leaned in closer. Though she had a mature demeanor for her age, her kisses were still clumsy. Ryosuke found her earnest attempts to respond to his affection endearing.
His younger sister, who never asked for anything in return—
Still, she had desires.
The word "adolescence" seemed ill-suited to describe Marin, yet her instincts and body were maturing, drawing closer to adulthood with each passing day.
If she was unconsciously seeking something, it was his duty to satisfy her.
Long, slender arms. Smooth legs peeking from beneath her skirt. Shapely collarbones and a neck that carried a sweet fragrance.
"Ah... you said you wouldn't touch me!"
"Then shall I stop?"
"No..."
Marin, unusually sullen, continued, "Just hearing Nii-san's voice, just being touched by him... it's making me crazy. I used to hate being touched by anyone..."
"Even Nee-san?"
"Even with family, there should be some distance. But... Nii-san is different."
Her glass-like beauty was now flushed and softened with girlish vulnerability.
"I never imagined I'd get a reward like this... Ah, why are you being so... so gentle with me...?"
"Of course, because you're my precious younger sister."
"Mmm... Ah... Heh heh. That's the highest praise, isn't it? For a brother who's never been loved before, to hear those words..."
Even in this situation, she keeps hitting my weak spot.
"Correction. You cheeky little sister."
"Ah?! N-nii-san, not there...! Ugh, ah?!"
I embrace her slender waist, cradling her still-soft, slightly rounded hips. Her black underwear, designed to accentuate her curves, is stretched taut. As my fingers trace the crotch, her hips begin to sway back and forth.
"Ugh, ah...?! Eep, ngh!"
Through the damp fabric, I can feel the shape of her immature sex.
"You did this to tease me, didn't you?"
"Hah, ah—! Y-you're so easy to read... I love those vulnerable spots of yours..."
"Don't move your hips on your own. This isn't a proper spanking!"
"Ugh! Yes, I'm sorry, Nii-san—! Stay still... Mmm... Eep! Ah! Ahh?! I'll be the kind of younger sister Nii-san dotes on, so, so—! Aaaaah!"
Marin clung to him with stiff arms and legs, her body trembling.
"Nii-san, Nii-san—...! Ah! Ugh...! Ugh...! Ah...! Ugh...!"
Her back arched violently as she came, tears streaming down her face.
"Haa... Haa... Haa..."
"Heh. Sorry. I went too far, didn't I?"
"...Yeah... Don't teach your younger sister any weird stuff..."
Her body felt feverish, as if the air conditioning had completely failed. She buried her burning face against Ryosuke's chest.
Ryosuke gently stroked his younger sister's small back as it rose and fell rapidly, his touch more tender than before. His movements were almost parental, surprising even himself with how much he truly cared for her.
"...I'm so happy... That someone like me could be loved so much... I'll definitely make Nii-san happy too..."
Ryosuke responded to Marin's whispered, almost delirious words. To his surprise, his voice came out soft and gentle.
"Yeah. I'll hold you to that, Marin."
*****
Tomorrow will be another three updates, finishing the story.
(Scheduled for 6 AM, 12 PM, and 9 PM)
*****
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