I Love You So Much So Please Love More Than Just As A Girlfriend, Love Me As A Little Sister - Volume 1 Chapter 3: There’s No Way My Childhood Friend Is This Much of a Little Sister

Volume 1 Chapter 3: There’s No Way My Childhood Friend Is This Much of a Little Sister

A week had passed since Keita started his Rental Onii-chan job.

…Or so it went. The only “little sister” customer to show up was Hatsuba, and that was just for the first two days.

Since then, not even a religious solicitor had dropped by, leaving Keita to spend his shifts grinding free quests, event quests, or occasionally rolling the gacha. Oh, and the occasional Onii-chan training.

(Is this what a job is supposed to be?)

Pondering this, Keita trudged along the morning commute to school.

—Then, up ahead, among the students heading to school, he spotted Hatsuba’s back.

She was walking with a few friends, laughing cheerfully. He stared for a moment.

If he called out, she’d probably respond. …Maybe. He wanted to believe she would, at least.

The problem was her friends and the other students around. 

If Keita approached her, people would naturally wonder, “What’s up with them?” Since neither could afford to let their job situation leak, standing out was a bad idea.

Still, blatantly ignoring her felt like it took a different kind of courage—one his socially awkward self didn’t have.

So, Keita deliberately slowed his pace, putting some distance between them before Hatsuba could notice him.

(…This should be far enough.)

Hatsuba’s figure was out of sight. She must’ve already entered the school building.

Breathing a sigh of relief, he picked up his pace. He’d been walking so slowly that homeroom was getting dangerously close.

—But.

As the school gate came into view, Keita froze.

A group of students wearing disciplinary committee armbands was stopping people at the gate. A surprise uniform inspection.

(Crap…!)

Panicking, Keita turned to backtrack.

If the disciplinary committee was here, she was definitely around. He couldn’t let her catch him. Even if it meant being late, he’d kill time somewhere until the last second—

“—Majima-kun! Where are you going!? That’s not the way to school!”

A familiar voice called out from behind.

He should’ve just kept running, but Keita instinctively stopped.

Footsteps approached quickly, and a slender hand firmly grabbed his arm.

“Good morning, Majima-kun.”

Smiling brightly as she held him captive was a beautiful girl with long, black hair.

Hayakawa Nina. A member of the disciplinary committee from the class next door.

And… Keita’s childhood friend.

“Uh… M-Morning, Hayakawa.”

“Yes. And so, Majima-kun—just where exactly are you off to, turning on your heel so suddenly?”

“Well, uh… I forgot something…”

“Going back for it now won’t get you to school before the bell. Forgetting things is bad, but being late is worse. Give it up for today. I’ll lend you whatever you forgot.”

“N-No, that won’t work… I have to go back for it…”

“You have to? What did you forget?”

“Uh, well… My gym clothes! Yeah, I forgot my gym clothes! I can’t borrow those from you, right!?”

“No problem. I’ll lend you mine.”

“For real!?”

“But your class doesn’t have PE today, does it?”

“Ugh…”

His lie was effortlessly seen through, leaving him with nothing but a groan.

“If you didn’t forget anything, there’s no excuse for tardiness. Let’s go, Majima-kun.”

“O-Okay, I’ll go, just let go of me… H-Hey? Hayakawa?”

Ignoring his protests, Nina kept a firm grip on his arm and marched toward the gate. She breezed past the other disciplinary committee members, dragging Keita into the school building.

“Hey!? Where are we going!? Why am I the only one being hauled off!?”

“You’re a person of interest, Majima-kun. We’re heading to the disciplinary committee room for a special inspection.”

“What did I even do!?”

He pleaded from the bottom of his heart, but Nina didn’t loosen her grip.

Before he knew it, Keita was pulled all the way to the disciplinary committee room.

“Excuse me.”

“H-Hayakawa-san!? What’s wrong!? We’re in the middle of gate inspections…!”

A glasses-wearing girl, who’d been organizing papers, shot up like she’d been electrocuted. She looked ready to salute.

“Yes, a slight issue came up… I’m sorry, but could I use this room for a bit?”

“Understood! Leave it to us!”

With a perfect ninety-degree bow, the glasses girl left the room.

(…Wasn’t she the disciplinary committee president?)

A third-year, their senior. And Nina had her acting like that? Just who was Hayakawa Nina…?

“Now, Majima-kun. Take off your clothes and stand there.”

“What!? Why!?”

“No problem. I’ve locked the door.”

“That just makes it more alarming!”

Backing away instinctively, Keita met Nina’s calm, unwavering gaze.

“I said we’re conducting a body inspection. It’s to check for any suspicious items. That’s all. Asking you to undress has no inappropriate meaning. None whatsoever. Absolutely none.”

“I get that, but when you say it, there’s this weird intimidating vibe… W-Wait! Hold on!! Don’t undress me!! I can do it myself, I’ll do it!!”

As Nina reached for his uniform buttons, Keita frantically swatted her hands away.

“…There. I’m undressed.”

As instructed, he took off his jacket, leaving just his shirt.

Nina stared at him intently.

“That’s not enough. Take off your shirt too. And your pants.”

“No way, I’m drawing the line there!!”

“Hmm… Fine. You can stay like that.”

She spoke as if granting him a special favor, prompting Keita to let out a sigh.

“Let’s begin the inspection. Stay still until I say ‘okay.’”

“Got it…”

He nodded halfheartedly, but at that moment—

Squish. Something soft pressed against him, and Keita froze.

(…What?)

Glancing down, he saw long, glossy black hair. And a pair of slender arms wrapped around him.

“H-Hayakawa!? W-W-W-What are you doing!?”

“I told you! It’s a body inspection! I’m checking for anything hidden under your clothes by… by touching you!”

“But still! Is hugging me really—!?”

“I’m not hugging you! I’m merely extending my arms to touch your back! It’s not a hug!”

Was it, though? It sure felt like she was squeezing his torso tightly. And their chests were, like, completely pressed together.

“…Huff… Haa…”

“Hayakawa-san!? Why am I hearing heavy breathing!?”

“It’s… the smell! I’m checking your scent! I’m using all five senses to ensure you haven’t brought anything suspicious! There’s no ulterior motive!”

“Uh, uhh…!?”

Normally, that’d sound like a pervert’s excuse, but coming from Nina, it somehow felt… plausible? That was the scary part.

Her refined speech, graceful movements, and glossy black hair gave her the air of a classic Yamato Nadeshiko.

But her true nature? A terrifying disciplinary committee member feared by students and teachers alike. Rumor had it that a single scolding from her could turn a blonde gyaru into a braided, glasses-wearing literature girl.

And the one she had her sights set on most of all? None other than her childhood friend, Keita.

Nina was relentlessly strict with him. Despite being in different classes, she checked on him almost daily and always found some reason to call him out when she spotted him.

It’s not like Keita had done anything wrong. Not at all.

But there was an unavoidable reason behind this—

“Phew… That was… ahem! I’ve confirmed. It seems you haven’t brought anything inappropriate today.”

“‘Today’ you say, I haven’t ever brought anything questionable to date.”

“Now, let’s move on to your bag.”

Ignoring his feeble protest, Nina picked up Keita’s bag. Without even asking, “Can I open it?” she ruthlessly began inspecting his belongings.

(Well, whatever… It’s not like I have anything to hide—)

That’s when Keita remembered.

At the job, Rei had given him that Onii-chan Manual, telling him to bring it every time. To avoid forgetting, he’d stuffed it in his bag—

“Hold it right there!!!”

“Kyah…!?”

In a panic, Keita snatched the bag from Nina’s hands.

For a split second, Nina’s eyes widened in surprise at his intensity—but they quickly narrowed, glinting with suspicion.

“…Majima-kun? Why are you hiding it? Is there something in there you don’t want me to see?”

“N-No, it’s not like that…!”

“So there is something!?”

“Listen to me!?”

Nina lunged for the bag. Desperate to keep it away, Keita braced his arms, pushing back with all his might.

“Why won’t you let me see…!? You used to show me everything…!”

“You just opened it without asking!!”

“A-Anyway, Majima-kun, your libido is too strong!”

“What’s that outta nowhere!?”

“If you’re hiding it so desperately, it must be something inappropriate…!”

“It’s not!! Don’t just assume!!”

Ignoring Keita’s flustered protests, Nina bit her lip with a frustrated “Ugh…!” Her eyes looked almost teary.

He had no idea what was going on.

But one thing was crystal clear: this was a bad situation.

—Then, the warning bell echoed through the school. A literal godsend.

“Oh! H-Hey, Hayakawa, we’re gonna be late! Disciplinary committee members can’t be tardy, right? I’m heading out!!”

“Wait…! Majima-kun!?”

Before she could finish, Keita grabbed his bag and jacket and bolted out of the room. Nina’s voice called after him, but he pretended not to hear and sprinted.

He made it to his classroom and slid into his seat just as the final bell rang.

“Yo, welcome back, Majima.”

“Heard you were with Hayakawa-san again.”

“What were you doing in the disciplinary committee room, you dog?”

“Jealous. Die. Super jealous, die.”

“You guys…”

Keita, barely catching his breath, was met with his friends’ lukewarm stares.

…He didn’t get it at all, but to his classmates, Nina’s constant attention apparently meant “they’re super close.”

It was nice not being seen as just a disciplinary committee target, but how anyone could look at Nina’s terrifying demeanor and think that was beyond him.

(…She didn’t used to be like this.)

They’d met when they were little.

Back then, Nina was shy and reserved. She’d refused to do anything without Keita by her side, trailing after him like a little sister.

When Keita moved far away, they lost contact for a while. But last year, when he visited this high school for entrance exams, they ran into each other by chance.

“Could it be… Majima Keita-kun?”

He’d been shocked when she called out to him. Not just because so much time had passed, but because Nina had grown into a stunningly beautiful girl.

And… an astonishingly intense, overbearing honor student.

Still, they had been close, so Keita was genuinely happy to reconnect. When she said she wanted to visit his house to see his parents again, he’d been a bit nervous but agreed.

But that turned out to be a huge mistake, as he’d later learn.

When Nina came over, she barely greeted his parents before storming into his room.

Spotting the manga and light novels on his shelf—especially the slightly ecchi ones—she teared up and shouted:

“Majima-kun, you pervert!!! You cheater!!!”

He still didn’t get why she called him a “cheater,” but she probably meant something like “This is indecent!”

(When will she ever forgive me…)

As homeroom began, Keita let out a heavy sigh, already drained from the morning.

◆◆◆

“Majima-kun. I know you’re working hard, and I hate to say something so harsh to someone so dedicated… but sadly, there’s not even a hint of an Imouto-sama showing up today.”

“It’s not just today. There wasn’t one yesterday either, right?”

Keita retorted to Rei’s grave announcement.

“It’s proving tougher than expected. We’ve sunk quite a bit into online ads, too.”

“So that’s why those ads keep popping up…”

“But we can’t give up, Majima-kun. All great things start with steady promotion. …Which brings me to this.”

Pausing, Rei dragged a cardboard box from the corner of the room with a heave-ho. …Keita had a very bad feeling.

“Director, what’s that?”

“Promotional tissues. I want you to hand these out.”

“For real…?”

Rei opened the box with a pop. As promised, it was stuffed with tissues. But being tissues, it was surprisingly light when he picked it up.

“While you’re at it, grab a random little girl and give an Onii-chan demonstration. Live sales pitch.”

“That’ll get me arrested for sure!!”

After that exchange, Keita was half-kicked out of the shop.

(…No choice.)

He couldn’t just stand in front of the door, so he trudged toward the nearby main street.

“E-Excuse me… Want a tissue…?”

Careful not to block the path, he set the box at the edge of the sidewalk and held tissues in both hands.

But forget people taking them—nobody even glanced his way. Typical for tissue handouts.

(Ugh, the product itself is the problem… What’s with ‘Starting An Onii-chan Service’ anyway?)

Looking down at the slogan printed on the tissues, he let out a massive sigh. The pink background with bold yellow text looked like an ad for some sketchy hostess club.

(If Hayakawa or someone found out about this, I’d be toast… This morning was already close enough.)

He’d barely escaped by force, but he wasn’t confident he’d actually fooled her.

After all, this was Nina Hayakawa. Not only was she a formidable disciplinary committee member, but she was especially harsh on her childhood friend, Keita. She’d probably be waiting at the gate tomorrow, ready to chase him down again.

Thinking about it, it was almost miraculous he’d gotten through the afternoon without incident—

“Excuse me. Could I have a tissue?”

“Oh…! Y-Yes! Here you go!”

Keita’s heart skipped a beat. He’d been thinking about Nina, so for a split second, the voice from behind sounded like hers.

(Phew, that freaked me out… But if she actually saw me here, I’d be done… Especially with this ‘Starting An Onii-chan Service’ nonsense…)

Musing nervously, he turned to hand over the tissue.

Instantly, Keita froze.

The person who said “Thanks” and took the tissue had the exact same face as his problematic childhood friend.

(…Haha, wow, I must be exhausted. I’m seeing Hayakawa standing right in front of me? And it looks like she’s staring at the ‘Starting An Onii-chan Service’ tissue I just gave her?)

Heart pounding, cold sweat pouring, Keita’s mind spiraled.

The next moment, the Nina (illusion) (probably) in front of him looked up and gave a radiant smile—one so bright it nearly stopped his heart.

“Majima-kun… Care to explain what this is all about?”

◆◆◆

A few minutes later.

Keita had brought Nina (…or rather, been dragged by her) back to the run-down building where the shop was located.

“I see… So this is where the scheming vixen who’s seducing Majima-kun is hiding.”

“Seducing vixen!? Hey, don’t just barge in!”

Ignoring Keita’s attempts to stop her, Nina stormed into the building.

“Excuse me!!”

“Hm?”

SLAM! Nina threw open the door and strode into the shop. Rei, who’d been tinkering with a laptop, looked up with a “What’s going on?”

“Well, well, Majima-kun! Finding a new Imouto-sama in such a short time? As expected of our top Onii-chan—I knew I saw something in you!”

“N-No, Director, she’s not a customer—”

“Majima-kun, be quiet. I’ll handle the explanation from here.”

Cutting off Keita’s attempt to clarify, Nina stepped forward with a swoosh!

“Nice to meet you. I’m Hayakawa Nina, Majima-kun’s childhood friend.”

“Majima-kun’s…?”

Rei glanced at Keita for confirmation. Keita nodded, then desperately signaled with his eyes: She’s a disciplinary committee member and super strict! If she finds out I’m doing this kind of job here, I’m toast!

“I see. Nice to meet you, Hayakawa-san. I’m Nonaka, the manager of this establishment.”

“Then, Nonaka-san, I’ll be blunt. Please make Majima-kun quit this job.”

“Hm… And why’s that?”

“It’s inappropriate! I don’t mean to judge professions, but this kind of job is not suitable for a high school student! As both a disciplinary committee member at his school and his childhood friend, I cannot allow it!”

“What are you saying? Inappropriate? Hayakawa-san, you’re misunderstanding something.”

“Misunderstanding!? It’s rental! Rental! The idea of Majima-kun being lent out to some shameless woman, forced to do this and that—it’s absolutely, absolutely unforgivable!!!”

“Uh, Hayakawa…?”

“That’s where you’re wrong.”

Pointing sharply at the increasingly agitated Nina, Rei caught her off guard. Nina froze, blinking rapidly.

“Wha… What do you mean…?”

“Indeed. Hayakawa-san, you seem to think Majima-kun is being made to do something scandalous, but that’s not the case. Because our service isn’t just ‘rental’… It’s Rental Onii-chan.”

Nina stared at Rei with a “Huh?” expression. Keita, equally baffled, echoed, “Huh?”

“I don’t understand! What difference does ‘Onii-chan’ make!? The things he’s doing are still the same, aren’t they!?”

“Not at all. Think logically. Imagine a man and a woman embracing. What would you think?”

“It’s scandalous! Indecent! They should be separated immediately!!”

“Now, what if those two were siblings? Would it still be indecent?”

“Uh… W-Well… I wouldn’t say it’s indecent… They’re siblings, after all.”

“Exactly, Hayakawa-san. The same applies to our Rental Onii-chan service. Even if they’re hugging, sleeping in the same bed, or—dare I say—taking a bath together and washing each other’s backs, it’s not scandalous at all because they’re siblings. It’s perfectly wholesome.”

“That’s… that’s just sophistry!! Even if you call it ‘siblings,’ it’s still just part of the job—”

Mid-rant, Nina suddenly froze, as if struck by a realization.

“…If they’re siblings, it’s not scandalous?”

“Precisely.”

“…No matter how lovey-dovey they get?”

“Absolutely.”

“So… things that would be indecent for regular high school boys and girls… become completely fine if they’re brother and sister…?”

“That’s right. I guarantee it. Majima-kun, you agree, don’t you?”

“Me!?”

Why was she dragging him into this?

“Well, Majima-kun!?”

“W-Well, if you ask me out of nowhere like that…”

“Why are you hesitating? Or what? Are you saying that loving and cherishing your little sister as a brother is somehow indecent?”

“Of course not!! A brother caring for his little sister is totally natural!! It’s noble!!”

“Noble…”

Nina murmured, echoing Keita’s words.

Keita flinched. He’d let his true feelings slip, but saying that in front of a non-otaku like Nina was sure to earn him a weird look.

“N-No, Hayakawa! I didn’t mean it in some creepy incest way, just, like, ‘Siblings being close is nice,’ you know…!”

“Um…! Is this Rental Onii-chan service something high school students can use!?”

“—Huh!?”

For a moment, Keita’s mind went blank, unable to process what Nina had just said.

“W-Wait, Hayakawa!? What are you saying!?”

“D-Don’t misunderstand! One shouldn’t criticize something without understanding it first! That’s all! I’m not interested! Absolutely not!! …So!? Can high school students use it!?”

“Of course they can. Rental Onii-chan is an extremely wholesome service. High schoolers, even elementary schoolers, are welcome.”

“You’ll definitely get arrested!!”

As Keita shouted, he could’ve sworn he saw Nina do a “Yes!!” fist pump… but no way she’d be excited about this, so it must’ve been his imagination.

“Then pick a course from this menu. This one lists the paid options.”

“Thank you! I’ll take a look right away!”

It was bizarre. As Nina took the menu, she looked happier than Keita had ever seen her. The pressure must be making him hallucinate.

(W-Why is this happening…)

No answer came, of course.

◆◆◆

“W-well then! I’ll be in your care, Majima-kun!”

“Uh, yeah… Same here…”

Nodding, Keita felt slightly overwhelmed by Nina’s unusual enthusiasm.

They were now one floor above the “Onii-chan’s Room” from before, in the room for the “Relaxing Room Course.”

As the name suggested, it was decorated like a living room, with a sofa, TV, and even a kitchen visible in the back. According to Rei, it was called “A Living Room for Two.”

Keita and Nina sat side by side on the sofa.

The rental had technically started, but with Nina as the customer, Keita was even more clueless about how to act than with Hatsuba. One wrong move, and he could imagine her declaring “Out!” followed by a brutal roundhouse kick. The tension was suffocating.

—Then.

(…Hm?)

Something noisy tickled Keita’s ear, making him tilt his head. Was it the wind… or breathing?

“Haa… Haa… HaaHaa…!”

“Wah!? H-Hayakawa?”

“Hah! S-Sorry, I got too arous—er, I mean, nervous!”

For some reason, Nina had been peering at Keita’s face from an unnervingly close distance. With those words, she hurriedly backed off.

“Ahem! S-So, about becoming siblings… Specifically, how far are we supposed to—I mean! What kind of things should we do!?”

“Uh, well… Do you have any preferences, Hayakawa?”

“Preferences!? I have so many I couldn’t possibly choose—COUGH! No, I mean, I’m not familiar with this kind of thing!! I’ll leave it to you, Majima-kun!!”

“O-Okay, sure…”

Her excessive enthusiasm was a bit concerning, but it was probably just nerves. It’s Nina, after all.

Overhearing their exchange, Rei chimed in with, “In that case,” and approached with yet another menu… giving Keita a very bad feeling.

“Director, what’s that…?”

“Oh, nothing major. Not every Imouto-sama is an expert in sibling scenarios, right? So, for those Imouto-samas, we’ve prepared a set menu combining ‘Character Archetypes’ and ‘Situations.’ If you’re unsure, why not pick from these?”

“I see! That sounds intriguing! Let me take a look!”

“By the way, this ‘Onii-sama Set’ seems like it’d suit Majima-kun’s tastes.”

“Hey!? Don’t just—!”

“I’ll take that one!!!”

“Hayakawa!?”

“Don’t misunderstand! It’s standard to go with the staff’s recommendation at a new place!! That’s all it is!! No special intentions whatsoever, none!!”

Nina’s eyes sparkled, her breathing suspiciously heavy. To an outsider, she might look like an excited weirdo, but knowing Nina, she must have some deep reasoning. No way my childhood friend was that kind of pervert.

“Th-Then, I’ll call you right away…! Ahem… ‘Onii-sama’…?”

Nina’s soft, gentle whisper carried an air of refinement.

Her elegant, ladylike demeanor made the title fit her too well, catching Keita off guard with a surprising thump in his chest.

“Y-Yeah… What’s up, Haya—”

He stopped, remembering his exchange with Hatsuba. Right now, he wasn’t Nina’s childhood friend—he was her Onii-chan. So, he should use her first name.

“Onii-sama?”

“No, sorry. What’s up… uh, Nina?”

“COUGH!?”

Instantly, Nina reacted as if she’d coughed up blood.

Not literally, but her response was so dramatic—collapsing to the floor—that it might as well have been.

“H-Hayakawa!? Hey, what’s wrong!? Hang in there!”

“Haa… I can’t… breathe…! Gasp…!”

Clutching her chest, Nina trembled violently. No matter how you looked at it, this was a bad scene.

“D-Director, ambulance! Call an ambulance now!”

“Calm down, Majima-kun. An Onii-chan doesn’t panic.”

“How am I supposed to stay calm in this situation!?”

“Now, now, Imouto-sama, relax. Breathe easy… Hee-hee-hoo. Hee-hee-hoo.”

Crouching beside the twitching Nina, Rei began coaching her with Lamaze breathing.

It probably wasn’t the breathing that helped, but soon enough, Nina regained her composure.

“Hayakawa…?”

“Sorry, Majima-kun. I startled you… But I’m fine now.”

Rising gracefully, Nina sat back on the sofa as if nothing had happened.

“I apologize… I lost my composure for a moment.”

“That was way beyond ‘losing composure’…”

It looked more like someone writhing in agony after being poisoned.

“Hey, are you sure you’re okay? If you’re feeling off, maybe you should head home—”

“No way!! Going home is out of the question!! This is too wonderf—COUGH! I mean, I haven’t experienced it fully yet! Quitting halfway would reflect poorly on my position as a disciplinary committee member!”

“Look, your disciplinary status doesn’t apply here…”

“Anyway! Let’s continue! Come on! Hurry!”

Pushed by Nina’s bizarre enthusiasm, Keita was forced back onto the sofa. Nina promptly sat beside him, resuming the exact same position as before her collapse.

“Onii-sama… Thank you for another hard day. I’ll brew some tea now.”

“N-No, you don’t have to go out of your way…”

“Please, don’t hold back. Now, if you’ll excuse me.”

Standing gracefully, Nina headed to the kitchen. Sounds of her preparing—apparently with a kettle and tea leaves provided—echoed back.

“Sorry for making you wait, Onii-sama.”

“Thanks… Uh, I always feel bad making you do this.”

“Not at all. Taking care of Onii-sama is my joy.”

Fully immersed in her “little sister” role, Nina smiled elegantly. As expected of an honor student, her performance was flawless.

According to the menu, the “Onii-sama Course” was set as: “A refined, ladylike little sister harboring romantic feelings for her brother, and a brother who, aware of her feelings but bound by their sibling relationship, pretends not to notice—a bittersweet, intense, forbidden love romance.”

It was a classic sibling trope, but with Nina as the partner, Keita was inwardly on edge. She was playing the “little sister” perfectly now, but the moment it ended, he could easily imagine her scolding, “This is immoral!”

“Onii-sama…? Is something wrong?”

“N-No, it’s nothing.”

Nina peered at him with concern. Trying to hide his nerves, Keita leaned away slightly.

But—for some reason—Nina leaned in closer.

“No… Lately, Onii-sama, you’ve changed. You’ve been avoiding me.”

“Th-That’s…”

Keita’s heart skipped a beat. He knew it was part of the act, but it felt like she was talking about their actual relationship.

“Could it be… because of that incident?”

“Th-That incident…?”

“Because I… found that book in Onii-sama’s room. ‘Will You Love Me Even If I’m Your Little Sister, As Long As I’m Cute?’—that light novel…”

“GACK—!?”

The coffee Keita had sipped to calm himself shot straight into his windpipe.

Why? Because that light novel was the very same slightly ecchi rom-com Nina had caught him with long ago.

“N-No, Haya—Nina!? What are you talking about…!?”

“It’s not that, Onii-sama! I’m not angry with you… I was just jealous!”

Leaving Keita bewildered, Nina’s performance grew even more passionate.

“Even though I feel so strongly for you, Onii-sama, you direct your affection toward illustrations on paper, not me… That made me so frustrated, so sad… That’s all it was!”

“No, that makes me sound like I have some weird fetish! It’s not like that!? It’s really not!!”

“No more excuses! No matter what kind of fetish Onii-sama has, I would never judge you!”

“That’s not what I mean!!”

“I just… want you to direct it at me, not someone else!!”

Nina’s voice reached a fevered peak. At the same moment, her hand gripped Keita’s tightly.

Then, with a swift tug—

Before he knew it, his palm was buried in something soft.

To be specific…

Nina’s chest.

(…What’s!?) (T/N: He said this in English.)

The shock was so intense his reaction turned straight-up American.

His palm sank into a soft, delightful sensation. He could probably keep kneading it forever. Endorphins were probably flooding his brain. Alpha waves, too.

“N-No, H-Hayakawa…!?”

“Calling me by such a distant name makes me sad… Please, call me Nina like you used to, Onii-sama…”

“No, I mean, Nina, my hand! My hand!!”

“…Is it unpleasant?”

Her grip tightened, pressing his hand even deeper. The overwhelming softness made him feel like his brain was melting.

“N-N-N-No, it’s not about it being unpleasant or not…!! R-Right!! We’re siblings!! Siblings!!”

“But the book Onii-sama was reading was a story of siblings falling in love and getting married… If that’s what Onii-sama desires, I’ll make it come true. Because I… am Onii-sama’s future partner.”

With glistening eyes and flushed cheeks, Nina gazed straight at Keita.

“So, please… No more hiding. Tell me your true feelings, Onii-sama… If you’ll accept me… please, do whatever you want with this body…”

Still pressing Keita’s hand to her chest, Nina leaned in slightly.

Her gaze, so close, was so earnest, so intense, it didn’t feel like acting.

Even though he knew better, Keita couldn’t help but feel a flicker of illusion.

As if they really were siblings.

And as if he’d been in love with this “little sister” for a long, long time—

“N-Nina…”

“Onii-sama—”

Before he knew it, Nina had closed the distance, her face inches from Keita’s. Her delicate lips slowly drew closer—

The next moment, the alarm blared.

The rental time was over.

“…Extend it!! I demand an extension!!”

“Hayakawa!? What are you saying!?”

“But it was just getting to the good part—COUGH! I-I mean, once I start something, it’s my principle to see it through to the end! I can’t stop here!! Please, extend it!! I’ll pay!!”

“I hate to disappoint someone enjoying themselves, but we’re closing for the day. No extensions. Come back another time.”

Nina collapsed to the floor, as if the world had ended.

“No… To stop at such a half-finished point…”

“Don’t be so down. The shop and your Onii-chan aren’t going anywhere. Come back next time for the rest. We’ll be waiting.”

“Yes, absolutely!”

“‘Absolutely’!? You’re coming back!?”

“Of course! As Majima-kun’s childhood friend and a disciplinary committee member, it’s my duty to ensure he doesn’t stray from the right path!”

“But didn’t you just say you were against me working here…?”

“W-Well, that’s…!”

When Keita pointed this out, Nina let out a series of exaggerated coughs.

“B-Back then, I had some misunderstandings about this job! But after experiencing it myself, I fully understand Nonoka-san’s explanation. As a disciplinary committee member, I’ll officially approve your work here!”

“For real…?”

An unexpected stamp of approval. Was that okay for a disciplinary committee member?

“But! I’ll be keeping watch! To ensure you’re doing it properly, I’ll come back regularly to check on things!”

“Wha…!?”

“It’s only natural! As your childhood friend, it’s my duty to make sure you don’t get involved with other girls—I mean, cause trouble for others!”

“How little do you trust me…?”

“Don’t look so hurt! I-I don’t think you’re that kind of person! But humans are weak to temptation! I’m just staying close to make sure you don’t fall to the devil’s whispers!!”

Perhaps because Keita looked genuinely upset, Nina spoke with unusual desperation.

Her words gave him a small sense of relief. Ever since the light novel incident, he’d thought she hated him, but it seemed she hadn’t completely written him off.

“Then, Imouto-sama, please sign this contract. Once you write your name, the sibling contract is official. Majima-kun will be your Onii-chan.”

“I see, let me take a look! …What’s this ‘Point Card Terms of Use’?”

“We offer a points service. You earn one point per rental, with various perks based on points accumulated. It’s free to join—just provide your name and phone number, and we’ll make one for you.”

“Please, sign me up!”

“You’re actually doing it!?”

Nina was clearly dead-set on coming back. Wasn’t she taking her disciplinary role a bit too seriously?

“Well, I’ll head out for today. I’d love to walk home together—COUGH! I mean, make sure you don’t take any detours, but I have a curfew.”

“Yeah. Be careful.”

The words slipped out naturally. Nina looked slightly surprised.

Keita was surprised too. Lately, he’d been so intimidated by Nina that he couldn’t talk to her as casually as he used to.

Maybe it was thanks to today’s job. He felt like he could talk to her like old times again.

“…Yes. You be careful too, Majima-kun. No detours, got it?”

Sounding almost motherly, Nina left the shop.

Her smile was softer than usual—almost like they’d gone back to their childhood days.

◆◆◆

“—I’m home.”

After parting with Keita at the job, Nina returned home and headed straight to her second-floor bedroom.

Her parents were out at an opera and wouldn’t be back until late. With no siblings, Nina was alone in the house. Her greeting was just a habit.

Entering her room, she closed and locked the door.

Instantly—her dignified expression melted into a goofy “nihera” grin.

“Nfufufufu…! I’m back, Kei-kun!!”

With a sloppily delighted face, Nina rushed to a massive poster on the wall. Staring back was none other than Keita.

On closer inspection, the poster wasn’t alone. A photo of Keita (secretly taken) sat on her desk. A handmade Keita-lookalike plushie. A pillowcase with Keita’s face printed on it. And so on… The room was overflowing with absurdly high-quality “Keita merch” covering every surface—walls, floor, even the ceiling.

It was like the private room of a fanatical idol otaku.

But Keita was just a high schooler, not a celebrity, so no official merch existed. Every item in the room was meticulously crafted by Nina herself.

“Nfufufufu… Kei-kun, Kei-kun, Kei-kun… Haa, Kei-kun…”

Clinging to the poster, Nina rubbed her cheek against it with a sweet, clingy motion. Her utterly relaxed face and practiced movements screamed, “Yup, this girl’s nuts,” a stark contrast to the prim and proper “Hayakawa Nina” at school.

After thoroughly nuzzling the poster, Nina let out a satisfied “Fuu…” and flopped onto her bed.

(Still… today was truly an amazing day.)

Hugging her handmade Keita plushie by her pillow, she dreamily recalled the day’s events.

When she first heard about Keita’s job, her world went dark with dread—but now, having experienced it herself, she wanted to send Manager Nonoka a gold coin for hiring him.

“If you’re siblings, it’s not scandalous.” What a glorious phrase! All the things she’d held back until marriage—those this-and-thats—could now be done freely as “siblings.” Just imagining it made her face split into a goofy grin.

Nina’s parents were kind but held strict views on chastity.

Dating was for marriage. Absolutely no premarital intimacy.

As a naturally serious child, Nina had faithfully followed their teachings.

Everything must wait until marriage.

So—for her childhood friend and first love, Keita—she’d suppressed her urges, holding back from openly pursuing him.

(…Keita-kun.)

Gazing happily at the self-made poster on her wall, she sighed.

They hadn’t started dating yet, but Keita and Nina had already sworn their futures to each other.

She’d never forget that childhood moment: “Will you marry me?” “Sure!” A passionate, unbreakable promise. Keita acted like he’d forgotten, but it was surely just shyness.

…Truth be told, Nina had her own reasons for avoiding talk of those days. Keita didn’t seem to remember, but… that incident had happened.

But while they’d been apart, an unexpected change had crept in.

Sitting up, she pulled a book from her shelf.

‘Will You Love Me Even If I’m Little Your Sister, As Long As I’m Cute?’ The very light novel she’d found in Keita’s room.

It was about a little sister obsessed with her brother, using every trick in the book to make bold advances. Being “bold” was the selling point, with a half-naked heroine on the cover and racy illustrations dominating the pages.

Finding it had shocked Nina.

Not because Keita was into something ecchi.

But because he was directing his ecchi interests at something other than her.

Nina staunchly opposed premarital intimacy, but once married, she saw no issue. If her husband had unique tastes, it was a wife’s duty to indulge them. Whatever Keita wanted—S, M, even incest vibes—she was ready to embrace it. Bring it on.

(But… but Keita-kun’s getting distracted by this paper girl…! My chest is bigger than this cover girl’s! If he’d just wait two years, I’d let him touch all he wants!!)

Still, she could understand why Keita might turn to such things.

Under Japanese law, men couldn’t marry until 18, women until 16. Even with a fiancée, high schoolers were left with pent-up desires.

She’d heard teenage boys’ libidos could outmatch wild beasts. Expecting him to wait until graduation was harsh.

(But! That problem’s solved now! I’ve found a way to legally flirt with Keita-kun without waiting for marriage!! Don’t worry, Keita-kun! We don’t have to hold back anymore! All your overflowing desires? Your ‘little sister’ Nina will take care of them!!)

It was written right in this light novel: Love transcends sibling bonds. No—better yet, brothers are meant to marry their little sisters.

(Fufufufu… Onii-sama… mchu!)

Basking in blissful euphoria, Nina kissed the cheek of the Keita poster.

That night, happy laughter echoed endlessly from Nina’s room—