My sister Arisu Sakayanagi is a yandere

When you're staring into the abyss, the abyss stares right back at you. And when you find yourself standing at the edge of your own depths, you come to realize that the abyss isn't as terrifying as you once thought.

It never was, and it never will be. No, the real horror isn't the abyss—it's boredom.

And I found myself staring straight at that boredom, a dull and suffocating void called life, being forced to sit through lessons about things I already understood, yet still having to listen because it was deemed necessary.

Because that's how the world worked. I wasn't a god. I wasn't immortal. I was just a student, sitting in a classroom, watching as a teacher stepped onto the stage, opened the rule book, and made us read rules we already knew—explaining things that were so painfully obvious, it was insulting.

He droned on about the point system, explaining how one point was equivalent to one yen, and that students would be given a subsidized 100,000 points per month.

What he didn't explain, however, was the fine print—the terms and conditions hidden beneath that seemingly generous allowance.

Students had to prove their worth to maintain that income, but the teacher didn't bother to mention that.

No, he just skimmed the surface, letting the students revel in their ignorance, happily believing they had a guaranteed 100,000 yen coming in every month without a single catch.

I know the teacher isn't deliberately hiding it out of malice. No, that's not his style. He's just following the rules—because here, the school's regulations are absolute.

Unlike the unscrupulous Class C teacher, who'd bend the rules for their own gain, the one standing before me has a moral standard. And that standard is annoyingly high.

If we wanted to uncover the truth, we'd have to pay for it. Buying information directly from him might be expensive, especially compared to bribing some desperate upperclassman who's already broke and in need of cash, but does that even matter?

It's not about money. It's about power.

It's about flexing dominance. When someone raises the issue and questions the teacher about it, gathering a class-wide crowdfund to get the answer, they aren't just buying knowledge—they're buying respect. In an instant, their position in the class solidifies. They become an authority figure, someone people look up to. And the best part? Everyone else ends up paying the price for them.

With a little investment, you could gain power, influence, and recognition. Who the hell wouldn't want that?

But me? I couldn't care less about ruling this class. Not because I lack ambition—far from it—but because this class would never allow me to become an absolute ruler.

Unlike in Class C, where I could unleash my full potential, here, my teacher wouldn't support me. In fact, he'd actively get in my way.

My classmates wouldn't obey me. I wouldn't be uniting them—I'd be dividing them, forcing them to resist me. They'd see me as a tyrant to overthrow.

And honestly? That sounds like a pain in the ass. I wouldn't get a single night of peaceful sleep. I'd be wasting all my time scheming, counter-scheming, dealing with internal conflicts, and constantly looking over my shoulder.

Not worth it.

That's why I have no interest in leading this class.

But someone might...

I shift my gaze toward my cute little sister and smirk.

"What is it, brother? Are you feeling so impatient that you want me to do perverted things to you right here in class?" Arisu asked with a chuckle.

Of course, she was joking—only a complete retard would take her words seriously.

And the world was never short of those kinds of retards.

Of course, I wasn't going to lose my composure just because she teased me so damn hard, even though she almost made me pop a boner in the middle of class.

"Of course, I want to, my dear sister. As much as I'd love to, but well... what do you think about the monthly points that the teacher explained to us? Do you think there's something off about it? Do you want to confirm it?"

Just because our father is the headmaster doesn't mean he spoon-feeds us every little detail about the school's rules.

He only gave us a general warning about how things worked and granted us some convenient authority to make our lives easier—nothing more, nothing less.

For everything else, we had to figure it out ourselves, and I had no doubt that Arisu had already put the pieces together.

"Are you really that heartless, brother?" Arisu feigned hurt, letting out an exaggerated sigh. "Since you already understand it, why don't you use this opportunity to get to know our class better?"

Of course, 'getting to know our class better' was just her way of making things sound more refined. If I translated her words into blunt reality, it meant: 'Why don't you use this opportunity to establish dominance in the class, but instead of doing it yourself, you're trying to throw the problem onto me?'

That's what Arisu was really implying.

"Well, if you're not interested, maybe someone else will..." I mused, chuckling as my gaze shifted toward a particular person—someone, or rather something, that I found worth investing in.

Arisu pouted, clearly not liking the idea of losing control over the situation.

"Fine, fine, my heartless brother," she relented with a dramatic sigh. "I'll do it. You don't need to trouble yourself worrying about the others."

Then, without hesitation, she raised her hand and addressed the teacher. "Teacher, I have a question regarding the points system."

The teacher shifted his attention to Arisu. "Go on."

"The 100,000 points we received—are they permanent, or are there specific conditions required to maintain that amount of income per month?"

As soon as she dropped that question, Class A practically exploded.

The moment her words sank in, several students raised their hands, voices overlapping as they spoke up.

"Yes, teacher! Are the points going to be permanent?"

"Will our monthly income decrease in the future?"

More and more students joined in, their curiosity turning into a chaotic flood of inquiries. When their own interests were at stake, there was no hesitation—they all wanted answers, and they weren't about to let the teacher get a word in before they bombarded him with even more questions.

Watching the chaos unfold, I loved every single minute of it. So, what are you going to do now, bald guy? The one who's supposed to be Arisu's rival?

I could see the bald guy struggling, wanting to cough and regain control of the class, but no one gave a damn about him.

Their attention was fixed solely on the teacher, not on some wannabe authority figure.

And before he could even open his mouth properly, my sister was already a step ahead of him.

Her voice rang out loud and clear, asserting her dominance over the entire room.

"How much is it, teacher? How many points do we need to know this information? You mentioned it before, didn't you? That points could basically buy everything—does that include information as well?"

The moment her question left her lips, the entire class fell into complete silence.

Dozens of sharp gazes locked onto the teacher, demanding an answer.

The teacher let out a sigh, maintaining a firm expression as he finally responded.

"Alright, everyone. Arisu's question is indeed an excellent one. Yes, as long as it falls within the rules and limitations of the school, points can be used to purchase anything—even information regarding your monthly income."

"How much is it, teacher? I'm willing to pay 60,000 points for it," Arisu pressed on, her tone unwavering.

Gasps echoed throughout the classroom.

"So generous…"

"She's an angel…"

"No, she's everyone's angel…!"

The students of Class A were practically trembling with admiration, their hearts overflowing with gratitude.

Meanwhile, I just deadpanned at the whole spectacle.

If only they knew about the sadistic devil they just praised.

"Teacher! We're willing to pay as well!" someone suddenly shouted, slamming their hands on the table.

"Yes! Yes! You don't need to make our angel spend her own points! We'll pay for her instead!" another one joined in, his voice brimming with an almost fanatic level of motivation.

And just like that, with one simple display of fake generosity, Arisu had nearly the entire class eating out of the palm of her hand.

They were simping for her, offering their own resources just to gain her favor.

Tsch… Tsch…

She didn't even need to spend a single point of her own. With nothing but carefully calculated words and a well-placed display of false kindness, she had manipulated them effortlessly.

Sitting back in her seat, she let her classmates scramble to pay for her while simultaneously earning their undying respect.

This wasn't just cunning. This was art.

"You're getting better and better at it, sister," I praised, running my fingers through her hair in slow, deliberate strokes.

"Brother... you should also take the initiative to pay if you don't want to attract their attention, fufufu..." She smirked devilishly, and my face darkened for a moment. Of all the things I despised in this world, spending money was at the top of the list—despite having more than enough of it.

I had spent most of my life with a business-oriented mentality, obsessed with accumulating wealth. The idea of watching my fortune grow was thrilling, but the moment I had to part with even a single cent, it pissed me off beyond reason. It wasn't because I was short on money—far from it. It was the principle. Every damn bill, every single coin in my possession was mine. Mine. And I only spent it on things that I believed truly deserved it.

Unfortunately, paying for information was not one of those things. To me, it was no different from paying taxes—completely and utterly fucking pointless. I hated taxes. I avoided them whenever I could, not because I was trying to be a rebel or anything, but because people were always finding ways to sink their hands into my pockets in the form of these goddamn mandatory payments. And for what? I never saw a single damn benefit from them.

Especially the police in my country. Those bastards lived off our tax money, yet when shit hit the fan and our belongings were stolen, they wouldn't lift a fucking finger unless we slipped them some extra cash under the table. Useless leeches, all of them.

This was exactly why I did everything in my power to minimize my official income while maximizing the amount of money I received through alternative means. Gifts—yes, gifts. People giving me money of their own free will, out of "kindness" or "appreciation," which meant that legally, it wasn't taxable. It wasn't tax evasion. It was simply playing the game the right way.

Understand?

So, how could I avoid this without making myself the one to pay for it?

Of course, by painting a bigger target to draw their attention away from me.

I grabbed a piece of paper, wrote something on it with my pen, then crumpled it into a ball.

Without hesitation, I tossed it straight at the bald guy's head.

His smooth, shiny scalp made direct contact with my paper missile, and he flinched slightly before looking around in confusion.

His brows furrowed as he scanned the classroom, trying to figure out who the hell had just thrown something at his head.

The entire class was focused on the teacher. And just like them, I too acted as if I was paying attention—after all, I had already done my part.

As the bald guy unfolded the paper and read the message, his eyes widened in realization. A second later, he cleared his throat and stood up.

"Ahem…! Everyone, listen up! I will pay 80,000 points for all of us!" His voice echoed through the room like a damn thunderclap.

The class was instantly thrown into chaos. Shocked gasps filled the air, and the expressions on their faces screamed disbelief.

"80,000 points?! That's insane!" someone blurted out.

"No way! How the hell is he supposed to survive on just 20,000 points for a whole month?!" another student shouted.

Despite the uproar, the bald guy ignored their reactions completely. Instead, he locked eyes with the teacher and spoke with unwavering determination.

"Will that be enough, teacher?"

The teacher gave him a calm, assessing look before nodding. "It will do… but unfortunately, it's still not enough. We need a total of 420,000 points to cover everything."

Without missing a beat, the bald guy straightened his back and declared, "Then I'll pay in cash. I have full confidence that the rest of the class will pitch in to cover the remaining amount."

His words carried a tone of absolute conviction.

Without hesitation, he handed over the 80,000 points, and the teacher accepted it.

Just like that, all eyes in the room were now glued to the bald guy.

A chain reaction followed—one by one, the rest of the class, now pressured by the situation, began reluctantly handing over their points as well.

Meanwhile, I remained in the background, watching it all unfold with a smirk. I didn't lift a single damn finger, nor did I even pretend to reach for my wallet. Arisu and I had successfully slipped out of the spotlight.

And it wasn't just us—some of our classmates were doing the exact same thing, acting as if they were asleep or too engrossed in their notes to notice what was going on.

Mission accomplished.

"Brother... You're nasty." Arisu pouted, her lips forming a slight frown as she noticed how everyone's attention was locked onto the bald man.

"That's what happens when you think you can scheme against me, my dear sister." I chuckled, my amusement barely contained. "You may have improved, sure, but your little games have never been enough to make me lose—never have been, never will be."

She didn't say a word in response, only letting out a long, defeated sigh.

Every single one of her carefully crafted plans had gone up in flames the moment she thought she could drag me into them and control the outcome.

She underestimated me.

Again.

Now, the bald man had emerged victorious, standing at the top, yet the true mastermind behind all of this... was me.

I was the one pulling the strings from the shadows, orchestrating every move, setting the pieces in place while the others danced to my tune.

It didn't matter to me who sat on the throne—as long as they were willing to abide by my rules, play my game, and follow my terms, I would support them, nurture them, even elevate them to heights no one else could.

But the moment they dared to stand in my way...

I would crush them without hesitation.

"Brother... It was just a small amount of money. Was it really necessary for you to go this far?" Arisu finally raised her head, her eyes locking onto mine, searching for an answer, for some kind of reasoning behind my actions.

"It was never about the money, Arisu," I said, my voice unwavering. "It was about whether my money ended up in deserving hands or not. And let me be clear—I don't like this school enough to willingly hand over a single damn coin to them."

"Okay..." Arisu deadpanned, her expression flat, unimpressed. "I think you seriously need to chill, brother. With this kind of mindset, you're never going to find a single moment of peace in your entire life."

"Rather than wasting your time worrying about me, you should focus on reclaiming your position, dear sister," I said, my tone playful but laced with an undeniable edge. "At this rate, he'll take over our class in no time—unless, of course, you decide to do something about it."

"I didn't lose to him. I lost to you," Arisu corrected, her voice firm, brimming with confidence. "I may not be able to defeat you, but that doesn't mean I can't crush him whenever I feel like it."

"You'll see the results tomorrow, brother," she added, rising to her feet with the help of her cane.

A final glance in my direction, a silent challenge in her eyes. "But don't interfere ever again. And in return, I won't interfere with yours."

With that, she turned away, following the rest of our classmates.

Without hesitation, she stepped forward, paying the necessary points to the teacher—her way of proving her point.

Never intervene with mine?

I let out a dark chuckle at that ridiculous statement.

Since when have you ever not intervened in my life, my dear sister?

Don't make me laugh. You've always stuck your nose where it doesn't belong, always tried to twist things in your favor.

And yet, despite all your so-called intelligence, all your carefully crafted schemes, none of it has ever meant a damn thing to me.

You see, I don't play by the rules. I never have, and I never will.

Rules? Morality? Those are nothing more than suggestions to me—guidelines for the weak to follow so they can delude themselves into thinking they have power.

And when you fight someone like me, someone who sees those rules as nothing more than a joke, then you've already lost before the battle even begins.

If you want to surpass me, then go ahead.

You need to be at least more ruthless, crueler, and much better at figuring out how to use rules and morality to your advantage instead of being trapped by them.

Until then, I'll watch your career with great interest.