I recalled the promise I made to her in this very hospital room when we were kids—

My younger sister’s health had deteriorated around age five, leading to her admission here.

At that time, our parents handled the hospitalization paperwork. Being too young to manage such adult tasks,

I could only stay in this room, keeping my sister company as she sat on the bed, crying.

“Perhaps, ever since this illness was destined for her, Rei could never leave this hospital room…”

As she spoke, Rei—the girl who’d grown up playing with me since childhood—sobbed uncontrollably, tears streaming down her face.

As a kid, probably because she was my sister and I hated seeing girls cry, I reached out and gently patted her head.

“Don’t… don’t cry. Um… if you have to stay hospitalized, I’ll be here with you… I’ll play with you every day!”

Awkwardly, I turned my head away, unable to look directly at her face.

“Really?”

Rei moved her tear-wiping hand aside, her moist, cerulean eyes fixed on me. I kept stroking her little head while thumping my chest.

“A real man never breaks his promise!”

“Then… it’s a promise…”

Rei carefully extended her pinky finger, wanting to make a pinky promise.

“P-promise…”

I hooked my right pinky with hers.

“Whoever breaks it must swallow a thousand needles…”

“That sounds terrifying…”

Hearing this, she burst into laughter through her tears, a sweet sound filling the air.

Back then, I truly wanted to protect her.

I wanted to stay by her side no matter what—

Burdened with this illness since birth, while other kids played outside, she could only lie alone in a hospital bed.

After a few years of improvement, she was back in this snow-white prison.

This filled me with deep sympathy and guilt.

So I tried my best to spend as much time as possible with her.

Having free time every day to be with her was only a childhood thing.

As I grew up, worries piled up—

Though the Nakatani Family was large and could afford Rei’s medical bills,

that was only while our parents were alive—

When I was ten, and Rei had just finished her two-year hospital stay,

our parents died in a car accident. Afterward, they were slandered, freezing all their assets.

From then on, Rei and I were truly alone together.

We could only rely on each other to survive. But… not just living costs, the massive treatment fees crushed me.

Fortunately, at that time, my fiancée from the Nakatani arrangement—Mayuko Goshou—and her father, Takuto Goshou, covered Rei’s treatment and living expenses.

I dropped out of high school to apprentice in programming instead of finishing my studies.

Only after signing a contract with Takuto Goshou’s company could I gradually afford Rei’s huge medical bills.

Due to debts and other factors, both families pressured me to fulfill the engagement.

Time snapped back to the present. Rei’s tears had already soaked the snow-white blanket.

Her frail body looked like she hadn’t eaten properly, leaving her so thin.

“We promised, brother. You said you’d stay by Rei’s side.

If I’d known it’d end like this, it would’ve been better if Rei never got treated.

Anyway, you probably see me… see Rei as a burden, don’t you!?”

“No, I’ve never thought that… I’ve never seen you as a burden or anything else.”

I replied firmly, gently stroking her long hair.

“I just want to cure your illness. I’m a working adult now, so I can’t visit often. That’s why I thought Mayuko could visit you instead…”

“No need. Not anymore. I don’t need you or that woman ever again. Never come back!! If I’d known this would happen, dying together would’ve been better.

Don’t you agree?

Brother… you feel the same, don’t you?

Anyway, Rei will never let that woman have you. Never, absolutely never!”

Rei repeated it fiercely. Somehow, her words and smile filled me with deep fear.

Not knowing what she’d do next, I was clearly scared.

I asked in a trembling voice,

“What are you planning? Don’t do anything stupid, Rei…”

“Hehe, don’t worry. Rei won’t do anything stupid. Rei’s fate is already decided. Don’t worry, brother. Rei will protect you…”

At that moment, I didn’t understand her meaning.

Until then—

I lay on the floor, sharp pain in my back. Blood flowed from the wound, soaking my white shirt.

“Aaaahhh…”

Pain shot through my leg, making me scream.

I turned sideways, seeing the person who’d ambushed me with a kitchen knife.

Under the moonlight, her figure slowly emerged—her unfamiliar gaze and familiar face.

—My younger sister.

Rei Nidoume.

Her light blue eyes had lost focus.

Hidden under her long bangs, her cheeks were smeared with blood.

She wasn’t wearing her white hospital gown.

Instead, she wore a cute black-and-white gothic dress with lace trim.

—How did things turn out like this?

I recalled what happened about ten minutes earlier.

—After visiting her, I immediately threw myself into work.

I forgot Rei’s words, thinking she was joking.

Since I’d left documents at home, I returned to the Nakatani house for the first time in ages.

No matter how many times I flipped the switch, the lights wouldn’t turn on.

—Probably the circuit breaker’s broken. I’ll fix it tomorrow.

I took off my shoes and stepped inside.

The old wooden floorboards creaked underfoot.

The house was aged, so the boards made such sounds.

But I really couldn’t afford repairs—

I sighed deeply, entered the dining room, and grabbed the documents left on the table.

I’d been working on my laptop there.

Without these, I couldn’t complete the final steps.

“Brother, anyway, Rei can’t live much longer.

After killing you, Rei will die too. It’s all your fault, big brother.

Every single day, Rei looked forward to seeing you!

But no matter how long I waited, you called daily to say you wouldn’t come! It’s all your fault… all your fault.

How wonderful if only you and Rei were left in this world?”

“Uwaa… hahaha… hahahaha…”

Rei reached her small, pale hand toward the wound.

A deranged smile spread across her face.

“Come with Rei, leave this world—hahahahaha—meet father and mother, hahahahaha—”

I knew—

she was doing this to torture me with pain in the end.

Damn it—

So hot, so hot, so hot. So hot, so hot, so hot.

“Hahaha, brother’s blood—such a lovely color. I never expected it to taste like this.

So good, so good. Your pained expression is wonderful.

Rest easy, brother.

Rei won’t let you die easily. Rei will make you feel the pain before you leave with me.

Hahahahahaha, brother, do you know how much blood a human body can lose?

Rei never went to school, so I don’t know. Let’s test it here.”

“No… uwaahhh…”

My blood stained Rei’s pink lips.

Rei plunged her small hand into the wound, stirring it relentlessly.

—Plop plop, gurgle gurgle.

Though my body screamed in agony, my thoughts drifted far away.

When did my sister become so twisted?

Honestly, I had no idea why she wanted to kill me.

No, perhaps I did know—

Memories flashed through my mind like a lantern show—perhaps this was the real thing.

The memories that surface at death’s door.

For my sister, I must have been her only support.

Since childhood, she only wanted to be by my side. And I was the only one who stayed with her, always in the hospital.

After our parents died, trapped in this hospital prison, I was her sole reliance.

Yet I betrayed her. Instead of staying with her, I was defeated by the so-called “harsh reality.”

To pay debts, I was forced to get engaged to Mayuko Goshou.

Thanks to that, Rei became this twisted version of herself.

Life really isn’t like an RPG game, unlike that fantasy world.

Only when playing games could I truly feel at ease.

If only I could escape to that world.

Then, both she and I could escape this “harsh reality.”

Pain from my abdomen pulled me back to the “harsh reality.”

“Brother’s belly is so pretty. I wonder how beautiful it’d be if I took out all your insides? Hahahaha, hehehehe. It’s all your fault, all your fault. You abandoned Rei. At least now, in these final moments, I can be with you.”

In my peripheral vision, Rei held a knife backward, her expression both mad and sorrowful.

With my last strength, I lunged into her arms, holding her tightly.

—I poured all my strength into embracing her.

Rei was startled, but I leaned close to her ear, whispering the unspeakable words.

“Sor… sor… ry…”

I held her tightly, speaking haltingly.

Then, I felt my consciousness drift away.