Reincarnated in a Dating Sim, But the Heroines Are Way Too Possessive!

"Brother... I've already reserved the seat for our date. Our special date." My sister, Yuki Suou, smirked, her eyes gleaming with a strange, almost predatory intensity.

She didn't even seem to notice the way my face had gone pale, as if all the blood had drained from it.

If this had been my usual sister—the one I thought I knew—she would have asked me, with genuine care, what was wrong. She would've looked worried, maybe even panicked.

But now?

Now she looked like she was living in a world completely detached from mine, a world where nothing and no one existed except herself. Herself and her desires. Herself and her obsession.

My stomach churned as dread began to claw at my mind.

Was this bizarre behavior of hers proof that what I had written in the Future Diary was true?

How was that even possible? Where had this Future Diary even come from in the first place?

Were these diaries created by countless versions of myself from parallel worlds?

Were they warnings from those who had lived and failed before me?

Or were they fragments of my own past, twisted and repurposed by forces I couldn't understand?

They had told me that the load and save function wasn't reliable—that it wouldn't help me escape my fate.

Instead of being my salvation, the functions had become tools in a never-ending cycle of torment, dragging me deeper into this waking nightmare.

Those versions of me—trapped in an endless loop of suffering, constantly clawing for a way out—how had they managed to break free?

How had they taken the form of the Future Diary and returned to the starting point of this endless, hellish game?

Did they escape that monstrous creature by sacrificing everything, only to end up as my warning system?

Were these other versions of me not just failures, but also messengers?

Failed attempts to survive this nightmare, desperately trying to warn me about what lay ahead—knowing that their failure was the price I'd have to pay for their message?

If so, the thought was terrifying.

It meant that one day, it would be my turn to fail. My turn to lose the diary's protection. My turn to become just another stepping stone for some other version of me—a broken warning scribbled in the form of a Future Diary.

I swallowed hard, trying to push the thought out of my head.

None of that mattered right now.

What mattered was Yuki.

I needed to answer her before she spiraled even further into madness.

"Ah... Yes, the date. What was the name of the place, sister?" I asked, forcing my tone to remain light and casual.

"It's Cauldron of Hell," Yuki Suou replied without a hint of hesitation, her voice carrying the same nonchalance she might use when talking about the weather.

The Cauldron of Hell. Yeah, of course it was. I couldn't help but think it sounded exactly like the kind of place Lucifer Morningstar himself would open.

The irony amused me, and I cracked a small grin at my own joke. The thought of the devil flipping ramen noodles in a cauldron like some culinary overlord was darkly hilarious, even if it was just my mind running wild.

Do you know what they often say? When the world flips its lid and throws madness your way, the only way out is to embrace it. Salvation, if you can call it that, lies in diving headfirst into the chaos.

To fight evil, you have to become a greater evil. To battle hypocrisy, you must out-hypocrite the hypocrites. To conquer insanity, you must become the most insane person in the room.

That's my motto, my strategy, my philosophy for surviving in this twisted world.

I laughed, a low chuckle rising from my throat as I lingered on the thought.

The sound of my own laughter was hollow, mocking even, but it served its purpose.

To anyone watching, like my sister, it probably looked like I was genuinely amused—maybe even delighted about the idea of this so-called date at a ramen shop with a ridiculous name.

Yuki seemed pleased by my reaction, her expression mirroring my supposed joy.

In her mind, she likely thought I was just as excited as she was, that her invitation had filled me with the same warmth and happiness.

But if someone could peer deeper, if they could rip through the mask I wore so well, they'd see the truth.

Beneath the surface, I wasn't laughing because I found this funny. I wasn't smiling because I was happy. I was laughing at the absurdity of my own existence, at the tragedy of being trapped in my own warped mind.

Dark humor, that's all it was—a way to keep myself afloat, a way to shield the ugliness buried inside from everyone else, especially Yuki.

Because if she ever caught a glimpse of the rejection notions of her invitation hiding inside me, it wouldn't end well.

My survival depended on my act, on the fake cheer I projected. And for that reason alone, I couldn't afford to falter.

The best way to lie is with the truth. Show them something real, something genuine enough to sell the deception.

That's how I masked the chaos inside. That's how I kept people from prying too deep, from seeing what I really was.

So, I held onto her hand with a smile that felt both too heavy and too light at the same time.

I laughed again, a sound that probably made me look carefree, and said, "Alright, then. Let's see what this Cauldron of Hell has to offer."

And with that, the game began.

...

Diary 8

[Everything has gone wrong. I overestimated myself. I thought I could endure it, that I could suppress the pain, that I could mask my expressions just like Seven did. But no—I'm not as strong as I imagined. It was horrifyingly painful.]

[The ramen felt like it was boiling me from the inside out, burning my very soul. My resolve shattered like brittle glass, and before I knew it, I was screaming—an uncontrollable, guttural wail ripped straight from the depths of my lungs.]

[My sister and Alya noticed immediately. Their monstrous forms triggered in an instant, and before I could comprehend my failure, I was dead. Just like that.]

Diary 9

[Reading the eighth diary—the detailed, gruesome account of my torturous death at the hands of a bowl of ramen—was a horrifying experience in itself. I couldn't stop asking the question: how did Seven survive, but Eight didn't?]

[I pored over the seventh diary again and again, searching for an answer. It was maddeningly vague, offering nothing but cryptic advice: The key to survival is ramen. Do not expose yourself. Do not show your agony to your sister or Alya. Hold back everything inside you.]

[But the question remained, clawing at my sanity: how did Seven succeed where Eight failed?]

[I decided to experiment with another route. This time, I chose the least spicy option on the menu. But even the mildest offering of the Cauldron of Hell lived up to its name. It wasn't "mild" by any reasonable standard—it was a weapon designed to destroy.]

[The agony overwhelmed me, tearing through my insides like a raging inferno. I failed. Again. And once more, I died.]

Diary 10

[Everything is spiraling further out of control. I feel like I'm losing myself with each passing loop. Eight failed. Nine failed. And now it's my turn. The fear clings to me, a constant, suffocating presence.]

[Even the act of reading my own diaries fills me with dread, as if each word scratches at the edges of my sanity.]

[When I tasted the ramen again, the pain was unimaginable. It wasn't just physical—it was existential. My body screamed, my mind fractured, and I could feel my grip on reality slipping. The agony wasn't just something I felt; it became me.]

[I laughed. I laughed until my voice cracked and the sound turned hollow. My laughter wasn't ironic or bitter anymore—it was bleak, colorless, and void of life. The sound of it infected the room, spreading like a plague].

[My sister and Alya joined in, their own laughter blending with mine, creating a symphony of insanity. None of us were sane anymore. We were trapped, all of us, in an eternal loop of madness where nothing made sense, and nothing ever would.]

I check my phone. My chest tightens painfully as I scroll through the future diaries.

No more entries. Nothing left to guide me.

Is it my turn now?

My turn to descend into madness?

To be trapped in this endless loop of suffering?

Can I break free without the help of the diaries?

Or am I doomed like the rest?

"Brother, we've arrived. Welcome to the Cauldron of Hell. Fufufu…" My sister's voice snapped me back to the present.

She grinned at me with a twisted mix of cheerfulness and sadistic glee. "Are you ready, brother?"

Her smirk deepened, her expression so nonchalant it was unnervingly creepy.

Her laughter, her unshakable cheer in the face of our inevitable doom, made the fear claw at my chest even harder.

But I knew better than to show my fear.

I forced the same grin onto my face, matching hers perfectly.

A mask. Nothing more.

I knew what awaited me behind that door.

The die is cast. There is no turning back.