That Half-Finished Drink Was Lethal— What Happened When I Left My Bottle Behind in a 1:4 Male-to-Female World - 1

Chapter 1: That Man, Unaware — A Single Drink That Becomes Fatal

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1:4 Male-to-Female Ratio. Men made up only about a quarter of the population compared to women. In this world, where forming male-female couples was physically difficult, around 80% of women did not have a partner. And perhaps because of that, what people called relations between men and women had been elevated to a level of sanctity incomparable to past common sense.

Even the smallest everyday contact, such as a simple “indirect kiss,” became, for women in this world, a “once-in-a-lifetime treasure (memory)” they would savor until the day they died. Men, it seemed, had come to believe they were a privileged class who lived by absorbing women’s devotion. They accepted being served as a natural right and, as unconsciously as breathing, continued to demand even more devotion.

But “he,” who had no way of knowing such rules, Yuu Yuuki, lived “normally” day after day, unknowingly scattering “kindness” into the hearts of women who had long since dried up.

A single plastic bottle that Yuu had used to quench his thirst and casually left behind on the table. He didn’t know that it would drive an inescapable “lethal dose of love” straight into the heart of the woman living next door.

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Three months had passed since I came to this world. I had finally reached one conclusion. This other world, which closely resembled “Japan,” had completely reversed moral values regarding chastity between men and women compared to what I knew. Every time I saw a “men-only car” attached to a train platform, or a crime prevention poster on a street corner aimed at men saying, “Be careful walking alone at night. Wolves (women) are right nearby,” I realized once again that this was a different world.

Department store ads boasted not “Ladies’ Day,” but “Men’s Day: 5x points for male customers.” At first, I thought it was a joke, but this was simply “normal” in this world. Furthermore, because men were only about a quarter of the population, their rarity seemed to have made most men lazy, lounging around surrounded by multiple women without even trying to better themselves…

“Yuu, you really need to be careful, okay? When women find a guy like you, they’ll never let you go…”

One of the few senior coworkers at my part-time job would warn me with a worried expression every time we met. But since nothing particularly bad had happened to me so far, I brushed it off like it was someone else’s problem, thinking, “Senpai is just being overly cautious.”

In such a crazy… no, slightly unusual world, the path I chose to live peacefully was—

『To be sincere, to never lie, and to treat others with respect and genuine kindness.』

That was the unshakable stance I held as a person. Even in this overwhelmingly strange world, as long as I maintained that rhythm, I believed I could live normally without losing myself…. Completely unaware that this very idea of “normal” would become a pleasure powerful enough to ruin the lives of the starved women here.

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Click. I opened the apartment door. Inside, there was the sharp smell of junk food and the bluish glow of a screen lighting up the darkness.

“Welcome back, Yuu. You’re late. I was so hungry I was about to hit zero life before my phone battery did.”

A woman lay sprawled on the sofa, holding up her phone while using a bag of potato chips as a pillow. That woman was Miya Akutsu. With platinum-blonde hair that shimmered silver, several piercings in her ears, and a black leather choker accentuating her pale neck, she was a cool, rock-style beauty. Her limbs were toned like a model’s, yet she still retained soft, feminine curves.

Every time she moved in the oversized shirt of mine she was wearing, the perfectly balanced fullness beneath it, neither too big nor too small, traced a soft outline through the thin fabric. Her sharp, narrow eyes held both beauty and an intimidating edge that kept people at a distance. She was a legendary masked influencer with over two million subscribers, yet by the standards of this world, she was also an exceptionally “free-spirited” woman who had duplicated my spare key without permission and made herself at home in my room.

“…Miya-san. You came in again without asking, didn’t you? I told you to contact me before coming.”

“Eh, it’s fine, right? It’s not like anything’s gonna wear out. Besides, Yuu, you know what my room looks like right now, don’t you? That place isn’t fit for human life anymore. Kehyaha!”

Miya got up from the sofa and fixed her gaze on me like I was prey. As she moved, the collar of her shirt slipped slightly, emphasizing her collarbone and the shadow of her chest. Even among my shirts, she deliberately chose the ones that still seemed to carry my scent.

“Stop eating just chips and eat this instead. Miya-san, your skin’s been getting worse lately. If you’re an influencer, you should take better care of yourself.”

I sighed and set down a vegetable-packed salad and a tofu hamburger steak I had bought. But Miya narrowed her half-lidded eyes and twisted her lips into a sadistic grin.

“Ahaha! You’re as disgusting as ever. What, you going around scattering bait while pretending to be nice to everyone? Or are you playing the perfect ‘prince’ and waiting for me to melt? Huh? Trying to train me so I can’t live without you? Hey!”

“…No, it’s not like that. I’m just worried.”

When I answered plainly, Miya’s expression softened for a split second before her face turned bright red and she looked away.

She seemed determined to convince herself that my “goodwill” was some kind of elaborate scam meant to trap her. And yet, in reality, she ate the hamburger I offered more lovingly than anyone else would.

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Our first meeting went back about a month. When I returned to my apartment and happened to glance toward the neighboring unit, I saw a woman struggling with a mountain of luggage.

“…Haah, seriously, just die already. Every last one of them… What do they think women are…?”

Muttering curses, that woman, Miya, knelt in front of a heavy equipment case. Her platinum-blonde hair and sharp, half-lidded eyes gave her a cool, urban beauty that was breathtaking, but at the same time, the aura she gave off was pure rejection, pushing others away.

“Ah, that looks heavy. Want me to carry it?”

The moment I spoke, she froze. Slowly raising her head, her eyes were filled with enough distrust to kill.

“Hah…? Who the hell do you think you are…? Some cheap pickup attempt? Kehya! Don’t make me laugh!”

An intense rejection. But I had already seen the state of her room behind her, piles of unpacked boxes and garbage. If left alone, there wouldn’t even be space to step. Even if it was meddling, I believed in helping each other when needed.

“…Well, I’ll just carry this inside for now. Excuse me.”

Ignoring her insults, I casually lifted the equipment case.

“Wha… hey! You—don’t just…!”

Leaving her stunned, I continued moving the luggage without a word. Her gaze dropped to my arms, and she seemed about to say something before stopping herself.

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A few days later, when I heard a loud crash from next door, it was the same story. When I called out through the door and stepped inside, she was sitting in the middle of shattered glass.

“…That’s dangerous.”

Saying that, I silently borrowed a broom. I cleaned up the shards and, while I was at it, folded her scattered clothes and moved them aside.

“…You. What the hell are you, exactly? You’re a man, so why are you…”

“No, I just can’t relax when things are messy. I’ll leave right after I finish cleaning. Moving around made me a bit thirsty.”

I downed about half of the sports drink in the plastic bottle I had brought and set the half-empty bottle on the table. At that moment, though, my phone vibrated. It was a message from my part-time job senpai.

『Contact me immediately.』

In a hurry, I left her room.

“I won’t drink this anymore, so please throw it away.”

I thought I had said that, but in reality, I had simply forgotten the bottle. After returning to my room, I realized, “Ah, crap. I left the bottle,” but going back felt like a hassle, so I left it as it was. That casual remark became a “lethal dose” that would shatter the life of the woman left behind. 

At that time, Yuu had no way of knowing…. The drink meant to quench thirst had turned into a deadly poison that would bring her reason to its end.

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