Product of Causality

The moment I opened my eyes, I snatched up the smartphone lying scattered under the bed.

As if to prove that everything from the night before had been no dream, a good-night emoji from Ijin was waiting for me.

Leaving my unfinished assignments untouched, I sat on the edge of the mattress and opened SNS.

The past had shifted by 1.2 percent. I had to see with my own eyes what butterfly effect that tiny fracture had set in motion.

I searched Ijin’s ID and entered her feed.

In the original history, her profile should have held not a single trace of me.

I scrolled slowly, tracking the footprints of the past.

Among the flood of posts, photos from two years ago and four years ago surfaced like ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠stepping stones.

In the heavily filtered photo, Ijin was smiling brightly, and beside her stood me, awkwardly throwing up a peace sign.

Even in the rewritten timeline she was still Kang Minjun’s woman.

In the corner of the photo where she showed off the luxury bag he had bought her, I simply happened to be standing there too.

Beyond that, every few months there were pictures of us eating pasta together or desserts from cafés we had visited side by side.

These were clearly the new memories that had been injected into my head, yet seeing them with my own eyes left me with a strange feeling.

But that was all.

I combed through hundreds of posts like a detective hunting lice, yet there was not a single photo of me facing Minjun as a third party or of the three of us hanging out together.

I immediately opened the DM window.

I needed to analyze the density of the conversations Ijin and I had exchanged.

The chats continued off and on, but a clear line was drawn between us.

We teased each other and I put up with her little complaints, yet there was not a shred of the sticky tension that existed between lovers—no matter how hard I looked.

Just as Minjun had said, I was nothing more and nothing less than a harmless male friend, practically family.

The most comfortable person in the world… and yet someone she would never see as a man. A convenient pushover, if you wanted to put it that way.

That was the pitiful result of my past self changing by a mere 1.2 percent.

“Not easy, huh. Sigh…”

I checked the SNS account of Kang Minjun that was listed on Ijin’s profile.

Scrolling down, a three-year-old university newspaper article caught my eye first.

In the photo, Minjun stood tall in a crisp suit, wearing a confident smile.

That was not the end of it.

I could even see an internal company article from the major corporation where he currently worked.

Perfect.

A guy who was good-looking, smart, gentle in personality, and held an iron grip on the opinions of everyone around him.

He almost looked like a flawless human being.

Ijin, on the other hand, worked at the same major company, yet unlike full-time employee Minjun she had started as an intern and was still grinding it out at the bottom.

An intern girlfriend fighting desperately in the special circumstances of an office romance, forever standing in the shadow of her perfect boyfriend.

I found myself nodding without meaning to. Of course she trusted him completely, leaned on him, and considered marriage the natural next step.

Yet that very inferiority complex of mine had become the key that let me slip into the cracks.

I ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠also had a way to feed present-day information into the past and slowly tear him down.

Of course, that would take far greater effort.

I spent the entire day researching every change in Ijin’s and Minjun’s rewritten realities, then researching them again.

For the first time, the guy who usually skipped studying to eat, shit, and jerk off was actually using his brain.

The sun had long since set and sleep was gently tugging at me when a call lit up the screen.

The name on the display was Kim Jaeo.

The loser friend I had stuck with since freshman year of college—the same type who froze up the second a girl appeared.

I only comforted myself by thinking I was a better human being because, unlike him, I didn’t chase every pretty face and kept my eyes fixed solely on Ijin.

“Hey, Jaeho.”

“Yo, how’ve you been? Still job-hunting?”

“Yeah. Something like that. But why haven’t you been asking me to game lately?”

The two of us had always stayed up late gaming, burning through our mid-twenties youth together.

“Ah, that? I’ve been going to an English study group these days~ Trying to crawl out of this shitty life a little.

Oh, and there’s a girl there who’s started catching my interest? She’s seriously my exact type.”

“What? Dude, she is never interested in you. Another one-sided crush ending is as clear as day.”

Then, suddenly, I became curious about a third-party view of my relationship with Ijin.

“Hey, but honestly—looking at me and Ijin, what kind of relationship do we seem like to you?”

“What kind of relationship? Just best friends, right?

Honestly, even if you locked Ijin in your studio apartment nothing would ever happen. You’re that kind of guy.

I still find it amazing. Real friends between a guy and a girl actually exist.”

“Ah… yeah. I see.”

I fell silent for a moment.

So my past had been perfectly trapped inside the “male friend” frame.

“Anyway, we said we’d meet this weekend. I’ll spill the tea about her.

Watch and learn how this hyung does romance.”

“Yeah, sure~ It’s not like this is the first or second time for you.”

We were still laughing and bantering when it happened.

The instant the clock at the top of my phone screen hit 00:00, a sharp ring echoed through my skull and a subtle, itchy sense of wrongness wrapped around my entire body.

“…Hey Seonwoo, sorry, but I have to cancel hanging out tomorrow.”

Huh?

Just a moment ago Jaeho had been chatting excitedly, yet now a faint wall had appeared in his tone.

Our friendship hadn’t soured, but there was a strange awkwardness, as if we had drifted a little farther apart.

“Why? What suddenly came up?”

“You know that girl from the study group.

We’ve started texting privately lately.

She just messaged me asking to grab a meal together tomorrow. Sorry.”

Even so, I forced myself to stay calm and kept the conversation going the way I always did.

“W-what? All of a sudden? Up until a second ago it was just a crush, wasn’t it?”

“Do I look like you? When I decide to do something, I do it.

Anyway, I’m really sorry. Next time I’ll buy you a meal. Let’s meet then.”

“Uh… yeah? Okay… sleep well.”

I stared down at the abruptly ended call screen.

Looking at the clock, an entire day had already slipped away.

The second I hung up, a blue status window flashed into existence in front of me, accompanied by a warning chime.

1.8 percent…

The number had climbed a little higher.

I immediately opened the DM window with Ijin.

“…Whoa.”

A gasp escaped me on its own.

The overall skeleton remained the same, yet the volume of conversations and posts Ijin and I had exchanged had clearly swollen.

If the total density before had been 100, it had now expanded to a solid 120.

The line was still drawn, but compared to the original history the frequency with which Ijin messaged me first and shared her daily life had grown noticeably denser.

My past self had clearly pulled off another win.

I yanked open the diary lying by my pillow.

Sure enough, dark crimson letters were writing themselves in real time across the page for March 20th.

My grip tightened on the diary. Fresh memories of the new past flooded into my mind, and the corners of my mouth slowly curled upward.

At the same time, Jaeho’s rewritten reality clicked into place inside my head.

Because my past self had poured time and attention into Ijin, the hours I used to waste every day rotting in PC bangs with Jaeho had decreased.

Thanks to that, Jaeho had either wrecked his college GPA a little less or met more people, living a slightly better life overall—until finally a connection formed with the girl he liked at the study group and they even started texting.

The law of causality was merciless.

When you gain one thing, the density of the relationships you originally held is shaved away.

So because of me, that loser bastard’s life got salvaged.

Well, whatever. Good for him. Not my problem. The only thing that mattered was Ijin.

Just like the present me, my past self—knowing the future—was burning with pure venom.

The cracks were widening little by little… but with absolute certainty.