The Protagonist's Sister Loves Me, But She's Definitely a Yandere. - Chapter 10: The Email

Chapter 10: The Email

A few days had passed since everyone found out about my connection with Runa.

My life had been filled with noise ever since. Of course, the main topic was “Can you introduce me?”

Thankfully, with exams coming up, the chaos wasn’t as bad as I’d expected.

I stifled a yawn, staring blankly at the clock, just waiting for lunchtime to arrive.

The current class was math.

Important formulas, key exam topics —all the stuff I really didn’t want to hear.

I took notes with half my brain engaged, barely hanging on.

Through my tear-blurred vision, the second hand of the clock seemed to crawl at a snail’s pace.

Thanks to my last name, I ended up with a window seat.

I liked it. The hallway side was noisy with students constantly coming and going.

Here by the window, the soft sunlight streaming in was a nice bonus.

The downside? It made me sleepy.

No avoiding it —the gentle warmth was like a lullaby.

(Ugh, I hate exams…)

I was never good at studying. No strong subjects, but plenty of weak ones.

I knew in my head it was important for my future, but I couldn’t bring myself to care that much.

Still, failing would mean extra remedial classes, and that was a pain I wanted to avoid.

I glanced at the guy in front of me.

Fast asleep. Not just dozing —out cold, like he’d given up on staying awake entirely.

With his arms serving as a pillow, his head buried in them, he was completely out. There was no point in even trying to wake him up.

That sleeping figure belonged to none other than Hinata Ichinose.

Despite his attitude, he was a top student. He consistently ranked in the top 10, and any points lost for poor class participation were easily offset by his natural charm and social skills.

People like him probably breeze through life without a care.

And if he needed help, he could always ask Rika or Yuri-senpai.

“…?”

As I swallowed yet another yawn, my phone buzzed in my pocket.

Class was nearing its end anyway. I carefully pulled out my phone and checked the screen, making sure the teacher wouldn’t notice.

The moment I read the notification, I felt my breath catch in my throat.

An unknown email address.

Who even uses email anymore? Nowadays, everything’s done through messaging apps. The only time I use email is when I have to sign up for some app or website.

The address was a jumbled mix of letters and numbers. The sender’s name read:

(“Your Lover”…?)

My cheek twitched. A cold sweat instantly broke out on my back.

I quickly glanced around, but no one was looking at me.

Was it someone in this class? My heart pounded, and alarm bells rang in my mind.

The sound of chalk scratching the board seemed to drift farther and farther away.

I tapped the notification, opening the email app.

As I read the contents, my heart pounded even harder. My mouth was dry, and I struggled to swallow.

The message was proof that someone was watching me.

[Sleepy Shinji-sama is so cute. You need to pay attention in class, okay? What if you fail your exams? But, but, I love a clueless Shinji-sama, too!]

Any trace of sleepiness vanished instantly.

I was wide awake now.

Who? Who is watching me?

I’d let my guard down over the past few days since the threatening letter incident seemed to have died down. But now it was clear —the sender was definitely my stalker.

Somehow, they’d gotten hold of my email address.

I glanced around the classroom again, but no one was looking at me. No one even seemed to be sneaking a glance at their phone. Sure, someone could be hiding it, but it didn’t seem like anyone here was the culprit. I had no leads.

My phone buzzed again. My head snapped down, eyes locked on the screen.

Whoever this sender was, they were not sane.

Pretending to be my lover, obsessively tracking my every move —we weren’t even dating.

If this was someone targeting Hinata, I could understand. But why on earth were they fixated on me —someone completely average in every way?

[Panicking Shinji-sama is wonderful, too. Just wait for me, okay? When everything is ready, I’ll reveal who I am. I won’t let you go. We’ll live together forever and even share the same grave. This is already decided. Oh, by the way, I’m not a classmate, just so you know.]

I’m being watched. Every move I make is being watched.

Calm down, calm down. I needed to think this through.

The person claimed they weren’t one of my classmates. I couldn’t fully trust that, but for now, I’d take their word for it.

I glanced out the window. Students were scattered across the field, doing P.E., while others were in the building opposite, busy with classes.

…No good. There were just too many possibilities.

I closed my eyes for a few seconds and decided to push back.

I didn’t expect a real answer, but I had to try.

[Who are you? Why are you doing this?]

The reply came faster than I thought —less than a minute later.

[I’m your future wife, Shinji-sama. I do it because I love you. Isn’t that reason enough?]

[What you’re doing isn’t normal. If you love me, just show yourself already.]

She claimed her motive was love, but her actions were pure obsession.

This was not normal. She was stalking me, trying to control everything about my life. Her way of thinking was warped, twisted.

For someone like me, who just wanted a peaceful high school life, she was a genuine threat.

I remembered those news stories about stalkers attacking their targets.

A chill ran down my spine.

[It’s still unlikely now. I’m just laying the groundwork, bit by bit, to make everything perfect. Once I’ve made your heart turn toward me—then I’ll reveal myself. So please wait for me♡]

After that, no matter how many messages I sent, there was no reply.

I ran a hand roughly through my hair, trying to shake off the uneasy feeling bubbling inside me.

“Did you see yesterday’s stream? It was crazy!”

“I know, right? So funny! Hey, let’s hit the cafeteria.”

“My boyfriend hasn’t even read my messages. Ugh.”

“He’s probably just busy. Don’t worry about it!”

It was then I realized —class was over.

I’d been so absorbed in my thoughts that I’d completely lost track of time. The classroom was now alive with noise and movement. Some students headed to the cafeteria, while others stayed to chat with friends.

“Ah! There you are, Shin-nii!”

Just as I tried to process everything, a familiar, cheerful voice cut through the noise.

The class buzzed even louder. Even Hinata, who’d been out cold a moment ago, sat up with a start.

In a strange way, maybe this was a good thing. Focusing on Runa was better than worrying about some faceless stalker. I took a deep breath.

She walked quickly to my desk, her shoes tapping lightly against the floor.

Smiling brightly, Runa stood before me, holding two lunch boxes wrapped in black cloth.

“…You’re always so sudden.”

“I made you lunch.”