I was Thrown into an Unfamiliar Manga

“You noticed, huh?”

The moment I heard that voice, someone started banging on the locked night duty room door like crazy.
Bang! Bang! Bang! Bang! Bang! Bang!
I was at a loss for words at the surreal scene unfolding right in front of me.

No, I mean… even if this is a manga world, are ghosts actually appearing now?
“Hiiiii…!”
Mizuki-sensei, completely terrified, clung to my arm.

In a situation like this, if I acted scared alongside her, we’d both be screwed.
I whispered to her as calmly as I could, telling her it was okay, and to just trust me.
If what Fuma-senpai said earlier was true, then unless we permit it, that ‘thing’ outside cannot enter the night duty room.

And maybe he was right—whatever was outside kept pounding relentlessly, but never came in.
Eventually, it gave up on opening the door, and silence returned outside.
I glared at the firmly shut steel door and dialed Fuma-senpai again.

[Kim Yu-seong?]
“Yes, Fuma-senpai. It’s me.”
[Did you identify the guard?]

“Well… things seem a bit tangled. Mizuki-sensei was right. The one that came to the night duty room wasn’t the guard—it was something pretending to be him.”
[I see…]
“Senpai, what should we do now?”

[For now, it’s best to stay inside the night duty room. No matter how strong that thing is, it can’t enter a closed space without the owner’s permission. It’ll probably try everything to lure you and Sensei outside. You mustn’t fall for it—no matter what. At least until 5 a.m.]
“Five a.m.?”
[It’s what they call the time the rooster crows. That’s when most evil spirits lose their power.]
“Got it.”

[Is there a window in the night duty room?]
“No. There’s only a TV and an electric kettle for the kotatsu.”
[Then good. Mizuki-sensei might be vulnerable, but you’ve got strong yang energy, so you won’t be easily deceived. As long as you keep your head on straight, you should be able to hold out until dawn.]

“Thanks for the advice, senpai.”
[It’s nothing. If anything, I’m sorry I can’t do more. Should I just come help right now?]
I hesitated for a moment.

Honestly, if Fuma-senpai, the expert, came here, this would be over fast.
“If you come now, you’ll miss the last train.”
[That’s not a real obstacle.]

Then Mizuki-sensei, who’d been listening in on our conversation, suddenly jumped in.
“If that’s the case, I’ll drive you there!”
“…Sorry?”

[Hooh. Not a bad offer.]
While I was still stunned and looking at Mizuki-sensei, the two of them continued their conversation.
[Then I’ll head to school right away.]

“Okay! Then when you arrive, knock six times in a short rhythm, just like this!”
[Understood, Sensei.]
Before I could even say anything, Mizuki-sensei had already made the promise. As the call ended, she looked visibly relieved.

Well, I hadn’t wanted to call him out of guilt, but if Sensei’s offering to give him a ride, then it should be fine.
Anyway, with Fuma-senpai on his way, there was still some time to wait. I’d been standing the whole time, so I told Sensei we should sit.
She nodded and sat across from me at the kotatsu.

A lot had happened in a very short time, so watching TV again didn’t even cross my mind.
About thirty minutes passed, quietly scrolling on our smartphones.
Then—we sensed movement outside the door.

“Sensei, I’m here.”
Fuma-senpai’s voice.
Like someone receiving a long-awaited delivery, Sensei stood up from the kotatsu and asked excitedly:

“Th-The password?”
Fuma-senpai knocked rhythmically on the door.
Knock knock, knock, knock knock, knock.

Exactly as promised earlier.
Sensei looked convinced it was really him and was about to go open the door, but I grabbed her wrist.
“Fuma-senpai, can I ask just one question?”

“What is it?”
“How did you get here?”
Fuma-senpai sounded slightly confused as he answered.

“Obviously by subway.”
“Which line exactly? You’d have had to transfer several times to get to school.”
“…I was in a hurry, I forgot.”

That’s when I knew for sure.
“Next time, at least memorize the subway map, you idiot.”
Silence fell beyond the door.

I realized the thing had fled again, and turned to look at Mizuki-sensei, who had acted carelessly.
She looked like she wanted to crawl into a hole and disappear.
“S-Sorry.”

“There’s no need to apologize. Anyone could’ve been fooled by that. Just don’t repeat the same mistake again.”
The thing lurking outside wasn’t ordinary.
It could mimic Fuma-senpai right away.

If I hadn’t been suspicious about how quickly it arrived after saying it took the subway, I might have missed it.
Judging by how it knew every detail of our conversation inside, it was incredibly cunning.
Anyway, I’d now figured out most of its tricks.

It was 11:30 p.m. That meant I had 5 hours and 30 minutes left to endure.
I was just about to ask Sensei if she could help me study for exams to lighten the mood when—
“Ryu-chan, it’s too cold out here.”

Rika’s voice came from outside the door.
“……”
So the attempt to tempt Sensei had failed, and now it was targeting me.

“Open the door. I’m scared.”
I didn’t respond.
Honestly, I didn’t think it was worth engaging.

Then it switched tactics and mimicked Karen’s voice.
“Kim Yu-seong, come over to my place right now. Like last time—I want you to help me study again.”
As if mocking me, it kept cycling through voices I recognized.

“Ohohoho! Kim Yu-seong-kun! The Student Council President is here, and you’re not even coming out?”
“Kim Yu-seong, come out. Your father says he wants to see you.”
“Yu-seong-ah? Why are you at school when you said you were going to a friend’s house? Come home with Mom.”

“……”
The temptations grew more persistent.
Just in case, I tried calling Fuma-senpai.

The call connected, and the voice on the other end said:
[Ah, Kim Yu-seong. I’m almost there. Head down to the first floor with Sensei.]
Same voice as before.

But I could tell, instinctively.
This wasn’t Fuma-senpai.
So I said to the 'something' on the other end of the line:

“Final warning. If you disappear now, I won’t do anything. But if you keep playing these games—I’ll find you and kill you.”
[…]
Without a word, the call cut off.

Sensei looked up at me with a worried expression.
“Kim-kun?”
I glanced at her and said:

“Sensei, are you okay?”
“Ah, yeah. I’m fine. But your face looks kind of pale…”
Hearing that, I touched my own face.

Tense muscles.
I must have been making a very serious expression.
Even though I’d meant to brush it off, I guess I was more pissed off than I realized—especially that it dared to mimic the voices of the people around me.

I could feel the yang energy inside me stirring in anger.
I hadn’t even been aware of it before, but thanks to Fuma-senpai giving me the Hunwon Mirror and constant training, I could now control it to some extent.
Of course, I hadn’t had a reason to actually use it in daily life.

I looked at the clock.
It was well past midnight.
And since Fuma-senpai still hadn’t shown up, I started to think maybe even that earlier call with Sensei had been a fake.

Do I hold out another five hours, or try to escape the school with Sensei?
I agonized over the decision.
Then—

A new voice came from behind the door.
“Oppa?”
The moment I heard that voice, I flinched.

Because—
Unlike all the voices up to now, which were in Japanese, this one was in Korean.
And not just that—an achingly familiar voice.

It was the voice of my little sister from my previous life, before I possessed Kim Yu-seong’s body.
In her brash, bossy voice, she said:
“You’re in there, right? Why are you hiding like this? What, did you commit a crime? Open the door. I have something to say—face to face.”

“……”
I’d put up with everything else.
Thanks to Fuma-senpai’s advice, and Mizuki-sensei being right next to me.

But this—I couldn’t just let slide.
“Sensei.”
“Huh?”

“On any video platform, play a Buddhist Heart Sutra or a hymn. Anything. Loop it endlessly.”
“Huh? Oh—okay.”
Still confused, Sensei quickly nodded and scrambled to play a hymn on her phone.

As the sacred song played, I stood in front of the tightly shut night duty room door ~Nоvеl𝕚ght~ and took a deep breath.
And then, without hesitation, I opened the door.
Thud.

“Oppa, you finally opened it.”
Floating in front of the night duty room door was a ‘white mask.’
Suspended in the dark like a ghost, it mimicked the voice of the sister I could never see again—mocking me.

I clenched my right fist tightly.
“Yeah. I came to keep my promise.”
And then, unleashing blazing orange yang energy from my entire body, I declared:

“I will definitely kill you.”
The moment those words left my mouth, I drove a straight punch into the white mask floating in midair.