Actions

Work Header

Rating:
Archive Warnings:
Category:
Fandom:
Relationships:
Characters:
Additional Tags:
Language:
English
Stats:
Published:
2026-08-15
Completed:
2026-09-05
Words:
34,862
Chapters:
7/7
Comments:
242
Kudos:
402
Bookmarks:
82
Hits:
5,028

Watch Out for Serial Killers

Summary:

Baek Saheon was reluctantly enjoying a seemingly harmless company dinner when it ends with him being brutally murdered by none other than his former roommate, Kim Soleum.

Inspired by The Law of Immutability by Pigism.

Notes:

(See the end of the work for notes.)

Chapter 1: And Then There Was One

Summary:

Baek Saheon was reluctantly enjoying a seemingly harmless company dinner when it ends with him being brutally murdered by none other than his former roommate, Kim Soleum.

Notes:

T/W: Death, Blood & Gore, Graphic Violence, Heavy Angst, Language, Alcohol, and misunderstandings galore.

I needed my BSH/KSE angst fix <3

Spoilers for Part 1 & Part 2 ahead.

(See the end of the chapter for more notes.)

Chapter Text

‘How irritating.’

 

Baek Saheon downed a glass of Soju, irritably glaring at his fellow coworkers.

 

He was inside a barbeque restaurant at a company-mandated private dinner. Obviously, the invitation had been limited to everyone involved in Director Ho Yuwon’s secret project. A project that not even he knew the express purpose of despite having been forcibly dragged into the whole mess.

 

And the one who had dragged him in…

 

He stared daggers into the back of the culprit feeling his mood spike in fear and aggravation. Wearing a black cat mask and surrounded by the remnants of the former Team D Squad, was the psychopath Kim Soleum. 

 

Crash!

 

He flinched.

 

The bastard Kim Soleum had shattered his glass. 

 

He shuddered. Who was crazy enough to anger him to that extent?

 

“Do you know that person?”

 

Of course not everyone invited knew the identity of each other, seeing as they had been told they must wear their company-provided masks. The person who asked though, he recognized.

 

‘Assistant Manager Jin Nasol of Team A Squad.’

 

Despite looking visibly like she would rather be anywhere else but here, she was sensible enough to notice the strange mood surrounding the cat-masked man and fish for answers surrounding his identity.

 

Baek Saheon smiled politely, “Not really.” Inwardly though, he cursed her for asking. 

 

‘Of course I know who he is! He’s my former roommate and a dopamine-addicted psychopathic freak!’

 

He poured himself another glass of bitter alcohol. 

 

“Hey.” His eyebrow twitched. “Pour me one too.”

 

“Of course.” He says, diligently pouring alcohol for the Assistant Manager with gritted teeth. 

 

“Oho! Pour me one too!” Dolphin slid into the booth beside Assistant Manager. 

 

'Great, another headache!'

 

Dolphin, who was on the same squad as Assistant Manager, blinked brightly at him with a twinkle in her eyes.

 

The familiar feel of danger raced up his arms as he poured the drink.

 

“So,” Dolphin popped her lips. “That Darkness last night was fun, right?”

 

Far from it actually. The tunnel Darkness they traversed while telling Ghost Stories had once again made him consider running away from this company and Kim Soleum.

 

“I’m so glad Mr. Cat is such a good person~” Dolphin smirked. “It makes me wish all ya bad people would just die.”

 

It was a terrible idea to even talk to Dolphin considering her weird criteria between good and bad people. How she saw Kim Soleum as a good person was beyond him.

 

But perhaps because he found himself incensed at Dolphin’s words, he told her,

 

“He’s not.”

 

Dolphin tilted her head. “Hm?”

 

“That bastard’s a psychopath. He’s the kind of guy who finds pleasure in seeing people suffer. The freak gets a dopamine rush out of it, he told me himself.”

 

“There’s a limit to being blind, y’know.” Dolphin said playfully but there was a dangerous glint in her eyes that told him he was playing a dangerous game.

 

He looked Kim Soleum’s way and inevitably, he felt his mouth go parch. His hand gravitated toward the alcohol to quench it. Then he slammed the glass down.

 

“I’ll convince you.” He said, wiping his mouth. 

 

Without much thought, he described the endless psychological torture his former roommate had inflicted on him. How his roommate was only keeping him alive for his amusement, how much pleasure the freak saw from seeing people squirm in panic like ants beneath his feet, how he wasn’t even sure if the psychopath was even human.

 

And the longer he talked, the brighter Dolphin’s eyes seemed to shine. As if she found each fear-inducing thing he said about Kim Soleum as good deeds!

 

Unbelievable!

 

Talking about that bastard though, it was a sort of cathartic release. With copious amounts of alcohol to calm his tremors, the more confident he became to describe how horrid that freak treated him. And compared to that kind, selfless Jisan agent—

 

“—nothing more than a selfish, conniving psycho!” He finished, punctuating his grief with a slam of his cup.

 

“Okay!” Dolphin clapped. “You’ve convinced me!”

 

Aha! He leaned back, satisfied. “See, now you know the truth. That fucker is a bad-”

 

“I’ll use my wish potion!”

 

All thoughts halted at the word ‘wish.’ “What?”

 

“Truth is…” And Dolphin leaned in close. “I’ve already saved enough points for a wish potion. I just didn’t know how to phrase my wish.”

 

He stared at her. “And now you do?”

 

“Yes, thanks to ya, I know how to phrase my wish.”

 

A flash of greed encapsulated his mind at the thought that perhaps he could steal her wish potion. But then the thought deflated.

 

'What would I even wish for?'

 

His sister was properly laid to rest. His village hometown which was his nightmare was also resolved. And his survival now was all but ensured. And it was thanks to that Jisan agent that he didn’t even know why he continued slaving away at the company.

 

Well-

 

Wait.

 

A chill spread up his spine. “That wish- what is it?” He couldn’t care less if it was rude to blatantly ask about someone’s wish.

 

“Hm…” She tilted her head within her right hand and tapped her left index finger down as if she was considering his question. Then, with a much too chipper tone, “You’ll see!”

 

An instinct, hard-wired and honed for survival, made him jolt upward from his seat. 

 

He needed to go. He needed to run-

 

But before he could, he lurched. 'Fuck! The alcohol…'

 

“I’ll take him from here.” An arm grasped his shoulders. “Director, let me walk Goat out to a taxi.”

 

“You needn’t ask for permission, Mr. Cat! All is well as long as you come back.”

 

Baek Saheon gritted his teeth, despising himself for his inebriated state in front of his boss and in the arms of his worst nightmare.

 

“Yes.” The tone was smooth with a dark promise. 'H-He wouldn’t be crazy enough to kill me once we are alone right?'

 

As they left, he heard the low murmur of Assistant Manager Jin Nasol, “Highly dangerous.” The same tone she used when she was categorizing a threat.

 

Baek Saheon hung his head low as he was carried out of the establishment. If he could ignore how close his tormentor-

 

“Hey, I heard what you said back there.”

 

He scrambled away from Kim Soleum, uncaring if it made his head dizzy and close to puking his guts out. “S-Sir!”

 

'Shit!'  When did he get cornered into an alley? Why didn’t he pay attention?

 

“Y-You misheard.”

 

“Did I?” The being tilted his head and crossed his arms. Those dark eyes hidden behind that mask glinted a bloody crimson red. “I perfectly recall you calling me a ‘selfish, conniving psycho’… among other unsavoury words.”

 

The man smiled as if he found pleasure in the fear he instilled in Baek Saheon.

 

“No- No, I wouldn’t- to you” 

 

Fuckfuckfuck! His legs were shaking, he couldn’t breathe, and his head spun with panic.

 

You?” A hand grasped his shoulder. The force so hard, it knocked him against the wall. Shit! Was his roommate always this strong? Wait- was his shoulder seriously dislocated?

 

“S-Sir!” He immediately corrected. “I-I’m sorry! I misspoke! It won’t happen again!”

 

“Hm.” The force relented. “I’ll hold you to that promise.”

 

Baek Saheon gritted his teeth, tears stinging his eyes. Pathetic! Pathetic!

 

“But what you said wasn’t very nice.” And the overbearing pressure was back again, along with it snapping the last of Baek Saheon’s sanity.

 

Fuck. This.

 

“So what? Am I fun enough for you? Going to tear a limb just because you couldn’t take some insults?” 

 

The figure paused and it pissed him off further. 

 

“What are you? Just what are you!”

 

He laughed hysterically.

 

“I know! A coward!” He was spouting nonsense. Anything to provoke the bastard. To get a reaction besides that stupid cold expression. “You’re a coward--Hrhk?!”

 

Crack!

 

Something… Something had pierced his abdomen. 

 

But he couldn’t look down because Kim Soleum was right there- right there!

 

'That- That psycho! He actually-'

 

Blood splurted from his mouth, splattering on the lower half of Kim Soleum’s face.

 

His eyepatch loosened, falling from his face.

 

And what he saw-

 

A monster looking apathetically down at him, face half-covered in shadow, blood red eyes with no emotion behind them but disgust. The bright luminescent red halo stretched behind that head, as if mocking him. The shadows stretched large within the alley, shapeshifting into a dinosauric lizard creature.

 

His vision darkened and his breathing grew more laborious.

 

'To think I’d die here instead of inside a Darkness.'

 

Damn it. He couldn’t even keep a promise to that Jisan agent.

 

With trembling, blood-tinted lips, he dared to utter his final words, “Go back to hell, Kim Soleum.”

 

.

.

.

 


 

“Hah!” 

 

Baek Saheon gasped awake.

 

Vrrr

 

A vibration in his left pocket.

 

Dully, he pulled out his phone. There was a text message notification.

 

—watch out for serial killers

 

“Good. You got it.”

 

Baek Saheon’s head shot upward. 'What-'

 

Standing there, in a cleanly pressed suit, was Kim Soleum. He pocketed his phone, clearly satisfied with the message he had just sent.

 

“You-”

 

“You?”

 

He flinched so hard, he jumped half a foot away.

 

Kim Soleum sighed as if he was dealing with a misbehaving child. “Get out of the doorway. I have work.”

 

It was then that he realized he was in the same dorm room he once shared with Kim Soleum.

 

'What kind of hell is this?' He thought as he stiffly moved aside.

 

As soon as the door closed behind Kim Soleum, he all but collapsed.

 

“Hah.” He swept his hair up, cold sweat dripping.

 

His shoulder was fine with no dislocation. Assessing the rest of his body showed no signs of serious trauma that he had accumulated over the past year- besides the eye.

 

And checking the date- 

 

It was a Saturday, nearly a year in the past.

 

I’ve gone back in time?

 

Then, he turned Kim Soleum’s last words to him in his mind. He’s going to work?

 

'On a weekend?'

 

A disconnected oddity was sure signs of a dream.

 

'Perhaps I'm in a coma?'

 

Knowing the damage the bastard had done to him, it felt more likely he had died.

 

But there was another oddity as well.

 

On his wrist, a number was marked on it clearly in red.

 

9

 

'What even is this?'

 

He tried rubbing it off but it stubbornly stayed on, as if it was embedded in his skin.

 

'What insane fucker put a tattoo on me?'

 

He didn’t want to even think about the immediate answer his mind drifted to.

 

Splashing cold water on his face and pacing anxiously around his apartment, he paused.

 

There was a strange blocky thing in his pocket.

 

Digging it out, his eye trembled.

 

A cassette tape.

 

‘Shouldn’t this already have been resolved?’

 

First the text message and now the tape that his bastard cousin had left him. 

 

‘Did I really die and return to the past?’

 

‘And if I really did…’

 

Thinking back to the circumstances which led him here, a strange thought turned in Baek Saheon’s head.

 


 

Hmm, hmm-hmm, hmmmm, hmm-hmm-hmm.

 

The cassette tape was humming. 

 

Just like before.

 

It was late evening and his roommate had returned home.

 

Kim Soleum stared at him, pale-faced. And when the next round of humming began, he bolted.

 

A feeling, akin to deja-vu, sparked within Baek Saheon as he threw out the cassette tape before he ran and followed his roommate into a bus.

 

“...How did you end up with that thing.” Kim Soleum said, panting as the bus started to drive down the road.

 

“My relative left it behind, but more importantly,” He thrusted up his wrist. “Can you see this?”

 

Kim Soleum looked at him as if he was the crazy one.

 

“Why are you looking at me like that, Supervisor? Do you see the number or not?”

 

“...A number? What?”

 

So he couldn’t see it.

 

Kim Soleum shook his head. “It looks like you picked up something you shouldn’t have. Why didn’t you have it inspected? You work at a company that assigns grades to ghost stories.”

 

“...It’s too late for that.”

 

To think he would have to go through this ghost story again after returning to the past.

 

“Next time, think before you act, why don’t you.” His murderer scolded him.

 

“Hah!”

 

Baek Saheon leaned back in his seat, letting the bus continue its journey. A journey that wasn’t stopping anytime soon.

 

Kim Soleum, sensing the bus should have stopped by now, stood up warily.

 

Click!

 

Hmm, hmm-hmm, hmmmm, hmm-hmm-hmm.

 

Humming, coming from the radio, filled the old, rickety bus. A familiar melody of an old pop song from the 1980s or ‘90s. Just listening to it gave him a headache.

 

[This stop is ‘Horizon Mountain Lodge’]

 

The destination came into view. The doors opened.

 

Stepping off the bus, he spotted a bike that he now recognized as belonging to the Supernatural Disaster Management Bureau.

 

‘Jisan agent…’

 

But the agent was a different one. Agent Bronze. He recognized the man from his previous life.

 

He was…

 

Decent.

 

But he’s not better than the Jisan agent.

 

The Agent Bronze he remembered was steadfast in his beliefs. Hard to persuade and disgustingly followed the government’s book like his life depended on it.

 

An unforgiving man like him didn’t deserve to work with his Jisan agent.

 

‘Best to avoid him.’

 

As if watching a movie flashback, he went through the motions of redoing this Darkness. Meeting the people inside the cabin, listening to the lodgekeeper explain there was a landslide outside, and… turning into their assigned rooms.

 

Except he didn’t do that last part.

 

Knock knock

 

Kim Soleum startled as Baek Saheon twisted the door knob into the man’s room without waiting for anyone to answer the door.

 

“You’re-- here early.” The raven-haired man was caught in front of an open wardrobe reaching for a large, one-handed axe.

 

Carefully, Baek Saheon closed the door shut behind him. And locked it.

 

“I know what your plan is.”

 

“...!”

 

He stepped closer. “You’re going to enlist my help to murder everyone. Only, we’re going to pretend to kill them to fulfill this Darkness’ requirements, right?”

 

Kim Soleum, whose eyes had not so much as blinked, slowly nodded. He cleared his throat. “Good. I won’t have to waste time explaining it all to you. If I have your cooperation-”

 

“I’ll help you with the plan.”

 

The tension in Kim Soleum’s shoulders eased.

 

“But in return,” He leaned in close. “You have to die.”

 

“!”

 

Baek Saheon’s hands rushed forward to grasp Kim Soleum’s neck, squeezing tightly.

 

“Krfh! Hik!” The bastard made for an abandoned grab for the axe only to be knocked against walls and furniture.

 

Limbs flailed wildly and nails scratched desperately against Baek Saheon’s forearms.

 

Finally, they landed in the bed where he could put his full weight into squeezing the life out of the fucker who killed him.

 

“Bye bye.”

 

Veins popped out and the face became more pallid, tears were squeezed out. And the eyes which were so desperate, became hollow until the body went slack.

 

'Haha! I did it!'

 

He stepped away from the body, marveling at his handiwork.

 

But then- he felt a terrible shiver go up his spine.

 

He looked up. A pink bunny delicately placed on a folded white towel, untouched. It was the same small plush that freak always carried with him and talked to.

 

Its beady black eyes- as if it was staring into his soul.

 

‘Impossible.’

 

Taking an axe from the wardrobe, he hacked up Kim Soleum’s limbs, a strange pleasurable sensation running up his spine each time the axe fell down. That psychotic bastard who had tormented him and killed him before looked unrecognizable now. There was no way he could rise up from the dead and kill him anytime in the future.

 

He smiled, wiping the sweat off his face only to smear blood.

 

“Not so scary now, you bastard. Turns out you can die.”

 

‘I know I said I would only kill Kim Soleum but the Jisan agent would understand if I went further, right? The Jisan agent had fought so hard to save me, I’m only returning the investment.’

 

And-

 

And-

 

‘These people are disgusting, aren’t they?’

 

He remembered the summary given by his murderer in his previous life.

 

The ‘married couple’ were an adulterous pair.

 

The college students were perpetrators in a bullying case that resulted in a classmate’s death.

 

The old man was a wanted child predator.

 

They were already sanctioned to die by the government. The same organization his Jisan agent belonged to.

 

Leisurely, he picked up the axe.

 

‘Why stop at one?’

 

The couple burned in the oven.

 

The students shredded in the backyard.

 

The old man sliced grotesquely in the living room.

 

And then the two others he couldn’t get to. The one that died by allergy and the other by landslide. 

 

Each time, he felt a strange thrill when they died.

 

All that was left was the DMB agent.

 

The axe trailed noisily behind him, staining the floor with a long line of blood. 

 

Baek Saheon never found the act of killing fun before. He wasn’t like that psychotic bastard. 

 

Still, if the Jisan agent knew the reason why he was doing this, surely he would forgive him, right?

 

No.

 

He lowered the bloody axe.

 

The Jisan agent he knew wouldn’t want the lives of these people to end. The idiot would even offer himself up as a sacrifice if it meant even one of these people would get to live. Perhaps even think of the same solution that dead Kim Soleum had thought of- No. Discard that thought. It's too close to-

 

His head ached. His hands trembled.

 

“Civilian,”

 

He stopped.

 

Agent Bronze, dressed in all black, regarded him with steady eyes.

 

“You have been caught in a Supernatural Disaster. Within this Disaster, a designated individual, referred to as the serial killer, will firmly believe that they are inheriting a legendary murderer’s legacy and undergo mental and physical transformation.”

 

Under the black raincoat, a gleaming butcher knife was pulled out.

 

“We classify this state,”

 

“Contamination.”

 

Baek Saheon raised his head.

 

“Do not worry. This Disaster is supervised under the government’s Disaster Management Bureau. I am Agent Bronze, and I can assist you.” A pause. “I have just one question.”

 

Baek Saheon clenched his hands. “...I have one too.”

 

“...I see. Then it will be an exchange.” A slow, steady exhale. “That civilian that was with you on the first day, are they still around?”

 

“I killed him.”

 

There was no frivolous gasp of surprise, only acceptance. As if the Agent before him had already made that exact conclusion. “He must have been your first kill. That’s unfortunate. He had- a good heart- one made of silver.” An inhale and exhale. “You may ask your question.”

 

“Is there… an agent in your division with a nice voice?”

 

“...”

 

“I’m sorry, there are many agents in the bureau that could fit that description.”

 

“He’s kind, and selfless with no regard to his own life. He’s someone who would save even a selfish bastard like me. I just, need to know a name or- a description of his appearance.”

 

“I’m sorry again but… if there was someone like that in the Bureau, I don’t know them. But, an agent like that would certainly be of a great asset to us.”

 

Asset.

 

For some reason that word rang in his head, but he had no energy to argue or move.

 

“Civilian,” A cold knife sinks into him. Smooth and efficient, part of procedure. “You’ve done enough. Rest now.”

 

As the darkness seeped into him, he couldn’t help but curse Kim Soleum. Curse him for leading him to this death, curse him for making him live this life again. Curse him for making him turn into someone like him. A monster.

 

Then he died.

 

And actually, this was one of many deaths.

Notes:

The alternate beginning:

KSE: Take this man to the company housing (shuts taxi door too hard and cracks the windshield)
BSH: ...
BSH: Can I go to the hospital actually?
Taxi Driver: ?!
(your reminder that KSE is in his lizard body form at the beginning of this chapter)

I'm so excited to bring this fic to you all! I'm currently on my second reread of GSGW so apologies if I misremember things/names or characters are a bit more OOC than usual. This fic is inspired by a webtoon that I really enjoyed reading the timeloop mechanics of and the story. I definitely recommend giving it a read! I enjoy hearing all your thoughts and constructive feedback <3
 
See you all in the next chapter and
watch out for serial killers

Inspired by The Law of Immutability by Pigism on Webtoon!