The Genius Mechanic's Audition
I stood in the middle of a cutting-edge underground facility beneath Eunpyeong-gu in Seoul. The space, roughly 1,650 square feet and packed with the latest equipment, was none other than Dr. Cash's Laboratory. No one else knew that Sehwa, Dr. Cash, and I were currently here.
Sehwa looked around and murmured, “I can’t believe a place like this exists under Seoul…” Having already transformed into the cold and powerful Leona once, she maintained a surprising degree of composure. Meanwhile I lay on a wheeled stretcher, still pretending to be half-dead.
“Even on the brink of death, those eyes? What a strange kid.”
Dr. Cash said it with genuine disbelief because I kept acting utterly fascinated by every machine in the room. Sehwa shot her a sharp glare.
“Auntie, just focus on treating him…”
“I know. And if you keep calling me Auntie, I really will toss this guy aside. It’s Dr. Jennifer Cash. Pick one—Doctor, Dr. Cash, or Professor Cash.”
“…Yes, Doctor.”
Sehwa reluctantly settled on the formal title. In truth, Dr. Cash looked so young it wouldn’t have been strange to call her “Noona.” Her early forties were impossible to believe. To me she was an infuriating bitch, but to others she probably looked like a sexy young researcher.
Dr. Cash moved me onto a machine that resembled an MRI and began operating the controls. I knew exactly what it was—an advanced medical device used by Beast Slayers to treat injuries. A low hum filled the air. The moment the cylindrical chamber closed around me, blue light enveloped my entire body. The accompanying beeps scanned me in real time, and I widened my eyes in feigned amazement.
I continued pretending to be impressed even as the device healed every cut and bruise on my skin. It wasn’t over-technology that fixed wounds instantly; still, because it had been invented by Dr. Cash—one of humanity’s greatest geniuses—its healing speed far surpassed even the most advanced hospital equipment of 2533.
With a soft hiss, a pale green liquid sprayed across my wounds and rapidly closed them. It was a compound antibiotic and regenerative serum of her own design.
“I copied the serum that matches your tissue and used it to treat you. It might itch for about a day, so bear with it. And count yourself lucky. You survived because you were wedged in a gap between large pieces of debris. Otherwise you’d have been crushed flat. Understand?”
Her tone was rather domineering. By now my body felt considerably better, so I lifted my head and looked down at myself before asking,
“Serum…? What is it made from? Stem cells? The wounds are healing so quickly it seems like you incorporated kinetics as well… How did you manage that?”
How about it? Isn’t your interest in me skyrocketing?
Dr. Cash looked thoroughly fed up. “You really are insane. Do you even understand what just happened to you?”
“Pardon?”
I pretended to think hard before answering. “When I woke up I was trapped between debris… Sehwa came to help… and, uh, the Doctor used a Polymus alloy mechanical arm to clear the wreckage.”
“I can’t tell if you’re out of your mind or not. They called you a freak genius who swept every prestigious competition at a young age… The description fits perfectly.”
“How did you know that?”
“I ran a background check.”
She said it without shame. I widened my eyes in surprise. “A background check?”
“I had to make sure you weren’t dirty.”
Since she offered no further explanation, it seemed I had passed her suspicion. Well done, Marcela.
With a mechanical whir the device slowly ejected me. I had been wearing nothing but underwear, yet I sprang to my feet without hesitation even though Sehwa was watching. It wasn’t embarrassment I was overcoming; the action was entirely intentional. I was playing the part of a mad engineer.
“Could I take that machine apart for a quick look? Or at least let me analyze the components of the medicine sprayed on my body…”
“Try it and I’ll cut your hands off. Shut up and put some clothes on.”
“…Huk!”
Only then did I pretend to feel shame and hurriedly cover myself. Dr. Cash shook her head and pointed toward a room in the corner.
“There’s a wardrobe in there. Wear anything you like.”
“Yes…”
After changing into somewhat oversized clothes, I walked over as Dr. Cash turned on the TV in the corner of the lab. Every channel was broadcasting breaking news. Of course they were—something impossible had actually happened.
Sehwa came to my side. “I was shocked too. The building collapsed and that horse-headed monster came out… It looked at me and Seunghyun like we were food.”
“…So you ran away?”
At that, Sehwa gave an ambiguous smile. “No… it’s not that simple. I’ll tell you later. Let’s finish watching the news first.”
“R-right…”
The veteran anchor continued, stuttering slightly. “This life-form, which resembles a monster from legend, was s-s-slayed—ah, pardon me. It appears to have been slaughtered by a sky-blue flash of light. The sudden white-night phenomenon that occurred beforehand is currently being analyzed by experts…”
Tsk tsk. For an experienced anchor, that stutter is something else. You’re supposed to tell the citizens about the legendary path of the Beast Slayers that’s about to begin. So pull yourself together.
The broadcast continued with reports of casualties and every other detail before ending. In the final segment they even brought on self-proclaimed science-fiction experts to debate why such an event had occurred. Nothing was clarified.
Sehwa’s rise as Earth’s protector would come a little later. She would earn her fame once the demonic monsters began appearing in earnest. I tilted my head and looked at her.
“Wait… they keep mentioning the white-night phenomenon and the flash of light?”
“…They do.”
“There was definitely a blinding light even before you found me…”
“That’s correct.”
“And the Doctor over there seems to have played a huge role in resolving this, plus this lab is full of things I’ve never seen before… and crucially, it looks like you two already know each other…”
After a brief silence I let out a hollow laugh. “Heh heh… No way… It can’t be…”
At my reaction, mischief sparkled in Sehwa’s eyes. She had completely fallen for my flawless performance.
“What do you think is going on?”
“Why are you doing this? It’s scary…”
“Scary? That’s completely different from how you were drooling over the machines earlier. Do I seem strange to you now?”
“Hey, stop messing with me. You’re actually starting to freak me out.”
“You do look scared. Look at the goosebumps on your arm.”
Sehwa reached out and stroked my arm. I liked the skinship. Give me more… No, I had to keep acting terrified.
“If you keep this up I’m just going to leave…”
“Where would you even run to? We’re completely sealed in. How would you open the door? Do you know the password? Is it fingerprint-activated?”
“……”
“Pfft… I’m joking. You’re thinking exactly what I expected.”
“What exactly am I thinking right now?”
“You’re thinking that I’m the one who killed that monster. Aren’t you?”
“…No?”
“Of course you are. I know you well. I figured you’d catch on.”
Thanks, Sehwa. But you know me well? I’m not sure I can agree with that.
I placed one hand on my chest and breathed heavily. Sehwa rushed over to support me.
“Jihyeok! Are you okay?”
“Just… give me a moment to calm down…”
“I guess I went too far with the joke… I’m sorry…”
For a short while I acted confused—body trembling, eyes darting. Then I gradually regained composure, returning to my sharp-witted persona. The moment I straightened up, Dr. Cash, who had approached without me noticing, spoke.
“Your courage is smaller than a minnow’s.”
I made an excuse. “In a situation like this, how many people could stay perfectly calm…”
“For someone in your position, you’re calm enough. Now then, shall I erase your memories and send you back… or…”
Erase my memories my ass. As if such a thing exists. You’re testing me right now. Fine, I’ll play along.
“Wait! Stop! You can erase memories?”
“It’s not impossible.”
“You want me to forget this heaven? No way. I’ll stay here until I’ve researched every machine in this lab. Cut me open if you want.”
“All right. Lie down.”
“Pardon?”
“You said cut you open. I’ll do it.”
My pupils shook violently. Sehwa quickly stepped in.
“Doctor, that’s enough joking. And please don’t erase Jihyeok’s memories.”
“There’s no such device. I was just teasing him. But tell me honestly—is this guy trustworthy?”
“He’s the most trustworthy person in the world.”
Sehwa’s answer was firm as a blade. The most trustworthy… So she ranks me higher than Yu Seunghyun? Or at the same level? That’s rather pleasing.
Dr. Cash, seeing the conviction in Sehwa’s eyes, nodded. Perhaps because Leona could only transform if she possessed a sense of justice, the doctor seemed to trust Sehwa’s judgment. Since Sehwa was already a hero of justice, it made sense to place faith in her.
Truthfully, there had never been much reason to suspect me. I wasn’t a monster like Amducias… On the surface I was nothing more than an ordinary, innocent victim. Whatever the case, it was good for me. It would make infiltrating this place much easier.
“Fine. Hey, you. Disassemble this.”
Dr. Cash tossed me a small cylindrical object. I caught it, examined it with great interest, and nodded. Since the examination is over, she won’t scan me again.
I secretly returned my body to its modified state, then moved to a desk in the corner of the lab that was covered with tools. I prepared to show Dr. Cash what I could do. It’s a flashbang. She gave me this to disassemble? That damn woman…
This was a consumable I had used often in the game—an anti-monster flashbang with power beyond comparison to ordinary ones. It had originally been made for use against criminals, but from now on it would be used against monsters, so the name fit. If I mishandled it and the thing detonated, my vision would be severely impaired even if I didn’t go blind. My eardrums would take a hit too.
I wondered if she still didn’t trust me, but Dr. Cash had always been a bit unhinged. This wasn’t strange behavior for her. Thinking the disassembly would take a long time, she told Sehwa she had something else to discuss and led her into another room. Perhaps she was taking cover in case the flashbang went off.
I pulled the relevant data from the flood of information in my mind, analyzed the flashbang, and began disassembly. At the same time I enhanced my hearing, pricking my ears to eavesdrop on the two women.
Dr. Cash’s questions began immediately.
“What do you mean?”
“It was… like something inside me was telling me I had to defeat evil. I also felt I had to destroy that monster.”
I can hear perfectly. Keep talking.
“Are there more monsters like that?”
“In that case… I would step forward. You said so yourself, Doctor. That device has bound itself to me.”
“It’s not that…”
I had already finished disassembling the flashbang. I paused my work, looked around the lab, and smirked. I’ll make you regret leaving me alone. Marvel at my ability and hire me—whether as an assistant, intern, or employee. I won’t even ask for a salary. I’m one of the richest men in Korea, after all.
I secretly brought over several consumables intended for future Beast Slayer use and began taking them apart while keeping my ears open.
“No…”
Aether. I already know. Like in other magical-girl erotic games, it was a mysterious and omnipotent energy fueled by sexual arousal and mutual affection. It stood at the opposite pole of Malice, a benevolent force and the source of every Beast Slayer’s power. Dr. Cash had fused Aether with Polymus and various rare substances to create the Devices.
After listening to the full explanation, Sehwa sounded stunned.
“J-Jihyeok is my…”
Sehwa fell silent. I knew exactly why she was hesitating. It wasn’t embarrassment. She had never had sex with Yu Seunghyun, so she was flustered.
Your virginity belongs to me. There’s no way I’d let a guy like Yu Seunghyun have it.
In the original story, the monsters’ second wave would have arrived much later—after Sehwa reluctantly followed Dr. Cash’s advice and slept with Yu Seunghyun. But this time was different. Why? Because I was the Demon King who could deploy monsters whenever I wished. I would arrange things so she had no choice but to sleep with me. I also planned to add extra functions to her Device, so look forward to that.
Having finished my thoughts, I shouted, “Doctor! Are there any more of these?!”
The lab floor was covered with an enormous quantity of parts. I had precisely disassembled roughly ten consumables and laid them out neatly.
“What? You already finished disas—huh?!”
The reaction on Dr. Cash’s face when she opened the door was one of pure shock. Naturally. In less than ten minutes I had safely dismantled the carefully crafted items she had poured her heart into.
My eyes sparkled as I asked, “The routine was consistent, so it was easy… Shall I reassemble them?”