Experiment (2)
After Seol-hwa emptied the last drop from the syringe and withdrew the needle, she stayed silent for a while. The ECG monitor kept its steady waveform, blood pressure readings showed only a minor rise without triggering any alerts, and Ha Yul's breathing looked regular on the surface. Seol-hwa watched that quiet intently. Reactions to this kind of drug usually sent some small, discordant signal first—tremors in the fingertips, pupil dilation, a spike in heart rate, some awkwardness that stood out from the norm. Yet Ha Yul's body, with that strange quality Seol-hwa had always felt, seemed to be quietly preparing something deep inside.
A few minutes later, the first sign arrived without warning. The muscles along Ha Yul's arms, shoulders, sides, and thighs swelled. The blood vessels just beneath her skin became sharply defined for an instant. It wasn't the exaggerated bulk of a bodybuilder. It was more like an extra layer of dense fiber bundles being woven into her already finely honed frame. The muscles tightened and hardened in a short burst before the swelling eased. Even after it subsided, they hadn't returned to their original state. The volume looked nearly the same, but the density had changed, leaving the elasticity and rebound tension heightened from within.
Seol-hwa's eyes sharpened the moment she saw it. She immediately fetched a portable scanner for muscle condition, neural response pads, and blood-flow analysis sensors. Once she attached the sensors to Ha Yul's arms, abdomen, and thighs and the readings began appearing on the monitor, Seol-hwa lightly pressed her fingers against the muscle of Ha Yul's arm to confirm it herself, then smiled in satisfaction.
"It turned out much better than expected. Muscle density, fiber strength, and elasticity have all clearly improved. What's even more interesting is that instead of increasing volume like most enhancement methods, it responded by layering in high-density muscle."
For a woman whose body had only been trained in external arts, this approach was more efficient, but she hadn't expected it to come out this cleanly. "Vascular elasticity is stable, heart-rate fluctuation stays within acceptable range, and there's no acute ischemic response. At least the first experiment can be called a success."
Before Ha Yul could fully register the changes in her own body, the word "success" from Seol-hwa sounded oddly distant. Instead, she flexed and extended her arm. It felt tighter with less effort than usual. When she rolled her shoulders, the muscles supporting the joints seemed far more solidly anchored. The inner thighs and glutes didn't just feel stronger—they reacted faster and felt more compact. If she picked up an axe or hammer right now, she could probably deliver a deeper, stronger strike with a shorter wind-up.
It's definitely stronger, but... There was also a faint sense of unfamiliarity, as if she were temporarily borrowing a body that wasn't quite hers yet.
Seol-hwa continued while removing the sensors one by one. "Of course, there are some minor side effects. As muscle density and elasticity increased, your weight likely rose accordingly. And while instantaneous output has grown stronger, endurance has probably decreased a little. The more muscle you have, the more blood flow and lung capacity it demands."
Muscle itself could be built through training, nutrition, or external intervention like this, but lung capacity was largely innate, and while blood flow could be optimized from its existing state, it couldn't be increased indefinitely. "In short, you're much stronger in short bursts now, but you'll be at a disadvantage in prolonged fights."
Ha Yul nodded at the explanation. For someone trained in external martial arts, her body understood that much without needing words. Though still seated, she could already feel the subtle shift in her center of gravity. It wasn't simply that she had become heavier—the pressure her posture exerted on the floor had changed slightly.
Seol-hwa turned off the monitor and added one last remark. "Well, there are ways to inject the same type of toxin into the organs and blood vessels for reinforcement. Strengthening the myocardium, alveoli, and vascular walls together could narrow the gap between output and endurance to some degree. But that's not something we should touch right now. You need time to grow accustomed to the physical changes and adapt. If we interfere internally before your body fully accepts its new state as its own, it could truly break."
Ha Yul never heard the rest of Seol-hwa's words clearly. At first, it felt as though a lump of hot metal deep inside her body was slowly heating up. The heat began tracing along her nerves from within. It resembled the familiar warmth that used to overtake her after finishing a hunt, before returning home. But it was only similar—far faster, far more violent, and above all, far too blatant in its direction. As if her body had been fed the illusion that it had grown stronger, the urge to expend that reinforced power somewhere immediately began to boil over. She knew this sensation: overflowing strength, sharpened senses, an inner heat that made everything tingle. Yet it had never risen like this, choking her throat within mere minutes.
Ha Yul drew a long breath and spoke in a low, cracked voice. "……Just knock me out already."
Seol-hwa did not grant the request. Instead, she examined Ha Yul's eyes, breathing, the trembling muscles below her neck, and the tension in her thighs from very close range. After glancing once at the backrest and armrests of the examination chair, she slowly approached Ha Yul.
"I never expected you to be mentally fine just because there were no physical side effects. If anything, that side was always more likely to be the problem. While you were hospitalized and recovering, I read up on the data about you and picked up some rumors. How you go hunting for women once a hunt ends. The side effects of mutations and the martial arts you've learned. Everyone has their own way of dealing with it, but using sex to forget pain is more common in this line of work than you'd think. Especially since it's very efficient at soothing overstimulated senses and aggression."
As she spoke, Seol-hwa climbed onto Ha Yul's thighs so they faced each other. The examination chair had originally been meant to securely restrain patients or test subjects, but now its backrest and armrests created an entirely different kind of tension. The moment Seol-hwa's weight settled on her thighs, Ha Yul's heat-addled body reacted instantly. The already burning flesh met an even hotter stimulus, and the flames spread as if they had found oxygen.
Seol-hwa looked down at the reaction with a seductive expression. Her black hair spilled over Ha Yul's shoulders and chest. Beyond the thin lab gown, the soft curves beneath her shirt rose and fell slowly with each breath at close range.
"Would you like me to help with that? I may not look it, but I'm a martial artist too, so I'm sturdier than I appear. So even if you can't control your strength a little, like you're worried about now, nothing will break."
Ha Yul looked up at Seol-hwa through vision slightly blurred by the heat and asked, "……What are you thinking?"
Seol-hwa chuckled. "Curiosity. Preference. And a researcher's diligence in wanting to confirm the experimental results with my own body. Which excuse do you like best? I don't mind if it's all three."
Ha Yul clenched her jaw for a moment. It was too late to scatter the heat inside her with alcohol, and it was rising too fast and too sharply to simply sleep it off. What would happen if she pushed Seol-hwa away right now and left? Could she stay sane while walking down the research institute corridor, riding the elevator, crossing the parking lot or street, and reaching home? Or would she lose control midway and grab the first person she saw in the worst possible scenario?
She thought of Chae-won and Su-min, but that was even more dangerous. Meeting them in this state would likely mean she couldn't control her strength, and she might hurt them. That was the last thing Ha Yul wanted.
In the end, she asked once more. "……Is there another way?"
Seol-hwa answered with complete honesty. "As I said earlier, the standard method is to knock you out with a paralytic or sedative toxin. Forcibly calming you before your heart rate spikes further and putting you to sleep before your mind breaks is the safest response. But looking at your current condition, that doesn't seem like it would solve anything."
It was obvious she would relapse before the drug took full effect. "Injecting the toxin multiple times might calm you down, but it's not really recommended."
Ha Yul knew she couldn't stall any longer. Instead of pushing Seol-hwa away, she raised her arms and pulled the slender waist into an embrace. The body heat beneath her palms was vivid. Seol-hwa's body was, as she had claimed, sturdy. Though she looked slim, her center was solid, and both muscle and flexibility could be felt.
"What if someone comes in midway?"
Seol-hwa replied calmly while held in Ha Yul's arms. "That won't happen. I told everyone in advance not to come looking because I'd be busy working in the lab. This is the kind of workplace where people get sensitive when they're focused, so everyone understands that much. Especially when I say it, they tend to respect it even more. Maybe because of my background."
Ha Yul's voice, thick with rising heat, was nearly a growl. "Don't come crying later saying it hurts."
Seol-hwa didn't even lower the corner of her mouth at that. Instead, she leaned closer and whispered, "You should be the one not to fall for me, Ha Yul, when you already have two lovers. I hate love triangles. Fighting over hair in the lab isn't my style."
The moment that half-joke ended, Ha Yul stopped hesitating. She cupped the back of Seol-hwa's neck and pressed their lips together. The first kiss was rough. She poured the suppressed heat into it, deep and fierce, and Seol-hwa didn't back down. She gripped Ha Yul's shoulders, accepted the kiss, and soon slipped her tongue in, exchanging saliva. As the hot, wet, breathless kiss stretched on, Ha Yul's hands slid from waist to back, then beneath the hem of the shirt. The skin under the thin fabric was smoother and firmer than expected.
Seol-hwa twisted her waist slightly while straddling Ha Yul's knees, pressing their bodies closer, and that posture only stoked the boiling heat inside Ha Yul more provocatively. What had begun as emergency treatment to suppress side effects on the examination chair had long since crossed the line where such excuses could explain the deepening kiss and explicit touches.
Ha Yul held Seol-hwa's waist and kissed her deeply for a long time without pulling away, while Seol-hwa responded with one eye observing the test subject's reactions and the other eye enjoying the flames she herself had ignited. Even then, the heat raging inside Ha Yul showed no sign of calming, but at least it no longer thrashed without direction. Touching Seol-hwa's body heat and response, the overheating concentrated on one person instead of scattering, and therefore grew even more intense.