A pill, or dan-yak, is a concoction of various ingredients artificially designed to make absorbing qi through internal energy more efficient. However, no matter how potent a pill might be, if consumed recklessly, it would be nothing more than a nutritious supplement. To truly benefit from it, one must focus and transform the qi from the pill into internal energy.

“Ssss… Hooo…”

Chun-bong, having had the pill forcibly shoved into her mouth, was no exception to this rule.

To ensure the pill didn’t just pass through her system as waste, she began concentrating on circulating her qi.

“There’s no reason this shouldn’t work.”

Seo-jun immediately moved behind Chun-bong, placing his hand on her back. As he focused, the flow of her internal energy became clear to him, almost as if he could see it.

“Qi is influenced by one’s mindset. If you believe you can do it, you really can.”

Of course, it might not work, but in the worst-case scenario, the only loss would be the pill. If things didn’t go as planned, they’d just lose one pill—no big deal.

Focusing on the flow of Chun-bong’s internal energy, Seo-jun took a deep breath.

Since the Azure Cloud Qi Technique was derived from the Divine Cloud Qi Technique, their flows were quite similar. Seo-jun quickly adapted to the subtle differences and observed how the qi from the Black Muxin Pill integrated into Chun-bong’s internal energy.

“The neutral qi is turning into yin energy.”

The yin energy from the Azure Cloud Qi Technique began to absorb the pill’s qi, but soon, the yin energy started to freeze due to the cold yin energy that was blocking her qi pathways.

“If left like this, she’ll eventually have to expel the qi from her body.”

Now was the time to intervene. Seo-jun would transform the pill’s qi into warming yang energy during the conversion process.

“Chun-bong, you trust me, right?”

He imagined her response as an affirmative, and golden energy began to emanate from Seo-jun’s body.

What’s the difference between yin and yang? Yin is stillness, and yang is movement.

From a modern perspective, it’s not too different from thermal energy. When the particles in an object are active, the energy increases; when they slow down, the energy decreases.

This corresponds to the vibration of particles. Whether qi is a particle or a wave didn’t matter much—just understanding it roughly like this was enough.

“Wait, does that mean the Taiji is in thermal equilibrium?”

His thoughts wandered briefly, but he pushed them aside for now. This wasn’t the time for that.

It’s impossible to fit martial arts neatly into a scientific framework, so Seo-jun just had to trust his instincts.

“Hot and lively.”

He grabbed hold of the freezing qi from the Black Muxin Pill and pushed it, causing it to flare up.

“Mm…”

As the qi became more agitated, a groan escaped Chun-bong’s lips. If it continued like this, it would strain her body.

Controlling the level of agitation, Seo-jun guided the qi along the path of the Azure Cloud Qi Technique, assisting Chun-bong’s small circulation of energy.

He could feel the qi slipping through the very narrow, frozen pathways.

“Okay.”

He had a grasp on it.

A faint smile appeared on Seo-jun’s lips. Now that he had a feel for it, he discarded all theory. From this point on, he would act purely on instinct.

“What should I call this?”

There’s nothing like giving something a name to solidify the concept.

“Ah, yes.”

Yin-Yang Reversal.

That sounded good.

Geum Hee could feel the qi inside her being guided against her will.

It was definitely qi inside her own body, but it was being controlled by someone else’s will. The sensation made every hair on her body stand on end.

“What an unbelievable talent…”

Despite her shock, she didn’t stop circulating her energy. However, she soon felt the qi from the Black Muxin Pill freezing over due to the cold yin energy in her blocked qi pathways.

“So, this is how it ends.”

It would be a lie to say she wasn’t disappointed. Of course, she had held out hope, but in truth, this was the most likely outcome.

She wasn’t too disheartened. Instead, she felt a pang in her chest, grateful for how much he had done for her.

“You idiot. If you had just taken it yourself, it would have benefited you so much more. You could have gotten one step closer to becoming one of the hundred greatest martial artists in the world…”

The thought of Seo-jun becoming one of the top martial artists filled her with a strange sense of pride. It was odd—she just felt a little regret that she wouldn’t be there to see it.

Seo-jun, roaming the martial world using their family’s secret techniques. The thought of the martial world buzzing over his name sent a thrilling shiver through her.

“Well, he’s practically my disciple, so it makes sense.”

She was about to give up and expel the qi.

Thump!

Her heart pounded, and warmth began to spread throughout her body.

In shock, she examined the flow of qi closely.

The qi from the Black Muxin Pill, which had been converted into the internal energy of the Azure Cloud Qi Technique, was suddenly transforming into yang energy without any warning.

“That’s impossible… This goes against all logic.”

But no matter how much she marveled, the yang energy continued to spread rapidly, like dye dispersing in clear water.

The yang energy then began to force its way through the tiny frozen pathways, gradually expanding them. The warmth of the yang energy was melting the cold yin energy.

“My body…”

It felt like it was thawing. A body that had always been trapped in winter was now bathed in the warm sunlight of spring.

Entranced by the warmth flowing through her, she allowed her qi to guide it, and the internal energy’s flow became increasingly smooth.

The stifling tightness in her chest eased, and the coldness in her fingertips softened and warmed.

She had forgotten what warmth felt like. A faint smile formed on her lips as she let herself be carried away by the flow.

“Whew…”

Seo-jun exhaled deeply and opened his eyes. His entire body was drenched in sweat, and he didn’t look particularly satisfied.

“Maybe I was asking for too much.”

He had hoped to completely cure her blocked meridians, but that seemed to be beyond his reach.

Clicking his tongue, Seo-jun gently lifted the now-sleeping Chun-bong into his arms.

“Stupid kid…”

She was smiling in her sleep, looking more like a child her age for the first time, which put his mind at ease.

After laying her down properly on the floor, he touched her hands and feet. Sure enough, they were warm now.

Before, they had been cold and stiff like someone with severe chills, but now they were warm and soft, like a baby’s skin. Not bad for a girl who was seventeen.

Seo-jun chuckled to himself and then, as if suddenly struck by exhaustion, collapsed beside Chun-bong.

Yin-Yang Reversal. As grand as the name was, it had been no easy feat.

Though he was smiling, it felt like his head might split in half at any moment.

“…You’d better be grateful later, Geum Chun-bong.”

With that, Seo-jun lost consciousness.

The sound of birds chirping woke Seo-jun from his sleep.

He groggily sat up, holding his pounding head and groaning.

“Ugh…”

Did he overdo it yesterday? The Yin-Yang Reversal had definitely been overkill.

“Well, if all I get out of it is a headache, that’s not too bad.”

He dismissed it with a shrug and reached for the water container nearby. The first thing he had replaced as soon as he got some money was the water supply.

Gulp.

“Ah…”

It was still unpleasant, but it was infinitely better than the filthy water he used to drink.

“Damn this wretched world.”

Selling well water—he was tempted to bash someone’s head in.

As he started to clear his head, he noticed something unusual near his legs.

“You…”

Chun-bong was sound asleep, clinging tightly to his leg. Without thinking, Seo-jun reached out to pat her head, but—

“Hey, hey! Wake up!”

“Huh, what’s going on?!”

Chun-bong jolted awake and frantically looked around. Seo-jun pointed at her head.

“Your hair! Why do you have so many white hairs?!”

“White hairs…?”

Looking confused, Chun-bong gathered her hair in her hands and brought it in front of her eyes.

Her black hair was now streaked with white. Chun-bong stared at it blankly before letting out a chuckle.

“It must be because of the cold yin energy.”

“Is that bad?”

“No, it’s nothing serious. It’s just a change in hair color.”

Chun-bong waved her arms enthusiastically.

“My body feels great! I’m full of energy!”

She laughed, looking genuinely pleased. Relieved, Seo-jun stood up.

“You’ve also grown taller, I think?”

“Huh?”

Chun-bong tilted her head, and Seo-jun realized her head now reached about chest height. Considering how much he had grown over the past year, it seemed she had grown a couple of inches overnight.

“Wha… what?!”

Chun-bong, startled, quickly began patting her chest.

Thump, thump—

The hollow sound echoed. While her height had increased, her chest was still as flat as ever. She hung her head in disappointment.

“…Damn it.”

“Don’t worry. There’s a demand for that kind of… Ow! Why’d you hit me?!”

“Just shut up!”

It seemed she was in good health, at least.

Having come to terms with her lack of chest, Chun-bong suddenly lowered her head, staring at the ground.

“…Hey.”

“What?”

“Thank you… I didn’t expect you to go this far for me…”

Fidgeting, Chun-bong grabbed his sleeve with her small hand.

“Attacking the Black Tiger Sect, giving me the pill… And then, even though I don’t know how you did it, turning the yin energy into yang energy…”

She glanced up at him with her lips slightly pouting.

“It’s all thanks to you, oppa!”

“…”

Chun-bong’s face turned bright red as she awkwardly shouted at him.

“Say something, damn it!”

Seo-jun, still in shock, slowly reached out his hand. He gripped her under her arms and effortlessly lifted her into the air.

“Yo! You cute little rascal! You’ve finally called me oppa!”

“Let me go! Are you obsessed with being called oppa or something?!”

“Oh, you adorable brat!”

He hugged her tightly, rubbing his cheek against hers. Chun-bong, horrified, started kicking wildly.

“Let go of me, you bastard!”

“Ugh!”

One of her kicks landed squarely in Seo-jun’s groin, and he crumpled to the ground. Is it broken…? He checked and, fortunately, everything was intact.

“Ooof…”

“Are… are you okay…?”

Chun-bong, now feeling a bit guilty, gently patted him on the back.

“Evil brat…”

“Hey, I’m really sorry, okay?”

Since she apologized, he decided to let it slide. Seo-jun wiped away the tears that were threatening to fall and forced a smile.

“Anyway, we’ll find another medicinal pill later and fully cure you. You should be fine for now, right?”

“Y-Yeah… But are you sure you’re okay? You’re not, you know… broken?”

“I’m fine. Want to check?”

“Are you crazy?!”

Chun-bong snapped, but then held back. She must have really felt bad.

“Alright, then.”

Anyway, with the Black Tiger Sect more or less dealt with, maybe it was time to try unifying the back alleys.

“And I should also find out what happened to that woman.”

The woman he had met on his first day in the martial world. He couldn’t help but wonder how she was doing now.