Walnut Tree

Tang Mujin recalled Goiyi's words.

—My wife and daughter did not die because there were no physicians who could heal them. They did not die because there were no medicinal herbs, nor because we had no money. They died simply because the physicians in my hometown did not know what other physicians elsewhere already knew.

—That is why I became a physician. To gather all the knowledge of medicine into one place.

Goiyi's goal had been to collect every form of medical knowledge in the world, and his dream was a world where no one suffered from illness.

At first glance, that dream sounded noble. But at the same time, it was strangely unsettling.

Most people's dreams are centered on themselves: I will become the greatest under heaven. I will become the richest in this land.

But when the subject of the dream becomes someone else, it feels odd: Your becoming the greatest under heaven is my dream. You should become the richest in this land.

Goiyi's dream went one step further—there was no subject at all. He didn't care who became the greatest physician, or who gained wealth through medicine, or even who practiced the art.

Looking back, Goiyi's dream wasn't the dream of an individual at all, but more like the mission of a collective. Something no one person could accomplish alone.

Knowing how burdensome a dream it was, Goiyi needed someone to carry it on after him. And the one he chose was Tang Mujin.

—You owe me a debt.

—Just remember well that you are indebted to me.

Goiyi had emphasized this "debt" not for its own sake, but because he wanted Mujin to continue his dream, whether Mujin wished it or not. Mujin sighed.

Old man… you could've just said it plainly.

Now it was clear whom Goiyi had gone to find.

He had devoted his life to collecting medicine across the Central Plains, become one of the Three Great Physicians, and compiled his knowledge into a medical text.

Then, after the Medical Sage was slain, Goiyi had seized the Manbyeongseo and passed it to Mujin. Two of the Three Great Physicians' arts were now in Mujin's hands.

That left only one last target: the Demonic Physician.

But like everyone else, Mujin knew little about him.

That he could heal with unmatched skill, but was even more terrifying when it came to killing. That he dealt more in poisons than remedies. That he rarely emerged from Xinjiang, deep in the Demonic Sect's territory.

Did the old man really go into Xinjiang? To storm the Demonic Sect alone and seize the Demonic Physician's text?

Mujin shook his head. Impossible. Goiyi was no fool.

His plan didn't end with merely stealing a text. He had intended to bring it back to the walnut tree in Huizhou. So he must have found a method with better odds than charging into Xinjiang himself.

But what method?

As Mujin pondered, he lifted his head and found Seol-yeong's round eyes watching him.

Though he had said nothing, she seemed to sense something from his expression. Some kind of intuition.

"What were you thinking?"

Mujin almost explained but stopped.

He was planning to go after Goiyi. If it were somewhere less dangerous—like Bongshan or Huizhou—it would be fine to bring Seol-yeong along. But this time, it might mean venturing as far as the Demonic Sect's territory in Xinjiang.

Instead of answering, Mujin asked in return:

"Seol-yeong."

"Mm?"

"If you had to choose between Luoyang and Chengdu, where would you rather go?"

"Chengdu."

The answer came instantly.

She had not forgotten the resolve she made when she left Mount Song. Life in Luoyang had been pleasant, but it was only a stop along the road she meant to travel—with Mujin—toward Chengdu.

Mujin untied the money pouch from his waist and pressed it into her hands. The weight of silver coins clinked dully.

"Use this for travel. Go to Chengdu first. Ask where the Tang Family Clinic is—someone will tell you. Find my father, explain everything, and he'll surely give you a proper room."

Seol-yeong didn't answer. She only studied Mujin's face.

To anyone else, he looked the same as always. But she could sense the subtle difference. His expression was stiff, unlike usual.

She clasped his hand. Instinct told her: Mujin had made a dangerous decision.

She pushed the pouch back into his hands.

"I don't know what this is about, but I'm going with you. I won't blame you, no matter what happens."

"You can't."

"Why not? I've been practicing that lightfootwork you taught me."

She clumsily mimicked the steps.

But she had no inner energy and only a few days of practice. Her clumsy movements were worse than simply walking.

And lightfootwork could not solve every problem—not unless she were a master among masters.

"You can't."

"Why not? At least tell me where you're going!"

"Sorry. But it'll be fine. Go ahead first, wait in Chengdu, and I'll come soon."

"If it's really fine, then why can't I come?"

"…"

He had no answer. He simply turned his head away.

Seol-yeong too fell silent for a long time.

At last she let out a heavy sigh. She wasn't so foolish as to cling endlessly to her own will.

"…Fine. But give me three days before you go. No—at least two."

"Why?"

"There's something I want to give you."

"…Alright."

The two left the hill and returned to the inn in Huizhou.

Seol-yeong shut herself in her room and didn't emerge for two days.

***

When she finally came out, she held a wooden cylinder.

Without explanation, she handed it to Mujin.

"Here. Take it."

Mujin examined it. Not quite the length of a handspan. At first glance it looked like a paintbrush case, but it was far too thick—at least the width of two fingers across.

"What is it?"

"Something I thought you might need someday. I'd been sketching and working on it in my spare time. I didn't expect to have to finish it so quickly."

She pointed at the side of the cylinder, where a long strip of leather dangled like a tail.

"If you're in danger, pull this leather cord hard—just not so hard that it tears."

Then she rubbed her thumb across a small raised section at the bottom.

"And press here. The tension will snap the cord, and the needles inside will fire forward."

She gestured with her hands, mimicking something spinning. Whether she meant the needles would whirl as they flew, or that some part of the mechanism rotated inside, Mujin couldn't tell.

But he chose not to think too hard about it. Just as Seol-yeong couldn't fully grasp the principles of his medicine or metallurgy, Mujin couldn't fully understand the mechanics of her inventions.

"So… pull the cord, press the back, and needles will shoot out the front?"

"Right."

"So, it's basically like a disposable slingshot or bow?"

"Exactly. But don't underestimate it just because it's small. It'll be far more powerful than most bows or slingshots."

While they had been living in Luoyang, Seol-yeong often asked Tang Mujin to make little things for her.

Sometimes she asked for useless or broken needles, other times she asked him to shave down tiny parts. It seemed all of that had been for the sake of building this cylinder.

Seol-yeong continued her explanation.

"Once you pull the leather cord, you have to use it quickly before the leather loses its strength. At most, within one or two gak. And you can't store it too long unused either. If the leather degrades, the thing becomes useless."

"Got it. What's this cylinder called?"

"Hmm. I never thought of a name. Should I call it the Heavenly King's Needle Tube?"

"That's quite the grand name."

"If I gave it a weak-sounding name like Little Bee Needle Tube, then in a real crisis you might hesitate to grab it."

So, she wanted him to trust it even in a moment of danger.

Mujin laughed lightly and pulled Seol-yeong into his arms. Though she hadn't bathed recently and was a bit scruffy, she didn't smell foul—there was instead a faintly sweet warmth of skin.

Startled by Mujin's sudden action, Seol-yeong stiffened for a moment. But soon, she spread her arms and hugged his waist. The two of them stayed like that for a long time.

To an outsider, it might have looked like children playing house.

But for these two awkward souls, it was more than enough. Sometimes, clumsiness makes things possible.

Mujin released his hands, stood up, and looked straight into Seol-yeong's eyes.

"I'll be there soon. Wait for me in Chengdu. Understand?"

"…Alright."

Seol-yeong too gazed back at him.

Mujin flashed a confident smile like hers, then left the inn.

Now he had to move, to track Goiyi's trail.

***

The Demonic Physician rarely left Xinjiang.

More precisely, he had no reason to. For his experiments, he could find materials, assistants, and even living test subjects all within Xinjiang.

But flip that thought around, and it meant that if something special enough arose, he would leave Xinjiang.

And news of a zimsae was such an event, even for him.

The zimsae was a massive bird with jade-green feathers. Its size and its crested head were unusual, but what made it infamous across the land was not its form—it was its poison.

Ordinary birds carried no venom. But the zimsae did. From youth it fed on vipers, venomous snakes, blister beetles, and centipedes, storing their toxins in its body.

Its venom was so potent that if a man merely touched it, his hand would rot. If it brushed the eyes, it caused blindness.

Some even claimed that if the giant bird flew over rice fields or farmland, the crops below would wither and die.

The poison was deadliest when ingested. No one had ever survived even the tiniest taste of zimsae flesh. And liquor brewed with its feathers was so tasteless and scentless that it was often used in assassinations.

For the Demonic Physician, who cared more for poisons than cures, zimsae venom was priceless.

The problem was that the bird was vanishingly rare. Always scarce, and in recent years rarer still.

Even the Demonic Physician, who could acquire almost anything, could scarcely obtain a feather of the bird, let alone a living specimen.

Worse, it was no bird that ordinary hunters could catch. Who would dare hunt a bird that rotted your hand at a touch?

To capture one, he would have to go himself.

He had waited years for such news. And when he heard a zimsae had been spotted in Qinghai Province, he immediately set out by carriage.

Qinghai was one of the vastest regions of the Central Plains, but sparsely settled. It could take three full days of travel to reach even a small village.

As if that weren't enough, blizzards raged like madness.

The carriage slowed to little more than a man's walking pace, but the Demonic Physician didn't care.

Then, suddenly, the creaking carriage stopped. Perhaps the driver was avoiding a pit? But even after some time, it did not move again.

He wondered if he should ask what was happening—when one of the carriage doors swung open.

A man in black stepped inside.

That alone wasn't unusual; all of the Physician's retainers wore black.

The odd thing was that instead of reporting the situation, the man sat down beside him as if it were natural.

"Ugh, damn cold. My hands and feet are frozen stiff."

The man brushed snow from his coat with an easy manner and shut the door.

"…Who are you?"

When the Physician asked, the man scoffed as though incredulous.

"What a rude brat. Not even a 'Who might you be?' but just 'Who are you?' Where did you learn such manners?"

"Answer me."

"If you've made me wait months in this frozen backwater, shouldn't you start with an apology?"

Grumbling, the man pulled off his face-wrap, revealing the gray-streaked hair of a middle-aged man.

It was a face the Demonic Physician knew well. Goiyi chung.

Goiyi demanded as though reclaiming a deposited item:

"Demonic Physician. You must have written a medical text, haven't you? Hand it over."

"Medical text? Don't spout nonsense. I never wrote such a thing."

The Physician dismissed it coldly, but Goiyi spoke as though he knew better.

"Impossible. Physicians are born desperate to leave records. Countless martial artists die without ever writing a manual, but I've never seen a physician go to the grave without leaving a medical text. Not even those old fools who swore to end their lineage could destroy their writings in the end."

The Physician clicked his tongue and laughed. Goiyi wasn't wrong.

Young doctors always recorded symptoms and treatments. Over the years, those notes grew, and with careful order they became medical books. The Physician had done the same.

But he had no intention of giving it up. Especially not to someone who had just slaughtered his retainers and boarded his carriage.

Dark mist of killing intent pooled over his palms. His voice turned icy.

"Too bad. You won't live long enough to leave behind any book of your own."

"Me?"

Goiyi smirked, tugging the corner of his lips.

"Of course I already left one, brat."

[T/L: Read extra chapters on my ko-fi page "Pokemon1920" : https://ko-fi.com/pokemon1920 ]