Near the docks of Wuhu Port stood the Namgoong Clan’s manor—or, more precisely, the manor of a trading company under their control. The distinction was largely meaningless, as it was still part of their domain.

Unlike the Namgoong Clan’s centrally located manor, the White Dragon Medical Pavilion’s Wuhu branch was situated on the outskirts of the port. This distance was why Jin Cheonhee chose to treat Thieving Phantom Gong Ya-geon’s granddaughter, Gong Yubing, at the Namgoong manor instead of transporting her to the branch.

In the 21st century, he would’ve rushed her to a hospital equipped with medical devices. But the treatment Jin Cheonhee devised for Gong Yubing didn’t require elaborate equipment.

“It’ll sting a bit.”

A thick needle pierced the smooth, muscular arm of Thieving Phantom Gong Ya-geon. Blood surged out, flowing into a specialized blood transfusion pack crafted by the White Dragon Medical Pavilion.

Jin Cheonhee glanced to the side.

There, a young girl lay with thin tubes inserted into both arms.

“Now… here we go…”

He stepped back.

Gong Yubing’s blood began flowing into Thieving Phantom’s body, while Thieving Phantom’s blood streamed into Gong Yubing.

“Will this… save my child?”

“Of course. Your granddaughter’s condition is called acute renal failure.”

“I’ve never heard of such a disease…”

“That’s because it’s usually fatal without treatment. Simply put, it’s caused by damage to the kidneys, located around here. We doctors call them the kidneys.”

Jin Cheonhee explained acute renal failure: the kidneys filter waste from the blood into urine, maintaining its purity. When they fail, toxins accumulate, causing complications like uremia, leading to death. Thieving Phantom’s expression grew grave as she listened.

“The good news is… about thirty to forty percent of her kidney function remains. If over ninety percent had been lost, permanent recovery would’ve been impossible.”

In the modern world, a dialysis machine could’ve helped. But not here.

If I could obtain the Immortal Divine Art[1], it might regenerate ruined kidneys… but in Supreme Heavenly Demon, it was only mentioned, with no one known to have mastered it.

Even martial world methods were limited.

Come to think of it… didn’t Master say Heavenly Commander Dong could regenerate severed limbs? Could the Blood Immortal Sect hold some hidden secret about stem cells? I’ll have to shake them down later…

While Jin Cheonhee entertained wild thoughts, his devised system began functioning.

Hum…

First, a device casting a minor curse activated within the formation, projecting power into the blood drawn from Thieving Phantom.

Jin Cheonhee paused his thoughts to examine it. To the untrained eye, it looked like a palm-sized square box, but inside, blood flowed through winding channels.

This was for transfusion safety. Transfusing one person’s blood into another could trigger immune rejection, even with matching blood types, causing clotting, blockages, or other side effects—turning the transfusion into poison.

Modern blood transfusion packs use radiation to remove white blood cells, preventing such reactions. In the past, with Wang Chaek-baek and his daughter Wang Gak-yeon, Jin Cheonhee had relied partly on internal qi and partly on luck, as the patient would’ve died otherwise. They’d been fortunate, but would luck hold again?

Martial artists, bolstered by inner energy, rarely faced issues, but what about civilians? Using formations for qi-based treatments had limits.

Jin Cheonhee refused to settle for that.

He’d searched for a solution to immune rejection and found it: curses.

He replicated the effect of a radiation irradiator with a curse, neutralizing white blood cells and platelets while preserving red blood cells and plasma. Without his knowledge of cellular anatomy and countless tests, it would’ve been impossible.

Sweat beaded on his forehead.

This… is harder than I thought.

The delicate control required was mentally exhausting. A throbbing headache and overwhelming fatigue set in, followed by a strange dizziness that felt like madness creeping in.

“Hyung?”

Yeo Ha-ryoon moved to support him.

“I’m fine.”

Jin Cheonhee pressed on.

Good. It’s working exactly as tested in the research pavilion! Human plasma dialysis, complete!

Satisfied inwardly, he continued explaining aloud.

“Right now, we’re sending your granddaughter’s tainted blood into your body through these tubes. Your body filters it, purifying it, and we send it back to her.”

A primitive form of kidney dialysis using a living body.

“Could… could such a thing be possible?”

“Not without special tools and arcane techniques. But it’s working well now.”

Indeed. Dialysis machines were products of modern science, impossible to replicate with this world’s technology. Nor could they be crafted like a LifeStraw.

So Jin Cheonhee devised plasma therapy, inspired by COVID-19 treatments where blood from recovered patients was transfused to others, carrying antibodies for partial effectiveness. It was a stopgap when no proper drugs existed.

Here, he used Thieving Phantom’s body as a filter, with curses mitigating immune rejection.

Human plasma dialysis, complete!

Heh, it’s insane. Even I think it’s crazy…

In the 21st century, this wouldn’t be done—dialysis machines exist. But in this martial world, where necessity drove invention, Jin Cheonhee had pulled it off.

The effects were already showing. Color returned to Gong Yubing’s face, and her bodily functions began recovering.

I need to write a paper on treating long-term poison exposure.

Back on Earth, an orthopedic friend had said, “I’ve never seen a bone break the same way twice.” Now, in this martial world, Jin Cheonhee could reply, “I’ve never seen a patient come in with the same injury twice.”

Perhaps it was the nature of this “mountain of blades, forest of swords,” but bizarre cases kept piling up. Jin Cheonhee was adapting, growing adept at improvisation.

Thank goodness I studied curses at Wannong and kept researching.

The martial world had countless poisons—not just ones that rotted flesh or melted organs, but those that tormented for years, leaving organs irreparably damaged even after antidotes. Martial artists might endure, but civilians couldn’t.

I need to prepare more.

Each bloodstorm in the martial world brought patients to the pavilion. So far, Jin Cheonhee’s knowledge allowed makeshift treatments. But how much longer could he manage?

Fear gripped him, yet his hands kept moving—there was no other choice. If he stopped, the patient would die. Even if treatment failed because the patient’s body couldn’t hold out, he had to try everything possible.

That was life. Saving was so hard, yet death came so easily—a struggle to drag someone from a swamp without knowing its depth or end, trudging forward until strength gave out.

Whether human knowledge fell short or the patient’s wounds were too deep, there was nothing to do but try.

Humanity had always advanced, failed, and advanced again. That was the essence of papers and statistics, the collective record of countless doctors and patients.

It’s like a tree…

On modern Earth, that tree was a given. Anyone could glimpse its shape, and after rigorous study, one might earn the chance to add a leaf or twig. Here, no such tree existed—no towering edifice of human knowledge. In this secretive martial world, medical arts were hoarded within clans, lacking the open exchange of modern science.

I know I can’t dismantle that mindset.

This was the martial world, and Jin Cheonhee was an outsider. Adopting modern methods outright would make him a target for exploitation or betrayal. But he could build knowledge and systems within his reach.

Maybe one day, even without me, it’ll pass to someone else.

With grudges in the martial world, he had to be ready to die anytime.

With that thought, Jin Cheonhee monitored Gong Yubing’s condition.