The Blood Fiend's Bastard, Part 1

The girl's name was Erika. Eri, for short. This was a fact I only learned after she was dragged into my clinic by Wangcho's rough hands and stuffed with a few pieces of bread.

"Munch, munch. It's not candy, but it's tasty, so I'll let it slide."

"So, Doctor. Are you saying this brat really isn't a Blood Fiend?" Wangcho asked, crossing his arms skeptically.

Sitting on the examination table, Eri was still nibbling on her bread, her eyes filled with wariness.

"She's a patient, not a Blood Fiend. Her diagnosis is Paroxysmal Nocturnal Hemoglobinuria, or PNH."

"Is that some kind of magic spell?"

"Something like that."

I tried to assemble various ways to explain PNH in my head. An autoimmune hemolytic disease where a mutation in the red blood cell membrane makes them vulnerable to complement attack, which... Yeah, no. There was no way they'd understand that. So, I went with a more intuitive analogy.

"It's a disease where the blood breaks inside the body."

"Blood can break?"

"Just think of it that way. It's also why her urine is dark when she wakes up in the morning. The blood is leaking out through her urine, leaving her body depleted."

I gestured with the beak of my mask toward Eri, who was eagerly devouring the bread.

"Just as beasts instinctively lick rock salt when they lack sodium, this child instinctively sought out pig's blood because her body was desperately short on blood."

This symptom is known as pica. When humans suffer from a severe iron deficiency, they develop cravings to eat non-food items—usually dirt, ice, or raw rice. In this child's case, that craving just happened to be blood.

"Ah... Tsk, tsk. To think we had no idea."

Wangcho clicked his tongue. Hearing that the child he thought was a monster was actually just a pitiful patient seemed to strike a chord with whatever sliver of conscience he had left.

Just then, Eri, still chewing on her bread, asked me a question.

"Mister."

"Call me Dr. Schnabel."

"Hey, Doc."

She really had a hard time with titles. I sighed and replied, "Yes, what is it?"

"How did you know the color of my pee?"

Eri's ruby-red eyes stared intently at me.

"Can healers tell ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠the color of someone's pee just by touching their stomach and peeling back their eyelids?"

Oh ho. I was secretly impressed. She had pointed out the leap in logic in my diagnostic process—something even Wangcho had glossed over as if it were completely natural.

She's sharp.

Diagnosing PNH on the spot based solely on anemia, jaundice, and splenomegaly was indeed a massive leap. It could have been liver cirrhosis, leukemia, malaria... The list of possibilities was far too long.

"You're a clever one."

I reached out and patted Eri's messy hair. The girl flinched and shrugged her shoulders, but she didn't pull away from my touch.

"To be honest, I got lucky."

"Eh? How disappointing."

"Deduction is simply a series of throwing darts at the target most likely to yield the correct answer. In the end, its essence is never entirely free from luck."

Anemia, jaundice, and pica. These three clues alone weren't enough to narrow down the candidates perfectly. But I had another clue.

"Wangcho told me."

It was Wangcho, not Erika, who reacted to my answer.

"Me, Doctor?"

"You said she 'comes to drink blood every night.'"

Comes to drink blood every night. That implied her anemia likely worsened during the night. If I built a hypothesis around that, everything fell perfectly into place. There were no glaring contradictions in this theory. And when that happens, you take a shot. That's what deduction is.

"Well?"

Eri's mouth fell open in a daze as she listened to my explanation. It must have seemed like magic, me reciting her symptoms as if I had been watching her the whole time. Seeing her reaction made the slight gamble in my deduction feel entirely worth it.

This is why taking a proper history is so important. There's a reason they emphasize that a doctor must listen to their patient. Sometimes, a tiny nuance in their words becomes the decisive clue. Well, as a trauma surgeon in my past life, I rarely had patients who were conscious enough to talk to me, though.

Honestly, it really was luck. If her morning urine had been normal, I would have smoothly transitioned to a different line of questioning. My next guess probably would have been asking if her stomach hurt. Fortunately, perhaps thanks to the power of the misunderstanding trope, I nailed it on the very first try.

"Has that cleared up your curiosity?"

A brief silence fell after my explanation.

How about that? Pretty cool, right? Don't I look like a genius? Like Sherlock Holmes?

While I was mentally hyping myself up, Eri nodded blankly. Wangcho let out an exclamation of awe on her behalf.

"Incredible... As expected of you, Doctor! Hearing it explained like that, everything fits perfectly!"

Wangcho clapped like a seal, his eyes sparkling. This was exactly why I liked Wangcho. His reactions were top-tier. Yes, keep clapping. I'm the protagonist here. I am Dr. Schnabel.

"Now that we know the cause, can this child be cured?"

At Wangcho's question, Eri's head snapped up. In her ruby-red eyes, which had been filled with resignation and distrust, a spark of hope flickered for the first time. She clearly expected that a doctor who could unravel the curse plaguing her so thoroughly would surely have a cure.

Bathed in their intense, expectant gazes, I replied nonchalantly,

"It's impossible. It's incurable."

"...Excuse me?"

Their faces froze instantly.

PNH. Paroxysmal Nocturnal Hemoglobinuria.

I wasn't sure if I remembered this so clearly because I was a trauma surgeon in my past life, but I recalled that the injections used to treat this disease were astronomically expensive. Was it Soliris? I remembered it being a crazy drug that cost about 500 million won a year. Even the cheaper alternatives were around 300 million won annually. I only remembered it because it was on the list of the world's most expensive medications—supposedly even pricier than cancer drugs.

Of course, I had no idea what the active ingredients of those drugs were, let alone how to make them. Recreating them in this world was utterly out of the question.

So, I spoke honestly.

"It will probably be difficult to cure this disease right now."

"...I see."

Eri nodded, the light fading from her eyes once more. The resignation that had previously clouded her ruby-red eyes returned, swallowing the brief spark of hope.

Just then, Wangcho hurriedly tapped my shoulder.

"Doctor, watch your phrasing!"

"?"

"Didn't you do the exact same thing during my gout flare-up?"

"Did I?"

Wangcho slapped his forehead at my response.

"That habit of blunting out 'It's incurable!' only to add 'but you can manage it if you take medicine' a whole minute later! That is a truly terrible habit!"

...Did I really do that? Come to think of it, I think I did. I vaguely recalled my seniors and residents pointing this out in my past life too.

Tsk. Was I really in the wrong? But from a doctor's perspective, if a disease is incurable, it's only right to say so. Curing and managing are completely different concepts. Just as no one in the world claims to "cure" diabetes, it was simply a disease that had to be managed.

"I cannot lie to my patients."

"This is why geniuses are so difficult! Still, there is a proper order and structure to delivering news! If you just blurt out the conclusion first, ordinary folks like us can't keep up with you, Doctor!"

Wangcho lamented. But I had plenty to say on that matter too. In medical school, they taught us to avoid giving patients false hope. No one sues a doctor out of resignation, but plenty of people sue out of a sense of betrayal. That was why I preferred to deliver the bad news first, which usually just happened to be the conclusion.

Unaware of my inner thoughts, Wangcho turned away from me and crouched down in front of Eri.

"Hey, kiddo. Try to understand him. The doctor is just like this."

As his massive frame folded, the hyena beastman's golden eyes came to level with Eri's ruby-red ones.

"I'm the same as you. I have a disease that won't go away, but as long as I take my medicine, I have absolutely no trouble living my life."

Wangcho looked back at me.

"It's the same for this kid, right, Doctor? There's a 'but' coming, isn't there?"

It was phrased as a question, but the nuance was heavily leaning toward 'there had better be a "but" coming.'

Under his silent pressure, I shelved the "180 Reasons Why PNH Is Incurable" that I had been organizing in my head and jumped straight to the point.

"Just as Wangcho said, you will have to live with this disease for the rest of your life. However, I can give you your normal life back."

It couldn't be cured, but it could be managed. In fact, her daily life would probably be less troublesome than someone with gout.

Wangcho sighed in relief at my reassurance. Light returned to Eri's eyes once more, though it was accompanied by a hint of annoyance. She looked pouted, as if she thought I had played a cruel joke on her. I didn't even need to read her eyes; her protruding lower lip made her feelings abundantly clear. I reached out and gently pushed her pouting lip back in with my finger.

"First, let's check your blood. The symptoms are textbook, but we need to confirm."

I turned around and pulled some tools from the drawer of the examination table. Wangcho watched me with a puzzled expression.

"What else is there to test?"

"As I said, deduction ultimately relies on luck. Unless you are one hundred percent certain, diagnosing based solely on circumstantial evidence is dangerous."

If you suspect a disease, you run a test. The tools I retrieved from the drawer were none other than a glass cup, vinegar, and a syringe. Holding the syringe, I gave Wangcho a nod.

Understanding immediately, Wangcho held Eri's arm.

"Stay still."

Wangcho covered Eri's eyes. In that brief window, I quickly drew her blood.

"Wangcho, press down hard. This disease makes it difficult for her blood to clot as it is."

Wangcho pressed a cotton ball firmly against Eri's arm. Meanwhile, I divided Eri's blood into two glass cups. Then, I added a few drops of vinegar to only one of the cups.

The Ham's Test, also known as the Acid Hemolysis Test. It was a diagnostic method that exploited how PNH red blood cells easily burst under complement attack in an acidic environment. The results were instantaneous. The blood without vinegar remained thick and turbid red. But the cup with the vinegar...

"Oh...! The color...!"

...turned into a clear, translucent shade of red wine. It was a stark hemolytic reaction—the bursting of red blood cells—so obvious that even Wangcho, who knew nothing of medicine, could recognize it instantly.

Tada~ It's magic.

If it weren't for my current persona, I would have made a playful joke like that. Instead, I simply patted Eri's head, praising her for holding still. Eri stared blankly at her now-translucent blood.

"What is... this? Magic?"

"Let's call it a trick rather than magic."

I prepared for the next step. Now that the diagnosis was complete, it was time for the prescription.

Since we can manage it with blood transfusions.

While PNH couldn't be cured, it could be managed to some extent through transfusions. However, before performing a transfusion, I needed to find a compatible blood type. I pricked Eri's finger again to collect a small sample. Then, I pulled out the blood samples I had stored in advance. To be precise, they were collected this morning. Lacking the technology to preserve blood long-term, it had become my habit to collect only enough blood from a few donors to last until the next day whenever they came for treatment.

"I'll need to borrow some of your blood, Wangcho."

Adding my blood and Wangcho's to the existing samples, I mixed them with Eri's blood.

"Hmm..."

The conclusion: the cross-matching test revealed that Eri's blood type was compatible with mine.

"Alright. We will perform a transfusion the day after tomorrow once the blood is ready. Until then, we'll focus on managing your nutrition here at the clinic."

"Trans... fusion?"

Eri tilted her head at the unfamiliar term. Leaving her to wonder, I turned to Wangcho.

"Take care of Eri until we do the transfusion in two days."

Wangcho nodded.

Two days passed, and the promised date arrived. In the meantime, 200 ml of my own blood had been processed into washed red blood cells. I had specifically processed it this way because transfusing whole blood into a PNH patient could trigger a hemolytic attack. However, the journey to create this preparation was rather complicated. Drawing the blood, having Wangcho's lackeys tie it to strings and spin it around to separate the heavy and light components, discarding the light part, rinsing it with saline, spinning it again, rinsing it again... It was only after working Wangcho's subordinates to the bone that it was finally complete.

I knew it. The pyramids really were built by human labor.

Sufficient labor can substitute for technology. And that labor can always be bought with enough capital. Following this formula, as long as you understand the underlying principles, even 21st-century medicine can be replicated at a 19th-century level of civilization.

Looks like it turned out well.

Just to be sure, I held the washed red blood cells up to the magic stone lamp. A clear, clean red. Pass.

"Alright. Let's begin."

I had Eri lie down on the examination table. Thanks to being fed properly for the past two days, some color had returned to her face. It was only natural after stuffing her with iron-rich foods. Any beast grows docile ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠on a full stomach. Eri, whose sharp edges had softened considerably compared to two days ago, asked,

"...Does it hurt?"

"It'll prick a little. Just bear with it."

I inserted the needle into Eri's arm. There were no amateur mistakes like fishing around for a vein. I had spent years making a living in surgery; I could find a vein in my sleep. The red liquid slowly began to flow into Eri's blood vessels.

One minute. Five minutes. Ten minutes.

"...."

Eri stared blankly at the ceiling.

"How do you feel?"

"...I don't really know."

No issues. Check.

"Tell me if you feel dizzy or short of breath."

Come to think of it, it had been a really long time since I had performed a transfusion myself. Ever since I finished my residency in my past life, I never had to find a vein. The residents or nurses did all of that. An hour passed, and the transfusion was successfully completed. 200 ml. It wasn't a massive amount, but considering her small stature, it was plenty.

"Rest well today. We'll check your condition tomorrow and decide if we need to give you more."

Eri nodded and climbed down from the bed. I asked her to confirm.

"How is it? Do you still feel the thirst?"

"A bit less."

"Good."

Pica is easy to correct. Once iron and red blood cells are replenished, the symptoms disappear quickly. In about a week, she would likely stop craving blood entirely.

"We'll keep doing these transfusions regularly. You'll probably have to do this for the rest of your life, but this alone will be enough to let you ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠live normally."

Of ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠course, it was impossible to cure Eri's disease with transfusions alone. If it were that simple, those multi-million-won injections would never have been developed. Furthermore, PNH was a disease that required additional medical management even alongside transfusions. However, I saw no need to bring that up and ruin the hopeful atmosphere. Besides, managing those risk factors is my job anyway. Living her daily life wouldn't be much of an issue. She no longer had to shove her face into a bucket and greedily gulp down blood. She would no longer be pointed at as a Blood Fiend, nor would she be kicked around by people like Wangcho.

Perhaps the reality of it hadn't sunk in yet. Eri fiddled with the bandage on her forearm. As if her body, now circulating warm blood, still felt foreign to her, she repeatedly clenched and unclenched her fists. Then, she looked up and met my eyes.

"...Why are you doing all this for me?"

"What are you trying to say?"

"I don't have any money," Eri mumbled in a barely audible voice. "All I have are these clothes. I can't pay you back for what you did, Mister... I mean, Dr. Schnabel."

The child knew the laws of the back alleys better than anyone. There was no such thing as kindness without a price. Especially in the Limbus Pit, unconditional kindness usually demanded a far more horrific price later on. I could see the distrust and anxiety in her eyes. Usually, what was needed to dispel this wasn't sincerity.

"Then you can run errands for me."

"What?"

In cases like this, what was needed was a simple give-and-take. I pointed to the clinic floor.

"You have to be managed by me regularly anyway. So, you'll work here. I'll provide your food and lodging."

"...Here?"

"I happened to need an errand runner. Fetching medicine, contacting patients, doing some light cleaning now and then. Think you can do that?"

"...Okay. I'll do it."

Her nod was stiff, like stamping a seal on a contract. But compared to just a few seconds ago, her guard had visibly lowered.

It's a strange thing. Simply turning unconditional charity into a transaction is enough to easily break down a person's defenses. Whether it's zero won or the price of a cup of coffee, even though it's practically free considering the quality of the treatment, setting up this tiny, almost meaningless threshold completely changes their reaction. It was the same back in Korea.

"Wangcho."

Having concluded the deal, I called in Wangcho, who had been waiting outside.

"It seems this child will be my new assistant starting today. Could you show her the ropes? Just like you did with the other kids."

"Understood, Doctor."

Wangcho gave Eri a gentle pat on the back. As Eri crossed the threshold, she looked back at me once. I gestured with my chin for her to go, and she turned and left. Once the two of them departed, I was left alone in the treatment room. Cleaning up the transfusion equipment, I chewed over our earlier conversation.

"All I have are these clothes. I can't pay you back for what you did, Mister... I mean, Dr. Schnabel."

"Well, I beg to differ."

I muttered to myself in the empty room. Erika might value herself at nothing more than that, but my thoughts were different. Let's break this down. A rare disease. A rare disease that I am the only person in the entire world capable of diagnosing. To top it off, her blood type is compatible with mine, despite her needing regular transfusions. Now, let me ask you a question. Would anyone who has read even a handful of web novels look at this child and think she's just a common extra? Not a chance!

And who knows? Maybe she's a polymorphed dragon. Or perhaps a future Sword Saint, or a childhood friend destined to become the strongest under heaven. In other words, this was an event. A low-buy event.

Well, maybe not. Granted, she wasn't the first child I'd taken in like this. A year ago, it was testicular torsion; eight months ago, phenylketonuria; half a year ago, congenital clubfoot; three months ago, congenital diabetes... A wide variety of children had passed through my hands. Each time, I treated them, hired them, and searched for their hidden talents. Though, so far, none of them had turned out to be the SSR or 5-star pull I was hoping for.

Still, this time feels a bit different. Just... different. It was hard to explain. But what if she turns out to be a dud too, after all this hyping up? Well, then it's just a shame. They say you keep performing the rain ritual until it actually rains, don't they?

Let's start her off with errands first. Just like the other kids. Eventually, a talent or two is bound to show up. I just hope it's the kind of talent I'm looking for.