Important Wisdom for Survival

As for why Youji was so excited, Xiang Shan naturally knew perfectly well.

The child was so happy because Xiang Shan had agreed to teach him some skills.

Xiang Shan admitted that revealing his identity had been somewhat risky. He had even considered the worst-case scenario—that the words "chivalry" and "righteousness" had been completely twisted in this era, and that knights had long since lost all reputation. In that case, he might have had to knock Youji unconscious and leave the town.

But he truly lacked common sense about this bizarre era. He genuinely needed someone from this time to help him. Besides, there were some brain-related modifications that he could not complete alone. If he wanted to restore his martial arts, he needed an assistant.

Youji was currently the only person Xiang Shan could trust. Xiang Shan had spent several months with him and knew that the child was kind by nature and very clever. He also had enough curiosity to want to understand this world.

In Xiang Shan's eyes, the child was worth training as an assistant, or even a disciple.

Xiang Shan had also given the matter of revealing his identity considerable thought.

After weighing the risks and benefits, Xiang Shan ultimately chose to come clean.

A few minutes earlier, Xiang Shan had personally watched the expression on Youji's face shift from astonishment, to fear, to relief.

"I saw how angry you were over what happened to the workers," Youji said. "I believe you're a good person, a good knight."

Afterward, Xiang Shan asked Youji where he could buy parts and borrow a set of specialized tools. Youji brought Xiang Shan to Doctor Schultz.

"Hmm, most of the parts you need are fairly common. I have most of them here." Doctor Schultz glanced over Xiang Shan's list and nodded. "But a few of them are quite expensive, so..."

"Don't worry. I have a way to pay." Xiang Shan took a spinal column from the bundle he carried with him. It gleamed silver-gray and felt heavy, nothing like a mass of calcium and protein. Its density was close to that of metal.

This was a relic left behind by Will Grand Dog: a vertebra.

Humans really could grow spinal columns like this. Xiang Shan had only just remembered that. In the twenty-first century, humanity had made tremendous advances in molecular biology and genetic engineering. Humans could alter their genes to make their bodies synthesize proteins containing metallic elements.

If someone used modified viruses to splice new gene segments into their body, then continued taking immunosuppressants for a period of time to suppress rejection between their original body and the newly generated proteins, the cells formed from those proteins would gradually replace the original cells. In the end, the person would evolve from Homo sapiens into an entirely new organism.

And this new hominid species, transformed from Homo sapiens, possessed far stronger adaptability toward cybernetic prosthetics. The metal-based proteins in their bodies formed natural wires and resistors. The threshold for brain-computer interfaces was lowered almost without limit, while the cells' resistance to mechanical damage rose sharply. Hardware implanted into the human body would no longer cause the necrosis of surrounding cells.

—Perhaps that was also why Xiang Shan could awaken again after lying unconscious for countless years.

From some point onward, humanity's cybernetic augmentation had raced forward like a wild horse breaking free of its reins.

Xiang Shan no longer remembered the finer details. But he still remembered that in his era, the spine had remained extremely important. A metal-based spine was a natural data transmission line with enormous channel capacity, and it was naturally compatible with neural signals, requiring no further adjustment. Many cybernetic modifications retained the brain, cerebellum, medulla oblongata, and spinal column as a complete set.

And now, Will Grand Dog's martial artist prosthetic still used this technology.

Xiang Shan remembered that Youji's mother, Yulia, had once sold a spinal column. This thing was still valuable now.

Doctor Schultz was startled. "You're selling that?" He looked at Xiang Shan's stick-figure-like prosthetic body. "You aren't planning to use it yourself?"

Xiang Shan pretended not to care. "No medicine."

"Medicine?"

"The kind of... thing you need when replacing a spinal column... what was it called?" Xiang Shan asked tentatively.

After receiving metal-based genetic fragments, cells became more resistant to apoptosis, and all the receptors on their cell membranes were rewritten. Earth's native viruses could barely harm these new humans anymore. In addition, higher body temperatures gave humans immunity to most old bacteria, fungi, and parasites. But that did not mean people no longer experienced rejection. Using someone else's spinal column would still trigger a rejection response.

—Of course, that was how things had been in the era Xiang Shan remembered.

Xiang Shan did not know how far Earth's technology had advanced after he fell unconscious. Youji did not know much about such professional matters either, so Xiang Shan could only probe Doctor Schultz.

Doctor Schultz nodded. "That's true... Anti-Messenger Immersion Agent is indeed hard to get."

He did not suspect much. After all, ordinary people never needed to replace their spinal columns in their entire lives.

"Yes, yes, Anti-Messenger Immersion Agent!" Xiang Shan nodded, pretending to have suddenly remembered. Fortunately, he had neither a face nor skin now, and even his voice synthesizer was a cheap, emotionless model. He did not need acting skills.

—Anti-Messenger Immersion Agent, a term I've never heard before... Messenger molecules, does that have something to do with messenger RNA?

Xiang Shan himself was an engineer. But he vaguely remembered that he had a friend who worked in biology and had discussed related topics with him.

—The Central Dogma: DNA transcribes genetic information into messenger RNA, then messenger RNA translates it into polypeptide chains. The polypeptide chains are folded by organelles and become proteins... Reverse transcriptase? No, probably not...

—Had this process already been reversed even further?

It seemed that technology had indeed continued to advance. That was Xiang Shan's conclusion. In his era, aside from special cases like prions, nearly all life processes basically followed the Central Dogma, the expression process of biological genetic information. It was almost impossible to reverse such life processes inside the cells of an advanced organism.

"However..." Doctor Schultz flipped to the end of the list and looked it over. "I really don't have these parts... These specifications shouldn't be usable for prosthetics, should they? And the final item: sheet metal less than one millimeter thick and under three centimeters wide? If you want those, you'd be better off looking in the scrap parts recycling bins at the eastern end of town."

Xiang Shan explained, "They're for making some... auxiliary tools."

"Judging from this list, you haven't received professional training, have you?" Doctor Schultz shook his head. "Many of your specification formats aren't standard. I don't know what kind of prosthetic you plan to make, but professional martial artist prosthetics are rare things, after all. I don't want you to waste hard-won good parts. How about it? Would you like to go online and look at some blueprints?"

"Go online?" Xiang Shan was startled. He remembered that the Internet had once vanished because of war. He truly had not expected this shabby-looking world to still have something like a network signal.

"Our town is rather poor, so there's no public network signal. But I set up a private one at home. If you sit in the middle of the living room, you should be able to receive it. I can give you a one-time access password..."

At that point, he paused. "But you'd better not download things casually, and don't enable holographic signal previews either..."

Xiang Shan was indeed tempted.

But in the end, he shook his head. "No, Doctor. Thank you for your kindness. The network must be expensive. I can't take advantage of you for nothing."

"That spinal column has already made me quite a bit of money." Doctor Schultz patted Xiang Shan's shoulder. "Besides, you saved my town. I really should thank you."

"No. I'm not used to accepting favors for no reason. If I need it, I'll come back and borrow your network." Xiang Shan still refused Doctor Schultz's offer.

Doctor Schultz did not invite him again. He quickly found all the parts Xiang Shan needed and lent him a set of professional biological tissue surgery tools.

After confirming that Xiang Shan had gone far away, Schultz went upstairs.

The mayor was in one of the rooms upstairs.

"Uncle, he didn't go online." Schultz looked strange. "Why did you tell me to make sure I invited him online?"

Schultz truly did not understand his uncle's request. Still, he had done as told. His uncle was the most knowledgeable person in town. When he was young, he had traveled far and wide and learned certain secrets.

"Dresden..." The mayor called Schultz by name. "Turn off the network first."

Schultz nodded and directly issued a command through his brain-computer interface, disconnecting the household network.

He usually saved on network fees this way anyway.

"Do you know, Dresden?" The mayor seemed to be recalling the past. "When I was young, I offended an official and had no choice but to flee far from home."

Schultz nodded. "That's true, but you were lucky. That official later died..."

"He was assassinated by a knight." After a moment of silence, the mayor said, "I was the one who called that knight here..."

"What?" Schultz screamed.

Colluding with knights was a grave crime against the Dyson Principles!

"I did not collude with a knight. I merely happened to encounter one in the wilderness and asked for help." The mayor snorted. "Your grandfather, my father, once told me that thugs like knights were actually easy to use. As long as you acted humble toward them, they would not make trouble for you. On the contrary, they would assassinate officials they considered guilty for the sake of some twisted sense of honor—they were actually easy to use. That is very important wisdom for our survival."

Schultz exclaimed, "You never told me..."

"That was before... The fewer people who knew this secret, the better." The mayor fell silent for a moment. "But now, things are different. The tax officer only took eighteen infants, fewer than the required proportion. We don't know how he plans to deal with us. We may only be able to rely on the strength of the 'knights.'"

Schultz immediately understood. "You mean... Shan is a knight?"

"I don't know what Mister Shan did before he lost his memory, but I know that all knights have one habit: they do not connect to the network casually. I spent a few days with a knight once. Before going online, they always made lengthy preparations." The mayor lowered his voice. "I don't know whether Mister Shan is a knight. But he can certainly fight—especially after acquiring that martial artist prosthetic body."