"The devils..." Instructor Han paused, choosing his words carefully. "How would one even put it? The devils are a direct byproduct of nuclear mutation combined with the extraterrestrial entities that escaped the crashed mothership in Africa. You see, when a small fraction of humanity survived the nuclear collapse, they didn't enter the bunkers alone; they preserved various animal species as well. Scientists recognized that animals played a vital role in human survival, not just for sustenance, but for ecological balance. Many species of flora were preserved too, though they also mutated.
"The catastrophe began when the escaped aliens actively cross-bred with these surviving animals. These creatures were already undergoing rapid genetic unlocking due to the ambient radiation, but the introduction of alien DNA corrupted them entirely, turning them into absolute abominations."
Han let out a heavy sigh. "The original aliens that fled the wreckage further evolved into our modern S-Class and A-Class devils, while a select few of the mutated earthly animals managed to cross that threshold on their own."
Glancing at the digital wall clock, he let out a sharp hiss. "My time is up. Who has a question?"
A slender hand flew up from the very front row. Han's eyes scanned the hall, settling on the young girl. "Yes, you. What is your question?"
The girl looked visibly nervous at first, but with a reassuring nod from the instructor, she gathered the courage to speak, her voice a little shaky. "Sir, why didn't the surviving scientists contain the animals to prevent them from mutating and evolving? Could they not have found a way to suppress it? If they had, maybe we wouldn't be dealing with devils today."
Half the lecture hall nodded in silent approval of her logic.
Instructor Han sighed, setting his digital tablet flat on the podium. "Humanity was still frantically clawing its way through a ruined world. They were desperately trying to engineer basic solutions against lethal nuclear poisoning. They barely had time for anything outside of immediate self-preservation. This genetic merging was completely unexpected; nobody planned for it, and no one thought it was biologically possible for these aliens to meticulously reproduce with Earth's wildlife."
The young girl nodded, seemingly satisfied with the answer, and sat back down to jot notes into her book.
Because the NHF—and the entirety of modern human civilization—lacked natural timber, cutting down the few preserved forests outside the Great Wall was strictly prohibited by global law to maintain the atmosphere. Consequently, almost all books inside the Wall were made of synthetic paper.
"Class is dismissed. Good luck, recruits," Han announced.
With that, the instructor exited the stage, checking his wrist. He had run exactly two minutes past his allotted time. I seriously need to learn better time management, he muttered to himself.
Outside the lecture hall, the campus of the New Human Federation Military School (NHF-MS) loomed vast and heavily populated. The grounds were meticulously decorated with synthetic flowers that possessed almost no scent. The sprawling complex consisted of pristine administrative buildings and tiered lecture halls representing different military departments. Massive resources were poured into this institution; after all, the military was the vanguard of human survival.
Walking along a paved walkway was a white-haired teenager. He possessed pale skin, sharp, slim features, and a tall frame, outfitted in the standard crisp gray uniform of an NHF military cadet and polished black leather combat boots. He clutched a synthetic textbook tightly to his chest, keeping his gaze firmly averted from the passing crowds. It was the same scrawny boy Instructor Han had noticed lurking in the highest row of the lecture hall.
Graves.
He had been inside the Great Wall for about three months now since the catastrophe in the outskirts. His true identity as a non-talent had remained completely undetected. The academy had conducted no further genetic testing upon his arrival; there was simply no need, as the military brass implicitly trusted the biometric results transmitted from the outer compatibility camps.
When Graves had first arrived, the sheer mechanics of life inside the Wall had left him entirely shell-shocked. Back in his dormitory, there was a mechanized contraption attached to the wall that could seamlessly generate hot water just for him to bathe. Then there were the flat, square screens mounted in the common rooms that projected vivid, moving images. Everything around him during that first week felt profoundly alien. He had even been ordered by his superiors to bathe three times a day, a directive issued with such gravity that Graves originally thought the world might end if he skipped a session.
But if there was one luxury he worshipped above all else, it was the food.
It had been deeply surreal for him to sit before varied, steaming delicacies every single day. Back in the slums, his diet consisted entirely of stringy, toxic devil meat scavenged from carcasses. Eating three square meals a day felt like walking into heaven. For the first time in his life, he didn't feel the gnawing pang of hunger, nor did he feel the desperate urge to join a lawless hunting gang just to risk his life for scraps.
I wish Old Man Lee were here to enjoy this with me, he would often find himself thinking.
Still, he was gradually adapting to the culture shock, especially regarding the automated washrooms. He had recently felt a surge of pride after finally mastering the buttons, remembering how he had mistakenly boiled his own skin during his first attempt. He had also been utterly thunderstruck to discover that citizens inside the Wall considered bathing a private, solitary act—a massive contrast to the public, contaminated rain-catchers of the slums.
Yet, some anxieties refused to fade. Every time the low-flying military jets screamed over the academy rooftops, flying so low the air vibrated, Graves would tense up, terrified the massive metal birds were going to plunge directly into the skyscrapers.