Since they had already been gathered into an army, they would certainly be discovered if they were to move together. Most of the soldiers hid in the forsaken towns and mines not far away from the “Great Iron Plants” and would turn into a surging torrent below the ground at an order.

Only Long Yangjun, Li Yao, Li Jialing, and the few experts in the army were bold enough to approach the Great Iron Plants and contact the local Nepenthe believers who were directly commanded by the Grand Guardian.

The underground worlds were essentially a giant maze made of countless caves that were connected through tunnels and gaps. Theoretically speaking, it was easier to defend than to attack. As long as an elite troop was sent to block the critical tunnel between two caves, nobody would be able to move between the two places.

However, the Great Iron Plants was a developed mining area that had been operating for a hundred years. There were simply too many complicated, interconnected holes and channels. Even the most experienced miner might not know where exactly a deep, dark branch inside a certain tunnel led to.

In the meantime, in order to transmit fresh air and clean water from the top to the bottom, and to ship the precious resources from the bottom to the top, tremendous ventilation and logistical systems were required.

In the past tens of thousands of years, the demons had built such tube systems, and so did the Star Ocean Imperium and the Star Ocean Republic. Naturally, the Imperium of True Human Beings was not an exception either.

The tube systems abandoned by the previous regimes became the best shortcuts for the secret march. It was impossible to catch them with the few Immortal Cultivators in the area.

Among the Nepenthe believers, there were old miners who had spent their entire lives with rocks. Li Yao was also an unparalleled expert when it came to traveling in ventilation tubes. They crawled from the cracks into the ventilation tubes, from the ventilation tubes to the tunnels, and from the tunnels to an abandoned cave that had been drained decades ago smoothly without meeting any trouble.

According to the regulations of the excavation industry in the Imperium of True Human Beings, caves that had been completely drained must be filled with rocks and rapidly-consolidating liquid metals to ensure the stability of the entire tectonic structure and to prevent the massive collapses and tectonic movements from affecting the worlds of Immortal Cultivators on the ground.

However, the cost to refill the rocks was very high. For the greedy, corrupted Immortal Cultivators, the regulations were nothing but nonsense. The Black Iron Group was under the name of the Dongfang family at the beginning. The capital was not the Dongfang family’s territory. Why would Li Minghui care about the regulations at all?

Therefore, the Great Iron Plants was surrounded by dark, empty caves that had been abandoned. The Nepenthe believers spent a few years digging through most of the caves before they covered the caves with disguises carefully. The rocks in the area were like a tree that had been hollowed by ants. They were full of holes inside but showed nothing outside.

Li Yao and Long Yangjun crawled out of the depths of such a cave. They had bypassed the guards of the Black Iron Group and appeared on the rocks not far away from the Great Iron Plants.

Wearing the gray cape, everybody seemed to be melted with the rocks nearby. As they observed the general picture of the Great Iron Plants from the high stance, the first thing that could be seen was naturally the well of magma at the center of the factories, which looked like an erupting volcano.

The torch that was ignited by billions of fires was burning and screaming furiously. Although they were several kilometers away, they could still sense the scorching heat. Sparks seemed to be splashing on their faces when they blinked.

According to Long Yangjun, below where the Great Iron Plants was at was a place where three mother lodes of fiery spiritual energy were gathered. They could yield the very intense and stable spiritual energy of the fire class. In the terms of the modern Cultivation civilization, there was a magma belt below the Great Iron Plants, which had a super high temperature, a super high pressure, and a very steady tectonic structure. Also, since there were a few rare mines nearby that had a high reserve and an excellent quality, a lot of purification factories were established on the spot to refine the minerals with the geothermal energy. The raw minerals would be shipped to the surface of the planet after they were refined into concentrates. In such a way, the cost would be significantly reduced.

Li Yao looked far away and did see the geothermal factory that was constructed around the well of flames, as well as the mines, purification factories, and fashioning factories that were based on the geothermal factory. There was also a factory that produced the components of magical equipment.

The refining furnaces large and small rose all the way to the dome of the space like cold giants, making the underground space that was supposed to be spacious rather suffocating.

The trickiest problem for underground refining was not the water but the discharge of poisonous wastes. Li Yao noticed that a lot of giant tubes with powerful attraction forces were distributed on the dome and the wall of the Great Iron Plants. They were pumping the black air that was so dirty that it was almost consolidating without any stop. After multiple filtering procedures, the toxins were all screened out and compressed into very small cubes, and the air that had been cleaned would be provided back.

Although the thousand most powerful air cleaning devices for industrial purposes were working at the highest efficiency, the air was still filled with all kinds of choking flavors. Even Li Yao felt slightly uncomfortable, as if somebody had stuffed two clusters of hybrids of rubber and asphalt into his nostrils. He truly wondered how the workers and their families could handle it.

“In fact, the Imperium of True Human Beings is just like the New Federation before your return. A lot of demon workers are used here. To be more exact, the ‘demonic cells’ inside the body of the bottom-level workers are activated through all kinds of drugs, giving them a myriad of uncanny ‘abilities’ that have severe side effects.”

Long Yangjun said in a low voice, “Or rather, ever since the demons’ reign collapsed ten thousand years ago, humans have never stopped enslaving demons at the center of the cosmos. Leaving aside the high-level demons, the strong and sturdy low-level demons are the best labor force. Who could’ve been determined enough to slaughter all the ‘livestock’? Wouldn’t it have been a great waste?

“Of course, to defend the dignity and pride of mankind, and for ‘humanitarianism’ reasons, the simple and crude approaches to completely transform humans into bizarre-looking demons are rare today. However, to partly modify the organs inside a human body or to let the human beings with certain demonic genes to mate according to the principle of ‘eugenics’ so that offspring with certain functions may be produced, just like how pet dogs are bred, has never stopped.

“For the workers living inside the heavily-polluted factories below the ground, their respiratory system is more like demons than like humans, which allows them to survive and work in the heavily polluted area.

“But the advantage comes with a cost. The demonic genes can only help improve their working abilities in their prime years, but they cannot stop the lethal heavy metals from accumulating inside their bodies. The final result will be a significantly reduced longevity and the possible damage to their intelligence. For the owners of the factories, that is not exactly a ‘cost’ at all. After all, they do not need the miners to live to the end of their natural lives or to have a high intelligence. It will be easier to control the workers if they are dumber.”

Li Yao was both scared and infuriated. “Those Immortal Cultivators are truly unbelievably sordid!”

“I’m afraid that you are wronging the Immortal Cultivators.”

Long Yangjun said coldly, “The Immortal Cultivators are just the successors of the practice, not the founders. Back in the Star Ocean Republic, those sanctimonious Cultivators built ‘model factories’ on the surface of the planet during the day, and such factories were beautiful and full of flowers and birds. But below the ground where the sunlight could not reach, weren’t they doing exactly the same thing? After all, since the demonic genes of those workers had been activated, they could be considered to have been corrupted by demons, or simply a part of demons.

“Demons are the greatest enemy of mankind. Then, neither the Cultivators nor the Immortal Cultivators should have any guilt when enslaving the ‘demons’, right?”

Li Yao was silent. He suddenly wanted to appreciate Jin Xinyue for what she had done in the past hundred years.

If it weren’t for her resistance with the demons, would the Star Glory Federation have kept so many cruel factories like those here today?

They were certainly not the things that should exist in Li Yao’s dream world!

Apart from the fatal gas, the deafening noises raised by the thousand air-cleaning devices when they were functioning with the full power also hovered above the Great Iron Plants incessantly like thousands of snakes that were dripping venom, finding a way into everyone’s ears.

Li Yao tried concealing his spiritual energy to the minimum and just resisting the noises with his tough body. But very soon, his mouth was dry, his heart was racing, his back was covered in sweat, and his veins were bouncing. Countless dark and bloody thoughts popped up in his heart.

“How about it?”

Long Yangjun said with a smile, “You should understand now why so many people are crying, screaming, and begging me to practice the Serenity Arts, shouldn’t you? It will certainly be worth it if the skill can do nothing other than to resist the ceaseless noises!”

Narrowing his eyes, Li Yao observed the air cleaning magical equipment above his head that was running stridently. He shook his head and said, “This is unreasonable. Even though it may be a high-power air cleaning system for industrial purposes, as long as it is carefully produced and regularly maintained with the replacement of quieting pads, such earsplitting noises will be impossible. There’s no reason why the Imperium of True Human Beings cannot resolve the problem that even the Star Glory Federation can take care of!”

“Like you said yourself, it needs to be ‘carefully produced’ and ‘regularly maintained with the replacement of quieting pads’. Each replacement will mean that parts of the factories have to be shut down. The cost is very high, alright?”

Long Yangjun said, “Compared to such a high cost, it will be a lot cheaper to simply offer three headsets to every worker and their family every month. Which approach do you think an Immortal Cultivator like Li Minghui will adopt?”

Li Yao frowned. “The air cleaning system is running all the time, which means that the noises will not be away for a single second. Wouldn’t it be very inconvenient for the local residents to talk to each other with their ears stuffed every day?”

“Such an inconvenience can’t be better!”

Long Yangjun said, “They might as well not talk and just shut up and work for the Immortal Cultivators diligently. Wouldn’t that be much greater?”