My Apocalypse System Arrives 10 Years Early

Chapter 579: Chapter 358: A Tragedy Caused by an Excrement Explosion

”Let’s go, then.” Kanna stood up and led everyone out immediately. After all, they had no luggage to pack. For wanderers, leaving was as simple as deciding to go.

The ”Oasis” they were in was the habitat of the Black Fire Profound Crows. The firelight and warmth made the area ”vibrant with life.” But it was also fraught with danger.

Kanna glanced one last time at her homeland, then resolutely led her people into the cold and darkness. In her pocket was a compass with a broken case, which she had retrieved from the stomach of an Exotic Beast. Along with it were some half-digested human belongings, but only the compass was still barely usable.

They hadn’t gone far before they had to stop again. An ”old man” simply couldn’t walk any further. He was in his forties, but looked as haggard and aged as someone in their fifties or sixties.

Kanna used her Earth Superpower to dig a temporary Shelter, and everyone hid inside.

She went out again to find some edible plant tubers. Along the way, she ambushed a lone, injured Exotic Beast. Seeing that it was likely not poisonous and was edible, she hacked off one of its legs and dragged it back. Bringing the whole carcass was impossible; it was too large and would have hindered her movement.

The remaining corpse was left behind, where it could attract the attention of other Exotic Beasts or some of Earth’s other mutated creatures.

When she returned to the Shelter, everyone was ecstatic to see they had Exotic Beast meat to eat.

The leg weighed dozens of kilograms, enough for everyone to have a full meal. Although the meat was tough and tasted awful, it was more nutritious than plant tubers.

Additionally, the foot had four sharp claws. Kanna fashioned them into spears and distributed them to the able-bodied young adults in the group.

Along the way, Kanna also collected some ”Sun Bones”—the skeletons of dead Black Fire Profound Crows. These bones were rich in heat and could be held for warmth. However, they had to be wrapped in multiple layers of cloth to prevent burns.

The bones also emitted the aura of an Exotic Beast, causing other beasts weaker than the Black Fire Profound Crows to give them a wide berth.

Throughout their journey, Kanna relied on her Earth Escape Superpower to find food and help everyone escape disaster multiple times. She felt very fortunate that the superpower she had awakened was so practical. While some Exotic Beasts could burrow, they didn’t possess Earth Escape.

Those burrowing Exotic Beasts simply dug at the ground with their claws to tunnel through. It wasn’t true Earth Escape. As a result, their digging speed was slow, and they couldn’t go very deep.

She had escaped disaster on several occasions by using her power to go deep underground.

In fact, many Exotic Beasts in the vast Black Mist Star Realm could use Earth Escape. However, those skilled in the ability were generally poor at long-distance interstellar travel. That was why these Exotic Beast races had not followed the grand army to the Solar Element.

As for the Divine Tier and Divine King Realm beings submerged deep within the Moon and Earth, that was because upon reaching the ”Divine” Tier, one gained the ability of ”Divine Communication.” They didn’t need to learn Earth Escape; it came naturally.

This was especially true for the Divine King Realm. Not only could they use Earth Escape, but they could also escape into the ”Dark Universe.” Deep in the Earth Core, the Divine King Realm Exotic Beasts fought over the ”Sovereignty of Earth” within the Dark Universe, because the ”Sovereignty of Earth” (the Heart of the Earth) was hidden there.

Even though Kanna was agile and quick-witted, losses along the way were still unavoidable. By the time they had traveled more than a hundred kilometers, the group had shrunk from thirty-seven people to twenty-nine—a loss of eight people!

’By the time we reach the Holy City, there probably won’t be many of us left. We might not even make it there at all.’ Kanna sighed softly. She had her people hide in a temporary Shelter, reinforced its cover, and told everyone to lie low. Then, she set out again to find food.

This time, her luck was better. She happened to stumble upon an Underground City on the China-India Border.

She used Earth Escape to sneak into the city and stole some food, warm clothing, and a few lighters and flashlights.

However, this Underground City was occupied by the Upper Caste, who were strictly cracking down on the Lower Caste, especially the Dalit untouchables. Any who were found would be exiled or killed.

’My people can’t get in. Otherwise, I could bring them inside and we could try to eke out a living in this Underground City. Or I could leave them here, go find Li Sheng alone, and come back for them after getting his permission. But clearly, that’s not realistic.’

An idea suddenly struck Kanna. She disguised herself, slipped into a district with a signal, and went online using her old Communication Device. This was an Indian Underground City, after all, and its infrastructure wasn’t particularly good—unlike the Underground Cities in China, where nearly every nook and cranny had network coverage.

Kanna sent an email to one of Li Xiang’s public addresses. With a ”just-give-it-a-shot” attitude, she humbly introduced herself, explained her past connection to him, and expressed her admiration. She added that she was leading a group of her people on a thousand-mile journey to seek refuge with him, hoping to arrive safely and meet her idol soon.

After sending the email, she sighed. ’I wonder if Li Xiang will even see it. And even if he does, will he pay it any mind? Would he send a team to come get me?’

’Heh, I’m probably overthinking it. Li Sheng is so busy, why would he notice a nobody like me? Even if he sees the email, he probably won’t care. And he’d certainly never send anyone to help. I’m so naive.’ Kanna knew, deep down, that this was a useless effort. But she just had to try.

’It would be wonderful if Li Xiang could come and save me and my people.’

Her people had spoken of making a pilgrimage, but the road was long and perilous. If she were alone, she’d be seventy or eighty percent confident she could reach City No. 03. But leading about thirty ordinary people, there was absolutely no chance.

They hadn’t even covered a tenth of the distance yet, and eight people had already died.

It was just that staying cooped up in that place was also a death sentence. That’s why she had led them to set out. This way, with a persistent thought (hope) in their hearts, maybe everyone could hold on a little longer.

’Maybe we should just live on the outskirts of this Underground City? I could sneak in every day and steal a little food to keep everyone alive.’

Just as Kanna had this thought, the entire Underground City suddenly shook. The RUMBLING sound of an explosion echoed up from the lower districts. Startled, Kanna quickly activated her superpower and fled at top speed. Since she was already on the outskirts of the Underground City and hadn’t entered the core area, her escape was swift.

Even though she was fast, the massive shockwave still hit her, making her chest tighten as she coughed up a mouthful of blood. Back at the temporary Shelter, everyone was in a panic, not knowing what had happened.

”Could it be? Was that Underground City attacked by Exotic Beasts?”

”No way. There was no warning at all. It was clearly an accident.”

Kanna had guessed correctly. It really was an accident in the Underground City. However, it was an accident of a kind she never could have imagined, not even in her wildest dreams.

’This is bad. The Underground City has probably been exposed. It’ll be attacked by the Exotic Beast Army soon. I have to lead my people away from here, quickly.’ Kanna reacted fast. Ignoring her injuries, she glanced at her compass and immediately led everyone onward, continuing east.

Sure enough, not long after they left, an overwhelming Exotic Beast Army swarmed in and began to lay siege to the Underground City.

Plagued by internal turmoil and external threats, the Underground City didn’t even last an hour before it was breached by the Exotic Beast Army and turned into a living hell.

As for why the explosion had suddenly occurred, not even Jiang Cai’Er, whose Eye Liners were spread throughout the Underground City, could find the cause.

And after the Underground City suffered a massive explosion and a large-scale Exotic Beast invasion, it was destroyed. Almost all personnel were wiped out, and the network and cameras all went ”offline,” making it even more impossible to investigate.

In reality, this is what had happened at the time:

The rulers of this Underground City, the Upper Caste, had been slaughtering or expelling the Lower Caste en masse. This led to a labor shortage for menial jobs. As a result, feces began to accumulate more and more. In just one or two months, tens of thousands of tons of it had collected in the cesspool at the bottom of the city.

Tens of thousands of tons of feces piled up and fermented, producing an extremely high concentration of methane. The ventilation system was also in disrepair and broken, allowing the gas to become increasingly dense.

Biogas is primarily produced by the anaerobic fermentation of organic matter. Its main component is methane (CH4), typically making up 50-70% of its volume, followed by carbon dioxide (CO2) and other gases like hydrogen sulfide.

Among these, methane is the main flammable component. Other gases, such as hydrogen sulfide, are toxic, and inhaling too much can be fatal.

According to some sources, each ton of organic waste (such as feces) can produce approximately 20-30 cubic meters of biogas during anaerobic fermentation, with a methane content of about 50-70%.

Let’s assume an average value—say, 25 cubic meters of biogas per ton of feces, with a methane content of 60%. The total biogas production would then be 50,000 tons × 25 m³/ton = 1,250,000 cubic meters of biogas. The methane portion would be 1,250,000 × 0.6 = 750,000 cubic meters.

The heat of combustion for methane is approximately 55.5 MJ/kg, or about 15.4 kWh/kg. The density of methane under standard conditions (0°C, 1 atm) is approximately 0.717 kg/m³. Therefore, the mass of 750,000 cubic meters of methane is 750,000 × 0.717 kg ≈ 537,750 kg, which is about 537.75 tons of methane.

The total combustion energy of the methane is 537,750 kg × 55.5 MJ/kg ≈ 29,840,625 MJ.

One ton of TNT is equivalent to about 4.184 GJ (or 4184 MJ). Therefore, the total TNT equivalent is 29,840,625 MJ ÷ 4184 MJ/ton ≈ 7,130 tons of TNT.

Of course, not all the biogas would be fully combusted or detonated upon ignition. But even if we take just one-tenth of that, it’s equivalent to 713 tons of TNT. Two-tenths would be 1,426 tons of TNT.

For comparison, a small tactical nuclear weapon (like the United States’ W54 warhead) has a yield of about 1,000 tons of TNT.

At that moment, in a district near the bottom of the Underground City, a man from the third caste went to use the toilet with a cigarette dangling from his lips. He noticed a strange smell but could tolerate it. It was a dry latrine, after all, and he was used to them from back in the age of peace.

In India, proper toilets were scarce even in the age of peace; dry latrines were everywhere.

After the man squatted down, he flicked his lighter, intending to light his cigarette. But he never could have imagined that with a FWOOSH~, he had just ignited the biogas.

Instantly, a massive combustion and explosion occurred!

Furthermore, it happened in the relatively enclosed space at the very bottom of the Underground City, so the force of the explosion may have been even greater than that of a small tactical nuclear weapon.

This kind of Underground City was already cramped, and the construction quality of the Indian Underground City was mediocre at best. And so, disaster struck.

In truth, incidents in underground cities caused by safety hazards like fires were not uncommon in any country. But one caused by an exploding mountain of feces? That was truly a first.