Chen Mang glanced at the train's panel. He still had 10,000 units of iron ore remaining. That 110,000-unit haul had lasted him quite a while.

Without hesitation, he spent 4,400 units to upgrade the [Vehicle Sound System] to Level 10, unlocking its two corresponding Advanced Effects. As a white-grade accessory, it was relatively cheap to upgrade.

[Vehicle Sound System Level 5 Advanced Effect]: If the train is equipped with 'Headlights' and the 'Train Auxiliary AI,' the headlights will automatically change color and pattern in sync with the music, creating a synchronized light show.

[Vehicle Sound System Level 10 Advanced Effect]: Can emit ultrasonic noise above 20,000 Hz. Consuming a higher-level Energy Stone allows for the generation of even higher frequency ultrasonic noise.

The first effect was straightforward enough.

The normal human hearing range falls between 20 and 20,000 Hz—a product of natural evolution. If humans could hear lower frequencies, they would be constantly tormented by the sound of their organs squelching and churning. Anything above 20,000 Hz was inaudible to the human ear.

"Hmm."

Chen Mang pondered for a moment but couldn't think of a practical application for the second effect. Unless, perhaps, certain monsters could hear at extremely high frequencies, allowing him to use the sound system as a sonic weapon against them.

Oh well. Better to have it than not.

He then turned his attention to the [Internal Fire-Control System]. This was currently the only weapon system on the Stellar aimed inward. It was expensive to craft, costing a full 1,000 units of iron ore—pricey for a green-grade accessory.

Upgrading it was also costly. He hadn't been willing to spend the resources before, but now that he was flush with iron, it was time to upgrade everything he had previously neglected.

In truth, upgrading this particular accessory seemed unnecessary. After all, it was aimed at humans, and against humans, a single bullet from a heavy machine gun was lethal, whether it was a Level 1 bullet or a Level 10 one.

The system consisted of several miniature heavy machine guns, with one embedded in the ceiling at the end of each carriage. Like the main machine guns, upgrading it didn't increase its power, but rather its rate of fire, range, and other stats. The actual damage depended on the Level of ammunition loaded. A low-level machine gun couldn't use high-level bullets; to use Level 3 ammo, the gun itself had to be at least Level 3.

So, logically, a Level 1 system should have been more than enough.

The only reason he was upgrading it to Level 10 was to see its Advanced Effects, lest he miss out on something truly broken.

After spending a whopping 45,000 units of iron ore, the green-grade "Internal Fire-Control System" was finally upgraded to Level 10, and two new effects emerged.

[Internal Fire-Control System Level 5 Advanced Effect]: Can fire blank rounds. Consumes 1 unit of iron ore per 10 blanks.

[Internal Fire-Control System Level 10 Advanced Effect]: Can fire neural-shock rounds. These rounds are non-lethal but inflict excruciating pain.

"Huh?"

A look of bewilderment crossed Chen Mang's face. It wasn't because the effects were so powerful, but because...

He had assumed the Internal Fire-Control System, like the Tripod Heavy Machine Guns, would only gain boosts to fire rate and range. He hadn't expected the upgrade to also increase the number of guns.

The Stellar had ten carriages and one locomotive. Originally, there was one miniature machine gun mounted on the ceiling of each. Now, there were ten machine guns on the ceiling of every single carriage.

"..."

Sitting at the console, Chen Mang stared up at the ten machine guns embedded in the ceiling of the control car. The black muzzles were aimed directly at the door, maxing out the intimidation factor.

A riot?

He no longer had to worry about riots.

The Stellar currently had only four external, outward-facing "Tripod" machine guns. But it now had a staggering 110 internal, ceiling-mounted miniature machine guns. With 110 guns ready to fire, they could effortlessly slaughter not just 1,000 rioting slaves, but double that number.

It was the definition of efficiency.

This is insane!

—-

Outside the train.

"Uncle Li, you got a lead?" the young man whispered, sidling up to him secretively.

"Mmm."

Uncle Li's eyes narrowed, focusing on a middle-aged man in the distance. He had found his target. He had observed the man all day. While he worked hard at mining, Uncle Li had noticed him constantly studying the train's external accessories. He didn't know what the man was planning, but he was a dangerous element—a man with ideas.

Just then—

The middle-aged man suddenly broke away from the crowd. He quickly finished his bread and began walking stealthily toward the No. 10 Goblin Carriage, clearly up to no good.

"This is our chance!"

Uncle Li's eyes lit up. He immediately stood and followed, heading for the same carriage. His opportunity to shine had finally arrived!

If he could take the man down the moment he tried to cause trouble, he would surely win Boss Mang's favor. Promotion, status, wealth, and glory would be within his grasp!

"Quick, follow me!"

"Right."

The young man didn't hesitate. He grabbed a rock from the ground, stuffed it in his pocket, and hurried after Uncle Li. At the end of the workday, all pickaxes had to be returned to be handed out again the next morning.

A dozen seconds after the middle-aged man slipped into the No. 10 Goblin Carriage, Uncle Li and his would-be confidant arrived. Heart pounding with excitement, Uncle Li scanned the carriage's interior, ready to catch the saboteur red-handed.

He looked around, but the carriage was empty.

He looked again, more carefully this time, and saw the middle-aged man crawling into one of the refrigerators. The man found a spot near the door, lay down, and prepared to sleep.

"Huh?"

Uncle Li stared, completely baffled. What the hell? He was acting so suspiciously, like he was about to pull something, and he sneaked back to the carriage just to go to sleep?

In a daze, he watched his dreams of wealth and glory shatter. "You're not here to cause trouble?" he muttered, forgetting himself.

"Cause trouble?"

The man lying at the entrance of the refrigerator heard him. He propped himself up, glanced back at the two of them, then settled back down into a comfortable position, his voice thick with exhaustion.

"If you two are planning something, leave me out of it."

"The first time I laid eyes on Boss Mang, the word 'loyalty' was etched in my mind. I would never do anything to harm Boss Mang or the Stellar. I was born to serve Boss Mang, and I will remain loyal until the end. If you're planning to cause trouble, keep your distance from me. I want no part in it; I just want to mine."

"Hmm?"

Uncle Li's brow furrowed. What kind of bullshit is that? he was sneaking around like a damn thief, and now he is spouting nonsense about loyalty?

Just then—

"Uh..." The young man standing beside him poked him cautiously. "Uncle Li," he said meekly, pointing up at the ceiling of the No. 10 Goblin Slave Carriage. "You might want to look up."

Though confused, Uncle Li instinctively looked up. He froze, his face going blank as he fell silent.

After a long moment, he turned and went to check carriages No. 7, 8, and 9. He returned without a word, walked to the edge of the underground river, and stared into the churning water, his eyes filled with despair.

Ten...

Ten of them...

Ten goddamn heavy machine guns, mounted upside down on the ceiling of every single slave carriage, covering every corner with no blind spots. In ten seconds, they could wipe out an entire carriage full of slaves.

It was easier than killing chickens.

He clearly remembered there being only one gun on each ceiling this morning. How had it become ten by the time he got back?

Yes, he understood the logic. The number of slaves had increased, so, of course, more internal firepower was needed to deter any trouble and secure Boss Mang's position. He would have done the same. But wasn't Boss Mang being a little too cautious?

Were there ten internal machine guns per carriage just for deterrence?

Or was it so that if he was in a bad mood one day, he could just reset the board in ten seconds and get a new batch of slaves?

"Uh... um..."

The young man sidled up to him again. "Uncle Li," he whispered awkwardly. "So... are we still going ahead with the plan?"

"..."

This time, Uncle Li remained silent for an even longer period. Finally, he erupted. "Plan? Plan my ass!"

"In this situation, who the hell would dare to cause trouble?! Even the most suicidal idiot would have his legs turn to jelly at the sight of those ten machine guns! There are only four guns on the outside of the train, but over a hundred on the inside! Who the hell would dare to riot?!"

"Mmm," the young man nodded in agreement. "I think you're right. So, new plan. What's the new plan, Uncle Li?"

"What new plan? There is no new plan!" Uncle Li spun around, his face flushed with anger and embarrassment. "You're always asking me for a plan! What do you think I am?"

"My external brain."

"You—"

Uncle Li took a deep breath, turning back to the river crashing against the rocks. He calmed himself and said, each word deliberate, "Don't rush me. Give me time. I'll think of a new plan. Using a clueless rioter to get ahead won't work anymore. Let me think."

"Um... Uncle Li, I have a plan."

"You? Let's hear it."

"Well, I was thinking, the Stellar needs managers now, right? Since there are so many slaves. Why don't you just go to Boss Mang and tell him you have talent and management experience?"

"..."

Uncle Li turned his head slowly, staring at the young man with a deadpan expression. "What do you think?"

"If the world were that simple, everyone would be successful."

"Just wait for my new plan."