To the west of the main vein cavern, the earth was honeycombed with countless tunnels. Like a complex, three-dimensional spiderweb, these passages wove through the bedrock, connecting to smaller satellite caverns in the distance.

Some were deep, some shallow; some vast, others cramped. Together, they formed the skeletal structure of Wu Yuan’s underground empire.

Wu Yuan ran the numbers in his head. Including the peripheral caverns, his territory now spanned over 1,000 mu—roughly the size of a university campus back on Earth.

Beyond the core vein, the rat demons and common rats had excavated their own living quarters. The real estate hierarchy was simple: the closer a burrow was to the main vein, the denser the Spiritual Qi, and the stronger the inhabitants.

It was a thriving ecosystem. The outer perimeter fed into the core, contributing resources and labor to Wu Yuan’s growing ambition.

Lieutenants like Big Old Black commanded massive fiefdoms of their own. Black’s personal cavern spanned nearly 100 mu and boasted its own dedicated Moon Spirit Grass plantation.

As for the population? It had exploded like a geyser.

Even after accounting for the brutal attrition rate of Wu Yuan’s relentless work schedules, the colony now exceeded 100,000 common rats. The elite corps of rat demons—those who had successfully awakened Spiritual Qi—numbered nearly one hundred.

Every rat had a hole. These burrows were scattered like stars across Little Green Mountain, hidden in root systems, buried under boulders, or dug deep into the clay. It was a vast, subterranean neural network.

And thanks to the Spirit Mulberry’s roots, that network was online.

Wu Yuan could transmit orders instantly. His grip on the ore vein was absolute, and his influence over the mountain was spreading like a plague. He was racing down the path to becoming the undisputed Underground King of Little Green Mountain.

With a steady supply of Spirit Plants and a self-sustaining cycle of resources, his “family business” was finally solvent.

Standing on the polished stone platform overlooking his domain, Wu Yuan felt a surge of emotion. His chest swelled as he surveyed the bustling activity below.

I’ve been in this world for a year, he thought, his mind drifting. Finally, I have a foothold. For now, I hide in the dark, burying myself in cultivation. But one day… one day I will walk in the sun, and they will bow and call me ‘Daoist Rat’.

One month later.

Silence fell over Little Green Mountain.

The vibrant sounds of the forest were strangled by a howling wind that carried a palpable aura of killing intent. Overnight, the world had been cloaked in silver.

Winter had arrived, not with a gradual cooling, but with the sudden violence of a executioner’s blade. It was a season of “dripping water freezing instantly, and breath turning to frost.”

In this white hell, traces of ordinary wildlife vanished. Only spirit beasts with cultivation bases strong enough to burn Qi for warmth could survive the biting cold.

Wu Yuan hadn’t expected the season to turn so abruptly.

He stood at the entrance of his tree-root hut, peering through the translucent barrier of the [Blood-Binding Mystic Silkworm Formation]. Outside, the world was a blur of white death. Inside, thanks to the array, the temperature remained cool but livable. The rats simply retreated underground, safe in their warm tunnels.

“I wonder how long this will last,” Wu Yuan muttered, a frown creasing his brow. “I hope it isn’t like the spring—a year-long winter would be disastrous. This mountain is getting stranger by the day.”

Bibo waddled up beside him, his usually cheerful face etched with worry.

“Great King,” the otter said, his voice low. “For now, the attacks on the outer spirit lands are sporadic. But if this cold persists… desperation will set in.”

Bibo gestured to the white void outside. “Starvation and frost are powerful motivators. Soon, every beast on the mountain will realize that our valley is the only place with warmth and food. We will be a beacon in the dark.”

Wu Yuan nodded slowly. He wasn’t worried about supplies. His territory was practically overflowing with food.

The rat demons feasted on Snake Tooth Rice, while the common hordes subsisted on a variety of subterranean fungi. Since taking over the cave, Wu Yuan had assigned Xiao Huang, the agricultural specialist, to selectively breed high-yield mushrooms.

The results were… unique.

Take the “Meat Mushroom.” It looked like a grey stone, but if you poked it, the thing wriggled with the disturbing texture of raw muscle. It grew aggressively—hack off half, and it would regenerate overnight. It needed only a pinch of dirt to survive.

True, it was slightly toxic. But Wu Yuan had spun that into a positive feature.

“The toxicity isn’t a flaw in the food,” he had told a hesitant subject. “It is a flaw in your constitution. Eat up. It builds poison resistance.”

Then there was the “Insect-Pot Mushroom,” shaped like an earthen basin filled with sweet, sticky spores. It acted as a natural trap for subterranean insects, providing the rats with occasional protein snacks.

To maximize efficiency, Wu Yuan had implemented a “Colonial Expansion Policy.” Every adult rat was given a starter kit of spores and kicked out of the nest to dig their own burrow. As they spread, the Spirit Mulberry roots followed, extending Wu Yuan’s sensory network and reducing the population density in the main cavern.

It was a perfect system.

With the ore vein as the capital, the Peach Forest and Bamboo Grove as transit hubs, and the various Middle Grade spirit lands as fortified outposts, Wu Yuan had effectively checkmated the mountain.

He controlled every significant source of Spiritual Qi.

“I have to thank that Giant Bird Demon,” Wu Yuan mused, watching the snow swirl against the barrier. “If it hadn’t eaten 90% of the local competition before it left, I never would have conquered these lands so easily.”

He had exploited the time gap perfectly. The bird had cleared the board of high-level threats, leaving a power vacuum that Wu Yuan’s swarm had rushed to fill. The new generation of spirit beasts was still young and weak—no match for an army of 100,000 rats.

Now, his legions guarded every resource node day and night.

The wandering beasts of the mountain could only watch from the freezing shadows, eyes green with envy, coveting the warmth and Qi of Wu Yuan’s lands. But they dared not attack.

Bibo and Big Old Black patrolled the perimeter constantly. Any “thorn” that poked its head out was swiftly removed.

But order came at a price.

The “Beast Tides” were becoming frequent. Driven by the instinct to cultivate—and now, the instinct to not freeze to death—loose coalitions of desperate monsters would throw themselves at the rat swarm’s defenses.

So far, they had all been repelled.