The person who arrived was none other than the Grandmaster of the Path of Formations at Iron Wall Pass, Elder Mo.

The old man was still wearing that plain, faded robe, his hands clasped behind his back. His gaze swept across the warehouse before finally settling on Su Ming's workbench.

"How many have been repaired?" Elder Mo's voice was somewhat hoarse, betraying no emotion.

"Reporting to Elder Mo, today I have repaired thirty-two 'Earthen Shield' formation plates, fifteen 'Blazing Fire Cone' formation plates, and additionally modified twelve warning plates," Su Ming lowered his head and reported truthfully. 𝘧𝑟𝑒𝑒𝘸𝘦𝘣𝑛𝑜𝘷𝑒𝓁.𝘤𝘰𝓂

Elder Mo's cloudy old eyes narrowed slightly as he slowly walked over to the wooden crate.

He casually picked up one of the 'Earthen Shield' plates repaired by Su Ming, his rough fingertips gently rubbing over the healed cracks on the surface of the formation plate.

A moment later, the old man's eyebrows twitched.

"The Water Refining Method?" Elder Mo looked at Su Ming, a flash of surprise in his eyes. "No alchemical fire was used, but water spiritual energy was used to permeate and fuse. This technique..."

"This disciple's spiritual root is water, my fire techniques are not proficient, so I could only find an alternative path," Su Ming said respectfully. "Although it is not as sturdy as fire refining, it has the advantage of not damaging the veins of the formation lines, and... it's somewhat faster."

"Somewhat faster? It's more than just that."

Elder Mo put down the formation plate, a note of appreciation entering his tone. "Fire refining is rigid, but it easily makes materials brittle, unable to withstand a second impact. Your water refining method preserves the material's toughness. On the battlefield, toughness is often more important than hardness."

Having said that, Elder Mo's gaze fell upon the pile of modified warning plates.

He picked one up and gently exhaled a wisp of spiritual energy.

A circle of gentle, watery ripples spread out, instantly covering the entire warehouse.

Elder Mo's expression finally changed.

He looked deeply at Su Ming, as if trying to see through this seemingly ordinary Qi Refining stage disciple.

"Integrating the circulation principle of the 'Minor Heavenly Cycle' into such a low-grade magical implement, transforming rigidity into fluidity." Elder Mo slowly nodded, a faint smile appearing at the corner of his mouth. "Su Ming, this old man indeed did not misjudge you. What you said that day, 'do not seek its source, only observe its momentum,' was not empty talk."

Su Ming felt a slight relief in his heart, knowing he had passed this hurdle.

"This disciple only wished to give his comrades one more chance at survival," Su Ming appropriately expressed a hint of "comradeship."

"A fine sentiment, 'one more chance at survival.'"

Elder Mo took out a cyan jade token from his sleeve and lightly tossed it onto the workbench with a crisp 'clack.'

"Since you have such intentions and such talent, this old man cannot be too stingy. This token grants you access to the side hall of the Spiritual Hub Hall, allowing you to peruse the formation diagrams on the 'Yi'-numbered bookshelf. There are some insights into intermediate formations there, perhaps useful to you."

Su Ming's pupils contracted sharply, and his heart skipped a beat.

The side hall of the Spiritual Hub Hall!

What was stored there wasn't the common goods found outside, but the practical essence left behind by generations of formation masters at Iron Wall Pass, even touching upon the core structures of some intermediate formations.

"Many thanks for Elder Mo's guidance!" Su Ming bowed deeply. This time, he was sincere.

Elder Mo waved his hand dismissively, turned, and walked out. His retreating figure seemed somewhat desolate yet also straight and tall.

"Work hard. The formations of this Iron Wall Pass need a change of blood."

Only after Elder Mo had gone far did Su Ming straighten up, snatch the jade token, his knuckles turning slightly white from the force of his grip.

"Master, with this, I can look up deeper geomancy monitoring formation diagrams," Su Ming lowered his voice, unable to hide the excitement in his tone.

"Don't rejoice too soon," Lin Yu poured a bucket of cold water on him. "That old man is shrewd. Giving you access to the diagrams is also a way to squeeze every last bit of labor out of you. But it's fine, it's mutually beneficial. Go quickly, see if there's anything good that can strengthen your 'Earth Hearing.'"

...

The side hall of the Spiritual Hub Hall.

It was much smaller than the main hall, but also much quieter.

Su Ming, holding the jade token, passed through layer after layer of restrictions and headed straight for the 'Yi'-numbered bookshelf.

His goal was clear—to find formation diagrams related to 'spiritual energy fluctuation conduction' and 'microscopic resonance.'

There weren't many jade slips on the bookshelf, only a few dozen. Su Ming extended his divine sense, rapidly filtering through them one by one.

'Theory of Spiritual Pressure Conduction in the Wind Howl Formation'... too chaotic.

'Geomagnetic Traction Technique'... too heavy.

'Deconstruction of the Cloud and Mist Maze Formation'... too abstract.

Time passed bit by bit, and fine beads of sweat appeared on Su Ming's forehead. It wasn't until his divine sense touched a gray jade slip covered in dust in a corner that a strange fluctuation made him stop.

'Spiritual Resonance Resonance Fragmentary Manuscript.'

Su Ming's heart stirred, and his divine sense instantly sank into it.

This was a fragmented manual about the combination of ancient 'Sound Cultivators' and formations. It discussed how to use specific runes to make two completely different spiritual energy frequencies resonate, thereby achieving the effect of 'locating by sound, sensing across space.'

Among them, a complex rune named 'Spiritual Resonance Resonance' caught Su Ming's attention.

The structure of this rune wasn't as square and rigorous as traditional formation lines. Instead, like sound waves, it presented a form that spiraled outward.

"Marvelous..."

Brilliant light shone in Su Ming's eyes, and he couldn't help but inwardly praise. "The core logic of this rune is to amplify weak vibration signals thousands of times through spiritual energy resonance!"

He had been troubled by the fact that although the 'Wood Demon Core Fragments' buried underground were sensitive, the signals they transmitted back were too weak and blurry due to the excessive distance, making it impossible to accurately locate the specific numbers and digging paths of those 'Earth-Devouring Moles.'

If he could carve this 'Spiritual Resonance Resonance' rune into the core fragments...

"Master, I have a way!"

Su Ming suddenly opened his eyes. Not bothering to wipe his sweat, he quickly committed the structure of the rune firmly to memory, then turned and left the side hall.

...

Late at night, all was quiet.

Stone House Number Seven, Sector C.

Su Ming sat cross-legged on the floor. The stone slab in front of him had been pried open, revealing the hidden compartment buried deep underground.

Inside the compartment, the fingernail-sized Wood Demon Core Fragment was emitting a faint green light, its glow flickering bright and dim along with the vibrations underground.

"Ready?" Lin Yu's figure floated in mid-air, his expression also turning serious. "This is delicate work. Wood demon cores are fragile. If you mess up the carving, this only 'ear' will be ruined."

"Don't worry, I know my limits."

Su Ming took a deep breath, adjusted his breathing, calming his mind until it was as still as water.

He extended the index finger of his right hand, a drop of intensely compressed dark blue water coalescing at its tip. This was his original spiritual liquid refined using the 'Like Water Art,' pure to the extreme.

"Begin!"

Su Ming let out a low shout, his fingertip touching the Wood Demon Core Fragment.

He didn't start carving directly. Instead, he first enveloped the fragment with water spiritual energy, sensing the faint pulse of vitality within it.

That was the pulse of the wood element.

What he had to do was use his own water element spiritual energy as a bridge to 'plant' the 'Spiritual Resonance Resonance' rune into it. Water nourishes wood, allowing the two to perfectly fuse.

This was an extremely mentally taxing process.

Veins bulged on Su Ming's forehead, his eyes fixed intently on his fingertip.

In his 'Observation Micro State' vision, the internal texture of the wood demon core was like a complex maze. He had to control that wisp of spiritual energy, navigate through the maze, avoid all obstacles, and construct a spiral-shaped resonance corridor.

One breath, two breaths, three breaths...

Time seemed to freeze.

Lin Yu didn't dare to even breathe heavily, afraid of disturbing Su Ming.

Finally, as Su Ming's finger trembled slightly, the final stroke of the rune closed.

*Hum—*

The Wood Demon Core Fragment trembled violently. Its originally faint green light instantly surged, then rapidly contracted, turning into a deep, ink-like green.

An invisible wave of fluctuation, following the fragment, madly spread deep underground.

Su Ming only felt a 'boom' in his mind. The previously blurry underground world instantly became clear.

It was like cotton stuffed in his ears being suddenly pulled out.

*Shasha...*

*Zhi zhi...*

*Crack crack...*

Countless subtle sounds flooded into his Consciousness Sea like a tide.

That was the sound of rocks being gnawed, the sound of sharp claws scratching at soil, and even the roar formed by the convergence of countless tiny heartbeats.

Su Ming's face instantly turned deathly pale, his body trembling uncontrollably.

"What's wrong?" Lin Yu asked urgently.

Su Ming slowly raised his head, his eyes filled with unconcealable shock. He opened his mouth, his voice as dry as a traveler who had walked in the desert for three days and three nights.

"Master..."

Su Ming pointed at the ground beneath his feet, his finger trembling violently.

"It's not rats... not a few hundred of them..."

"Down there... is a river."

"A river composed of Earth-Devouring Insects... a living river."

In his perception, those densely packed red dots were flowing along the direction of the earth veins like black blood, madly flowing and gnawing beneath the very foundations of Iron Wall Pass.

And the direction of that flow was precisely aimed at the most critical 'Heavenly Pivot Position' of the pass.

Compared to this, the ground collapse in Sector D three years ago was nothing but a minor incident.