"This man is a wily old veteran."

After walking some distance, Lin Yu commented within the Consciousness Sea, "Although his words are harsh, this kind of person is often more reliable than those hypocrites who spout benevolence and righteousness. Following him, at least you won't be inexplicably sold out."

"He was testing my method of receiving the formation plate just now," Su Ming said in a low voice. "He used a clever force, not brute strength. He noticed."

"Good that he noticed," Lin Yu said. "Here, showing your value is more important than hiding your clumsiness. Only when they think you're useful will someone give you a hand when danger strikes."

Stone House Number Seven in the Bing District was located at the very edge of the camp, right next to a section of abandoned city wall.

Pushing open the heavy stone door, the furnishings inside were simple to the extreme. A stone bed, a stone table, and a few meditation cushions piled in the corner. Simple soundproofing and temperature-gathering runes were carved on the walls, but they were already peeling and worn.

No one was inside, clearly a single room, or perhaps the roommate was still on duty.

Su Ming closed the door and checked the interior restrictions.

"Too crude."

Su Ming shook his head. "The defensive restrictions here are full of holes. If someone was eavesdropping outside, it'd be no different from standing right in front of me."

He pulled out several Formation Flags from his storage pouch and skillfully laid down a simplified version of the "Minor Heavenly Cycle Water Rhythm Formation."

As faint water ripples spread across the walls, the noise inside the room instantly vanished, becoming deathly quiet.

"Master, is it safe here?"

"Temporarily, no high-level divine sense prying has been detected," Lin Yu said. "The spiritual energy fluctuations here are too chaotic, which actually provides natural cover. Hurry up and plant that thing."

Su Ming nodded and walked to the darkest corner of the stone house.

He took out his commonly used Mystic Iron small shovel. Without using spiritual energy, he acted like an ordinary mortal, carefully prying open the floor slab and digging down about three feet.

The soil showed an eerie dark red color, hard as iron.

Su Ming took out the beast-skin pouch Mingyue had given him from his chest and poured out a fist-sized fragment shaped like dead wood.

This was the "Wood Demon Core Fragment."

The moment it was taken out, the fragment trembled slightly, as if sensing some rhythm deep within the earth.

"This thing is a good treasure," Lin Yu praised. "The Wood Demon race is most sensitive to vibrations. That girl Mingyue might seem careless, but this gift is truly thoughtful."

Su Ming placed the fragment at the bottom of the hole, then took out a sensing talisman and stuck it on top. He then refilled the soil, covered it with the slab, and finally used a "Mud Transformation Technique" to seal the seams flawlessly.

After finishing all this, Su Ming sat cross-legged on the stone bed, closed his eyes, and lightly pressed his fingers against the ground.

A faint, almost imperceptible connection transmitted through that sensing talisman to his fingertips.

Thump... thump...

That was the heartbeat of the earth, also the faint tremors caused by countless demonic beasts moving underground miles away.

"This is my 'Earth Hearing.'"

A faint curve appeared at the corner of Su Ming's mouth. "With this, any movement within five miles underground won't escape my ears."

"Alright, enough showing off," Lin Yu yawned. "Hurry up and memorize that inspection map Zhao Tiji gave you. The structural diagram of the Big Dipper Seven Stars Demon Locking Grand Formation, even if it's just the tip of the iceberg, is enough for you to chew on all night."

Su Ming gathered his focus, took out the jade slip from the cloth pouch, and pressed it against his forehead.

A massive amount of information instantly flooded his mind.

Countless spiritual energy pipelines crisscrossed inside the city walls, like the meridians of a human body.

As Su Ming looked, his brows gradually furrowed.

"Master, look here."

Su Ming's consciousness lingered on a certain node within the jade slip. "This is the inspection area of the third squad Zhao Tiji is responsible for, located on the flank of the 'Celestial Pivot' position. Logically, this should be a buffer zone for spiritual energy backflow, with the lowest pressure. But..."

"But the data for these backflow pipelines is wrong," Lin Yu's voice also turned serious. "The flow rate is thirty percent lower than the theoretical value. Either the pipes are clogged, or... someone is intercepting the flow downstream."

"Or the formation's foundation is damaged, and spiritual energy is leaking underground," Su Ming added.

Master and disciple exchanged a look (though within the Consciousness Sea).

"Finding a problem as soon as we arrive, what luck," Lin Yu clicked his tongue. "Don't say anything for now. That wily old veteran Zhao Tiji is there tapping and beating every day, he can't possibly not know. If he didn't mention it, either he can't fix it, or... he mustn't fix it."

Su Ming nodded, burying this suspicion deep in his heart.

He continued immersing himself in the complex formation diagrams, like a dry sponge greedily absorbing every bit of formation theory from this monumental grand formation.

Night deepened, the wind outside Iron Wall Pass howled like ghosts and wolves.

And under the dim lamplight in Stone House Number Seven of the Bing District, a young Formation Master held that black iron nameplate, his gaze profound.

"No matter how many rules there are here, no matter how much blood is stained on the formation lines."

Su Ming muttered to himself, "I just want to survive and get those fifty thousand Military Merits."

"Even if I have to pry open the floor tiles of Iron Wall Pass one by one."

...

Morning light had not yet broken through. A layer of bluish-gray mist shrouded the top of Iron Wall Pass's walls.

The Mystic Iron rock beneath their feet transmitted a dull, deep pulse from the earth veins, mixed with the low hum of the light barrier's operation, making their feet go numb.

Outside the wall, the fierce astral winds howled, whipping up black dust—whether ash or sand—that pattered against their protective spiritual light.

Looking out, the distant horizon was shrouded in a turbid haze.

No beast roars, no flames, only a suffocating gloom, as if even light was devoured there.

Zhao Tiji walked at the front, his steps heavy yet rhythmic, each footfall landing precisely in the gaps between the nodes of the formation's spiritual energy flow.

"Forget all those formation diagrams you memorized in your heads."

Zhao Tiji didn't turn around, his voice somewhat fragmented in the wind yet exceptionally clear. "Diagrams are dead, formations are alive. Especially here at Iron Wall Pass, the spiritual pressure changes every moment."

He stopped by a beacon tower, pointing at the flowing spiritual light below. "Watch it. Don't look with your eyes, use your divine sense to touch it, to listen to its flow rate."

Su Ming stood at the side rear of the team, following the instruction and extending his divine sense.

At the edge of the "observation micro state," the originally continuous light barrier decomposed into countless surging rivers in his vision.

"Fast flow rate means there's a blockage downstream; slow flow means insufficient power supply upstream; flickering brightness means the node is gasping, about to give out."

Zhao Tiji turned around, his single eye sweeping over everyone. "What we need to do is clear those clogged blood vessels before this giant beast dies of exhaustion."

This was the "Wartime Spiritual Eye Vein Observation Method" Zhao Tiji taught.

Crude, direct, yet more suited for the battlefield than the complex calculations taught in the sect.