Before him, the Rank 1 Mud Skin Gu and the Rank 1 Grey Stone Gu floated slowly in midair, enveloped in Rank 2 Red Iron Primeval Essence.
These were the two primary materials at the heart of refining the Rank 2 Earth Birth Gu.
According to the theory Lin Mu had run through his mind countless times, what he needed to do now was split his focus.
He had to maintain an absolutely smooth and precise output of Primeval Essence to simultaneously suppress and guide the two Gu worms' entirely different, faint wills, forcing them to gradually dissolve and merge under the weight of that essence.
Theory is always perfect and full of promise.
Reality dealt this fledgling refining apprentice a sharp blow to the head.
Crackle——
The moment the Red Iron Primeval Essence forcibly compressed the two Gu worms' wills, a needle-sharp pain stabbed through Lin Mu's mind.
His inexperienced micro-control was nowhere near absolutely smooth.
Despite his best efforts, the Primeval Essence output wavered by the smallest margin — a fraction too heavy on the Mud Skin Gu's side, a hair too light on the Grey Stone Gu's side.
That infinitesimal imbalance, in the microscopic world of Gu refinement, was enough to trigger a tsunami.
The two Gu worms' already incompatible wills collided violently in midair, lashing back against each other.
"Not good."
Lin Mu's pupils contracted.
Before he could move to the next step — feeding Primeval Stones into the unstable fusion mass as fuel to neutralize the conflict — the faint ball of light that had barely begun to take shape expanded with visible, violent instability.
Bang!
A muffled explosion rocked the chamber.
The light mass shattered. The shockwave, laced with Primeval Essence backlash, struck Lin Mu in the chest and sent him stumbling back a step.
Clatter.
The remains of the two Gu worms dropped lifelessly onto the hard stone table.
The brutal cost of failure was laid bare in an instant.
The Mud Skin Gu — the primary base — had its shell completely shattered. It dissolved on the spot into a puddle of foul-smelling, reeking liquid and ceased to exist entirely.
The Grey Stone Gu had barely survived with its body intact, but its surface was riddled with dense cracks, its luster extinguished to the point of near-darkness. It was clearly heavily damaged — rendered a useless husk for the foreseeable future.
The first refinement attempt ended in a catastrophic furnace explosion.
Dozens of Primeval Stones' worth of materials, gone in less than ten breaths. Not even a full sound to mark their passing.
But Lin Mu looked at the wreckage on the table and felt neither the urge to curse nor any trace of discouragement.
He simply drew a long breath and carefully cleaned away the filth and residue.
"Knowledge gained from books is always shallow. True understanding only comes from doing."
Lin Mu stared at his own faintly trembling hands and murmured to himself, a deep reverence in his eyes.
"Knowing the formula and memorizing the theory is one thing. Being able to shape it into reality with Primeval Essence, without a single deviation — that is something else entirely."
The image of Fang Yuan's effortless, almost artistic refinement technique surfaced unbidden in his mind.
"He could refine high-rank Gu worms with his eyes closed in the most desperate circumstances. That was five hundred years of muscle memory, built in a sea of corpses and blood, through an incalculable expenditure of resources."
"I'm nothing but a novice. Expecting to succeed on the first try? That's the dream of a fool."
No wasted emotional energy.
Lin Mu closed his eyes and began replaying every detail of the failure in his mind with frenzied focus, cross-referencing each moment against the descriptions of Gu refinement in the original story.
"The Primeval Essence output must never falter — it has to be absolutely steady, like drawing silk from a cocoon."
"Splitting focus is the core. There can be no priority between the two — the balance must be perfectly even."
"The moment the light mass begins to contract and the wills approach the point of collapse, the timing of feeding Primeval Stones as catalyst cannot stall for even a tenth of a second..."
After chewing over these critical points dozens of times in his mind, Lin Mu did not immediately reach for the second set of materials.
He sat cross-legged, letting the Red Iron Primeval Essence circulate freely through his Aperture, spending a full shichen restoring the mental energy he had burned through in that state of extreme concentration.
Sharpening the axe does not delay the woodcutting.
He had prepared five sets of cheap practice materials. The one thing he was not short on was chances to fail.
Several shichen later, the breathing in the chamber once again became faint as a thread.
Lin Mu opened his eyes. His gaze was calmer than before.
He reached to the left side of the stone table and took out the second intact set of Mud Skin Gu and Grey Stone Gu.
The second refinement attempt began.
This time, with the painful lesson behind him, his Primeval Essence control was noticeably steadier.
The pale-red Red Iron Primeval Essence moved like two immensely gentle yet irresistible hands, enveloping the two Gu worms.
Under the smooth, even suppression, the wills of the Mud Skin Gu and Grey Stone Gu still struggled — but they did not clash violently.
Before long, the outlines of the two Gu worms blurred within the Primeval Essence and successfully merged into a basin-sized mass of soft white light.
"Hold steady..."
Fine beads of sweat broke out across Lin Mu's forehead. His eyes were locked onto that white mass.
The most critical step had arrived — feeding the fuel.
He freed his left hand and grabbed a fistful of crystalline Primeval Stones from a hidden compartment without looking, dropping them one by one into the floating mass of light.
Hiss! Hiss!
The moment each stone entered the light mass, it was like ice falling into boiling water.
The raging Dao Mark energy instantly drained every trace of heaven and earth essence from it, dissolving it rapidly into a fine grey-white powder that drifted downward.
As the Primeval Stones were fed in one after another, the basin-sized mass of white light began to contract sharply.
Bowl-sized... apple-sized...
The fusion of wills inside the light mass had reached its most intense and most fragile threshold. The white light grew blindingly bright — like a miniature sun on the verge of detonation.
In the final moment, as the light mass contracted to the size of a fist and was on the verge of fully crystallizing —
Lin Mu's mental energy, strained by the prolonged and terrifying degree of concentration, finally gave out. His consciousness slipped — just barely, just for an instant.
The Primeval Essence stuttered by half a beat.
Bang!
Without any suspense, the balance inside the light mass broke in an instant.
A muffled explosion louder than the first tore through the chamber. The blinding white light shattered like broken glass.
The second refinement attempt ended in failure once again.
This time, both Gu worms were critically wounded, hovering on the edge of death.
The shockwave knocked back Lin Mu's hood. His face had gone pale, and a thin line of blood seeped from the corner of his mouth — the mark of the backlash.
He did not wipe it away.
Instead, in the dim chamber, the light in his eyes grew brighter and brighter — more and more fervent. A fierce, almost savage grin pulled at the corner of his mouth.
"That's it..."
Lin Mu stared at his own hands, trembling faintly from the Primeval Essence drain. "I touched it. That line — that point of equilibrium where Primeval Essence and will intertwine."
He could feel it clearly. He was only the thinnest layer of paper away from breaking through.
Time lost all meaning in that sealed underground room.
A full day and night passed.
The floor of the chamber was blanketed in a thick layer of grey-white Primeval Stone powder — deep enough to swallow the soles of a shoe. It was the remains of hundreds of Primeval Stones, drained of every last drop of their essence.
Three of the five cheap practice sets on the stone table were gone.
Now.
Lin Mu's eyes — threaded with terrifying red veins — were locked onto the violently churning mass of white light in midair.
His face was paper-white. His hair was soaked through with sweat and plastered to his forehead. He looked like a gambler who had not slept in three days.
But his mind was in a state of absolute, all-consuming focus — frenzied, stripped of every stray thought.
The fourth attempt.
The fourth set of materials hung suspended in midair. After three failures, Lin Mu's Primeval Essence output had finally reached a strange and wondrous state.
Smooth as silk. Unbroken as flowing water.
The light mass held steady in midair, showing no sign of collapse.
"Feed the stones."
Lin Mu's left hand became a blur — mechanical, precise — dropping Primeval Stones into the light mass one after another.
Dissolving. Contracting.
Basin-sized, to bowl-sized, to fist-sized...
The white light had grown so blinding that Lin Mu was forced to squint. But his hands did not hesitate for even a hundredth of a second.
Every moment of feeding a Primeval Stone was a perfect replica of the timing he had run through in his mind hundreds upon thousands of times.
"Last one."
Lin Mu held his breath. His heart seemed to stop beating entirely. He drove the final Primeval Stone in his hand hard into that fist-sized mass of extreme radiance.
Hummm——!
No explosion. No backlash.
After swallowing the last Primeval Stone, the blinding light mass imploded with a sudden, violent inward contraction — and then, in the silence of the chamber, a deep, resonant hum rang out, filled with the pulse of life.
The radiance receded like a tide.
A brand new Gu worm — roughly the size of a walnut, its entire body a grey-brown, its shell covered in natural stone-vein patterns, radiating a dense and weighty Earth Path aura — settled steadily into Lin Mu's sweat-and-dust-covered palm.
Rank 2 Earth Path. The Earth Birth Gu.
It was a Gu worm with no combat capability whatsoever — not even particularly useful as a support. Utterly ordinary, found everywhere. And yet, for precisely that reason, it was the first Gu worm most refining apprentices ever produced.
Lin Mu stared at the mud-clod of a Gu worm sitting in his hand.
The corner of his mouth pulled upward — and kept pulling — until it broke into a low, unrestrained, near-delirious laugh.
"I did it... I actually did it."
He gripped the Gu worm tightly, feeling the fresh new connection forming between it and his Aperture.
A full day and night without sleep. Hundreds of Primeval Stones reduced to ash. In this moment, every last bit of that cost transformed into the richest possible return.
This was not the value of a single Gu worm.
This was a qualitative leap in experience.
Through sheer, grinding stubbornness and an overwhelming expenditure of resources, he had finally taken the cold, detached descriptions in the original story and forged them into muscle memory that belonged entirely to himself.