In the end, Lin Mu abandoned the idea of pursuing the Three Watches Gu.
The Three Watches Gu could triple the flow of time and deliver terrifying cultivation efficiency — that much was true. But its side effects were equally lethal. Not only would his lifespan burn at three times the rate, but any wound sustained in combat would fester and bleed at three times the normal speed as well.
That kind of cultivation method — drinking poison to quench thirst, courting death with open arms — was not something Lin Mu had been driven to yet.
If the unconventional paths are closed, then use the most grounded method of all — Primeval Stones, and time.
With his mind made up, Lin Mu wasted no further time. He entrusted Old Ma with the task of procuring resources and Gu worms on his behalf.
The two of them, living under the terrifying shadow of the Rank 4 female demon Wuxiang, were already bound to the same rope — rise together, fall together. Lin Mu no longer bothered with any pretense of concealment. He directly allocated five thousand Primeval Stones to purchase Rank 2 supplementary Gu worms capable of accelerating his cultivation progress.
Even Old Ma, who had seen more than most, couldn't help but draw a sharp breath at that figure.
As the saying went: the only flaw of expensive things is that they are expensive.
In the Gu world, even a Liquor Worm — a Rank 1 Gu — fetched only a few hundred Primeval Stones at most. Among Rank 2 Gu worms, even something as costly as the Red Iron Relic Gu, which could unconditionally advance a minor stage, had a reasonable upper ceiling on its price.
Five thousand Primeval Stones, dropped into the Rank 2 Gu worm market, was an astronomical sum — enough to stun any merchant senseless, and more than sufficient for Lin Mu to acquire any Rank 2 Gu worm he desired.
Once the funds were dispatched, Lin Mu sealed himself away entirely.
Back in the Silent Stone District, he began a cultivation session that was as grueling as it was efficient.
With all affairs handed off to Lin Ping and no mundane interruptions to contend with, Lin Mu gave himself completely over to it. Sparing no thought for the cost in Primeval Stones, he crushed stone after stone and drew in their essence, flooding his Aperture walls with Primeval Essence day and night without rest.
Time lost all meaning in that dim underground chamber.
Two full months passed.
Boom.
With a violent surge and expansion of the primeval sea within his Aperture, Rank 2 upper stage — achieved.
In the very instant of the breakthrough, the Four-Flavor Liquor Worm, dormant in the deepest recess of his Aperture, stirred and seized the moment.
Like a ravenous beast, it swallowed great mouthfuls of the newly converted higher-grade Primeval Essence. After an exquisitely refined purification, it expelled streams of Primeval Essence that were darker in hue — like congealed blood, dense and terrifying.
It was supremely pure — Rank 2 peak Primeval Essence.
Lin Mu slowly opened his eyes. He felt the overwhelming power surging through him, so abundant it nearly spilled beyond his body. The corner of his mouth curved into a cold, deeply satisfied smile.
At this moment, in terms of Primeval Essence quality and explosive output alone, he had the absolute standing to look down on the vast majority of Gu Masters at the same rank.
Not long after Lin Mu consolidated his upper stage breakthrough and emerged from seclusion, Old Ma brought equally welcome news.
Heavy rewards draw bold men. Under the crushing weight of five thousand Primeval Stones, Old Ma's intelligence network had operated at full capacity and successfully located three rare Rank 2 Gu worms that met Lin Mu's requirements.
That evening, the two met at the shop.
"All three of these Gu worms can significantly accelerate cultivation progress — rare finds, each of them. But each has its own strengths and drawbacks."
Old Ma laid three sealed jade boxes in a row on the table and spoke with a grave expression.
"The first: the Empowerment Gu. As the name suggests, it allows a higher-ranked Gu Master to forcibly channel their own Primeval Essence into a lower-ranked cultivator — like pouring enlightenment directly into the mind — rapidly elevating the recipient's cultivation. The drawback, however, is severe. The infused essence is ultimately of a foreign type. Over time, this causes the qi and blood within the host's Aperture to stagnate and the Primeval Essence to become impure and chaotic. Combat power at the same stage will be significantly diminished, and it may even permanently sever the potential to advance to higher ranks."
"The second: the Affection Gu. An extremely unorthodox dual cultivation Gu. When a male and female Gu Master activate it simultaneously, the interplay of yin and yang accelerates cultivation for both parties. However, this Gu worm has one particularly fatal characteristic — it heavily favors the female party. In other words, the one who absorbs the essence — the female — will advance at a rate far exceeding that of the male."
"The third is called the Gathering Primeval Gu. This one does not act directly on the body — it acts on the environment. It enhances the concentration of Primeval Energy in a given area, dramatically increasing the natural rate at which Primeval Essence accumulates within a Gu Master's Aperture. The condition that limits it, however, is this: it must continuously consume vast quantities of rare natural treasures as fuel to sustain its operation. In plain terms — it is a bottomless pit. Extraordinarily expensive to maintain."
Lin Mu listened to Old Ma's introduction in full, then stared at the three jade boxes on the table and fell into thought.
"The Empowerment Gu is tempting, no question."
He turned it over in his mind.
"With Wuxiang's terrifying Rank 4 middle stage cultivation, if she used the Empowerment Gu on me, I could reach Rank 3 in an extremely short time. And it would align perfectly with her inheritance condition — she needs to cultivate another successor to Rank 4."
"But."
Lin Mu shook his head with decisive finality and pushed the first jade box aside.
"Foreign Primeval Essence leads to an unstable foundation, diminished combat power, and self-destruction of everything I've built. If I chase this momentary gain, I'll be nothing but a hollow shell even if I reach the higher ranks. This kind of poison-drinking shortcut is absolutely off the table."
As for the second jade box, Lin Mu barely glanced at it. A flicker of undisguised contempt passed through his eyes.
"Affection Gu? Favors the female party?"
A cold laugh rose in his chest.
Doing all the work so someone else reaps the reward — that was something Lin Mu would sooner die than do.
With every option carrying hidden dangers eliminated, Lin Mu's gaze locked onto the final jade box.
The Gathering Primeval Gu.
For most people, the cost was a fatal flaw.
But for Lin Mu — who had spent the early period amassing wealth with ruthless efficiency and had even harvested an entire caravan camp — a flaw that could be solved with money was no flaw at all.
"This one."
Lin Mu made the call without hesitation. He paid Old Ma two thousand Primeval Stones on the spot and took the Gathering Primeval Gu.
Then, with the same reckless intensity, he poured nearly another two thousand Primeval Stones into purchasing rare natural treasures rich in pure Primeval Energy — all entrusted to Old Ma to procure.
Several days later, his underground chamber was unrecognizable.
Using those two thousand Primeval Stones' worth of rare materials, with the Gathering Primeval Gu at its core, Lin Mu assembled a top-tier cultivation environment inside the chamber.
The concentration of Primeval Energy within that space surpassed even the natural primeval springs in the deepest reaches of Black Blood Stockade. Every breath felt as though pure Primeval Energy was seeping in through every pore.
With the terrifying absorption capacity of his pseudo-Grade A talent, the unceasing purification of the Four-Flavor Liquor Worm, and the heaven-defying environmental enhancement of the Gathering Primeval Gu all working in concert —
Lin Mu closed his eyes once more.
The rate at which Primeval Stones were being consumed each day was so extravagant that even the pampered core heirs of the Shang Clan or the Jia Clan — with all their deep reserves — would never dare squander resources so lavishly at such a low rank.
But the returns on that extravagant cost were equally monstrous.
The Primeval Essence level within Lin Mu's Aperture rose at a rate visible to the naked eye — surging upward day by day, hour by hour, rocketing toward the wall that marked the absolute limit of Rank 2.
Rank 2 peak stage.