The moment Lin Mu recognized those familiar rows of English letters, his hands — still holding the tattered beast-hide scroll — began to tremble. Faintly, uncontrollably, in a way that was exceedingly rare for him.
His breathing nearly stopped. A primal shudder from the deepest part of his soul surged through his entire body like a current of electricity.
Otherworldly Demon.
As someone who had read the original story in full, Lin Mu understood exactly how much weight those two words carried in the Gu world.
In this realm, the Central Continent's Heavenly Court sat supreme on high, possessing dedicated methods for detecting and eliminating Otherworldly Demons.
Throughout the long and bloody history of the Gu world, every Otherworldly Demon who had carelessly exposed their identity and been captured — by the Heavenly Court or by other hidden powers — had met a fate of unspeakable horror.
Soul extraction. Spirit refinement. Total annihilation.
Whoosh.
Under the force of that extreme shock and vigilance, a dense, bone-chilling killing intent erupted from the depths of Lin Mu's eyes.
The corner of his gaze — sharp as a reaper's blade — locked onto Lin Wuxie, who stood nearby with a blank, uncomprehending expression.
What if this boy let something slip?
Even if he only mentioned in passing, to some stranger on some future day, that there had been a scroll covered in "strange tadpole symbols" —
In the eyes of those ancient, high-ranking cultivators who had lived for centuries, even the faintest thread of a clue could be followed all the way back to Lin Mu, pulling him straight into a death trap from which there would be no escape.
Kill him. Clean and simple.
The killing intent churned wildly through Lin Mu's chest. But after a long, stretched silence, he drew a slow breath, bit down hard on the tip of his tongue, and used the sharp pain to crush the impulse back down.
Don't lose your footing. This scroll has only ever been touched by him, and the cave is well-hidden. There should be no external probing measures left on it by anyone else.
Lin Mu ran the calculations in his mind with cold precision and forcibly steadied himself.
To be absolutely certain, he turned around. His expression had returned to that unfathomable, authoritative composure.
"Wuxie."
Lin Mu closed the scroll slightly, his tone grave and solemn. "What is recorded on this scroll is classified intelligence belonging to Shadow Sect — it concerns a covert operation of the highest order."
"I need to decipher it here. Go stand guard thirty paces outside the cave entrance. Kill anything that approaches, without exception. I cannot be disturbed."
"Yes! Your disciple obeys!"
The moment Lin Wuxie heard the words Shadow Sect classified, a fervent light blazed in his eyes.
He withdrew from the cave immediately and took up his post outside, standing watch with rigid vigilance.
Once Lin Mu had confirmed the surroundings were absolutely secure and no second pair of eyes could observe him, he turned back around. By the faint available light, he began to read the dying letter written in his mother tongue with careful, meticulous attention.
Fortunately, the English was not particularly obscure — plain, everyday language throughout. Lin Mu could follow it well enough.
The opening line:
"Hi. Whoever you are — if you can see and understand these words, I'm going to assume you're a fellow countryman. Haha, it's been so many years, I've nearly forgotten how to spell in English."
Reading that opening — casual, yet carrying an undercurrent of quiet desolation — Lin Mu felt the tension in his nerves ease, just slightly.
What followed was the thoroughly absurd and helpless lament of a man who called himself Kevin — an Englishman:
"God only knows what I went through. As a proper Englishman, I always assumed that if I ever transmigrated, it would be to a medieval kingdom full of magic, dragons, and knights. So why — why — did I end up in this Eastern, Chinese-flavored, utterly brutal cultivation world?!"
Every line dripped with the bitterness of lived experience.
"I did not transmigrate alone. Back then, a friend named David arrived in this world alongside me."
"But David's luck was terrible. He didn't understand how cruel this world was. Some very modern habits of his drew attention, and he accidentally exposed himself. A mysterious power took him away. He never came back."
"David was a true hero... He never gave up my existence. Not once."
"If not for his silence, I would have been erased from this world long ago."
"Fellow countryman, take my advice: no matter how great your ambitions, learn to conceal who you are. Never — never — let anyone see any trait that marks you as not belonging to this world."
"I survived in this world for a century or two, carrying David's share as well. I married a local woman. I had children. I even managed to advance my cultivation through sheer luck. But I traveled the entirety of the Southern Border and never found the road home."
"Now my lifespan is nearly spent. I gave away everything I owned, came alone to this desolate wilderness, and left my family behind — all so that in my final moments, I could speak freely in my own language, without fear, and leave behind some proof that I once existed."
Reading those words, something churned deep inside Lin Mu. He could feel it — that extreme, suffocating loneliness of living every day beneath the shadow of death.
"Fellow countryman, I leave behind no earth-shattering immortal techniques. But by combining what we learned of biology back on Earth, I deduced an entirely original set of Gu recipes."
What followed was a meticulous account of how Kevin had observed the feeding and digestive habits of leeches, toads, and other creatures native to the Southern Border — and through self-taught intuition alone, had combined the Transformation Path and the Strength Path to piece together an extraordinarily rare system of Gu worms.
This included not only the complete refinement formulas for the progression from Rank 1 Small Swallow Gu all the way to the Rank 3 Great Swallow Gu, but even his speculative partial formula for the Rank 5 Heaven-Swallowing Gu.
He had simply lacked the talent and resources to push the deduction all the way to a Gu Immortal-level formula.
"But this system has one fatal flaw."
Kevin identified the core of the problem with rigorous precision:
"Swallowing without expelling — forcibly absorbing foreign Dao Marks of different types — causes terrifying impurities to accumulate within the body without cease."
"Once those impurities exceed what the physical body can bear, the host will suffer qi deviation, triggering a catastrophic backlash. Their cultivation will be permanently sealed, incapable of advancing a single step for the rest of their life."
Lin Mu drew a slow, deep breath.
"However, to solve this problem, I drew on knowledge from Earth."
Kevin had incorporated concepts from modern medicine and developed the core supplementary Gu worm for this entire system — the Dialysis Gu.
Swallow and filter. The two worked in perfect tandem.
By using the Dialysis Gu to purge the rampaging impurities and excess Dao Marks from within the body, the flaw of accumulating corruption was perfectly resolved — and the ceiling of this Gu system's potential was elevated to a truly terrifying height.
A stroke of genius. Lin Mu couldn't help but silently marvel.
As expected — every Otherworldly Demon carried within them a potential that this world could not easily replicate.
At the end of the letter, Kevin wrote candidly:
"Fellow countryman, my home in the Southern Border is a village called Xu Family Village. My name in the Gu world is Xu You."
"I don't know when you'll read this letter. Perhaps they've already been swallowed by history. But if you have the time, I hope you'll go there — go and see how my wife, my children, and my descendants are faring. If you can, look after them when they're in danger."
To ensure that whoever found this letter would actually go, Kevin had even dangled bait with the shrewdness of a seasoned operator:
"In the depths beneath the ancestral hall of the Xu Family Village estate, I have buried several Gu worms I acquired through fortunate circumstance. Among them is even a Lifespan Gu."
A Lifespan Gu.
"As long as you are willing to go and watch over my bloodline, everything buried there — including the Lifespan Gu — is yours to take freely."
The writing grew increasingly faint and unsteady toward the end.
"I've written so much. I'm tired now."
"I truly hope... that after I die in this world, all of this will turn out to have been nothing but an extraordinarily long dream."
"When I wake up, David will be beside me again. We'll sit together on the sofa, drink an ice-cold cola, and spend an entire day playing computer games without a care in the world..."
Lin Mu finished reading the scroll in full. He put it away with careful hands and looked at the skeleton before him with an expression of profound complexity.
When in Rome, Kevin.
Something stirred quietly in Lin Mu's chest.
Kevin had written in English about how ill-suited he was to this brutal world, how little he clung to the mortal dust of cultivation. Yet in death, he had maintained the most standard meditation posture of a Gu Master in the Gu world.
And even in his final moments, he had used a priceless Lifespan Gu as an airtight open scheme — a perfect trap baited with greed, designed to hold whoever came after him in an iron grip.
In the end, this world had assimilated him completely.
But I'll accept this gift.
The realization struck Lin Mu all at once.
No wonder Lin Wuxie — despite having long since reached the formidable peak of Rank 1 — had been unable to break through the Aperture wall into Rank 2.
It was because he had only ever swallowed and never expelled. The impurities packed inside him had become a chronic, terminal blockage, sealing off the path to his breakthrough entirely.
And now — Lin Mu possessed the refinement secret of the Dialysis Gu, along with the complete advancement path that followed.
This was equivalent to seizing absolute control over Lin Wuxie's entire future cultivation.
Without the Dialysis Gu, Lin Wuxie would either stagnate permanently, or be torn apart from the inside.
This gave Lin Mu something far more substantial than mere deception — a perfect, concrete means of control.
Thoroughly satisfied, Lin Mu gathered the scroll and the remaining Gu worm husks from the ground and stored everything carefully in his Aperture.
He composed himself, restored that cold and inscrutable bearing, and walked out of the cave in long strides, calling back Lin Wuxie, who had been standing guard in the biting wind with rigid alertness.
"Senior Brother! What's the situation?" Lin Wuxie hurried over, eyes full of eager anticipation.
"Mm." Lin Mu gave his junior brother a measured pat on the shoulder and nodded with deliberate profundity. "The covert task left by the Sect has been clarified. The implications run wide."
"As for your cultivation going forward — I have a clear picture now. But this matter requires careful planning. We will discuss it in due course."
The moment Lin Wuxie heard that his cultivation had a path forward, he broke into a flurry of grateful, excited bows.
But standing at the edge of the cliff, facing the howling mountain wind, a flicker of contemplation passed through Lin Mu's eyes.
For now, the Black Bone King's inheritance had hit a dead end — the requirement to capture a Thousand Beast King alive made it impossible to pursue in the short term.
So the question now is...
Lin Mu rubbed his chin and fell into a familiar dilemma.
Return to Black Blood Stockade and quietly consolidate the gains from this expedition?
Or follow Lu Xingyun's detailed map and press further while already out here in the field?