Lin Mu held his breath and pressed his fingertips against the cold, cryptic-etched surface of the Pitch-Black Bone Plate.
Then, with a single mental nudge, he carefully drew a thread of supremely refined Red Iron Primeval Essence from the base of his Aperture and channeled it in.
"Hum——!"
This time, the Primeval Essence did not vanish like the dark-green Rank 1 essence had — dissolving into nothing, unable to find any purchase.
The instant it made contact with the Rank 2 Red Iron Primeval Essence, the bone plate — which had been still as a dead pool — seemed to suddenly come alive. A vast, irresistible suction force detonated from deep within it.
Lin Mu's vision went black. The world spun.
A thread of his consciousness was ripped clean from his body by that force and dragged directly into a strange, oppressive, lightless space.
Heavy.
That was the first sensation Lin Mu registered when his consciousness returned. It was the only sensation.
This space had no up, no down, no left, no right. In every direction, Earth Path Dao Marks pressed in — so dense they were suffocating.
His thread of consciousness felt as though it had sunk to the bottom of a ten-thousand-zhang abyss, buried beneath hundreds of millions of tons of rock and soil, all of it crushing inward from every side at once.
"What terrifying Dao Mark foundations..."
Lin Mu attempted to move forward — a simple extension of his consciousness — and found that even this trivial motion was devouring his newly formed Red Iron Primeval Essence at a ruinous rate.
The essence drained like a floodgate had been thrown open. The sensation of his soul being compressed and torn apart was agonizing beyond words.
Only in this moment did he understand.
Initial-stage Rank 2 Red Iron Primeval Essence was not the blade that would cut open the bone plate's secrets.
It was merely the minimum threshold to push the door open at all — a bare entry ticket that allowed him to survive in this terrifying space for a single instant without being crushed flat by the Earth Path Dao Marks.
"I can't hold on. The Primeval Essence is almost gone."
Within just a few breaths, Lin Mu's consciousness began to blur. The Red Iron Primeval Essence was nearly exhausted.
If it ran dry, this thread of consciousness would be ground to nothing — not fatal, but his soul would suffer severe damage, and he would be forever barred from the core of this inheritance.
In that life-or-death instant, just as he was about to cut the Primeval Essence connection and force himself out —
"Wait... blood hidden within earth..."
A memory flashed through his mind — something he had glimpsed, entirely by chance, during his first brief probe of the bone plate days ago.
He wrenched his collapsing focus back under control, and with a razor-sharp instinct honed through countless brushes with death, he reached through the crushing weight of that vast dark earth and locked onto a trace — faint, hidden, almost imperceptible — of a sweet, metallic blood scent.
"Found it."
In the seemingly impenetrable dark swamp to his left, a hairline thread of blood-red light flickered in and out of existence.
Lin Mu didn't hesitate for even a fraction of a breath.
He mobilized the very last dregs of his Red Iron Primeval Essence, seized that thread like a lifeline, and with every last measure of strength he had, swam forward along the trail of Blood Path Dao Marks.
"Pop."
As though piercing through an invisible membrane, the suffocating pressure of the Earth Path vanished without a trace.
His consciousness followed the blood-light and finally broke free of the swamp's grip, tumbling into a vast, empty, boundless core space.
Before he could draw even a single breath of relief, an immense, mountain-deep will — like an ancient dragon stirring from an age-long sleep — descended upon that core space with a thunderous crash.
The will was enormous. So enormous that Lin Mu's faint thread of consciousness was like a lone leaf before a tidal wave — capable of nothing but looking up.
Yet even beneath that crushing weight, a sliver of clarity remained in Lin Mu's mind.
This will is incomprehensibly vast to me right now — it could crush me without effort.
But compared to the wills of figures like the Giant Sun Immortal Venerable or the Reckless Savage Demon Venerable in the original story — wills that blanketed entire realms and spanned multiple eras — this still falls immeasurably short.
He assessed it quietly.
"This is a mortal will. The absolute limit of a being who has not yet transcended — peak Rank 5. The Black Bone King."
As the will surged and rolled, scattered Dao Marks throughout the void began to converge at speed, coalescing in Lin Mu's consciousness sea into a clear, ghostly silhouette.
It was a gaunt, withered old man draped in a tattered black robe.
He stood hunched, his hair and beard entirely white, his body like a dead tree stripped of bark.
The eyes sunken deep in their sockets were hollow and still — yet within that stillness lay an endless, weathered weight, the look of a man who had seen everything the world had to offer.
Those eyes regarded Lin Mu — this intruding insect — in quiet silence.
Judging by appearance alone, it was impossible to reconcile this figure with the absolute tyrant Old Ma had described — the one who had once swept across the Southern Border and commanded ten thousand bones.
The Black Bone King before him carried none of the imperious, world-dominating presence Lin Mu had imagined. Instead, he radiated the fading, twilight stillness of a candle guttering in the wind — a flame that might go out at any moment.
Lin Mu drew a slow breath, gathered his focus, and prepared himself for whatever trial was coming.
In the world of Gu, no inheritance left behind by a great figure was ever a free meal. They invariably followed certain rules, and bore certain heavy obligations.
The Flower Wine Monk, for instance, had left his inheritance to overturn the Gu Yue Clan and settle an old score. The earth spirits of certain blessed lands often imposed harsh and unyielding conditions before acknowledging a master.
Lin Mu had already steeled himself for the worst — whether it was exterminating some rival clan or tracking down some near-extinct heavenly treasure, he was prepared to agree to it all on the surface, collect the benefits first, and deal with the rest later.
What happened next, however, shattered every expectation he had.
The Black Bone King's spectral will did not offer warm greetings like the kindly old sages of storybooks.
Instead, with the cold indifference and perverse edge unique to a Demonic Path tyrant, it spoke.
The voice was like two dry bones grinding against each other, reverberating through the void:
"I did not establish this arrangement to benefit the world, nor to find someone to avenge me."
The old man's silhouette tilted its head slightly upward. In those hollow eyes, a bone-chilling arrogance and killing intent suddenly blazed:
"I spent my life sweeping across the Southern Border — those who submitted to me flourished, those who defied me perished."
"I filled fields with corpses and built mountains of white bone. Every so-called enemy, every self-righteous hypocrite of the Righteous Path — I killed them all. Cleanly. Not a single one left alive."
Lin Mu's heart jolted.
This was the true confidence of a peak Rank 5 Demonic Path colossus. Enemies? There were none — because he had slaughtered them all to the last.
But then the old man's voice shifted without warning. That arrogance collapsed in an instant, replaced by something frantic and deeply, desperately despairing.
"And yet... I am not willing to accept it."
The Black Bone King's silhouette trembled violently, as though seized by some extreme agony.
"My talent was exceptional. I dual-cultivated Blood and Earth. I dominated an entire region. And yet I was trapped at the peak of Rank 5 for two hundred years. Two hundred years."
"I walked every inch of the Southern Border's ten-thousand mountains. I exhausted every scheme I had. I burned through my lifespan. I used every method available to me — I even ventured into death zones at the risk of my own life... and still. I could not knock open that door to immortality."
The gulf between mortal and immortal — vast as a chasm with no bottom.
In this moment, the tyrant who had once stood above all others finally shed every last defense he had, and let out the most helpless, most desolate lament a mortal could make when faced with the immovable laws of heaven and earth.
"Hear me, successor."
The Black Bone King's silhouette fixed its gaze on Lin Mu and spoke the inheritance condition that left him utterly dumbstruck:
"My inheritance sets no task of vengeance. It imposes no elaborate trials. From beginning to end, my inheritance carries only one purpose — become a Gu Immortal."
"If you can use the foundation I leave behind to shatter the shackles of mortality and ascend to immortality — then on the day of your ascension, use your immortal essence to awaken this last thread of will I have sealed within the bone plate..."
The old man's voice dropped lower, carrying in it something close to pleading:
"And let this useless mortal will of mine... borrow your eyes... to see, just once... what it looks like to be an immortal."
Just to watch?
Just to see what immortality looks like?
Lin Mu's consciousness stood frozen in place, unable to recover for a long moment.
The shock passed. His relentlessly rational mind spun into motion and grasped, in an instant, the cruel logic of what he had just heard — logic so absurd it bordered on a joke from the depths of hell.
What kind of inheritance condition is this?
If you truly ascend to immortality, then the killer moves and resources left behind by a mere peak Rank 5 mortal are worth less than scrap paper and broken copper to you — you wouldn't need his help at all.
And if you fail to ascend — if you die at Rank 5 just as he did — then it doesn't matter either.
Because by that point, you will have long since spent every last reward his inheritance had to offer. When you're dead, who is left to honor the promise of awakening his will?
It was a transaction with no losing side — and a paradox dripping with bitter irony.
The Black Bone King's inheritance — the one that the outside world might tear itself apart searching for, that could ignite wars of annihilation — and at its core, the wish driving it all was this pitiable, this lamentable.
A tyrant of an era. And his greatest obsession in the moment before death was simply to secure a seat as a spectator in this world.
"Hum——"
Having spoken his final wish, the spectral silhouette of the Black Bone King — sustained through who knew how many ages — finally exhausted its last measure of strength and began to dissolve into the void, crumbling like ancient stone worn away by wind.
Points of light peeled away, one by one.
In the space where the silhouette had stood, two faintly glowing Gu worms now floated in silence.
One was entirely transparent, crystalline as glass — a Photo-Audio Gu. The other was shaped like a bamboo scroll, carrying the faint scent of aged parchment — a Bookworm.
These two Gu worms were clearly the Black Bone King's "first key" left for his core successor — within them lay the means to break open the situation and truly access the vast inheritance he had left behind.
And in that core space, now slowly collapsing into nothing, only one thing remained — the sound the old man had left behind as he dissolved, desolate beyond all words, as though it had crossed the full length of time itself and been branded into the deepest reaches of Lin Mu's soul:
"A Gu Immortal... to become a Gu Immortal..."