The Giant Hollow earthworm was unimaginably massive.
Even after losing its upper half, the remaining corpse still dwarfed Raizen Kō by several times over. Compared to it, his own body appeared pitifully small—barely one-seventh of its total length.
Yet Raizen Kō did not hesitate.
Driven by instinct and ambition alike, he devoured it greedily.
Bone shattered between his fangs.
Flesh dissolved into reishi.
Dark green blood soaked into the pale desert, vanishing into the spiritual sand before he could consume it. If not for that loss, Raizen Kō was certain he would have eaten every last fragment without leaving even a stain behind.
At one point, an absurd thought even crossed his mind.
Everything in Hueco Mundo was composed of high-density reishi.
Then… could the sand itself be nourishment?
He tried.
And nearly choked himself to death.
After coughing violently several times and spitting out a mouthful of white grains, he abandoned the ridiculous experiment in frustration.
Eventually…
The enormous remaining corpse—many times larger than his own body—was completely devoured.
Only then did Raizen Kō finally experience something new.
Fullness.
For the first time since arriving in Hueco Mundo, a deep and satisfying heaviness spread through his core.
"GRAAAAAH—!"
A long, thunderous roar erupted from his throat.
Dark golden spiritual pressure surged outward, swirling violently around his monstrous form like a living storm.
"…Is this…"
"…Evolution?"
Warmth flooded through every bone plate and segment.
A smile slowly curved beneath his mask.
An indescribable comfort followed—as though his entire existence were being reforged.
It felt strangely familiar.
Like lying on a warm bed in his previous life, while invisible hands kneaded every muscle and nerve into perfect alignment.
Then—
BOOOOM!
A towering pillar of dark-gold spiritual energy erupted from his body.
Within that roaring column, Raizen Kō's form twisted, expanded, and reshaped itself.
Bone plates thickened.
Segments elongated.
Patterns ignited.
The light pillar lasted only ten seconds.
But in those ten seconds…
His existence was rewritten.
When the dust finally settled…
Raizen Kō emerged.
His original body, once four to five meters long, had grown dramatically.
From head to tail, he now measured nearly seven to eight meters.
His centipede segments were broader and heavier, the pale bone now veined with faint dark-gold lightning patterns that pulsed with contained power.
Even the helmet-like mask covering his entire head bore new markings—jagged streaks of golden light etched across its surface.
His humanoid torso was no longer pale alone.
Black and gold patterns intertwined across his chest and arms, giving him an aura far more demonic, far more dangerous, than before.
"…So this is…"
"…A higher-grade Hollow…"
Raizen Kō inhaled slowly, feeling the dense spiritual pressure circulating through his core.
"I've stepped into a new stage."
Through half a month of exploration and the knowledge from his previous life, Raizen Kō had gradually pieced together the true hierarchy of Hollows.
The original records had been incomplete.
Not only Menos possessed ranks.
Even ordinary Hollows…
Had stages.
First Stage — Newly Formed Hollow
Freshly transformed souls.
Weak, unstable, driven purely by hunger.
The Lizard Hollow he killed upon arrival… and his original form… both belonged here.
Their strength depended almost entirely on the spiritual quality they possessed as humans.
The reason Raizen Kō had crushed that Lizard Hollow so easily…
Was simply because his human soul had been stronger.
Second Stage — Advanced Hollow
This was his current realm.
A Hollow that had devoured enough of its kind to stabilize its mask and significantly increase spiritual pressure.
Physically powerful.
Still far from Menos.
But already dangerous to most ordinary Hollows.
Third Stage — Giant Hollow
Massive beings dozens of meters long.
Their spiritual pressure approached the threshold required for Menos fusion.
The earthworm Hollow slain by the anomalous Gillian had belonged here.
Fourth Stage — Lower-Class Menos Grande: Gillian
Born from the fusion of hundreds of starving Hollows devouring one another.
Colossal giants.
Uniform in shape.
Over ninety percent lost their consciousness entirely, becoming walking weapons driven only by instinct.
They were often commanded by higher Menos.
Only an extremely small number retained self-awareness.
Those rare individuals…
Were the seeds of kings.
There was also a special category—
Degenerated Gillians.
Adjuchas that failed evolution due to injury or spiritual collapse, falling back into Gillian rank while retaining their former shape.
These beings were far stronger than ordinary Gillians.
Fifth Stage — Mid-Class Menos Grande: Adjuchas
Evolved from intelligent Gillians through endless devouring.
Smaller than Gillians, larger than ordinary Hollows.
Capable of commanding Gillians.
Capable of using advanced techniques:
Cero.
Sonído.
Yet cursed by an unforgiving rule—
Once bitten by a Menos of equal or higher rank…
Even the smallest loss permanently halted evolution.
Such beings could never again reach Vasto Lorde.
No matter how many souls they devoured afterward.
Sixth Stage — Upper-Class Menos Grande: Vasto Lorde
The apex of Hollow evolution.
Human-sized.
Exceedingly rare.
Possessing combat power rivaling Shinigami Captains.
The true rulers of Hueco Mundo.
"…This path…"
"…Is unimaginably long."
Raizen Kō did not celebrate excessively.
If this were already the era of Arrancar and Espada…
Then even Vasto Lorde would not be enough.
At his current level, he was still nothing more than dust waiting to be crushed.
Without knowing the timeline…
Strength was the only answer.
The only survival.
The only future.
Urgency burned within him.
After stabilizing his new form, Raizen Kō carefully examined himself.
And soon…
He discovered something astonishing.
Two new abilities.
Innate Ability One — Reiryoku Concealment (Camo)
Raizen Kō could suppress his spiritual pressure to near zero.
Unless the opponent's spiritual pressure exceeded his own by more than two orders of magnitude, they would be completely unable to sense him.
Perfect for ambush.
Perfect for survival.
Innate Ability Two — Raiden Carapace (Flash Lightning)
Dark-gold lightning could be wrapped around his centipede segments.
Enhancing speed.
Enhancing cutting power.
Enhancing impact.
However…
It could only adhere to his body.
No projection.
No ranged discharge.
Learning this, Raizen Kō laughed softly.
"With this terrain…"
"I am now the perfect predator."
But then—
A memory surfaced.
The black-red beam.
The compression.
The annihilation.
A slow smile curved beneath his mask.
"…Ranged attacks…"
"…I already know one."
He raised his right index finger.
Reishi gathered.
Spiritual pressure compressed.
Five seconds passed.
A dense black-red sphere formed at his fingertip.
Then—
BOOOOOOM!
A beam of destructive light erupted forward, tearing through the desert and detonating against a distant dune.
Sand exploded skyward.
The shockwave rolled outward in a thunderous roar.
Raizen Kō stared in silence.
Then, softly…
"…Cero…"