The endless ocean stretched as far as the eye could see.
Above—
An endless blue sky.
Below—
An endless sea of sapphire.
There was nothing else.
No islands.
No ships.
No birds.
Only the rhythmic sound of waves...
...and the crisp crack of ice forming beneath Yuki's boots.
Crack...
Crack...
Each step he took instantly froze the seawater beneath his feet, creating a path of solid ice that vanished behind him moments later.
The deeper he ventured into the ocean, the quieter the world became.
It was as if everything had fallen into an unnatural silence.
Yuki continued walking without lowering his guard.
Then—
Thump!
His heart suddenly pounded once.
His body instinctively froze.
"...!"
A strange chill crawled down his spine.
At the same moment, Chichi spoke in an unusually serious voice.
"Yuki..."
"You've entered Illman's Domain."
"From this point onward, everything belongs to Illman."
"He may appear at any moment."
"So stay alert."
Yuki slowly nodded.
His expression became even more serious than before.
"So..."
"The moment I've been waiting for all this time has finally arrived."
"My battle against Illman..."
"It begins now."
After a brief pause, he tightened his grip around both swords.
"...This is the final step."
With calm determination, he resumed walking across the frozen sea.
Thirty steps...
Forty...
Fifty...
Then—
Something descended from the heavens.
A gigantic black cloud slowly drifted down from the sky.
It wasn't an ordinary rain cloud.
There was no thunder.
No rain.
No wind.
Instead...
It resembled an enormous mass of living black smoke.
The dark mist gently floated above the ocean before settling onto the surface of the water.
Yuki immediately stopped.
His muscles tensed.
Sweat slowly trickled down his forehead.
Without hesitation, he drew both swords and assumed a fighting stance.
"..."
The black fog slowly dispersed.
Little by little...
A figure emerged from within.
Yuki's eyes widened.
Standing in front of him...
...was a creature that barely resembled a human.
Its body was horrifyingly thin, almost like a walking skeleton.
Its skin was torn in countless places, exposing decayed flesh beneath.
Dark black patches covered parts of its body while the remaining skin was an unhealthy pale white.
Deep, hollow eyes rested beneath enormous black circles, making it appear as though it hadn't slept for centuries.
Large sections of its hair had fallen out, leaving uneven patches across its scalp.
Its arms trembled constantly.
Even standing still made it seem as though it would collapse at any second.
A grotesque hump rose from its back, twisting its posture into something barely human.
Yet despite its sickly appearance...
It stood perfectly upright.
Its eyes...
Were completely black.
Not merely dark...
But empty.
Like endless black holes capable of swallowing light itself.
Thick fungus covered its legs and spread beneath both armpits.
Boils and swollen blisters covered nearly every inch of its body.
Small, needle-like hairs protruded from its face like countless tiny spikes.
Its crooked yellow teeth twisted in every direction.
Then...
It smiled.
A slow...
Disturbing...
Unsettling smile.
It wasn't threatening.
Nor was it angry.
Yet simply looking at that smile filled one's heart with instinctive fear.
That creature...
Was Illman.
The embodiment of disease.
The ruler of every illness in existence.
Yuki instinctively took several steps backward.
His face twisted in disgust.
"T-That's..."
"Illman?"
"The final boss...?"
"He looks like he's already dead..."
Yuki instinctively covered his nose.
"What... is that smell...?"
"Ugh..."
The stench surrounding Illman was unbearable.
It was far worse than a landfill that had accumulated garbage for decades.
Even breathing became difficult.
Beside him, Chichi quietly said,
"That's Illman."
"The owner of every illness..."
"...and every virus."
Yuki frowned.
"...Eww."
Illman slowly turned his gaze toward him.
Then...
That same disturbing smile appeared once again.
The instant their eyes met—
Yuki's body became incredibly heavy.
"Gh...?!"
His knees nearly buckled beneath him.
His breathing grew uneven.
Seeing this, Chichi immediately spoke.
"Don't panic."
"He's nowhere near powerful enough to overwhelm you with aura alone."
"What you're feeling isn't pressure."
"It's the effect of his overwhelming stench and disease."
"You can defeat him."
"But only if you fight seriously."
"And never underestimate him."
Yuki steadied his breathing before nodding.
"...I know."
For several long seconds...
Neither of them moved.
Only the sound of waves echoed between them.
Finally...
Illman slowly raised one trembling finger toward Yuki.
His voice was weak.
Slow.
Almost lifeless.
"...Who..."
"...are..."
"...you...?"
Dark saliva dripped from the corner of his mouth.
The foul smell became even stronger.
Yuki lowered both swords before pointing one directly at Illman.
"My name..."
"...is Yuki."
"And I..."
"...am your death."
The moment those words left his mouth—
Yuki vanished.
BOOM!
The ice beneath his feet shattered as he rushed straight toward Illman at tremendous speed.
Without hesitation...
He swung both swords simultaneously.
Clang!
The blades sliced through empty air.
Illman had effortlessly stepped aside.
"Tch."
Yuki immediately turned around.
At the same time, Chichi spoke.
"I told you before."
"Don't underestimate him."
"Every illness that has ever existed..."
"...and even those humanity has never discovered..."
"...all reside within his body."
Yuki clicked his tongue.
"I know."
Illman tilted his head slightly.
Then...
He smiled again.
That same eerie smile.
"What's with that smile...?"
Yuki thought.
"Is he mocking me?"
Without wasting another second, he charged once more.
This time...
The ocean exploded.
SPLASH!!
Countless grotesque fish burst out from beneath the water.
Their flesh had long since rotted away.
Bones protruded through torn skin.
Black liquid dripped from their mouths.
Their empty eyes stared directly at Yuki.
An army of undead sea creatures rushed toward him.
"What?!"
Yuki immediately changed direction, narrowly dodging the first fish before cutting another in half.
Slash!
Slash!
Slash!
More and more undead fish emerged from beneath the ocean.
As he fought them off, Chichi explained,
"This is Illman's technique..."
"...WALEZO."
Yuki deflected another attack before asking,
"What exactly does it do?!"
"Black vines extend from Illman's legs."
"They travel beneath the earth... or beneath the sea."
"Anything alive they touch is infected."
"Afterward..."
"...they become undead servants under Illman's control."
"If you want to stop this technique..."
"...destroy the vines connected to his legs."
Yuki glanced toward Illman's feet.
There...
Thin black-brown vines were extending beneath the ocean floor.
"So that's it."
With a powerful swing—
WHOOSH!
A massive shockwave erupted from both swords.
The surrounding undead fish were instantly sliced apart.
Using the opening...
Yuki dashed straight toward Illman once again.
But before he could reach him—
The ocean erupted violently.
ROOOOAAARRR!!
A gigantic shark burst from the sea and landed directly between them.
Its enormous body towered over Yuki.
Its jaws were lined with countless blade-like teeth.
Its scales resembled solid steel.
Even its eyes glowed with the eerie light of the undead.
Chichi's voice echoed once more.
"That's..."
"...PIGALODONA."
"An undead fusion created from several of the world's deadliest aquatic predators."
"It won't be easy to kill."
Yuki narrowed his eyes.
"There has to be a weakness."
"Tell me."
For the first time...
Chichi remained silent.
The monstrous shark opened its jaws and released an earth-shaking roar that shook the ocean itself.
The blast forced Yuki several steps backward.
Then—
It charged.
The monstrous shark lunged toward Yuki at terrifying speed.
Its enormous jaws tore through the air as though they could swallow the sea itself.
Without hesitation, Yuki sprinted across the frozen surface.
Crack! Crack! Crack!
Each step created a fresh layer of ice beneath his boots while the undead beast relentlessly pursued him.
Only after several seconds did Chichi finally answer.
"You have to kill it in a single strike."
"It possesses an extraordinary regenerative ability."
"If you fail to destroy it instantly..."
"...it will simply recover."
Yuki's eyebrow twitched.
"...Thanks for telling me that now."
"If you hadn't mentioned it, I definitely would've figured that out myself."
Even in the middle of battle, he couldn't help but complain.
The shark closed the distance.
Just as its jaws were about to snap shut—
Yuki suddenly leaped high into the sky.
The massive beast couldn't stop its momentum.
It shot straight beneath him.
Now!
While still airborne, Yuki descended toward the creature's back.
Both swords flashed.
Clang!
The blades struck its scales...
...and stopped.
"...?!"
Yuki's eyes widened.
The scales were unbelievably tough.
Before he could react—
Crack!
Both swords shattered into pieces.
"...Damn!"
Using the shark's massive body as a foothold, Yuki immediately kicked off and jumped back into the air.
From a distance...
Illman quietly watched everything unfold.
His expression never changed.
That same disturbing smile remained on his face.
Without wasting a second, Yuki summoned another pair of swords.
Unlike the previous ones...
These blades radiated a far stronger aura.
"These should be enough."
He prepared to strike.
But just before his attack landed—
The shark suddenly dove back beneath the ocean.
"...!"
Yuki missed completely.
With nothing beneath him, he fell toward the frozen sea.
Although the magical boots created ice beneath his feet...
His balance faltered.
He landed awkwardly.
Before he could recover—
BOOM!!
The ice exploded.
The same shark burst out from beneath the surface.
Its enormous jaws opened wide.
And in a single motion...
It swallowed Yuki whole.
The beast immediately soared high into the sky.
Several seconds passed.
Then—
Slash!
A brilliant flash erupted from inside the shark.
Another.
Then another.
SLASH!!
The enormous body was instantly cut into countless pieces.
Blood rained across the ocean.
A lone figure descended from within the shredded corpse.
Yuki landed gracefully upon the frozen sea.
This time...
His footing was perfect.
The only evidence of what had happened was the dark blood staining his clothes and skin.
Yuki glanced at the remains falling into the ocean.
"If it hadn't swallowed me..."
"Cutting through those scales from the outside would've been much more difficult."
Without wasting another moment...
He charged toward Illman.
Halfway there—
Yuki suddenly shattered the ice beneath his own feet.
Crack!!
He disappeared beneath the ocean.
Illman slowly tilted his head.
For the first time...
He appeared slightly confused.
His empty black eyes searched the surrounding waters.
"...?"
Then—
Something happened.
The black vines extending from his legs were suddenly severed.
Slice!
Slice!
Every vine connecting him to the ocean floor was cleanly cut apart.
Immediately...
The undead sea creatures stopped appearing.
A moment later—
Splash!
Yuki burst out of the water while standing atop the back of one of the remaining undead fish.
As soon as he emerged...
He sliced the creature apart and landed before Illman.
Even after witnessing everything...
Illman's expression never changed.
He simply continued smiling.
That same grotesque smile.
Then...
He slowly raised one hand.
His fingers began stretching unnaturally.
Longer...
Longer...
Longer...
Until they resembled dozens of living tentacles rushing toward Yuki from every direction.
Yuki immediately tried to evade them.
However...
There were simply too many.
Dodging every single one was impossible.
Chichi spoke at once.
"This technique is called..."
"...TEFEBA."
Yuki's face immediately darkened.
"I don't need the name!"
"I need to know how to avoid it!"
Chichi answered calmly.
"You'll have to figure that out yourself."
"But..."
"There isn't a single part of Illman's body that cannot be cut."
Those words immediately made Yuki realize something.
"I don't have to avoid every finger..."
"I only need one opening."
While weaving through the countless fingers...
Yuki locked onto Illman's palm.
"There!"
Without hesitation...
He threw one of his swords.
The blade flew like a streak of silver.
Illman calmly intercepted it with one extended finger.
Clang!
The sword was knocked aside.
But—
Slice!
The finger itself was severed.
A thick black liquid oozed from the wound.
The instant it touched the ocean...
HISSSSS—!
The seawater instantly evaporated into clouds of steam.
Yuki's expression stiffened.
"...Shit."
"Even if I manage to wound him..."
"His blood itself is poisonous."
"One drop..."
"Even a single drop landing on my body..."
"It probably wouldn't kill me..."
"But the pain would be unbearable."
A chill ran down his spine.
He instinctively took several steps backward, creating distance between himself and Illman.
"Looks like..."
"It's finally time to use my skills."
Yuki tightened his grip around his remaining sword.
His sharp gaze remained fixed on Illman.
Illman silently stared back.
Then...
Something changed.
His smile widened.
Wider...
And wider...
Until it stretched across nearly his entire face.
His eyes suddenly became unnaturally lively.
His tongue slowly slipped from his mouth.
Then—
Countless tiny insects began crawling out between his crooked teeth.
One...
Ten...
Hundreds...
Thousands.
The swarm quickly filled the air before charging directly toward Yuki.
"...What the hell?!"
Yuki immediately turned and ran across the frozen sea.
The buzzing behind him grew louder every second.
"Undead creatures..."
"Stretching limbs..."
"Poisonous blood..."
"And now insects?!"
"What kind of monster is this?!"
Chichi's calm voice echoed once more.
"This..."
"...is only the beginning."
"Illman possesses countless techniques."
"Each one is born from a different illness."
"That..."
"...is why he is called Illman."
Yuki gritted his teeth.
The endless swarm continued chasing him across the ocean.
Without slowing down...
He desperately searched for a way to counter Illman's terrifying abilities.
The battle had only just begun.