The explosion swallowed the entire battlefield.
For several seconds, nothing could be seen.
The ocean continued roaring in the distance, but the sound of the battlefield itself had disappeared beneath the enormous cloud of smoke and mist.
Kaguya's Spiritual Beam had collided directly with the mysterious black sword.
And then—
BOOOOOOOOOOM!
The shockwave had spread across the edge of the world.
The mist slowly began to disappear.
Piece by piece.
The ground became visible again.
The ocean returned to view.
And finally—
Two figures emerged from the darkness.
Leo was still on one knee.
His breathing was heavy.
His body was covered with the injuries from the battle.
But the black sword was still standing between him and Kaguya.
Leo stared at it.
His eyes narrowed.
"What is this sword?..."
He looked at the blade carefully.
"Did it come here to save me?"
His eyes shifted toward Kaguya.
"Or did it come here for her?"
He couldn't understand it.
He had never summoned this sword.
He had never even understood why it had appeared around his waist inside the Wind Temple.
But now—
It had appeared at exactly the moment he was about to be defeated.
Leo slowly reached toward it.
The moment his fingers touched the black blade—
Hssssssss...
A strange sound came from the sword.
Steam began rising from its surface.
Leo froze.
"What?"
The black metal started changing.
Its solid surface began to melt.
But it didn't fall apart.
Instead, the sword transformed into a strange black liquid.
The liquid flowed upward.
Then it began moving around Leo's arm.
Leo's eyes widened.
"Whoa—!"
The black substance crawled across his body.
It moved around his shoulders.
Across his chest.
Around his back.
Down his legs.
It surrounded him like a living shadow.
Leo tried to move.
"What the hell is happening?!"
The liquid suddenly entered his body.
It dissolved into him.
And then—
BOOM.
A dark pulse spread through his entire body.
Leo's eyes widened.
The pain that had been overwhelming him suddenly disappeared.
The injuries across his body began recovering.
His breathing stabilized.
The strength that had almost disappeared from his body returned.
Leo stared at his hands.
"...It's healing me."
But this wasn't ordinary healing.
Something much deeper was happening.
The black energy was moving through his spiritual pathways.
It was repairing his body from within.
Leo's expression became serious.
"This power..."
He could feel it.
It wasn't unfamiliar.
He had felt this energy before.
Long ago.
Inside his consciousness.
Behind something he had been warned never to open.
The black sword completely disappeared into his body.
Then—
BOOM!
The darkness gathered around his right hand.
The liquid condensed.
It became solid again.
A sword appeared in his hand.
But this time—
It wasn't the strange giant blade from before.
It had become a katana.
A completely black katana.
Leo slowly lifted it.
The blade reflected no light.
Not even the light of the sky.
Kaguya stared at him.
Her expression changed.
"What... are you?"
Leo didn't answer.
Something was happening to his face.
The white area around his eyes slowly began turning black.
The darkness spread outward.
His eyes became completely different.
One eye remained surrounded by darkness.
Then—
The iris of one eye slowly turned red.
Completely red.
No ordinary color remained.
A dark aura began circulating around his body.
Not exploding.
Not raging.
Just moving.
Slowly.
Silently.
Like something alive.
Leo's expression became strangely calm.
Inside his consciousness—
The Lion King suddenly opened his eyes.
The moment he felt the energy—
His expression changed.
"No."
He immediately stood.
"Leo."
Leo's consciousness appeared before him.
"What?"
The Lion King stared at him.
"That sword."
Leo looked at him.
"You know what it is?"
The Lion King didn't answer immediately.
His eyes moved toward the darkness in the distance.
Toward the sealed door.
The same door Leo had been warned about.
The door that must never be opened.
The Lion King spoke quietly.
"That power..."
He clenched his teeth.
"...is coming from behind that door."
Leo's expression changed.
"The door?"
The Lion King nodded.
"I told you before."
His voice became serious.
"Never open it."
Leo looked toward the enormous sealed door inside his consciousness.
Black energy was leaking through the cracks.
Only a tiny amount.
But even that tiny amount had been enough to completely change Leo.
Leo whispered:
"So this sword..."
The Lion King looked at him.
"It isn't just a sword."
Leo stared at the black katana in his hand.
"It was sealed inside me?"
The Lion King nodded.
"And now..."
He looked worried.
"...some of that power has started leaking out."
Leo slowly tightened his grip.
"I understand."
The Lion King shouted:
"NO! YOU DON'T UNDERSTAND!"
Leo looked at him.
The Lion King pointed toward the door.
"If that door ever opens completely..."
He paused.
"...I don't know what will happen to you."
Leo became silent.
Then he smiled slightly.
"Then I won't open it."
The Lion King stared at him.
"Promise me."
Leo nodded.
"I promise."
The consciousness disappeared.
Leo returned to the battlefield.
Kaguya was still standing in front of him.
She had been watching everything.
Her expression had changed completely.
"Interesting..."
Leo raised the black katana.
Kaguya smiled.
"So you've found another power."
Leo didn't answer.
Kaguya suddenly disappeared.
BOOM!
Her blade came toward his neck.
Leo moved.
CLANG!
The black katana blocked it.
Kaguya's eyes widened.
Leo had moved faster than before.
She pulled back.
Leo followed.
SLASH!
Kaguya barely dodged.
A cut appeared across her Guardian armor.
For the first time—
She had been touched.
Kaguya stared at the damaged armor.
Then at Leo.
"...You."
Leo's red eye stared directly at her.
Kaguya attacked again.
Both of her chained weapons came from opposite directions.
Leo ducked beneath one.
Jumped over the other.
The black katana moved.
CLANG!
One weapon was knocked aside.
Leo turned.
BOOM!
He kicked Kaguya backward.
She flew through the air.
She recovered instantly.
The chains extended.
Her two weapons came flying toward Leo.
Leo didn't dodge.
He simply raised the katana.
SHIIIIING!
A dark wave came from the blade.
The two weapons were pushed away.
Kaguya's expression became serious.
She rushed forward.
Leo rushed toward her.
They collided.
BOOOOOOM!
The impact created a massive shockwave.
The ocean rose behind them.
Leo's wings spread.
Kaguya's weapons moved like extensions of her own body.
She changed weapons constantly.
Sword.
Blade.
Chain.
Hammer-like strikes.
Every movement was different.
That was the terrifying ability of the Weapon Master Guardian.
She had mastered countless weapons.
But Leo's black katana adapted to every attack.
Their battle moved across the entire battlefield.
CLANG!
BOOM!
WHOOSH!
CRASH!
Kaguya attacked from above.
Leo blocked.
She attacked from behind.
Leo turned before she arrived.
She threw her chained blade.
Leo cut the chain.
Kaguya immediately grabbed another weapon.
Leo's dark aura intensified.
His red eye followed her every movement.
For the first time—
Kaguya couldn't understand what she was fighting.
"This isn't normal Spiritual Energy..."
She thought.
"What exactly is inside this boy?"
Leo suddenly appeared behind her.
Kaguya turned.
Too late.
BOOM!
She was struck and sent flying.
She crashed across the ground.
Leo landed several meters away.
His black aura slowly moved around him.
Kaguya stood again.
Her armor was damaged.
She looked at Leo.
Leo looked back.
"You're finished."
Kaguya gritted her teeth.
"Don't underestimate me!"
She raised both weapons.
A huge amount of Spiritual Energy gathered around her.
The entire battlefield shook.
Leo lowered his katana.
His red eye became brighter.
Kaguya screamed and charged.
Leo moved.
One step.
Then another.
And then—
SLASH!
A single black arc crossed the battlefield.
Silence.
Kaguya stopped.
Her weapons fell from her hands.
Her red eyes slowly returned to their normal color.
The darkness surrounding her body began disappearing.
Her Guardian form started shrinking.
The giant pressure disappeared.
The red glow faded.
Kaguya fell to one knee.
"...What..."
Her voice became weak.
Leo walked toward her.
He lowered the katana.
"Wake up."
Kaguya looked at him.
The red glow in her eyes disappeared completely.
Her normal eyes returned.
She blinked.
"...Leo?"
Leo smiled.
"Welcome back."
Kaguya looked around.
She finally realized where she was.
"What... happened?"
"You were being controlled."
Kaguya touched her forehead.
Her expression slowly changed.
"...The Demon Queen."
Leo nodded.
"Yeah."
Kaguya lowered her head.
"I'm sorry."
Leo shook his head.
"You weren't yourself."
Kaguya looked at him.
Then suddenly—
The dark aura around Leo disappeared.
The blackness around his eyes vanished.
His red eye returned to normal.
His horns disappeared.
His wings faded.
His hair slowly returned to normal.
And the black katana—
Hssssssss...
It transformed into liquid.
The black substance flowed backward.
It entered Leo's body.
Then disappeared completely.
Inside his consciousness—
The black energy returned behind the sealed door.
The sword reappeared on the other side.
And the door remained closed.
Still sealed.
Leo opened his eyes.
Everything was normal again.
Kaguya slowly stood.
The two looked toward the battlefield.
The war was still waiting for them.
Leo extended his hand.
"Let's go."
Kaguya looked at his hand.
Then smiled.
She took it.
"Let's go."
A teleportation portal opened around them.
The two disappeared from the edge of the world.
And somewhere deep inside Leo's consciousness—
Behind the sealed black door...
Something moved.
Just once.
BOOM.
Leo's eyes opened for a fraction of a second.
Then the door became silent again.
The Main Guardian Arc had finally come to an end.
But the power behind that door...
Had only just begun to awaken.