"...Leo?"
The words barely left Kotaro's mouth before everything changed.
Dark energy exploded outward.
The magical circle beneath him shattered.
The floor cracked.
The walls groaned.
And then—
Kotaro vanished.
BOOM!
The shockwave alone blew glass and equipment across the chamber.
Leo's eyes widened.
"Shit—"
Then Kotaro appeared directly in front of him.
Not moving.
Already there.
The speed was absurd.
Even for a Taimanin.
Even for a Fuuma.
CRASH!
Kotaro slammed into Leo.
The impact launched both of them through the wall.
Then another.
Then another.
Concrete exploded around them.
Steel supports bent.
Alarms immediately began screaming throughout the facility.
Back in the chamber.
Everyone stared.
Silence.
Then Tatsuro's voice came through the earpiece.
"...That was Mach Jesus."
Nobody knew how to respond to that.
Meanwhile.
Several rooms away.
Leo crashed through another wall before finally stopping.
Dust filled the air.
Broken concrete covered the floor.
He pushed himself up.
His body unharmed.
But his expression had changed.
"Well."
He spat out some dust.
"That hurt my pride."
Across the ruined room—
Kotaro stood silently.
The transformation had fully completed now.
White armor-like biomass covered parts of his body.
Blue energy flowed through cracks in the structure.
A tail moved behind him.
Sharp wings folded against his back.
His eyes glowed.
And dark power rolled off him like a storm.
Leo immediately recognized the problem.
'That's not a Fuuma Demon Mark.'
Alex's voice suddenly appeared.
'Correct.'
James spoke next.
'It's mixed with something else.'
Leo narrowed his eyes.
'Blacklight?'
'No.'
Alex sounded disturbed.
'Something demonic.'
That wasn't good.
That was very much not good.
---
Kotaro looked around.
Confused.
Disoriented.
Like someone trapped between dreams.
Then his eyes landed on Leo again.
For a moment—
Recognition appeared.
"K-Ky..."
The words died.
Pain crossed his face.
He grabbed his head.
The room shook.
Energy surged wildly.
The transformation became unstable.
Leo slowly raised his hands.
Not attacking.
Trying to calm him.
"Kotaro."
No response.
"Kotaro, look at me."
The young Fuuma trembled.
Blue energy erupted from his body.
Machines nearby exploded.
Walls cracked.
"Kotaro!"
For a second—
His eyes focused.
Actually focused.
"Leo..."
Then the energy surged again.
And Kotaro roared.
The sound shook the entire facility.
Back in the main chamber.
Oboro stared toward the distant explosion.
"...Well."
Asagi pointed her sword directly at her.
"You knew."
Oboro sighed.
"I knew they were experimenting on him."
Another explosion echoed.
The floor trembled.
Oboro looked genuinely annoyed.
"I did not know they would succeed."
Tatsuro's voice came through everyone's earpieces.
"Correction. They didn't succeed."
Everyone blinked.
Rinko frowned.
"What?"
Tatsuro answered instantly.
"Their readings are unstable."
A holographic graph appeared on their communicators.
The numbers were ridiculous.
"Kotaro's body is actively rejecting whatever they put into him."
Yuuko paled.
"How bad?"
Tatsuro was silent for a second.
Never a good sign.
Then—
"Best case scenario?"
Another explosion echoed.
"He levels this facility."
Silence.
"Worst case?"
Everyone waited.
"...I don't have a worst case scenario chart big enough."
Back in the ruined room.
Leo stared at his cousin.
The transformation reminded him of something.
Not just a Fuuma Demon Mark.
Not just demonic power.
It reminded him of himself.
A power forced into a body.
A body trying desperately to control it.
The difference was—
Leo had years.
Kotaro had minutes.
The transformed Fuuma looked at him again.
The rage.
The confusion.
The pain.
All mixed together.
Then he crouched.
Preparing to launch himself again.
Leo sighed.
His Blacklight began spreading across his arms.
"Great."
More biomass formed.
Claws emerged.
The Hell Blade appeared in his hand.
Black water dripped from its edge.
"I came here to rescue my cousin."
Kotaro roared.
Leo pointed the blade at him.
"And now I have to beat some sense into him first."
Then Kotaro attacked.
And this time—
Leo charged too.
The two collided.
BOOM!
The shockwave ripped through the facility.
Windows shattered.
Steel supports bent.
Several unfortunate security cameras simply gave up and exploded.
Back in the control room, Tatsuro watched six monitors go black.
"...Those were expensive."
Kotaro's fist met Leo's claw.
For a brief moment, neither moved.
Then Kotaro grabbed Leo by the arm.
Leo immediately realized that was a mistake.
Not Kotaro's.
His.
"Oh no—"
CRASH!
Kotaro hurled him through a wall.
Then another.
Then another.
Then apparently decided walls were a suggestion rather than an obstacle.
Leo smashed through five rooms before finally hitting a reinforced support column.
The column lost.
Leo slid down the rubble.
"...Ok."
He stood up slowly.
"That hurt."
Not badly.
But enough to be annoying.
He rolled his shoulder.
Something popped back into place.
"Definitely hurt."
Across the ruined corridor, Kotaro stood silently.
The transformation wasn't becoming more unstable.
Quite the opposite.
It was stabilizing.
That worried Leo more.
The energy around Kotaro was becoming smoother.
Controlled.
Refined.
Like his body was adapting.
Like it was accepting the power.
'That's not good.'
Leo studied him carefully.
Over the years, he'd seen his mother's Fuuma Demon Mark several times.
Some people called it the Fuuma Demon Mark.
Others called it a Devil Trigger.
The name depended on who you asked.
Regardless—
The transformed Fuuma always looked intimidating.
Monstrous.
Like something straight out of a Kamen Rider villain organization.
His mother's form had been powerful.
Terrifying.
A perfect fusion of Fuuma bloodline and Taima particles.
Kotaro's was different.
Very different.
The armor was cleaner.
More complete.
The energy output was absurd.
And somehow—
It looked evolved.
Leo stared.
Then the realization hit him.
'Oh, you've got to be kidding me.'
Alex immediately understood.
'You figured it out.'
Leo mentally groaned.
'The Demon Mark gets stronger every generation.'
'Appears so.'
James sounded amused.
'Congratulations. Your cousin is apparently the next model.'
'Wonderful.'
'You don't sound happy.'
'Because I'm the one fighting him.'
Kotaro suddenly moved.
Leo barely reacted in time.
A claw slashed past his face.
The pressure alone carved a trench into the wall behind him.
Leo jumped back.
Then further back.
Then even further back.
"Kotaro!"
The transformed Fuuma stopped.
For half a second.
Just half.
Then his head tilted.
Like he recognized the voice.
"Le..."
The word came out distorted.
Broken.
But it was there.
Leo immediately pointed.
"There you are."
Kotaro twitched.
The energy around him flickered.
For a moment, the monstrous form seemed smaller.
Then the corruption surged again.
The moment vanished.
Back in the observation room.
Oboro watched the fight through a damaged monitor.
Asagi stood nearby with her sword ready.
Neither trusted the other enough to blink.
Yuuko stared at the readings.
"...Those numbers make no sense."
Tatsuro appeared on a nearby screen.
"They make perfect sense."
Everyone looked at him.
"They're horrifying."
Pause.
"But they make sense."
Rinko sighed.
"That's not helping."
Tatsuro zoomed in on the energy graph.
"Nomad artificially awakened the Fuuma Demon Mark."
"Impossible," Mizuki said.
"Normally yes."
He adjusted his glasses.
"However, they had one advantage."
Everyone waited.
Tatsuro pointed toward Kotaro's data.
"They had a living Fuuma."
Silence filled the room.
Nobody liked where that sentence was going.
Back with Leo.
Kotaro rushed him again.
This time Leo didn't dodge.
Their fists collided.
The floor beneath them exploded.
Both slid backward.
Kotaro stopped first.
Leo noticed immediately.
'His strength keeps increasing.'
Alex agreed.
'Adaptation.'
James sounded concerned.
'He's evolving during combat.'
Leo sighed.
'Why can't anything ever be easy?'
Then something happened.
Kotaro looked directly at him.
Not through him.
At him.
For a brief moment, the madness cleared.
The glowing eyes focused.
And Leo heard it.
"...Help."
The word was quiet.
Almost impossible to hear.
But Leo heard it.
Then the Demon Mark surged again.
The moment disappeared.
Kotaro roared and charged.
Leo tightened his grip on the Hell Blade.
His joking attitude vanished.
The grin vanished.
Everything vanished.
Only determination remained.
"Hang in there, Kotaro."
Black water began flowing from the blade.
His claws emerged.
His Taima particles flooded the corridor.
"I'm getting you out of here."
Even if he had to beat the Demon Trigger out of him first.
The battle continued.
BOOM!
Their fists collided again.
The entire floor cracked beneath them.
Leo swung with his claw.
Kotaro blocked.
Kotaro kicked.
Leo caught it.
Then Kotaro grabbed him.
"Oh come on—"
CRASH!
Leo was slammed straight through the floor.
Concrete exploded.
Metal supports snapped.
Leo dropped into darkness.
Dust filled the air.
For a moment everything was silent.
Then—
THUD.
Leo landed on another floor.
He blinked.
"...There was another floor?"
Apparently there was.
A second later—
BOOM!
Kotaro crashed down after him.
The lower chamber was enormous.
Old.
Forgotten.
Research equipment covered the walls.
Half-finished experiments sat abandoned.
Nomad apparently never threw anything away.
Kotaro landed.
His Demon Trigger form looked even more stable now.
Blue energy flowed across the white armor covering his body.
His wings expanded.
The room shook.
Leo slowly stood.
He cracked his neck.
"Ok."
He rolled his shoulders.
"New plan."
Kotaro immediately rushed him.
Leo sighed.
"There is never a new plan."
The Hell Blade appeared in his hand.
Black water flowed along its edge.
Leo entered a stance.
One he had used thousands of times over the years.
Then he remembered something.
"Oh right."
He pointed the sword.
"Water Ninja Arts."
He paused.
"...I still hate that name."
The elders had insisted on calling it that.
Even after seven years.
Leo still preferred Water Breathing.
It sounded cooler.
Kotaro attacked.
Leo moved.
Like flowing water.
Like a river changing direction.
Like a wave slipping around stone.
The Hell Blade danced.
Water Ninja Arts: First Form.
A flowing slash.
Black water erupted.
Normal water mixed with it.
The attack struck Kotaro directly.
For the first time—
Kotaro slid backward.
Leo grinned.
"Got you."
Kotaro looked down.
The armor on his chest had been cut.
Not deeply.
But enough.
Enough to prove something.
He could still be hurt.
Then Kotaro smiled.
That immediately worried Leo.
"Why are you smiling?"
The Demon Trigger Fuuma vanished.
Leo barely blocked.
BOOM!
The impact launched him through three pillars.
Leo rolled to his feet.
'He's adapting.'
Alex immediately answered.
'Correct.'
James sounded impressed.
'Actually, he's adapting faster than you did.'
'Wonderful.'
Kotaro appeared again.
Faster.
Stronger.
The room barely contained him anymore.
The Demon Trigger wasn't just empowering him.
It was evolving him.
Every second.
Every attack.
Every exchange.
Leo dodged another strike.
A pillar exploded behind him.
Then another.
Then another.
The entire floor was starting to collapse.
He sighed.
'Mom was scary.'
Kotaro punched.
Leo dodged.
'Grandpa was scary.'
Another punch.
Another dodge.
'But this?'
Kotaro's tail nearly took his head off.
Leo ducked.
'This kid is twenty-three and somehow became the strongest Fuuma in history.'
Alex laughed.
Actually laughed.
'Sounds familiar.'
Leo pointed mentally.
'Not helping.'
Kotaro rushed again.
The chamber exploded around them.
Water swirled around Leo's blade.
Black water mixed with it.
His Taima particles spread.
Searching.
Analyzing.
Waiting.
Because Leo wasn't looking for a way to win.
He was looking for a way to save him.
And those were two very different things.
For the first time in years—
The Blind Taimanin was losing ground.
Not because he was weaker.
But because he cared too much about the person standing in front of him.
Kotaro rushed forward.
The floor shattered beneath his feet.
His claw aimed directly for Leo's chest.
Fast.
Too fast.
Even Leo knew he wasn't going to dodge in time.
Then—
A voice spoke.
Not from outside.
Inside.
'Kid.'
Leo blinked.
'James?'
The voice sounded serious.
Which immediately worried him.
'Something is happening to you.'
Leo felt it.
A burning sensation.
Not painful.
Just... intense.
His back felt hot.
Like something was carving itself into his skin.
Like a mark was being written into existence.
His eyes widened.
'Don't tell me—'
A magical circle erupted beneath him.
Pink light exploded outward.
The entire underground facility shook.
Every light flickered.
Every machine overloaded.
Every magical sensor instantly broke.
Kotaro's claw came down.
Leo instinctively raised his arm.
Pink fire erupted.
BOOM!
For the first time—
Kotaro stopped moving.
His attack had been blocked.
Completely.
The chamber vanished behind a wall of light.
Pink.
Black.
Crimson.
The energy climbed toward the ceiling like a pillar connecting earth and sky.
Back upstairs.
Everyone stopped.
Asagi looked down.
"...Leo?"
Yuuko's eyes widened.
"No way."
Kurenai immediately drew her sword.
Not because she was afraid.
Because her instincts were screaming.
Something had just been born.
Even Oboro took a step backward.
And Oboro wasn't the type to step backward.
Far away.
In Hell.
Astaroth sat upright on her throne.
The smile vanished from her face.
For the first time in years.
She looked genuinely shocked.
"...Impossible."
The light slowly faded.
The flames remained.
Pink and magenta fire swirled through the chamber.
Like a living storm.
Like a crown of destruction.
Then everyone saw him.
Or rather—
What he had become.
The figure standing there barely resembled a human.
Its body was covered in sleek obsidian armor.
Black as midnight.
Every plate looked alive.
Sharp.
Angular.
Predatory.
Crimson energy flowed through the armor like blood through veins.
Glowing lines pulsed beneath the surface.
The helmet resembled a demonic skull.
Several glowing red eyes stared through narrow slits.
A crown of jagged horns curved backward.
Massive blade-like wings unfolded from his back.
Not feathered.
Not draconic.
Weapons.
Each one looked capable of cutting buildings apart.
Pink flames rolled from the armor.
From the shoulders.
From the wings.
From the tail.
A long bladed tail swept behind him.
Cutting a trench through solid steel without touching it.
Silence filled the chamber.
Nobody moved.
Nobody spoke.
Then Alex finally broke the silence.
'...Well.'
James sounded equally stunned.
'That's new.'
Leo slowly looked down at his armored hand.
Then opened and closed it.
The armor moved naturally.
Like it had always been there.
Like it belonged.
He could feel everything.
The Blacklight.
The Hell Blade.
The Fuuma bloodline.
The Demon Mark.
All of it.
Connected.
Unified.
Balanced.
Across from him—
Kotaro stared.
For the first time since the battle started.
The rage disappeared.
The confusion disappeared.
Even the Demon Trigger seemed shocked.
Leo looked at him.
His voice echoed through the chamber.
Deeper.
Stronger.
Almost metallic.
"Well."
Pink flames rolled from his shoulders.
"I guess we're both having a weird day."
For the first time since the fight began—
Kotaro laughed.
A short laugh.
Confused.
Disbelieving.
Like even he couldn't believe what he was seeing.
Then he pointed at Leo.
"...What the hell are you?"
Leo looked at himself.
Looked at the wings.
The tail.
The armor.
The flames.
Then shrugged.
"Honestly?"
He pointed at Kotaro.
"I was about to ask you the same thing."
To be continue
Hope people like this Ch and Give me power stones and as for the Devil Trigger look in the comment