It wasn’t that Killua had disappeared entirely.

He’d simply moved into the blind spot of Kastro’s line of sight, suppressing his aura to the utmost.

...

In the upper stands, Wing’s pupils narrowed.

"Zetsu...?"

He hadn’t taught that to Killua yet.

And yet—Killua had already figured out how to use it.

That made the third time Wing had been caught off guard by the two boys.

The first was when they immediately activated their aura nodes and grasped the concept of Ten.

The second was their performance during the four fundamental exercises.

Whether it was Killua or Gon, both of them had instinctively used techniques in combat that they hadn’t formally been taught.

"Zetsu, huh...?"

"But they’re still not quite there yet."

...

Killua launched toward Kastro.

And just like that, Kastro sensed him.

He glanced over his shoulder.

Killua had thought he’d nailed the opening.

But when their eyes met, a chill ran down Killua’s spine. He immediately pulled back, heart pounding.

No follow-through. No second strike.

He created distance again and exhaled deeply, his face darkening with tension.

"His senses... they’re razor sharp."

"Sharper than anyone I’ve ever had to assassinate."

"So this is what real Nen pressure feels like..."

"It’s far beyond the kind of threat Hanzo posed."

Still, Killua darted forward once more.

If this had been a real assassination mission, he would’ve turned and walked away the moment he was discovered.

But this was a match.

Killua wanted to win—wanted Gon to see him win.

And he’d noticed Kaizen arrive in the stands.

"I refuse to believe there’s no chance."

"There has to be an opening."

...

Kastro kept his gaze locked on Killua, tracking him easily.

While Killua was overwhelmed by Kastro’s sheer pressure, Kastro himself was quietly impressed.

"His growth is visible to the naked eye."

"He’s changed. Even within the course of this match."

Killua vanished again.

"Let’s go... one more time."

This time, he got closer.

But before he could strike, Kastro had already detected him.

The situation was locked in a deadlock.

Killua kept pressing.

Kastro barely moved.

...

In the audience, some spectators grew restless.

"What are they doing?"

"Why aren’t they fighting?"

Only those who truly understood the match felt the intensity hanging in the air.

"They’re both monsters."

"Yeah, that’s what a real fight looks like!"

...

Killua’s eyes narrowed.

"Guess I’ll have to use that."

He stopped cold.

In a flash, over a dozen Killuas surrounded Kastro—front, back, both sides—each one seemingly just as real as the original.

"What the hell?"

The audience stirred, startled murmurs rippling through the crowd.

Hisoka tilted his head toward Kaizen.

"That’s a Zoldyck signature technique. You sure it’s okay to bust that out in a place like this?"

Kaizen shrugged.

"Anyone capable of copying it won’t be stopped."

"And the ones who can’t—well, it won’t matter even if they watch it frame by frame."

"Someone was bound to figure it out eventually."

The truth was, it wasn’t exclusive to the Zoldyck family. Even the butlers of the house had used similar tricks.

And besides, in the Heavens Arena, techniques like this weren’t unheard of.

Still—using it now meant Killua was reaching his limit.

...

Kastro’s brows furrowed.

"Impressive... but not enough."

...

Then, Killua made his move.

Over a dozen afterimages surged toward Kastro at once, surrounding him like a pack of wolves.

Kastro stepped forward.

As if facing down a dozen enemies at once, he launched into motion.

Their speed was beyond what most eyes could follow.

Blows traded in a blur, invisible save for the sound.

...

The crowd exploded.

"That’s more like it!"

"This is insane!"

"Totally worth the ticket price!"

...

Up in the stands, a rookie assassin watching Killua’s performance felt his stomach twist.

"This kid’s terrifying..."

"Good thing we didn’t fight yesterday."

"There’s no way I could handle that."

"I’m not Kastro. If we’d faced off, I’d be lying face-down in seconds."

"And that kind of loss? It’d stick with me."

"No way I’d accept that."

...

The battle raged on. From one end of the ring to the other and back again, they clashed, over and over.

But something felt off to Killua.

Kastro wasn’t fighting at full strength.

There were clear openings—Killua knew they were there.

But Kastro didn’t react to them.

"What’s going on...?"

"Is he holding back?"

"Or is something else going on?"

Killua didn’t stop to figure it out.

The battle had reached a point of no return.

Once it started, neither side could step away.

Even if you wanted to retreat, even if you knew it was too much, the pressure of the other forced you forward.

Boom!Boom!Boom!

...

Hisoka sighed, interest fading from his eyes.

"Meh."

"Kaizen, this is getting dull."

"Your match setups are getting lazy."

Kaizen didn’t even glance at him.

"If it’s boring, don’t watch."

...

Killua’s stamina was tanking fast.

The match hadn’t been long in duration, but the energy burned was on another level.

It wasn’t even comparable to normal training.

A few minutes here felt like ten hours on the treadmill.

His movements grew slower.

Kastro noticed—and subtly adjusted.

He slowed down slightly, just enough to let Killua keep pace.

But still fast enough to force Killua to keep pushing, harder and harder.

To bring him to his limit—and maybe beyond.

Exactly what Kaizen had intended all along.

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Fanfic is completed on patreon.com/FanficsHub (1047 Chapters in total)