Not many people could have witnessed that fight.
Even fewer were in close contact with Killua.
Only Wing.
"Yes," Killua nodded.
Kaizen paused for a moment before answering honestly,
"It wasn't my full strength... but it was close."
"Hisoka is strong."
"You're not going to reach his level anytime soon. If you run into him again, it's better not to fight."
"For now, focus on the basics of Nen with Wing."
"A solid foundation is key—things only get harder after that."
"You saw how strong Kastro was."
"To be honest, Killua, the gap between you and Kastro isn't nearly as wide as the gap between Kastro and Hisoka."
Killua's expression grew serious.
At that moment, a question echoed in his mind.
He knew when Kaizen had first learned Nen—it was almost seven or eight years ago.
So… how long would it take him to reach Kaizen's level?
Before encountering Nen, Killua had thought he was already quite powerful.
That confidence slowly led to complacency.
During the Hunter Exam, he'd realized that both Hisoka and Kaizen were stronger than him. But back then, he couldn't quite tell how they were stronger.
He'd assumed it was just age and physical growth.
But after learning Nen, he understood—it was because of Nen.
Even after completing the initiation, Killua's grasp of Nen had still been vague.
But after his match with Kastro…
After watching Kaizen and Hisoka fight…
Only then did he begin to understand Nen's upper limits.
A living beast made entirely of aura.
Transforming aura into fire, lightning, ice, or storm.
Blades of wind. Rubber-like bodies. Entire arenas filled with energy.
If Nen could do all that, what couldn't it do?
Killua's mind was overflowing with possibilities.
He wanted to master the basics fast, develop his own unique Nen ability, grow stronger—strong enough to be among the elite.
"Kaizen," Killua asked, "how long do you think it'll take me to reach Kastro's level?"
Kaizen shook his head.
"I don't know. That's something only you can figure out."
"Kastro's going to be in Heavens Arena for a while. I've already spoken with him, and you have his contact."
"If you really want to know, fight him again."
...
Gon's eyes lit up.
"Kaizen, what about me?"
He had watched Killua's match with Kastro, and it was obvious Kastro was stronger than either of them.
That only made Gon want to fight him even more.
"Sure," Kaizen nodded.
"You can reach out to Kastro yourself. Or invite him to Wing. He's got talent, just like you two."
"Fighting you will benefit him as well."
It was the truth.
Killua and Gon both had exceptional potential.
And Kastro would gain just as much by clashing with them.
...
Just before mealtime, Kaizen brought out a box.
"Killua. This is for you."
"Huh? What is it?"
"A little something. Think of it as a hidden weapon."
Kaizen added, "It's laced with a strong poison. Don't use it unless absolutely necessary. Especially not in sparring matches—if your opponent gets hit, they might not survive it."
It was the same set of poisoned pins that Kikyo had once given Kaizen.
But now, they meant little to him.
Kaizen had grown too powerful—there were far stronger tools at his disposal.
And no one else in his group specialized in hidden weapons.
In Killua's hands, however, they could serve a purpose.
The poison was derived from the rare crystal feather bone.
Years ago, Kaizen had found one at the flea market.
Most of it had already been used. This was the last bit.
Now embedded in the rosary-style pin.
Killua took it, opened the box, and examined it.
"Thanks, Kaizen."
"You don't need to thank me," Kaizen waved a hand and stood up. "It's almost dinner. Head back. I've got some things to take care of."
Kaizen left the restaurant, walked toward the elevator, and returned to his floor.
Shizuku and the others had just about finished cleaning up.
Kaizen didn't need to pack.
He stored everything in the Sumas space anyway.
"Let's go."
"Mm."
...
Sure enough, Nina and the others came to see the group off at the airship station.
"Goodbye!"
"Goodbye, Captain!"
"Take care, Sally!"
"Bye-bye, Shizuku!"
"See you, Tessia!"
The four boarded the airship. Below, Nina and the rest waved from a distance. A few bees circled above Ponzu. Siper, wearing sunglasses, silently watched until the airship disappeared.
"Back to training," Nina said.
While Kaizen was away, Nina was essentially the team leader.
Her experience gave her that role.
Sally had lost her previous memories—everything Kaizen had told her was fabricated.
Shizuku struggled with short-term memory.
Tessia was the youngest.
Ponzu and Siper had only recently joined the team.
Nina was desperate to break through to B-rank Nen.
As for Ponzu and Siper, both were aiming for C-rank.
...
Kaizen had just boarded the airship when his phone rang.
The number was unfamiliar.
He answered.
"Hello?"
"Kaizen. It's me—Hisoka."
Kaizen's expression darkened slightly.
"From your voice, you sound like you've recovered. Why are you calling me? Want to fight again? Or do you have something else in mind?"
"I'm not looking for a rematch anytime soon," Hisoka replied.
"That fight was fun. Your ability and strength really gave me a thrill."
"I could tell you weren't using everything."
"But I'll leave that for later."
"I don't like playing with the same toy too often."
"This call... I just wanted to ask one thing."
"Kaizen—during our fight... how much of your power did you really use?"
Kaizen hesitated for a moment.
"About half."
Hisoka's pupils narrowed sharply.
------------
Fanfic is completed on patreon.com/FanficsHub (1047 chapters in total)