Killua watched the two of them play off each other, then looked at Wing's half-smiling expression, and finally at Leo's look of waiting for a good show.
He took a deep breath and lowered his head as if resigned to his fate.
"Master Wing."
He turned to Leo again, a hint of reluctance in his voice, but he still called out honestly.
"Hello... Martial Uncle Leo."
Gon also hurriedly followed suit.
"Master Wing! Hello, Martial Uncle Leo!"
Leo intentionally dragged out the last syllable.
"Mmm~~~ Not bad!"
He looked at Wing.
Although Wing had never let Gon and Killua call him Master, hearing the two children address him like this now still brought a gratified smile to his face.
Leo stood up.
"Good, since you've called me Martial Uncle, then as your Martial Uncle, I have to show some appreciation."
He walked over to Gon and Killua.
"I'll impart some cultivation knowledge to you."
In the original story, Wing only taught Gon and Killua some basic techniques, not even informing them about the Advanced and high-level applications of Nen, just like a certain mediocre teacher in One Piece.
Wing froze for a moment, then an annoyed expression appeared on his face.
Imparting cultivation knowledge? Then what was he, the Master, teaching?
He opened his mouth, wanting to retort, but looking at Leo's smiling face and remembering that he really couldn't beat him...
Wing picked up his book and began to read silently.
Whatever, he'd just treat it as giving himself a vacation.
Chiharu stood to the side, smiling awkwardly.
Gon, however, was so excited he almost jumped up.
"Really?! That's great! Thank you, Martial Uncle Leo!"
Killua rubbed his nose and looked at Leo.
He hadn't expected that this person would actually take the initiative to offer to teach them.
It seems... he's not that annoying after all.
Leo beckoned to them.
"Come here and sit down."
Gon and Killua obediently sat in front of him.
Chiharu also leaned in, listening intently.
Leo began to explain.
From the perception range of 'En', to the object attachment of'Shu', from the defensive reinforcement of 'Ken', to the localized condensation of 'Ko', and then to the distribution of Qi volume in 'Ryu'...
He explained in detail, one by one, the Advanced techniques that a Nen User needs to master.
Gon's eyes sparkled as he listened, nodding from time to time.
Killua was a bit nonchalant at first, but as he listened, his gaze gradually became serious.
Wing indeed hadn't taught them these things yet.
Or rather, he hadn't had the chance to teach them yet.
Wing sat to the side, watching leisurely.
He watched Leo seriously explain to the two children, the corners of his mouth curling up slightly.
Though he wouldn't admit it, he knew Leo was doing this to help him.
Both children were very talented; with Leo's guidance, their progress would be much faster.
He was happy to have the leisure.
It was a good chance to rest for a few days.
Outside the window, sunlight spilled into the room, shining on the group.
Time passed slowly amidst the explanations and questions.
Over the next few days, Leo completely instilled the basic framework of Nen Ability into the three children.
He spoke in great detail, without a single wasted word.
From the stability of 'Ten' to the application of 'Zetsu', from the Qi volume increase of 'Ren' to the ability development of 'Hatsu'.
He explained clearly what should be mastered at each stage and how to use it.
Gon's eyes shone as he listened, raising his hand to ask questions from time to time.
Killua was much quieter; he kept his hands in his pockets, occasionally nodding or frowning.
But Leo noticed that when he was listening, those cat-like eyes were much brighter than usual.
Chiharu sat next to Gon, listening very seriously.
Wing sat to the side with a teacup, listening leisurely and occasionally adding a word or two.
On the afternoon of the third day, Leo spoke about the practical application of 'Ken'.
"A qualified Nen User."
His voice wasn't loud, but it clearly reached everyone's ears.
"'Ken' must be maintained for over half an hour in battle."
Gon and Killua looked at each other, both seeing shock in the other's eyes.
"Half an hour?"
Right now, they couldn't even hold 'Ken' for more than a few minutes.
"How many minutes can you hold it for now?"
Leo asked.
"Five minutes..."
Gon scratched his head, looking a bit embarrassed.
Killua curled his lip.
"Seven minutes."
"That's in a static state."
Leo nodded.
"In battle, you also have to perform offense and defense, movement, and judgment simultaneously; the consumption of Qi will increase manifold."
"With your current level, you'll be lucky to last two minutes."
Gon and Killua fell silent.
"But this isn't your fault."
Leo's tone softened a bit.
"You've only been exposed to Nen for a month or two; being able to reach this point is already very good. There are no shortcuts in the cultivation of Nen; it's the accumulation of day after day."
He then taught the techniques of 'Ryu' and 'Ko', and finally mentioned a concept that made all three children prick up their ears.
"Vows and Limitations."
Gon blinked.
"What's that?"
"A means of strengthening one's Nen Ability."
Leo explained.
"By setting rules and restrictions for yourself in exchange for greater power. The stricter the rules and the greater the risk, the stronger the power obtained."
He paused, looking into the eyes of the three youngsters.
"But remember, once a vow is made, it cannot be broken. The price of breaking it could be the loss of your Nen Ability, or even your life."
Gon nodded seriously, Killua was lost in thought, and Chiharu recorded everything quickly in his small notebook.
Wing listened from the side without interrupting.
He certainly knew these things as well, but he had never taught them to these two children as systematically and unreservedly as Leo.
It wasn't that he didn't want to teach them, but that the time hadn't come yet.
But Leo clearly had a different view.
Three days later, Kastro returned to the Heavens Arena.
When he came to Wing's room, he saw this scene—Gon and Killua sitting cross-legged on the floor meditating, Chiharu adjusting his breathing nearby, Leo leaning by the window looking at the scenery, and Wing leisurely drinking tea.
"Master Leo, Mr. Wing, hello!"
Kastro lowered his head slightly.
Gon and Killua opened their eyes at the same time.
Seeing the silver-haired, white-robed figure at the door, Gon's eyes instantly lit up.
"It's Kastro!"
Killua also recognized him—a celebrity on the 200th floor of the Heavens Arena with an illustrious record and formidable strength.
"Hello!"
Kastro walked into the room, his gaze falling on the two children.
"They are my Senior Brother's disciples."
Leo introduced them simply.
"Gon, Killua."
Kastro looked the two children over and nodded.
Gon excitedly approached.
"Mr. Kastro, are you and Martial Uncle Leo in a master-disciple relationship?"
"Yes, Master Leo is my teacher," Kastro said.
Gon and Killua were both stunned.
Kastro was Leo's disciple?!
"That's amazing!"
Gon's eyes shone even brighter.
"The disciple Martial Uncle Leo taught is so strong!"
Killua didn't say anything, but his gaze toward Leo held a hint of complexity.
Leo stood up and patted the creases on his clothes.
"Kastro, I'll leave the rest to you."
Kastro was taken aback.
"Master Leo, are you leaving?"
"No, it's just that now that you're here, I can take a break."
Leo shrugged and explained.