"BOOM—!!!"
A massive explosion, like a thunderclap on a clear day, instantly shattered the morning silence of the Jujutsu High training grounds.
Debris flew in every direction.
Before the stunned gazes of Yuji Itadori, Megumi Fushiguro, and Nobara Kugisaki...
That hard clay gourd, nearly half a person's height, had actually been blown apart.
Indeed, it wasn't done with a fist or with jujutsu—it was done solely by blowing air into it.
"Phew..."
Yoru slowly exhaled a plume of white mist—high-temperature steam released after the air in his lungs had been compressed to its absolute limit.
He brushed off the clay fragments clinging to him, turned around, and flashed the three dumbfounded students a terrifyingly 'kind' smile.
"As you can see, this is advanced training for Total Concentration: Constant."
"Through high-intensity breathing, you strengthen your cardiopulmonary function, allowing your blood to instantly transport massive amounts of oxygen to every cell in your body."
"Cough, cough..."
Having said this, Yoru couldn't help but cough a few times, his face turning slightly pale.
Clearly, the internal injuries from his previous battle had not yet fully healed.
"When you can blow up this specially-made, high-hardness gourd without effort, then congratulations."
"Your physical capabilities will be roughly thirty percent of what mine are now."
There was a dead silence.
The three looked at the shards on the ground, then back at Yoru's harmless-looking face, and swallowed hard simultaneously.
"You... you're a monster!!!"
Nobara Kugisaki was the first to scream, clutching her head in a total breakdown.
"A gourd that hard would take effort even with a hammer!"
"And you just used your breath?!"
"Are your lungs made of iron? Or are you some kind of high-pressure air pump incarnate?!"
"Though it's hard to believe..."
Megumi Fushiguro crouched down and picked up a shard. Feeling its incredible thickness and hardness, his face went a bit pale.
"But if one can truly achieve this, their physical explosiveness would indeed reach a terrifying level."
"To reach this level without even using cursed energy reinforcement..."
A spark of fervor flashed in his eyes.
As a descendant of the Zenin family, although he inherited the Ten Shadows Technique, he had always hoped to further his physical martial arts.
Especially after seeing the power of a Heavenly Restriction like Toji's (though he didn't know that was his father).
"Let me try! Let me try!"
Only Yuji Itadori, the physical freak, showed no fear. Instead, he raised his hand with an excited expression.
"This looks like fun!"
"Oh? Then let's start with Itadori-kun."
Yoru produced three slightly smaller gourds from behind him and handed them over.
"These are entry-level; they're only a tenth as hard as the one just now."
"Just maintain a specific breathing rhythm, concentrate the airflow in your abdomen, and then..."
Five minutes later.
"Mmm-mmm-ghhh!!!"
Yuji's face turned the color of a pig's liver, his cheeks bulging like a pufferfish, and veins popped on his forehead.
He felt as if his lungs were about to burst.
But that damn gourd only vibrated slightly, showing no sign of cracking.
"Your rhythm is off."
Yoru's voice drifted in at the right moment as his bamboo sword lightly tapped Yuji's abdomen.
"Don't use brute force. Feel the flow of your blood. Imagine the oxygen is fuel and your heart is the engine."
"Inject the fuel into the engine and let it burn!"
Perhaps it was due to his unique constitution as Sukuna's vessel, or perhaps it was Yuji's innate talent.
The second after Yoru gave him the tip, the look in Yuji's eyes changed.
His breathing suddenly became long and deep, and his previously chaotic aura instantly tightened like a coiled rope.
Crack!
A faint sound of fracturing echoed.
A tiny hairline crack actually appeared on the surface of the gourd in Yuji's hands!
"Oh?"
Yoru raised an eyebrow, a hint of admiration flashing in his eyes.
"Not bad, Itadori-kun. You're a quick learner."
"Ha... ha... ha..."
Yuji let go, gasping for air as he collapsed onto the ground, drenched in sweat.
"I... I can't... anymore..."
"I feel like... I'm going to vomit up my internal organs..."
Although he looked pathetic, he could clearly feel the surge of power within his body from that moment.
That power was more direct and violent than simple cursed energy reinforcement!
"Hey, hey, are you serious?"
Seeing Yuji already making progress, Nobara gritted her teeth and picked up a gourd, unwilling to be outdone.
"How can I lose to this idiot!"
"Mmm—Cough, cough, cough!"
After just one puff, she was coughing so hard that tears streamed down her face.
"This isn't meant for humans! Yoru, you're a devil!"
Compared to Nobara's temper, Megumi was much more composed.
He didn't rush to blow into the gourd. Instead, he closed his eyes, adjusting his breathing rhythm and trying to integrate this breathing technique with his own cursed energy flow.
*'Total Concentration... Breathing...'*
*'Cursed energy... reinforcement...'*
The two forces intersected within him, creating a strange resonance.
Megumi's eyes snapped open. Although he didn't break the gourd, his explosive speed in that instant was twice as fast as usual!
"So that's how it is..."
"It's not just about strengthening the body. It acts as a pump for cursed energy flow, accelerating the activation speed of techniques?"
The way Megumi looked at Yoru changed.
This seemingly simple breathing technique was practically a godsend tailored for physical-type sorcerers!
If he could master this, his strength would definitely jump to a whole new level!
"Alright, that's enough for today."
Seeing the three of them exhausted like dead dogs, Yoru clapped his hands and dismissed the class.
"You can't rush this kind of training, or you'll damage your alveoli."
"Progress step by step, and stick with it every day."
"One day, you'll be able to blow up the big one just like me."
...
Night fell in the boys' dormitory.
Yoru sat alone on the windowsill. By the moonlight, he wiped down his newly acquired Special Grade Cursed Tool—Shiranui.
The pitch-black blade gleamed coldly in the moonlight, but a careful perception would reveal a dark-red glow, like flowing magma, deep within the metal.
This blade was sentient.
Ever since he got it earlier today, Yoru felt that the blade seemed to be craving something.
*Cling—*
He lightly flicked the blade, producing a clear, dragon-like hum.
Within that sound was an unmistakable hunger.
It was a thirst for blood. And not just the blood of ordinary humans.
It was a thirst for the blood of cursed spirits.
The stronger, the better; the more evil, the better.
"You feel it too?"
Yoru gently stroked the blade, feeling the faint heat radiating against his palm.
He looked out at the pitch-black night sky, where a storm seemed to be brewing.
"Don't be impatient. A feast will be delivered to our door soon."
Shiranui seemed to understand his words. The dark-red light on the blade flickered slightly before returning to silence.
However, the murderous aura emanating from it grew even more intense.
Yoru sheathed the blade, a cold arc forming at the corner of his mouth.
"The scent of a Special Grade Cursed Spirit..."
"I can already smell it."