"I say, are you guys playing house?"
Just as the three were feeling discouraged, a very lazy voice came from the end of the porch.
Yamada walked over slowly, holding a cup of hot tea.
Today he was wearing a very casual black yukata, with the thunder pattern kusanagi sword casually tucked into his waist, exuding a very relaxed pressure.
"Yamada-san!"
Seeing Yamada appear, Tanjiro's eyes instantly lit up, as if he had seen a savior.
His admiration for Yamada had reached its peak since that single sword strike at Mount Natagumo.
"Waaaah, Boss Yamada! This isn't training, this is one-sided abuse!"
Zenitsu immediately crawled over and tried to hug his leg, but was kicked away by Yamada with extreme disgust.
"You can't even handle a little girl, and you have the nerve to wail here."
Yamada blew on the tea leaves in his cup, walked over to Kanao, pulled over a cushion, and sat cross-legged.
"Kanao-chan, come, play with me."
Kanao glanced at Yamada and nodded.
After half a month of interaction, she had a very special sense of awe for this man who had forcibly confiscated her coin and completely changed Shinobu.
"Yamada-san is going to participate personally?!" Tanjiro's eyes widened, and he even held his breath.
"Ready, start!" Aoi acted as the referee and swung her arm down.
Swish!
The moment Aoi finished speaking, Kanao's hand had already shot out like lightning, reaching for the nearest cup of medicine with extreme speed.
This was the terrifying reflex brought by Total Concentration Breathing: Constant!
However—
Snap.
Just as Kanao's fingers touched the side of the cup, a hand had already strangely moved second but arrived first, pressing lightly on the back of her hand.
How is that possible?!
Kanao's pupils shrank, she hadn't even seen an afterimage.
She immediately tried to change her move to grab a second cup, but no matter how fast she was, Yamada's hand was like a prophetic ghost, always arriving 0.1 seconds early to pin down her target.
Snap! Snap! Snap!
Three consecutive attempts were all brutally suppressed.
"Too slow."
Yamada chuckled and flicked his finger casually, and the wooden cup full of medicine instantly flew into his palm. He didn't splash it at Kanao, but instead flicked his wrist with a sense of mischief.
Splash!
A full cup of pungent medicine flew over Kanao's head and splashed all over the face of Zenitsu, who was stretching his neck to watch the show behind her.
"Aaaaaah! Why me!!!" Zenitsu let out a shrill scream.
Yamada put down the empty cup and, seeing Tanjiro's shocked expression, explained, "See? This is called absolute reaction suppression. The reason Kanao-chan can crush you is because she maintains Total Concentration Breathing twenty-four hours a day, even while sleeping. This is called Total Concentration: Constant."
"Total Concentration... Constant?" Tanjiro was stunned.
"Breathing techniques can not only allow one to explode with power beyond limits in an instant but can also change the body's basic physical attributes through long-term maintenance."
Yamada stood up, walked to the edge of the porch, picked up a hard, specially-made large gourd, and threw it into Tanjiro's arms.
"If you can't even master this most basic constant technique, then when you encounter the Twelve Kizuki, you won't even be fit to be stuck between their teeth."
"From today on, besides the regular stretching, the three of you will blow into these gourds every day. Only when you can blow these gourds until they burst with your lung capacity alone will your 'Constant' be considered barely entry-level."
Yamada domineeringly issued the training targets, taking over the role of coach.
Looking at the large gourd in his arms that made a "bang bang" sound when tapped, Tanjiro gulped, but his eyes became determined.
"I understand. I will definitely do it. Thank you for your guidance, Yamada-san."
"Yamada."
Just then, Shinobu came out from the inner courtyard, holding a piece of stationery that had just been delivered, her face becoming unusually solemn.
She walked quickly to Yamada's side and whispered in a voice only the two of them could hear, "The Kasugai Crow has brought back definite intelligence."
"Traces of a demon have appeared on the Mugen Train. Master has already ordered Rengoku to go there and investigate."
"It's finally here."
Hearing this news, Yamada knew that the Mugen Train arc of Demon Slayer had officially begun.
"Tell Rengoku not to worry. When the time comes, I will go with him to participate in the investigation mission."
— — —
BOOM!
Accompanied by an extremely heavy explosive sound, a rock-hard, specially-made medicinal gourd finally shattered into a flurry of flying fragments amidst Tanjiro's flushed face and his desperate, all-out blowing.
"Whew... whew... I did it! Yamada-san, I finally blew up the largest gourd!"
Tanjiro supported himself with hands on his knees, panting heavily. Sweat soaked through his thin training uniform, but his dark red eyes flickered with an unprecedented light of excitement.
After several days of inhuman torture under Yamada's Spartan-style, high-pressure supervision, he had finally managed to engrave "Total Concentration: Constant" into his body's instincts.
On the other side, although Zenitsu and Inosuke were still rolling their eyes while trying to blow into medium-sized gourds, they were already able to maintain the breathing technique around the clock without interruption.
"Barely a passing grade."
Sitting on the corridor railing, Yamada casually tossed a half-eaten apple into the trash bin and stood up, clapping his hands.
"Since the foundation is more or less laid, pack your things and prepare to get out of here. There's work to do tonight."
"There's work to do? Could it be..." Tanjiro looked up, clenching his fists.
"Master has issued new orders. Large-scale civilian disappearances have occurred on the Mugen Train. Rengoku has already set out for the station ahead of time."
Yamada stepped down the stairs, casually pulled a pure black haori from a wooden rack, and draped it over his shoulders. "You three, bring your nichirin blades and follow me. Let me see how much you've actually improved during this time. If your performance is too pathetic, I'll kick you off the moving train on the spot."
"A-A train?! Why do we have to go to a place like that?"
As soon as Zenitsu heard they were going on a mission, he immediately clutched his head in terror.
Inosuke, however, snorted two trails of white steam from his nostrils. "I don't care if it's a train or a waterwheel! As long as it's prey, this Great Inosuke will cut it all down!"