Both of Them Were Stunned

Chinatsu's declaration left everyone at a loss for words. What she had said was just that impressive.

Zenitsu: S-so cool...

Inosuke: That's the spirit! Big Sis!

Tanjiro: Muzan... I'll settle this score and kill you together with my sister!

After hearing Chinatsu's words, the boy who had wanted to join the Demon Slayer Corps finally gave up on the idea. He said he would quietly pray for them all, and everyone gratefully accepted his goodwill.

Since it was getting late, they accepted the boy and girls' invitation to stay at their house for the night. The house wasn't large, so naturally, they couldn't each have a room of their own.

Tanjiro and the other boys crowded into one room, while Chinatsu carried the wooden box containing Nezuko into another.

Once she entered the room and shut the door, the wooden box was pushed open from inside. Nezuko slowly crawled out, looking relieved that she could finally come out, then flopped onto the floor and stretched out.

Nezuko really had it rough. She had gone so long without speaking and had to stay inside that cramped wooden box, unable to move freely. Watching Nezuko stretch her limbs to her heart's content on the floor, Chinatsu thought she should find an opportunity to let her try overcoming sunlight.

"Nezuko, want to practice your Breathing Style and swordsmanship?"

"Mm! Mm!"

Nezuko immediately scrambled up at the suggestion and sat neatly on the floor in excitement, looking like a model student who would make any teacher proud.

Nezuko hadn't progressed very far in learning Water Breathing. She was still nowhere near the point of producing "special effects."

Considering that she had only been seriously training for half a month, that was normal. Still, if Nezuko truly wanted to use Water Breathing in actual combat in the future, she might not have enough time...

Chinatsu taught Nezuko Water Breathing in their less-than-spacious room. Meanwhile, Tanjiro's room felt even more cramped with all three boys packed inside.

"Move over."

"It's already cramped on my side, okay?"

Inosuke was on the left, and Zenitsu was on the right.

Tanjiro was in the middle.

Despite the two of them jostling back and forth, Tanjiro remained asleep between them, breathing softly and steadily.

"How can Tanjiro sleep through all this?"

"This guy... his breathing's different from ours."

"Come on, isn't it normal for people to breathe at different rates?"

"No. Can't you tell? The way Tanjiro's breathing right now?"

"Huh?"

At Inosuke's words, Zenitsu took notice too. He sat up and carefully studied the sleeping Tanjiro.

A few seconds later, Zenitsu's calm expression abruptly crumbled, his face even beginning to twitch.

"Wait! Wait! Wait! T-Total Concentration Breathing?! Tanjiro's using Total Concentration Breathing right now! Am I seeing things? Is he pretending to be asleep?!" Zenitsu exclaimed in shock.

Beside him, Inosuke stared blankly at the sleeping Tanjiro, then suddenly reached out and covered his mouth and nose.

One second...

Two seconds...

Three seconds...

Tanjiro's eyes snapped open, and he bolted upright.

"What are you two doing?!"

"Tanjiro, tell us the truth. You were just pretending to sleep, weren't you?"

"Of course not. I really was asleep."

Tanjiro blinked in confusion. Once he learned why the two were puzzled, he couldn't help chuckling softly.

"What are you laughing at?"

"Nothing, nothing. I really wasn't pretending to sleep. My sister and I have just trained to the point where we can maintain Total Concentration Breathing twenty-four hours a day. That's also why we're so strong," Tanjiro explained with a smile.

"T-twenty-four hours!!!"

Zenitsu and Inosuke were utterly dumbfounded. If they hadn't believed Tanjiro wouldn't lie, and hadn't actually seen him using Total Concentration Breathing in his sleep, they never would have believed it.

Total Concentration Breathing was exhausting. After maintaining it for ten minutes or so in battle, they would have to stop, worn out and gasping for breath. Yet he could keep it up for twenty-four hours, even maintaining it automatically while asleep?!

"Tanjiro... you and your sister really are hardcore..." Zenitsu said, beads of cold sweat rolling down his face.

Beside him, Inosuke's eyes gleamed. "So if I can use Total Concentration all day too, I can beat Big Sis, right?!"

"Uh... it'll at least narrow the gap. That much is certain," Tanjiro answered after thinking for a moment.

He actually wanted to say that even mastering Total Concentration: Constant would hardly let them compete with his sister. After all, he had mastered it himself, yet she still completely overwhelmed him whenever they fought.

Chinatsu's unusual constitution gave her powerful physical abilities, allowing her to perform many movements ordinary people couldn't. Despite all their sparring sessions, Tanjiro had never beaten her once.

He decided to leave that part unsaid. Enthusiasm was a good thing.

"If you want to learn, I can teach you, though I don't know whether I have any talent for teaching," Tanjiro kindly offered.

Zenitsu and Inosuke exchanged looks. Inosuke agreed with an immediate nod, without a moment's hesitation. Zenitsu hesitated for a while before saying he could give it a try.

Before long, however, both Inosuke and Zenitsu regretted it. Forcing themselves to use Total Concentration Breathing beyond what their bodies could handle left them aching as though they had been beaten, while their lungs felt as if they were on fire.

"Ow, ow, ow!!! Tanjiro, how on earth do you do this?!" Zenitsu lay sprawled on his bedding, wriggling like a worm.

Inosuke wasn't doing much better. His fundamentals were the worst of the three; he only had his strong physique going for him. He had lasted even less time than Zenitsu.

Sitting on the floor, Tanjiro smiled at the two boys as they writhed in pain. "That's normal. You just need more practice. Everyone's like this at first."

You just need more practice.

Inosuke and Zenitsu suddenly realized just how wonderful a peaceful night's sleep would be.

The next morning.

Zenitsu and Inosuke stumbled out of the boys' room, aching all over. Their bodies clearly still hadn't recovered from pushing themselves too hard with Total Concentration Breathing.

Chinatsu also emerged from her room carrying Nezuko's wooden box, smiling and looking refreshed.

Although she had failed yet again to achieve the Transparent World, she was already used to it. Nezuko had made great progress with her Breathing Style last night, and that was what made Chinatsu happy.

Outside the house, a crow flew overhead to announce their next mission-the last dungeon before the death dungeon.

"Mount Natagumo."