"Brother Sosuke."
Tanjiro paused, then smiled. "Even a Demon Hunter as strong as you wouldn't pass up a chance to train, Brother Sosuke."
"Training is like rowing upstream. If you don't advance, you fall behind." Tetsu no Sosuke glanced at Tanjiro. "You certainly can't afford to slack off!"
Then he looked at Zenitsu Agatsuma, whose expression suggested he had nothing left to lose, and said with a smile, "Yushiro has already come up with a possible solution. We might be able to resolve the danger lurking inside you today. Stop looking so miserable and put in some effort! Hmm, since you're both here with me anyway, I'll teach you something else today."
"Something else?"
Tanjiro blinked. "What?"
Zenitsu Agatsuma was confused too, but mostly he was scared.
Earlier, he had thought the Meditation Method Tanjiro was learning looked impressive, so he had joined in. As a result, another version of himself had appeared inside his mind and wanted to eat him...
If he kept learning from the Hammer Pillar now, he probably really didn't have long to live.
Tetsu no Sosuke drew a gentle breath. "Constant Concentration!"
"A Demon Hunter's greatest asset against demons is their Breathing Technique," Tetsu no Sosuke said. "And Constant Concentration means keeping your Breathing Technique running at all times."
"At all times?" Tanjiro exclaimed in shock.
Zenitsu Agatsuma burst into tears with a wail. "We'll definitely die! Breathing Techniques put so much strain on us—we'll definitely die!"
Tetsu no Sosuke couldn't be bothered with Zenitsu Agatsuma. He said solemnly, "Constant Concentration is the first step toward becoming a Pillar. I don't expect you to master it right now. After all, strictly speaking, you haven't truly fought demons to the death since passing the trial. The demons you encountered during the trial were literally starving demons.