When humans are admired, they cautiously maintain their integrity.
They are unwilling to let those who admire them see their flaws.
After a long silence, Michikatsu spoke indifferently, "What is there about a person like me that is worth trusting?"
Mizuki lowered her head, looking at him, and asked a tangential question, "I know, Elder Brother hates Yoriichi, right?"
Michikatsu's eyes slightly narrowed upon hearing this, and he subconsciously looked away from Mizuki's gaze.
It was as if he had stripped naked in front of Mizuki, leaving no secrets whatsoever.
Mizuki didn't mind and said gently, "I actually envy him too... no, perhaps I should say I envy him to the point of jealousy. Jealous of Yoriichi's talent."
"That innate ability is something others can never reach, no matter how hard they try to catch up."
Michikatsu's lips parted slightly, showing surprise in front of Mizuki for the first time.
This was exactly Mizuki's method of treatment.
Step one: help Michikatsu build his self-esteem.
Step two: let Michikatsu know that someone shares his feelings—that they are both ordinary people oppressed by the genius Yoriichi.
Some things are unbearable to keep bottled up alone, but if there is someone to share them with, it won't be so painful, especially if that person can empathize.
This is also why the people you get along with are often your classmates or colleagues.
Because everyone shares the same position.
Michikatsu only saw today that his younger sister possessed such a gentle expression.
It must be because... He watched Mizuki for a moment, noticing the fine cold sweat on her forehead.
Sure enough... Mizuki had been suppressing her pain throughout their fight.
Michikatsu felt a rare pang of guilt.
Mizuki pulled out the wooden flute she wore around her neck from her chest area.
Michikatsu was slightly stunned. She was still carrying it?
Mizuki had never worn it around her neck before; she always kept it tucked away in her satchel.
This time, she deliberately brought it to emotionally manipulate Michikatsu.
Holding the wooden flute, Mizuki said with a smile, "Elder Brother, please take this dream of Mizuki's and strive to catch up to Yoriichi."
"Cough, cough... I will cheer Elder Brother on."
And then... once we pass twenty-five, let's leave this world together.
Having lived a second life, she was truly satisfied... Three years passed since then.
Yoriichi felt that his Elder Brother seemed to have changed.
Although his Elder Brother was still training as diligently as before, seemingly unchanged in every way.
Yoriichi just inexplicably felt that way.
"I lost." Michikatsu put away his nichirin blade, calmly accepting his defeat.
Yoriichi said gently, "Elder Brother's skill has improved again."
Seeing that their match was over, Mizuki waved to both of them, "Elder Brother, come and drink tea."
She poured the tea and handed it to them.
Yoriichi took a small sip and praised, "Mizuki's skills have improved too."
Mizuki rolled her eyes at him, "Brother Yoriichi, can't you change what you say?"
"It's the same line every time."
Yoriichi smiled, "How is your body? The Physician told me to keep an eye on you and make sure you don't jump around recklessly."
Mizuki was covered in black lines: "What kind of personality do others think I have?"
Michikatsu drank his tea and said indifferently, "A monkey."
"??" Mizuki looked at him with an expression of disbelief.
Michikatsu ignored her.
Watching the two of them playfully bicker, Yoriichi smiled first, but then, after unconsciously using the Transparent World to see the condition of Mizuki's lungs, he couldn't help but lower his eyelids and say apologetically:
"I'm sorry, Mizuki. It would have been better if I had been by your side at that time."
Mizuki paused, realized what he was referring to, and shook her head with a smile.
"That was my mission in the first place. I was just too careless."
"It's fine. I just sometimes can't help wanting to cough, but it doesn't affect my normal life."
Since then, Mizuki, who had difficulty using the Breathing Technique, retired from the Demon Slayer Corps' front lines and took charge of maintaining logistics work.
Occasionally, she was responsible for instructing the swordsmanship of new recruits, which allowed her to experience the thrill of being a teacher.
Only after hearing Mizuki say this did Yoriichi feel somewhat relieved inside.
Michikatsu, unwilling to mention Mizuki's illness, changed the subject: "More and more Swordsmen are awakening the Demon Slayer Mark, and the power of the Demon Slayer Corps is growing stronger day by day."
"Perhaps the struggle between humans and demons will end in our generation."
Yoriichi nodded, "Yes, the traces of demons have decreased significantly recently."
Undoubtedly, both the birth of the Breathing Technique and the awakening of the Demon Slayer Mark made the Demon Slayer Corps unprecedentedly powerful, curbing the growth of demons.
The two brothers still maintained an optimistic attitude, but Mizuki alone fell silent upon hearing these words.
More and more people in the Demon Slayer Corps were awakening the Demon Slayer Mark, and the original Hashira had all awakened the Mark.
After awakening the Demon Slayer Mark, Michikatsu quickly mastered the abilities of the scarlet blade and the Transparent World, becoming the second person after Yoriichi to master the 'Three Set'.
Mizuki, however, could only occasionally enter that Transparent World, and it was unstable.
As for the scarlet blade, which is activated by grip strength stimulating the sun energy within the nichirin blade, even Mizuki, whose physical fitness improved after awakening the Demon Slayer Mark, still lacked the grip strength necessary to change the nichirin blade's color.
She had completely fallen behind her two Elder Brothers.
The two brothers were leading the entire Demon Slayer Corps by a massive margin.
At that time, the three siblings stood on the Back Mountain, gazing into the distance.
"No one's strength can match yours or mine; the inheritance of the Breathing Technique is truly despairing."
"If this continues, these ultimate techniques honed by years of training might be lost."
Unlike Michikatsu's worry, Yoriichi's expression remained calm, and he said with a slight smile:
"Elder Brother, you think too highly of us."
"You and I are merely two passersby in the long history of humanity."
"A baby with talent far exceeding ours might be being born somewhere in the world right now."
"I believe they will eventually reach the same Realm as you and me."
"There is no need to worry. We just need to let nature take its course and wait for the day our lives fade away."
Upon hearing these words, Michikatsu's heart, which had just begun to change slightly because of Mizuki, sank back into the deep mire.
'Yoriichi, every time you smile, I feel utterly disgusted.'
'When discussing a heavy topic like the Breathing Technique potentially being lost, you still maintain that strange optimism... and smile...'
Mizuki looked at her two Elder Brothers, opened her mouth, but ultimately failed to speak.
She had actually seen it long ago.
Yoriichi completely ignored his Elder Brother's internal feelings about him—which was inherently the "indifference" of a genius toward an ordinary person.
When a genius speaks of their own mediocrity, how can the person chasing them possibly remain calm?
This year, Mizuki was twenty-three, and her two Elder Brothers were twenty-four... The Swordsmen who awakened the Demon Slayer Mark began to die.
Initially, everyone assumed it was sudden death caused by overtraining.
But soon after, another Demon Slayer Mark Swordsman died suddenly, the day after he turned twenty-six.
Eventually, even some of the original Hashira who had awakened the Demon Slayer Mark lost their lives.
Only then did the Demon Slayer Corps realize that all the sudden deaths were Swordsmen who had awakened the Demon Slayer Mark.
And they all shared one thing in common.
They were over twenty-five years old.
The Demon Slayer Mark was an ability that borrowed lifespan from heaven, pre-spending life; anyone who activated the Mark would not live past twenty-five.
Such rumors gradually began to spread within the Demon Slayer Corps.