Perhaps seeing hope in catching up to Yoriichi, or perhaps due to Yuko's brave swing of the sword in the mountains, Michikatsu's attitude towards his younger sister improved significantly.
Michikatsu tilted his head: "Did I say I wouldn't teach you?"
Yuko beamed: "I knew Big Brother was reliable."
"Heh heh."
Following the Sun Breathing, Yuko began training in Moon Breathing under Michikatsu.
Moon Breathing originated from Sun Breathing and is a derivative of Sun Breathing, but it is more powerful than the Five Great Breathing Styles, and is collectively known as Origin Breathing alongside Sun Breathing.
Even so, many people believed that Moon Breathing was completely unworthy of this title.
Although Moon Breathing was not as difficult to master as Sun Breathing, it still barred ordinary people from entry.
Fortunately, Yuko was not among them.
Taught personally by the founder of Moon Breathing, Yuko made rapid progress and quickly mastered Moon Breathing.
However... Michikatsu watched Yuko complete a set of Moon Breathing Sword Forms, shook his head, and said, "Moon Breathing is not suitable for you."
"Hoo~"
Yuko slowed her breathing and sheathed her katana, not refuting Michikatsu's words.
She knew her own situation best; she truly was not suited for Moon Breathing.
It wasn't that she couldn't use it, but rather that in terms of potential, she definitely couldn't reach the peak state like Michikatsu.
Just like when using Water Breathing, Tanjirou's talent was inferior to Tomioka Giyu's.
What suits oneself is the best.
"Compared to stubbornly sticking with Moon Breathing, tinkering with your Star Breathing might hold more promise."
"I have nothing left to teach you."
Yuko was speechless.
Star Breathing?
She hadn't even created the folder yet!
"Elder Brother, Yuko."
Just then, Yoriichi approached the two of them, carrying two nichirin blades wrapped in white cloth.
"Your nichirin blades have been forged."
Compared to later generations, where one had to master a Breathing Technique and pass a trial to become a member of the Demon Slayer Corps.
In this era, before Yoriichi's arrival, the Demon Slayer Corps relied on pure swordsmanship, using their nichirin blades to forcefully sever the heads of demons.
The casualty rate was extremely high.
Therefore, the Demon Slayer Corps was constantly short of Hands.
Although things were much better now, overall, Hands were still lacking.
As long as one learned a Breathing Technique, they could enter the field to slay demons, without the later rule requiring trials to select elites.
"Are they finally finished?" Michikatsu eagerly picked up his own nichirin blade.
He drew the blade, and the sword body visibly turned pale purple.
Yoriichi praised it: "What a unique color. The Demon Slayer Corps has never had a nichirin blade of this color."
Yuko also picked up her nichirin blade with great curiosity.
She didn't have many demands regarding the style of the nichirin blade; the tsuba, handle, and even the sheath were very plain.
*Clang!*
The nichirin blade was drawn, and Yuko waited expectantly for the nichirin blade to change color.
The sound of the sword being drawn attracted the attention of her two elder brothers.
A streak of pure white slowly climbed up to the tip of the blade.
It was the color of snow.
Faint snowflakes seemed to drift across Yoriichi's eyes. He raised the corner of his mouth slightly and praised, "What a beautiful color, just like white snow."
"Indeed."
Michikatsu, the jealous type, also rarely agreed.
"A pure white nichirin blade of this clarity has never..." Yoriichi paused, tilted his head, and looked at Yuko with slight confusion.
Yuko held the sword level, her left Hand pressing down on her right wrist, and shouted: "Bankai! Hakka no Togame!"
Michikatsu, Yoriichi: "..."
*Whoosh whoosh*... A gust of wind blew past.
Yuko cleared her throat and gave an awkward smile: "Just kidding."
The moment she saw the color of the nichirin blade, Yuko understood.
So that's how it is.
Yoriichi's nichirin blade was black, and hers was white—completely opposite colors. No wonder she lacked the talent to use Sun Breathing.
Yoriichi, who had been momentarily stunned by Yuko's inexplicable actions, recovered and said, "I think a pure white blade would be more compatible with Water Breathing or Wind Breathing."
Yuko nodded slightly; she thought so too.
Yoriichi himself was the founder of the Breathing Techniques, so seeking his guidance on the Five Great Breathing Styles was fine, but unfortunately, Yoriichi was often away on missions and couldn't teach her constantly.
Yuko had no choice but to visit the contemporary Hashira.
The exceptionally talented Michikatsu, after creating Moon Breathing, quickly became a pillar within the corps, rapidly becoming the second strongest member of the Demon Slayer Corps after Yoriichi.
Only Yuko was still searching for a Breathing Technique that suited her.
Sun Breathing was the ultimate culmination, but unfortunately, Yuko couldn't use it. While forcing the Breathing Technique wasn't impossible, her body would be the first to break down.
Although Moon Breathing could be used, the compatibility was always lacking.
After becoming a member of the Demon Slayer Corps, Yuko inevitably received missions outside.
Fortunately, during this period, most demons were not as powerful as those in later generations, and the Twelve Kizuki had not even been established yet.
As long as she didn't run into the Scum Boss, Yuko still had the ability to protect herself.
In her spare time, she successively visited the swordsmen of the Demon Slayer Corps who used the Water, Flame, Thunder, Wind, and Stone Five Great Breathing Styles.
The order was based on her preference.
Originally, Flame Breathing should have been the third stop. As the Breathing Technique whose effects were closest to Sun Breathing, Yuko preferred it over the others.
But judging by the color of her blade, she might be more compatible with Water Breathing, which is why she postponed learning Flame Breathing.
Due to the characteristics of Stone Breathing, its users' weapons were mostly two-handed heavy weapons. Yuko couldn't use them, so she only learned the Breathing Technique and gained a slight understanding of the Sword Forms.
Unexpectedly, Yuko displayed considerable talent in learning all Five Great Breathing Styles. This was the first time she felt she hadn't been overshadowed by her two brothers.
She! Tsugikuni Yuko!
A born prodigy!
Of course, this was also partly because the Sword Forms of the various Breathing Techniques had not yet been fully developed.
Compared to the Sword Forms of later generations that frequently reached Ninth Form or Tenth Form, the current Five Great Breathing Styles only had a handful of Sword Forms.
Yuko had good compatibility with all Five Great Breathing Styles, but if forced to rank them, Water Breathing and Wind Breathing were superior.
Yuko also focused on training in these two Breathing Techniques.
By the time she mastered the Five Great Breathing Styles, two years had passed.
That year, Yuko was twenty years old, and the Tsugikuni brothers were twenty-one.
Yoriichi and Michikatsu had firmly secured the title of the two strongest in the Demon Slayer Corps and frequently went out on missions.
Yuko, having deeply analyzed the principles of Breathing Techniques, began attempting to merge Water and Wind Breathing to create her own Breathing Technique.
On this day, Yuko was adjusting her breathing beneath the veranda.
A clear female voice suddenly rang out, "Yuko! There's a demon sighting in the western mountains. Please proceed quickly to subdue it."
Yuko looked up.
The Kasugai Crow circling in the sky was named Suzume, assigned to Yuko after she joined the Demon Slayer Corps.
Receiving the mission notification, Yuko sheathed her nichirin blade, packed her belongings, and set off.