Demon Slayer: The Journey That Began When I Became Yoriichi's Sister

It doesn't matter what Tsugikuni Ikuko's name was in her previous life, because she is called Tsugikuni Ikuko in this life.

As the eldest daughter of the nation, she had two twin brothers above her.

They are the eldest brother, Tsugikuni Iwakatsu, and the second brother, Tsugikuni Yoriichi.

That's right, she time-traveled.

I've been transported to the world of Demon Slayer... the world of the Pillars.

The immense popularity of Demon Slayer in her previous life meant that even someone like Ikuko Tsugikuni, who didn't follow the anime, inevitably came across related videos, and she became a fan due to its exquisite special effects and art style.

but……

She must have put it on too early.

Yuko, who had followed the anime for a whole season, had only occasionally come across videos about Yoriichi Tsugikuni on short video platforms.

The most famous one is, of course, the line—"What do you take life for!"

If she's not mistaken, Yoriichi Tsugikuni, the pinnacle of Demon Slayer, is her adopted second brother.

They should be characters from hundreds of years before the start of the story.

So the question is, how can she survive until the story begins?

"Sigh." With a wooden flute hanging around her neck, Yuko sat on the steps with her hands supporting her cheeks, looking down at her older brother, Tsugikuni Iwakatsu, who was wielding a wooden sword and fighting with their teacher. Her toes swung unconsciously.

"Yuko, you can't sit like that. You need to sit up straight."

Her mother Akeno's voice came from behind her. Yuko turned around and saw her second brother, Yoriichi Tsugikuni, leaning on Akeno as they walked towards her in a spoiled manner.

“Mother.” Yuko quickly changed from a casual sitting posture to a kneeling position, which she was still not used to.

In her past life, her mother was a lazy gambler who squandered the family's assets and was indifferent to her family. She was the type of person that was hard for her to respect or like.

So much so that she was completely unable to resist the overly gentle Akeno.

After sitting up straight, Yuko breathed a sigh of relief and reached out to greet her second brother, who was nestled beside her mother, "Yo, Yoriichi."

Who would have thought that the legendary powerhouse was actually a spoiled brat when he was a child?

Before she could finish speaking, Zhu Nai gave Yu Zi a sharp rap on the head. "How many times have I told you, you have to call me elder brother!"

"Hey, brother." Yuko rubbed her head in pain, unaware of the fleeting look of pain in Zhu Nai's eyes.

Zhu Nai, the mother, is a gentle person, but she can be surprisingly terrifying when she gets angry.

Faced with his unreliable younger sister, Yoriichi simply smiled gently.

His gentle mother and brother, as well as his lovely sister, are Yoriichi's most precious treasures.

Yoriichi helped his mother, Akeno, to sit down in the corridor, where Ikuko accompanied her.

He then went to watch from the side of his elder brother, Yan Sheng.

The teacher who taught Iwakatsu swordsmanship was one of his father's subordinates. When he saw Yoriichi standing quietly to the side, he couldn't help but hand him a wooden sword and smiled as he asked him to try it.

Exhausted and covered in sweat, Yan Sheng, whose body ached from being beaten by his father's subordinates, was able to rest for a while.

“Mother, Yuko.” He came to the corridor and looked up at his mother and sister.

"Brother~" Yu Zi greeted him with a smile, then focused her eyes on the field.

Yan Sheng frowned slightly, and looked back, not believing that his weak younger brother could withstand more than a few moves from the opponent.

Despite his talent and hard work, he never won against his father's subordinates.

However, to everyone's surprise, Yoriichi, who had only learned the sword-wielding posture from his father's subordinates, launched an attack with lightning speed and knocked down the tall and strong adult in the blink of an eye.

Yan Sheng's eyes were filled with shock, Zhu Nai's mouth was slightly open in surprise, only Yu Zi showed an expression of 'I knew it'.

He truly deserves to be called the pinnacle of talent; at the age of seven, he possessed power that is unimaginable to ordinary people.

Unlike the others' surprise, Yuan stared blankly at the bamboo knife in his hand.

I hate the feeling of hitting someone's body.

Yoriichi threw away his bamboo sword and sat back down in the corridor.

After a moment of shock, Iwakatsu finally came to his senses, sat down next to Yoriichi, and quickly asked, "How did you do that?"

Yoriichi lowered his eyelids and quietly replied, "When he prepares to attack, his lungs will definitely be working hard. Just make sure you can see the direction of his bones, the contraction of his muscles, and the direction of his blood flow."

"..."

Yoriichi's words left Kokushima dumbfounded; he couldn't understand what his younger brother was saying at all.

Zhu Nai's eyes flickered slightly.

Yoriichi, this child, can see gods with his eyes.

Yuko's eyes lit up; she knew this!

Swordsman, or rather, the highest level of martial arts.

Transparent world!

They possess the ability to see the enemy's weaknesses and attack patterns, as well as to conceal their own presence.

It's like perspective.

"Let's stop talking about swordsmanship. I'd rather play Sugoroku and kite with my older brother and Yuko."

Yoriichi's previous wish was to become the second strongest samurai in the country, but the discomfort he felt when hitting others made him give up on that wish completely.

Yan Sheng lowered his head, his hands clenched tightly on his thighs.

Yu Zi jokingly patted his shoulder and said in a mature tone, "Don't be so tense all the time, relax your body once in a while."

Yan Sheng slapped her hand away without any politeness, and left silently without even saying goodbye to his mother.

Yu Zi let out a long sigh.

She knew it.

Before her transmigration, Yuuko wasn't clear about the subsequent development of the main story, but she had seen Yoriichi's older brother in short video clips, who became the strongest demon under the Demon King Muzan.

Upper Moon One: Kokushibo

She didn't understand the "six-eyed lemon spirit" that netizens were talking about at the time, but now she seems to understand a little.

Very good, she must correct this kid's twisted mentality!

Yu Zi felt she could do it; after all, she was a college student in her previous life.

How difficult can it be to teach a child?

……

However, before she could complete the correction of Iwakatsu's personality...

Not long after, at night.

"Ikuko."

Yoriichi's voice startled Ikuko from her sleep. She opened the door and rubbed her eyes sleepily.

"What's wrong, Yoriichi?" Yuuko yawned and looked at Yoriichi. "Are you scared to go to the toilet alone?"

Faced with his unreliable younger sister, Yoriichi's expression remained as calm as ever, but this time it seemed to be mixed with a hint of sadness.

"My mother has passed away."

"Huh?" Yuko was suddenly awakened.

Zhu Nai...

Yu Zi opened her mouth, but couldn't say anything.

"You can ask your mother's servants for details," Yoriichi said quietly. "I need to go and say goodbye to my elder brother now."

"Goodbye?"

"I'm about to head to the temple."

Yuko then noticed the bag that Yoriichi had placed beside him.

Yoriichi's father was a superstitious man. As one of the twins, Yoriichi was born with ugly markings and was not valued by his father. If it weren't for his mother Akeno's protection, Yoriichi would have died at his father's hands at birth.

In comparison, the difference in treatment between Yoriichi and Iwakatsu was so great that it could be described as a master-servant disparity.

From clothing, food, housing, and transportation to education, the two are from different worlds.

As the one who was abandoned, Yoriichi had to go to the temple when he was ten years old.

To become a monk.

But... Yoriichi and Kokushibo are only seven years old.

Yuko is only six years old.

Yuko suddenly remembered the scene where Yoriichi defeated her father's subordinates.

What his father needed was an heir who could succeed him as the pillar of the family. Yoriichi's powerful talent had already reversed his situation with Kokushima.

Was it so as not to affect Iwakatsu that Yoriichi chose to become a monk early?

Just as Yuuko was in a daze, Yoriichi said, "Yuuko, I'm leaving."

Take care of yourself.

After saying that, Yoriichi picked up his bag and prepared to leave.

"Wait a minute," Yuko said instinctively.

Yuan paused for a moment and looked at her.

When it was Yuko's turn to speak, her mind went blank, and she didn't know what to say.

Should we ask him to stay?

A seven-year-old child...

But Yoriichi was already able to defeat adults, and was much stronger than her.

The silent sister was met with a gentle smile.