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

Butterfly House.

It has been a week since Uzui Tengen activated his markings and left.

The minor injuries on Tanjiro and the others had been completely healed without leaving a single scar thanks to Shinobu Kocho's skillful treatment.

"Yuko, Miss Tamayo said you should go see her when you have time," Shinobu Kocho said as she returned from outside the Butterfly Mansion.

Seeing the group of people forcibly dragging Zenitsu into a frenzied workout in the courtyard, Ikuko paused for a moment, then turned to ask, "Tamayo? Did they say what it was about?"

Shinobu Kocho shook her head: "No, not at all."

“I understand.” Yu Zi nodded lightly and stood up. “Then I’ll go out for a bit.”

The sun is about to set, which is the time when evil spirits are unleashed.

Ikuko left the Butterfly Mansion without saying goodbye to Tanjiro and the others.

……

Tamayo was assigned to a corner of the headquarters by Ubuyashiki because she needed to treat Yae's father.

Ubuyashiki was unaware that Muzan possessed the ability to pinpoint the approximate location of demons, but his caution ensured the Demon Slayer Corps remained safe.

Upon arriving at Tamayo and the others' residence, since Tamayo was in charge of the research, Ubuyashiki built a luxurious mansion there and delivered a large number of medical instruments and related items to Tamayo.

The logistical support was handled exceptionally well.

The street in front of the mansion was deserted, with no sign of human presence whatsoever.

Even members of the Demon Slayer Corps rarely come here.

The night was still hazy, just as it had fallen.

Yuko tried knocking on the door and waited for a moment.

crunch~

The door opened, and Yushiro, who looked like a cute little boy, appeared before them.

Yushiro stepped aside, saying, "It's you. Lady Tamayo has been waiting for a long time."

Ever since Yuko said to Yushiro, "You're always acting like a child, but no girl will like you,"

Yushiro had completely changed; he was no longer as reckless and irritable in front of them as before.

He has become more mature and composed, befitting his age.

"Excuse me." Yuko nodded slightly and followed Yushiro into the mansion.

It must be said that the Ubuyashiki clan is truly generous.

Such a luxurious house, given away so easily.

and many more……

Why is it that when both Tamayo and Tamayo come to be ghosts, Tamayo gets a house as a gift, but she doesn't?

Is this the difference in treatment between highly skilled personnel and security personnel?

Yu Zi was somewhat indignant.

unacceptable!

Yushiro shivered, feeling as if there was something unclean around him.

After walking a while, Yuko saw Yae helping an elderly man with short, gray hair take a walk along the gravel path in the moonlight.

"Ah, it's Miss Yuko!" Yae also noticed the two and tugged at the person next to him, "Dad! It's Miss Yuko!"

Yuko had come before, but at that time Yae's father had not fully recovered.

Turning a human into a demon is not a simple matter. Even with the successful example of Yushiro, it still took Tamayo quite a bit of time.

Yae's father was a kind old man. He had already heard from his daughter that Yuko had protected him from the demon hunters, so he respectfully knelt down to Yuko from afar.

Yuko disliked this kind of thing the most, but unfortunately, it was how others expressed their gratitude.

After spending some time there, Yuko wiped the sweat from her forehead and said goodbye to the two of them.

Throughout the journey, Yushiro showed absolutely no sign of being in a hurry.

If it were in the past, he would definitely have said that.

'How long are you going to keep talking, woman?! How long are you planning to keep Lady Tamayo waiting?'

There is progress.

Upon arriving at the pharmacy where Tamayo worked, Ikuko could smell a mixed aroma of herbs from a distance.

Yushiro knocked on the door and opened it: "Lord Tamayo, the person has arrived."

Tamayo was sitting in front of the microscope observing something when she heard this. She turned around and smiled gently, "Ikuko, you've come."

Ah, Lady Tamayo's smiling face~

Yushiro's eyes sparkled.

Although it wasn't directed at him...

Yushiro bowed slightly, left the room, and closed the door, giving the two of them some space.

"I heard from Ren that you wanted to see me?" Yu Zi nodded and, without any ceremony, found a stool and sat down.

Tamayo rummaged through the drawer for a while, then came to her side: "Well, let's not talk about that now, put your hand out."

“Damn…” Yuko paused, feeling a chill run down her spine as she looked at the needle in Tamayo’s hand.

Yu Zi's face turned pale: "Can you pretend I was never here?"

What does Yuko say?

"...I think it's okay."

However, Tamayo completely ignored her reluctance, pressed her arm onto the table, and drew a large tube of blood.

Yuko slumped weakly onto the table.

Actually, she's not afraid of needles; she was just stressed out by Tamayo.

Yuko simply buried her head under the table and stopped resisting.

But after waiting for a while without receiving the second injection, he looked up in confusion.

"Not smoking anymore?"

Tamayo sat back down in front of the microscope, seemingly looking at something.

Hearing this, she turned her head in confusion: "Does Yuko still want to have her blood drawn?"

Yu Zi quickly shook her head: "No, no, I don't want to!"

Tamayo brought her eyes back to the microscope and said, "Speaking of which, does Ikuko know anything about her Blood Demon Art?"

"Blood Demon Art?" Yuko paused, pondering for a moment. "As a demon, isn't Blood Demon Art an innate ability?"

"My Blood Demon Art can, of course, repair the human body and amplify the power of sword energy..."

She originally intended to extend the power amplification effect of the sword energy to other people, but she later discovered something.

Because my blood temperature is too low, if I apply it to the Nichirin Blade, it will prevent the blade from opening properly.

In terms of range and power, it is clear that her blood's amplification in this respect is not as good as the Crimson Blade, which can suppress the regeneration of evil spirits and cause intense pain.

This renders the ability somewhat useless, unable to be effective against evil spirits, and even counterproductive when facing powerful enemies.

Tamayo suddenly murmured, "As expected..."

"Ok?"

"Your blood is colder than the last time I drew it."

"temperature?"

"Don't you understand?" Tamayo thought for a moment and explained, "Your blood temperature is currently around minus seventy degrees Celsius."

"When we last drew your blood, the temperature was clearly around minus twenty degrees Celsius."

Yu Ziliu raised an eyebrow: "But shouldn't it freeze at such a low temperature?"

Although she had long forgotten most of her knowledge and hadn't used her brain much in recent years, it was impossible for her to still be liquid at minus seventy degrees Celsius.

and……

She couldn't help but make a small cut on her palm and rub it on the back of her hand: "It's not very cool, is it?"

Tamayo: "..."

Tamayo said helplessly, "Using yourself as a reference point is meaningless. You should try it on someone else."

"Moreover, ghosts are not beings that can be understood by common sense, and cannot be viewed simply from an ordinary perspective."

Yuko didn't quite understand and scratched her head: "So, is this a bad thing?"

"...It's hard to say right now..." Tamayo hesitated for a moment, then said, "But I don't think it's a bad thing."

"I just mixed your blood with mine, do you know what happened?"

"They've blended together?"

“…Cells, my blood cell regeneration rate has slowed down.” A vein appeared on Tamayo’s forehead.

How could a perfectly healthy person turn into an idiot after two hundred years?

Yuko finally understood: "The regeneration speed has slowed down?"