After Raising the Ghost King, I Joined the Demon Slayer Corps [Demon Slayer]

[Draft blurb, version 8.1, tentative]

What is it like to somehow transmigrate to the Heian era? Shenmu looked down at her own hands, roughened with thin calluses, and her pupils shook with shock.

[Please complete the final mission: Slay the Demon King.]

From the start, she had nothing but a battered sword. After using the System-provided Sun Breathing to save the Ubuyashiki couple in an act of heroism, Shenmu was brought, completely bewildered, before a bedridden boy.

"From now on, she will be your big sister, Tsukihiko."

Huh? What? How did I suddenly get a younger brother?

Her new little brother was not only in terrible health, but had an unbelievably bad temper. He'd gasp for breath just from turning over, and cough up blood whenever they argued. Since the Ubuyashiki Family had given her food and shelter, Ubuyashiki Shenmu began to raise the child with an easygoing attitude while searching for the Demon King's whereabouts. But things did not go as planned. Before there was even a trace of the Demon King, evil spirits invaded the family home. She figured she might as well go out in a blaze of glory, since dying didn't matter to her anyway. But when she woke up, she found herself in the Taisho era.

Thanks to her impressive performance speed-running Lower Rank Six at Mount Natagumo right from the start, Shenmu was brought in a daze before the leader of the Demon Slayer Corps.

Shenmu thought that although she wasn't related to them by blood, she was practically their ancestor. Helping her juniors solve their problems was only right... Wait, what? The Demon King was a member of the Ubuyashiki Family?

Oh dear, this was going to be a problem.

Since it was a little matter she could help with, she might as well save the world. What fun!

"I'll be in charge of the upcoming Hashira trials, everyone."

"Huh? You object? Then come and fight me!"

*

The Demon Slayer Corps had a new Sun Hashira, and she was frighteningly strong. After nearly speed-running Lower Rank Two following her defeat of Lower Rank Six, the Twelve Kizuki gathered for a meeting.

Just as everyone was trembling with fear, they saw Lower Rank Two get devoured in an instant by a massive arm.

"She's terrified of demons."

Hearing their boss say this cryptic thing, everyone lay prostrate on the ground, afraid to raise their heads.

"Remember, when you see her, you may only call her 'Lord Kibutsuji.'"

"Understood?"

[Reader's notes]

1. There are lots of original details! For instance, the demons mentioned at the beginning and Muzan's original name. Everything serves the story.

2. The friendship, romance, and family love are all very sweet (not really).

3. Kick the bucket out of the way! Kick the bucket out of the way! Kick the bucket out of the way!

Theme: Tentative.