After Reincarnating as the Ghost King's Twin Sister

After transmigrating to the Heian era, Mirai discovers that in this world overrun by yokai, she has also gained a frail older brother.

Just as she's trying to save her brother while training, a System suddenly appears and tells her that this world has a main quest.

[Warning: Your brother is about to become the millennium demon king, the progenitor of demons. For the sake of world peace, your choice should be, ]

Mirai slaps the System aside. "Hey, bro, I just ate the blue spider lily. Why don't you eat me, or we can have a one-on-one, and the winner becomes the demon king... Bro, why are you running?"

Muzan: She just slaughtered all the demons from before. How could I not run?!

Mirai's game of hide-and-seek with her demon king brother ends in total failure, so she has no choice but to keep working away at the System's [Heir to the Gods] quest.

Ever since becoming a demon, Mirai has been bad at reading other people's emotions, and she always feels like she's done a lot of things she ought to apologize for.

She teamed up with the Nurarihyon to attack Osaka Castle, bringing the Warring States period to an end and putting a certain samurai clan's head completely out of work.

She found a brother and sister on the verge of death in the pleasure district, turned them into demons, then insisted they go to school.

When the Wind Hashira was a child, she sent his father to jail, and couldn't even get him out.

She wrestled a wild boar in the forest, kidnapped "a pig," then returned both the boar and "a pig" to his mother.

Mirai muses, "Would apologizing now even help?"

The people Mirai thinks she owes an apology: ?

A thousand years pass in the blink of an eye, and the System interviews Mirai about her wish.

Mirai says, "Please get that unreliable god and my demon king brother to accept my challenge. This time, we'll hack each other to pieces, and whoever wins becomes a god."

Muzan: A chill runs down his spine.

The god: A chill runs down his spine x2.

Muzan: "What are you getting chills for? Do you have as much on the line as I do?!"

[Coming soon: Male-lead-perspective derivative romance, "My Life's Dream Is Romance"]

Story One: [Yokai General x Miko Kikyo]

As a great yokai, Tsukimiya has no interest in humans whatsoever, until he temporarily loses his powers and reverts to his original form, a little cub. By chance, the miko Kikyo takes him in.

Kikyo is constantly worried about whether this little kitten can survive when he manages to singe his own fur just by warming himself by the fire.

After regaining his human form, Tsukimiya returns to his territory.

His deputy finally breathes a sigh of relief. "You're finally back. Which yokai kingdom are we going to attack next?"

Tsukimiya muses, "How should I confess to that human miko so she'll say yes? Would all the territory I've conquered over the years be enough?"

Deputy: "What are you talking about? A miko would only want to exterminate a great yokai like you!"

Tsukimiya: "If she wants to use me for practice, I don't mind. As long as I don't die."

"???"

[Story Two: Leiga x Vermouth]

After living for centuries, Leiga, who can live forever, finally gets a girlfriend. The bad news is, she seems to be investigating and getting close to him in order to kill two of his secret identities.

Before Leiga can figure out what to do, one of his girlfriend's secret identities suddenly fakes her death.

"Insiders reveal: On the day of the Oscar-winning actress's funeral, her boyfriend meets her daughter in an intimate atmosphere. After learning of it, a friend of the actress beats the unfaithful scumbag!"

As the headline sets the internet ablaze, Leiga discovers that he's become the "unfaithful scumbag." "?"

But his Oscar-winning actress girlfriend and his girlfriend's daughter are the same person! They're all secret identities!

Leiga comes across her fans' heated comments online.

"Can't this scumbag die alongside our queen?!"

A friend consoles Leiga: "Don't read the hate comments."

Leiga replies excitedly: "You think I'm worthy of dying and being buried with her. Isn't that an endorsement? Thank you, everyone!"

Friend/Fans: ???

I met her one evening, when the sunset blazed across the horizon like a fire.

At this twilight hour, I met the witch who would fill my entire life.

Blurb screenshot saved (2026.07.17)

Reading guide:

I'll post a leave notice.

2. Under Jinjiang's classification rules, this story is categorized as no-cp+. There will be a few characters who have feelings for the protagonist. There are familial, friendly, and romantic relationships. The romance involves both male and female characters, but the protagonist never responds to anyone's feelings. The ending has no pairing.

3. Although this is based on a Japanese manga, I've made some changes to the setting for a better reading experience and to accommodate readers who aren't very familiar with Japan. Please remember to distinguish it from reality. If the historical setting in the story doesn't match what you know, that's my fault, but please understand that some details can't be changed without affecting the writing.

4. Let's respect one another. Please don't mention other authors' works under mine, and don't mention my work under other authors' works.

5. This story is officially serialized on Jinjiang Literature City. All forms of reposting are prohibited. Reading on the Jinjiang app costs only three fen per thousand characters, so it's very affordable. Thank you to everyone who supports the original!

Theme: Do your best and have a clear conscience