"Here's how things stand…"
Inside the room, Uchiha Hikari and Esdeath sat side by side, sipping fragrant tea offered by the Ubuyashiki family's daughters. Across from them, Ubuyashiki Kagaya began explaining the recent developments.
At the same time, in the otherworldly Infinity Castle…
Muzan Kibutsuji, dressed in a sharp suit and looking like a young man, listened to Kokushibo's report.
"…That woman still hasn't shown up?"
"No," Kokushibo replied, kneeling respectfully. "In this operation, Akaza and Gyokko nearly killed two of the Demon Slayer Corps' Hashira. But a special drug they had—small, about the size of a finger—allowed them to heal all their wounds almost instantly. They held out until sunrise, and we had to retreat because of the sun. As for my brother… that woman still didn't appear."
"A drug that heals wounds?" Muzan's eyes narrowed. "Something like a demon's regenerative ability? Could it be made from demon blood? Maybe the work of that Insect Hashira?"
"I don't know," Kokushibo said, his face expressionless.
A brief silence filled the air.
Muzan looked up at the ceiling, a flicker of violent intent glinting in his crimson eyes.
Time flies.
It had been nearly a year since the Spider Mountain incident.
In that time, Muzan hadn't left Infinity Castle once. Even when he needed to feed or conduct human-to-demon experiments, he had Kokushibo and the other Upper Moons bring him living humans, triple-checking that no Demon Slayers were tracking them. He'd taken caution to an extreme.
Yet…
After so long with no sign of trouble, Muzan couldn't help but grow suspicious.
That girl, supposedly the "reincarnation of Yoriichi Tsugikuni"…
Where had she gone?
Why, after appearing twice at Spider Mountain and Yoshiwara, had she vanished without a trace?
Even if she couldn't find him in Infinity Castle, shouldn't she have been hunting down other demons? Yet, in the memories of the nearly hundred demons killed by the Demon Slayer Corps over the past year, there wasn't a single trace of her.
It was strange.
To confirm the situation with this "female Yoriichi," Muzan had started probing the Demon Slayer Corps a few months ago—around the time Uchiha Hikari took Tanjiro to train at Korin Tower. These probes had grown increasingly bold, yet she never showed up.
This filled Muzan with doubts.
Was it a trap by Ubuyashiki?
Or… was there something else going on?
(Maybe that girl isn't Yoriichi's reincarnation at all. Just someone who looks similar, like Tanjiro Kamado…)
(Or perhaps she is his reincarnation but hasn't awakened her past life's memories or strength. Killing Rui and the Daki siblings doesn't mean she can take on me or Kokushibo. So Ubuyashiki's hiding her to keep her from dying too soon…)
Muzan's guesses were half-right.
Namely, that Uchiha Hikari wasn't Yoriichi's reincarnation.
But even with two extra brains, he'd never guess that Hikari wasn't even from the Demon Slayer world.
In any case, these theories made Muzan's mind start to race.
If this "female Yoriichi" didn't have the original's strength, now might be the perfect chance to kill her.
Otherwise, he might have to hide in Infinity Castle for another century. He'd already lived that kind of life once—he wasn't about to do it again.
Just as Muzan was wrestling with this dilemma, Tanjiro returned from the Dragon Ball world and informed Ubuyashiki about the revival plan. Ubuyashiki immediately sent the Demon Slayer Corps to collect the bodies of those to be revived.
Learning of this, Muzan dispatched three Upper Moons, including Kokushibo, to intercept the Corps. Thanks to the Senzu Beans, the results were less than expected, but the operation seemed to confirm his suspicions—
"It looks like that woman is indeed being hidden, likely at the Demon Slayer Corps' headquarters…"
"As long as we can get to that place…"
…
"…That's the gist of it."
In the meeting room at Demon Slayer Corps headquarters, Ubuyashiki coughed heavily before continuing, "Over the past few months, Muzan has tested us multiple times. This latest attack nearly killed Kyojuro, Tengen, and Mitsuri. He's likely convinced you're not with the Corps, Miss Hikari. If we give him a glimpse of hope that he can destroy us, he might not be able to resist taking action…"
"So…" Hikari picked up the thread, "you plan to leak some information to Muzan and set an ambush here to lure him out?"
Ubuyashiki nodded. "Exactly."
Hikari wasn't unfamiliar with this plan.
In the original story, Ubuyashiki had done just that—luring Muzan to the headquarters with its location, using hidden explosives and Tamayo's drugs to weaken him, then having the surviving Hashira gang up on him. He'd even sacrificed his entire family for it.
Without outside interference, the plan was solid—perhaps the only way to take down Muzan.
After all, Muzan's raw power outmatched the entire Corps. Even weakened by poison, he'd nearly wiped them out. If they didn't seize this chance and Ubuyashiki died, or the strongest Hashira, Giyu, grew old, the Corps might not even get a shot at mutual destruction.
But now…
"Miss Hikari, I know this is a bold request, but I hope you'll consider joining my plan," Ubuyashiki said earnestly. "If we can eliminate Muzan, I'd gladly offer the entire Ubuyashiki estate."
Hikari thought for a moment before replying, "I'm in, but I have two conditions."
"Name them."
"First, Muzan's mine," Hikari said, holding up a finger. "I'm interested in studying his body. I'll take him back with me, but I promise he won't harm anyone or create more demons. He likely won't appear in this world again."
"…That's acceptable," Ubuyashiki nodded.
While his goal was to kill Muzan outright, as long as Muzan stopped wreaking havoc, it counted as a win.
"Second, I want a piece of land in this country."
…
The land Hikari had in mind was the Hishikari Gold Mine in Kyushu, holding nearly 200 tons of gold. It hadn't been officially mined yet, and securing it would make her richer than robbing the Red Ribbon Army.
Of course…
Hikari hadn't visited Kyushu in the Demon Slayer world. Her knowledge came from the real world, so she'd need to confirm the mine's location in person before claiming it.
While the Ubuyashiki family's influence was mostly in Kanto, not Kyushu, as high-ranking aristocrats of the era, securing a mining claim shouldn't be too hard.
For now, Hikari and Ubuyashiki hashed out the rough plan and moved on—she wasn't too concerned with the details as long as Muzan could be drawn out.
Noticing her expression, Ubuyashiki said softly, "Miss Hikari, would you like to visit the Butterfly Mansion to see Kyojuro and the others? Or perhaps take a stroll in town to unwind? If you'd like, I can have Amane accompany you."
"…Butterfly Mansion first," Hikari said casually.
Though she hadn't been to the Demon Slayer world in a while, she'd built some rapport with Kyojuro Rengoku, Mitsuri Kanroji, and others last time. Since she was here, it made sense to check on their injuries.
If they were minor, she could even help heal them, thanks to Tsunade's Medical Ninjutsu.
…
That afternoon, Hikari and Esdeath headed to the Butterfly Mansion.
Hikari was something of a celebrity among the Corps, and with Ubuyashiki's endorsement, she moved freely. Kyojuro and the others lit up with surprise or delight when they saw her. Hikari nodded in greeting, her gaze lingering on Tengen Uzui for a few seconds.
From Ubuyashiki and Tanjiro, she'd learned about their injuries. Tengen had it worst—half his right arm was gone, leaving an empty sleeve. He could only eat and drink with his left hand. But seeing his three ninja wives doting by his bedside made it hard to feel too sorry for him.
"What happened? Didn't I teach you the Substitution Jutsu?" Hikari asked.
"…Master," Tengen scratched his head awkwardly. "The Upper Moon who attacked was tough. Even with Senzu Beans, Kyojuro and I couldn't beat him. If the sun hadn't risen, he might've killed us twice."
"Tch," Hikari clicked her tongue. "Rest up. Since you called me Master, give me some of your blood and skin samples later. I'll see if I can get you a new arm."
"…Huh?"
Hikari smirked, not mentioning Orochimaru or Dr. Gero. After some small talk, she and Esdeath left the infirmary for the courtyard.
Only then did Esdeath turn to her, puzzled. "Is this Muzan guy really that strong? Tanjiro and your friends seem kind of scared of him."
"He's alright," Hikari said, thinking it over. "For Tanjiro, he's tough—maybe Martial Arts Tournament quarterfinals level?"
"Oh…" Esdeath replied noncommittally.
A sudden idea struck Hikari. "Speaking of, Upper Moon Two, Douma, uses ice too, right? And he's got a thing for women. It'd be fun to see you take him on."
Then there was Upper Moon One, Kokushibo…
Since Hikari had taken on the "Yoriichi reincarnation" persona, she had to face off with this "foolish big brother" and see what kind of expression he'd make when he saw her red hair and crimson eyes.
With that in mind, Hikari opened the group chat and briefly mentioned the plan to lure Muzan out.
Bulma, Brand, and Yamato, who were online, responded quickly.
[Bulma: So, Tanjiro's side is about to hit the final battle?]
[Nameless: Pretty much.]
[Nameless: Muzan's got six Upper Moons, each with unique skills. Esdeath and I will each take one—I'll handle Kokushibo, Upper One, and Esdeath will take Douma, Upper Two. Any ideas for the rest?]
[Brand: Got any specific intel on them?]
[Nameless: Upper Three, Akaza, is a martial arts nut who loves challenging strong opponents…]
[Demon Princess: Leave him to me! I'll teach him how to behave with the fist of love!]
[Brand: Then Upper Four…]
[Little Monster: I'll take it! You've all been looking out for me, so I want to pull my weight.]
[Brand: Uh… guess I'll take Upper Five since no one else wants it.]
[Bulma: Wait, wasn't Upper Six that sibling duo Hikari caught last year? Has Muzan replaced them?]
[Nameless: Not sure. Maybe Nakime? Doesn't matter, Tanjiro can handle it.]
In a few messages, they'd divided up the six Upper Moons.
As for Muzan, the Demon King…
[Nameless: This might be a job for Miss Kikyo. Muzan has a place called Infinity Castle, a pocket dimension he can teleport to if things go south. We'll need your barrier techniques to trap him and keep him from escaping.]
Hikari's sealing jutsu could probably trap Muzan too, but she might not encounter him directly. And Muzan was slippery—if he got even a few seconds to teleport away, he could hide in Infinity Castle for another century, waiting them out.
"…Shame my Mangekyo doesn't have any space-based abilities," Hikari thought. "Maybe I'll talk to the Fourth Hokage or ask Kami about learning some dimensional ninjutsu or magic."