The Butterfly Mansion—managed by the Insect Hashira, Shinobu—served as a treatment facility for injured Demon Slayer Corps members, offering medical care and rehabilitation. Most of the caregivers were individuals without swordsmanship talent, including members of the Kakushi unit.
The Butterfly Mansion covered an extensive area—according to Shinobu, nearly the size of an entire residential district. Beige gravel paths wound between verdant trees, and the compound consisted of a continuous series of spacious two-story tiled buildings. Medical staff in black uniforms occasionally passed to and fro. Aside from the chirping of birds, no other sounds could be heard. Overall, the environment was tranquil and serene—an ideal place for recovery.
"This is the Butterfly Mansion... what do you think? Not bad, right?"
Shinobu turned proudly toward the woman beside her, clearly pleased with her domain.
"Mm... the environment is quite nice. It seems well-suited for rest and peace of mind."
The Shogun supported her chin lightly with her fingers, her eyes sweeping over the calm scenery.
"Mm-hmm~?"
Shinobu raised an eyebrow slightly, as if prompting her to continue.
"Phew... whoever chose this location must have had an excellent eye for it."
Seeing Shinobu's expression, the Shogun couldn't help but sigh softly. Still, she gave the praise with subtle intent, meeting Shinobu's gaze meaningfully.
"Hehe... thank you for the compliment~ Come, I'll show you around inside."
Pat...
Smiling with satisfaction at the praise, Shinobu once again reached out and gently took the Shogun's delicate hand, leading her indoors.
"Shinobu..."
The Shogun had been slightly bothered from the start.
"Mm?"
Shinobu didn't look back, but responded with a soft hum.
"I can walk by myself. You don't need to hold my hand."
Though she voiced a quiet complaint, she still obediently allowed herself to be led.
"I'm just worried you'll get lost~."
Shinobu glanced at the soft hand she held, a small smile tugging at her lips.
"...How could I get lost while following you like this?"
The Shogun countered calmly.
"Just in case. The paths here are quite winding, you know~? Or do you simply dislike me holding your hand?"
Regardless of age, Shinobu's natural temperament leaned toward that of a caring older sister. Her teasing tone was warm, playful.
"..."
Hearing that, the Shogun's violet eyes flicked upward to meet Shinobu's. For a moment, she seemed unsure how to respond, and turned her gaze away slightly.
"...No, I don't dislike it. I just thought... it might inconvenience you."
"Hehe... so that means you like it, right~?"
Shinobu leaned in, teasingly close to her cheek.
"...I didn't say that. Enough—don't tease me."
Caught off guard by the sudden closeness, the Shogun turned her head aside, a faint blush dusting her cheeks as she murmured softly in protest.
"Pfft... alright, alright~ let's go."
The sight of her reserved, flustered demeanor struck directly at Shinobu's heart. Still, she refrained from further teasing—knowing when to stop was a virtue.
"Where are we going?" the Shogun asked.
"Hmm—well, we could check out your room first, or go visit Tanjiro and the others. Either is fine."
Shinobu gestured toward the two branching corridors—one leading to the patient ward, the other to the residential area—and let her decide.
"Phew... let's go with you first," the Shogun said after glancing down both paths. She knew visiting Tanjiro and the others was Shinobu's responsibility, and didn't want to delay her work.
"Alright, then follow me."
Shinobu smiled lightly at her response—not surprised, but quietly pleased. She could tell the Shogun's choice came from thoughtfulness, and such small gestures spoke volumes about one's character.
"Will my presence interfere?" the Shogun asked, still letting her hand be held.
"Not at all... we're just going to check on their condition. It won't take long."
The door to Tanjiro's room was half-open, and even from afar, noise poured out—like the bustle of a marketplace.
"Seems they're fine now..."
Judging by the liveliness of the voices inside, Shinobu made her assessment. She gently released the Shogun's hand and pushed the door open.
Feeling the warmth of her touch fade, the Shogun instinctively rubbed her palm, where a trace of Shinobu's warmth still lingered.
Inside, Murata was standing beside the beds of Tanjiro and the others, complaining endlessly—
"The Hashira are absolutely terrifying!"
Murata kept grabbing Tanjiro's collar and shaking him back and forth.
"Ugh!! Murata-san, my back still isn't healed!" Tanjiro cried out in pain.
"What's going on?"
Having been fortunate enough to stay outside Mount Natagumo, Zenitsu was the only uninjured one among them. He tilted his head in confusion.
"They wanted to figure out what exactly happened on Mount Natagumo, so they made me report to the Hashira meeting! All the Hashira were glaring at me! It was pure hell!"
"What did they say?" Tanjiro asked curiously.
"They said the quality of new recruits has dropped, and that some members are causing trouble by disobeying orders! Then they asked who trained us and scolded us harshly! Do you think that helps? Telling someone like me that—does it help?! Seriously..."
Tap, tap...
"Well, it seems everyone's in good spirits~."
Shinobu suddenly appeared behind Murata like a ghost, her sweet yet mischievous tone sending chills down his spine.
"Yaaah!!! It's a Hashira!! Miss Kocho!! And—ah! Lady Raiden!!"
Hearing that voice—which to him was as terrifying as a demon's—Murata shrieked like a startled girl. He jumped to his feet and began bowing clumsily to the two purple-haired beauties before him. He already knew about the Shogun's new appointment; word had spread through the Corps quickly—another female Hashira was rare enough to cause quite a stir.
"Hello there~?"
Shinobu smiled gently, greeting as though nothing were amiss.
"Uh!! I—I didn't say anything! Excuse me, I'll be going now! Pardon me, Lady Hashira!!"
Whoosh!
In a flash, he vanished down the hall, leaving behind only a faint trail of dust.
"So hasty? Take care on your way~," Shinobu said lightly, covering her mouth in amusement as she called after the already-gone man.
"What's wrong with him?" the Shogun asked, puzzled.
"Nothing really... Many members of the Demon Slayer Corps suffer from mild PTSD. It's nothing to worry about," Shinobu replied with a wry smile, shaking her head softly.
"Miss Raiden, Miss Kocho... you two..."
Tanjiro froze for a moment upon seeing them—after all, both women before him were Hashira.
"How's your condition?" Shinobu asked, walking up to the bed and looking down at him.
"Thank you... I'm feeling much better now," Tanjiro answered honestly.
"Good... let me see."
Shinobu then reached out and placed her hand on his back—before suddenly delivering a sharp slap!
"Ahh! That hurts!" Tanjiro yelped.
"Hmm—much better. In that case..."
She picked up the medical chart from the nearby table, scanning it briefly before smiling sweetly.
"—It's about time to begin your functional recovery training."
"Functional... recovery?"
"Yes~."
Her smile was beautiful—but the darkness hidden beneath it was unmistakable. It was the smile of a devil in disguise.
...
...
A few minutes later—
"AAAAHHHH!! I'M GONNA DIE!!!"
"UWAAAAHHH!!!"
Agonized screams echoed through the spacious training hall, as if someone were being tortured. Ah... Inosuke, of course, was performing true to form.
"What... happened to them?" the Shogun asked, blinking in disbelief at the horrifying cries.
"Just functional recovery training~. Don't worry, they won't die. Come on—let's head to the residential area for a walk, hehe~."
With that, Shinobu passed by her with a playful smile, even giving her a cheeky wink as she went.
"..."
This woman... it's best not to provoke her.
The Shogun watched her retreating figure with a complicated expression, quietly thinking that to herself.
...
Around nine o'clock that evening, the sky was already completely dark. The Butterfly Mansion was now silent except for the sound of cicadas and the faint, lonely glow of the moon. During the day, this place was always filled with a warm bustle—but no matter who you were, sleep would eventually claim you.
Click...
After finishing her tea and returning the utensils, the Shogun stepped out of the tearoom. Just as she was about to follow the corridor back to her room—
"?"
She suddenly caught sight of a figure sitting on the rooftop. Her steps paused as she tilted her head, studying the purple silhouette perched atop the tiled roof.
Was that... Shinobu?
The petite girl sat alone, hugging her knees, her gaze seemingly fixed on the sky above. She didn't move at all.
The silvery moonlight wrapped her form in a faint, ethereal glow, making her solitary figure appear even more melancholic beneath the night sky.
"...?"
Perhaps sensing the gaze from below, Shinobu blinked and lowered her eyes, meeting the Shogun's gaze directly.
(Waves...)
The next moment, she smiled softly and gave a small wave—like a celestial maiden bathed in moonlight.
"What are you doing up there?"
The Shogun asked aloud.
"Me? Hmm—just moon-gazing. Do you believe that~?" Shinobu replied with her usual sweet and delicate tone.
The Shogun turned her head toward the distant moon. Indeed, the moonlight tonight was beautiful—perfect for quiet contemplation.
"Shogun... would you sit with me for a while? Just a little while."
Her voice carried a faint sincerity—an invitation both genuine and wistful. For some reason, the Shogun sensed that Shinobu at this moment wasn't as composed or playful as she was during the day. There was something softer, more fragile about her.
"..."
Without a word, the Shogun answered through action. Her toes pressed lightly against the ground, and with a graceful leap she landed silently beside Shinobu on the rooftop. She smoothed her kimono as she sat, her outfit now changed into her usual casual attire—a soft blend of white and violet. Her long hair hung loose, flowing gently in the night breeze.
"So beautiful... Shogun," Shinobu murmured upon seeing her.
"The moon?" the Shogun asked reflexively.
"The moon is beautiful, yes—but not as beautiful as the person sitting beside me."
"...Smooth talker."
The Shogun brushed a strand of hair from her shoulder, her tone calm but faintly amused.
"Look at those stars over there... they twinkle as if waving to us. I wonder who they are," Shinobu said softly, pointing to the starry sky that stretched like a silver river above them.
"...According to legend, the stars represent those who have passed away—and the memories they left behind."
The Shogun replied as her gaze followed the constellations. Unlike Shinobu, who sat hugging her knees, she extended her shapely legs forward, her white-stockinged feet glimmering faintly in the moonlight. Her calves hung slightly downward with gravity, and her high-heeled sandals slipped just enough to dangle from her toes, revealing the soft curves beneath the sheer fabric.
"The departed... including family?" Shinobu asked quietly.
"...Perhaps," the Shogun answered, glancing at her.
"My sister might be up there too," Shinobu whispered.
"...?"
Sister? This was the first time the Shogun had heard her mention that word. She had a sister? The word sister struck a sensitive chord within her—for she, too, had once had one.
"Your sister..."
"Mm... she's gone. Killed by a demon. Remember when I said one of the Upper Moons killed my family?" Shinobu said, her tone steady, almost casual. Perhaps she had long since grown used to it.
"That family member was my sister—Kanao's older sister, Butterfly Kanae."
"..."
The Shogun said nothing, simply listening. Her legs, which had been elegantly crossed, slowly lowered to rest quietly on the tiles.
"Pfft... You know, I wasn't always like this~."
Seeing the Shogun's subtle movement, Shinobu smiled fondly, a trace of amusement softening her eyes.
"I can imagine. Your current personality already gives me enough trouble," the Shogun replied dryly.
"Hehe... true enough. But once upon a time, I was quite different—young, fiery, proud, and quick to anger," Shinobu admitted with a light laugh.
"...Hard to picture. You really had such a phase?"
After a moment of quiet thought, the Shogun gave up trying to imagine it. The image of this Shinobu acting like that was far too strange to comprehend.
"Yes... it even surprises me sometimes. Back then, I always spoke my mind—so bluntly that I often offended others," Shinobu said with a self-deprecating smile.
"When my sister passed away... sigh... I decided to imitate her behavior—to face others with a smile, just as she always did. Because somehow, when I smile, it feels like she's still beside me, like she never left."
"You're not smiling now," the Shogun observed quietly, her keen eyes noticing the subtle shift.
"...No, I'm not. Maybe it's because I miss her. Every time I think of her, I get angry—angry at those demons. I hate them. My sister, my parents—they were all killed by them."
Shinobu's voice lowered, her tone uncharacteristically cold.
"When you're angry... you show no expression?" the Shogun asked.
"Pfft... you noticed that too~?" Shinobu blinked in mild surprise, then covered her lips with a small laugh.
"You're thinking of someone too, aren't you?" the Shogun asked softly.
"Mm... even after all this time, saying I don't miss her would be a lie. That kind of feeling—it's etched into one's very bones. No matter how much time passes—"
Shinobu shook her head lightly.
"—it never truly fades. Whenever the longing grows unbearable, like tonight, I sit on the rooftop and gaze at the stars."
She slowly raised her hand, as if trying to grasp the distant starlight, her fingers closing gently around the air.
"I understand how you feel," the Shogun murmured, her violet eyes softening as she watched the fragile figure before her.
"Hmm? Shogun... you too?" Shinobu asked, startled and a little concerned.
"...Not me. My mother." The Shogun shook her head slightly, clarifying. She had almost said 'my mom'—but such childish phrasing would have been far too embarrassing.
"Your mother..." Shinobu repeated softly, her gaze growing gentle, tinted with sorrow.
"Yes... my mother had a sister. They were twins," the Shogun said quietly.
"So that means... your mother's sister—"
"...She passed away." The Shogun finished the sentence calmly.
"..." Shinobu's eyes widened slightly.
"She was very kind to my mother... very gentle. The two of them relied on each other through hardship and sorrow. After she died, my mother was devastated. She shut herself away from the world, refusing to see anyone. And during that time... she gave birth to me. Every day, she would confide in me—bare her fragile heart, even cry before me. That was all she could do back then."
"..." Shinobu remained silent, listening intently. The Shogun's voice was calm and steady—perfect for storytelling.
"And afterward? What happened to her?" Shinobu asked softly.
"She recovered. She grew strong again—for my sake, and for the sake of our family. She told herself, 'I cannot collapse forever. There are still those who need me,' and through that, she found strength."
"I could see it—the change in her. In her personality, her outlook... everything shifted. All because of me, and because of our family."
Family—referring to their homeland, Inazuma.
"She must still think of her sister, even now. I understand that feeling... but I would never say 'I understand how you feel.' I don't have that right. I've never experienced the pain she felt losing someone so dear. And I don't want to. I'm afraid to. I don't want her to leave me. Never."
By now, her eyes shimmered faintly with unshed tears, the sight leaving Shinobu quietly entranced.
"So yes... I understand your feelings. That kind of pain never fades. But even so, we cannot stay trapped in the past. The road ahead is long, and we can only move forward. That is what it means to live, isn't it?"
She turned to look at Shinobu again, her tone soft but resolute.
"Shogun... are you alright?" Shinobu asked gently, her hand reaching up to caress the Shogun's cheek with tender concern.
"I'm fine. Just like you, I've grown used to it. Besides, as her daughter, I must be her emotional support—to keep her from falling again."
"...You're so kind, Shogun. And your mother too," Shinobu said warmly, offering her a genuine smile—different from the polite, practiced ones she usually wore. It was real, heartfelt.
"And you? Do you feel better now?" the Shogun asked softly.
"Mm, I do. Hehe... Tonight feels rather romantic, doesn't it~?" Shinobu replied with a playful smile.
Romantic, huh... In a way... yes, it was.
—At least, that's what the Shogun thought.