Morning – Hot Spring Hotel
Miyamoto Musashi appeared out of nowhere with a mischievous grin, holding up a frilly dress."Master~♪ I found the cutest outfit! It'll look amazing on you. Please, try it on!"
Shirou Muramasa froze."…Isn't this a little girl's dress!?"
Musashi brushed it off with a shrug."What does it matter? As long as it's cute, it works!"
"I refuse! Absolutely not!"
"What a pity."
"Good. At least you understand."
"Then I'll just do it myself. Don't forget—it's punishment time." Musashi's eyes gleamed with dangerous intent.
Shirou's survival instincts kicked in. He bolted for the door, but Musashi was faster—blocking the only exit with a single step.
"Martial Arts: Hidden Technique!"
Muramasa stumbled back in shock.
Musashi's cheeks flushed with a strange blush."Just once. That's all I ask. Beautiful things are beautiful… regardless of gender."
Doraemon, save me!!
Faced with her overwhelming obsession, Shirou realized resistance was futile. Today, escape was impossible.
When he finally emerged in the outfit, his eyes were lifeless. Already, he had decided to wipe this memory later—either with Doraemon's help or by using suggestion magic to force amnesia.
"It suits you perfectly," Musashi praised, her tone far too genuine.
Noon
Musashi returned, arms full of food. Judging by the broken vending machine, her "shopping" method was obvious.
"Master! Look what I found—fried tofu udon! This era's food is so convenient and delicious!"
"Instant udon? Not my favorite."
"…Eh?"
Shirou blinked at her strange reaction.
Musashi's eyes widened as if she'd just witnessed heresy."Impossible… There are actually people in this world who don't like udon noodles!?"
"…."
Afternoon
Still restless, Musashi yanked Shirou by the arm with overwhelming strength.
"Master~ After lunch, let's hit the hot springs again!"
As she dragged him off, Shirou sighed."Musashi, this is your third bath today. Too many hot springs aren't good for your health."
"It's fine. I'm a Servant. My body is always in peak condition, and I can just evaporate water with magecraft. I'm the perfect Miyamoto Musashi, twenty-four seven!"
…You could at least consider me.
"Hm-hm-hm~ Wine, dumplings, udon, and Master~" she hummed happily, inventing her own little tune.
Later, Musashi suddenly had another idea.
"Master, lend me your sword! Doraemon said it's a magical blade that counters automatically. If that's true, it's basically the pinnacle of swordsmanship—a total cheat weapon!"
"Don't break it. It's fragile without magical reinforcement," Shirou warned, though he knew it was pointless. With Musashi, the result was always the same.
Just endure. Endure until I can use the [Time Wrap] to repair the circuits.
"Don't look at me like that, Master. I treasure weapons. My sword is my weapon… and you're my weapon, Master. I take good care of my sword, so of course I'll take good care of you. Hehe~"
…Very good. Very spirited. Very Berserker logic.
Dusk
Shirou sat in the courtyard, exhausted, watching the sunset in the mirror world. By the end of the day, he felt like the adult—and Musashi the child.
"Master…"
He didn't turn around."…It's broken, isn't it?"
Musashi froze, guilt painted across her face. Slowly, she revealed the [Famous Sword: Denkamaru], snapped in two.
"It was just… too fun. I swear, I only used a little more power. Just a little! Master, you believe me, right? Doraemon has a time-rewind gadget, doesn't he? We can fix this!"
"But broken is broken."
"…."
Musashi lowered her head and bowed deeply."I'm sorry. This was entirely my fault. No excuses. Can you forgive me?"
"Yes. But I don't want to."
"Eh!? Master, that's so childish!"
"Of course. I'm not even seven years old. Being childish is allowed."
Night
Musashi's eyes sparkled as she carried in her latest discovery."Master, look! A game called ping-pong! Let's play! I finally know why that room had such a huge table."
Shirou glanced at the table, which was taller than his head."Musashi, you…"
"…Ah. Sorry. I forgot you're still a kid. Isn't the table taller than you?"
"Just hand me the ball."
Minutes later—
"Your forehand is sloppy, your backhand is weak, your footwork is loose, and your reaction is slow. Do you really want to challenge me? Keep dreaming!"
"…."
Musashi's smile twitched."Master… if you put it like that, I'll just have to get serious." She raised her paddle like a katana.
"Ping-Pong Style: Two Heavens as One!"
Bang!
The ball didn't just fly—it exploded into fragments the instant her paddle touched it.
"…That shouldn't even be possible."
Fireworks
Later, Shirou handed her a small bag of fireworks he'd found in the hotel's storeroom.
"Fireworks?" Musashi tilted her head.
"They're for decoration. No danger. Just light and sound."
"Oh, I know these! They exist in other worlds too. I even visited one where fireworks were turned into deadly weapons."
"…You mean cannons?"
"Yes! That was it!"
"Wanna try them?"
"Of course! When I was a kid, I begged my bastard dad to buy me some, but he refused. Said 'the daughter of the Miyamoto family doesn't play with childish toys.' Hmph. Well, now I've surpassed that bastard—and what I say is law!"
The fireworks lit up the night sky, crackling softly in the silent mirror world.
Musashi's voice grew quieter."…Thank you, Master."
Shirou looked at her but said nothing.
Her smile was faint, as if holding something back."I haven't been this happy in a long time. That's why I… couldn't help acting spoiled today."
"That wasn't spoiled. That was torture. I'll erase this day from my memory."
"Are you unhappy?"
"No. That's not it."
"…Then please, don't erase it. If I disappear from this world one day, your memory of me will be the only trace left behind."
"…I know."
Shirou whispered, lowering his gaze to the firework in his hand. The flame flickered, illuminating the smirk tugging at the corner of his lips.
Go ahead. Leave if you want.But I swear—I won't stay her Master if I don't avenge today's humiliation.
Musashi's strange, transient existence—tied to the Sky Eye and its shifting between worlds—didn't worry him. With Doraemon's help, there was always a solution.