Early morning at the Butterfly Mansion, the air was filled with the faint scent of herbs and the fragrance of wisteria flowers.
Three days had passed since Rin moved into this highest-level medical and logistics base of the Demon Slayer Corps.
During these three days, his routine had been so regular it was almost outrageous: eating, sleeping, occasionally finding a deserted corner in the backyard to increase his skill proficiency, and spending the rest of his time basking in the sun on the veranda.
"Aaaah! You guy, just how much are you going to eat!"
In the dining hall, Aoi Kanzaki, with her hair in twin tails, held an empty wooden bucket as large as a washbasin while looking at Rin sitting across from her with a face full of exasperation.
"Another bowl, please. Extra katsuobushi. Thank you," Rin said casually as he set down the seventh empty bowl he had stacked in front of him.
After merging with Uchiha Sasuke's template, although the amount of chakra in his body was enormous, refining chakra required an extremely large amount of physical energy as support.
Simply put, his current appetite was roughly equivalent to that of three adult men.
"You... do you think this is a refugee camp? Shinobu-sama clearly said you were a guest, but what kind of guest eats like a starving demon reincarnated!" Aoi complained angrily, though she still turned toward the kitchen to fetch the eighth bowl of rice.
Nearby, the three little nurse girls of the Butterfly Mansion, Kiyo Terauchi, Sumi Nakahara, and Naho Takada, hid behind the door pillars, blinking their big eyes as they peeked at this handsome but extremely voracious big brother as if he were an alien.
After eating his fill, Rin held a cup of hot tea and leisurely walked to the backyard of the Butterfly Mansion.
Sunlight filtered through the dense canopy, casting dappled shadows across the ground.
Under a nearby corridor, Kanao, with her hair tied in a side ponytail, sat quietly on the wooden floor.
In her hand was a specially made copper coin. Her calm purple eyes gazed toward the sky, and it was impossible to tell what she was thinking.
Suddenly, Kanao seemed to sense Rin approaching.
She looked at Rin, then at the empty space beside her, seemingly hesitating over whether she should greet him.
Her thumb flicked lightly.
Tinglee~~!
The copper coin flipped into the air, tracing a graceful arc.
She was accustomed to using a coin toss to make choices she could not decide for herself.
Heads meant greeting him. Tails meant ignoring him.
However, before the coin could fall back into her palm, a long, strong hand suddenly reached out from the side. Two fingers precisely caught the rapidly spinning coin in midair.
Kanao's usually blank expression finally showed a trace of surprise.
"Leaving your will to a cold piece of copper. Don't you think that's a bit too careless?"
Rin casually pulled over a small wooden stool and sat down across from Kanao.
He spun the coin twice on his fingertip, then flicked it lightly. The coin landed steadily on Kanao's skirt.
"A person's heart is always growing. If you don't want to talk, then don't. If you want to sit quietly, then sit quietly. If even something as small as deciding whether to greet someone has to be left to a coin, wouldn't life be too boring?"
Rin took a sip from his teacup, not caring whether Kanao responded as he continued speaking casually.
"The talent in your eyes is quite good. Your dynamic vision is excellent. You have good potential for sword training. Don't waste your energy on this boring coin-tossing game."
After leaving those words behind, Rin stood up and walked toward the infirmary without looking back.
Kanao stared blankly at the coin resting on her skirt, then looked up at Rin's relaxed, carefree back.
For some reason, the man's casual words had felt like a stone thrown into the still water of her heart, creating ripples that refused to fade.
She slowly reached out and tightly gripped the coin in her palm. Deep within those hollow eyes, it seemed as though something was quietly beginning to break through the surface.
[Ding! The host's casual words touched the closed heart of Kanao Tsuyuri, planting a seed that may change her fate in advance. Obtained dimension points: 300.]
...
Butterfly Mansion, High-Level Infirmary.
When the door was pushed open, a thick scent of disinfectant mixed with wisteria flowers drifted toward him.
Shinobu Kocho was wearing a white medical coat over her black Demon Slayer Corps uniform.
She stood in front of a workbench filled with various glassware and test tubes, concentrating on preparing a pale purple liquid.
Hearing footsteps, Shinobu Kocho turned around, her face immediately brightening with her signature gentle smile.
"Ara, Rin-san, have you had breakfast? Aoi was just complaining to me that you're about to eat up an entire week's worth of the Butterfly Mansion's rations."
"Can't be helped. I burn a lot of energy." Rin sat down without ceremony. "I heard from Aoi that you have something for me?"
"Yes." Shinobu Kocho set down the test tube and walked over to Rin, looking at him with a smile. "I'm very curious about that power of yours called 'chakra.' Not only does it give you physical strength that surpasses demons, but it also allows you to release lightning. As the medical head of the Butterfly Mansion, may I perform a small 'physical examination' on you?"
As she spoke, a fanatical curiosity for research flickered in Shinobu Kocho's deep purple eyes.
If she could analyze this power, perhaps she could develop even more potent poisons, or even allow ordinary swordsmen to gain strength comparable to a Lower Moon or even an Upper Moon.
"An examination is fine." Rin straightforwardly extended his right arm and rolled up his sleeve, revealing his firm and well-proportioned forearm. "But let's make this clear first. No blood draws, no cutting. Only pulse checks and routine examinations."
"How stingy. Not even a small tube of blood?"
Shinobu Kocho complained, though she leaned closer as she spoke.
She extended her cool, beautiful fingers and lightly rested them on the pulse at Rin's wrist.
The moment her fingertips touched his skin, Shinobu Kocho's brow twitched slightly.
What a strong pulse.
Steady and calm, yet containing a terrifying vitality like a dormant volcano.
She could even faintly sense a massive energy flowing through Rin's meridians, something completely different from the way Breathing Styles forcibly strain the body.
"Truly incredible..." Shinobu Kocho could not help leaning a little closer.
They were now very close.
Rin could clearly smell the faint, soothing scent of wisteria from her hair and see her thick eyelashes trembling slightly with surprise.
"Your physical condition is even more exaggerated than the Hashira who train all year round. This energy is nourishing your cells every second..." Shinobu Kocho sighed before looking up with her usual gentle smile. "Rin-san, if I dissected you, it might advance human medicine by fifty years."
This playful yet dark remark would have given anyone else goosebumps.
But Rin simply looked at her quietly, his gaze calm.
Vroom.
Without warning, Rin's originally black eyes instantly turned into an eerie crimson, with three tomoe spinning rapidly within the pupils.