Demon Slayer Corps Headquarters — Medical Room.
"You said… a Mark?"
Michikatsu stared at his younger sister in shock.
More precisely, he was staring at the red markings spread across her cheek.
They really did look somewhat similar to Yoriichi's.
Yuko nodded slightly. "I almost died to that demon. The sudden awakening of the Mark is what saved my life."
"From what I understand, this ability only manifests when the body surpasses its limits."
Michikatsu's stunned gaze remained fixed on her, unable to understand her words.
Until now, both the Demon Slayer Corps and Michikatsu had believed that the mark on Yoriichi's forehead was simply a birthmark.
But now Yuko had awakened one too.
After a moment of silence, Michikatsu clenched his fist. "You're saying… your body got stronger?"
"Yes. I don't know the exact mechanism, but I can clearly feel that my strength has increased."
After resting for several days, Yuko had fully recovered from her weakness. She could distinctly sense the changes in her body.
Michikatsu suddenly stood up, gripping the hilt at his waist. "Come with me to the training grounds."
He had to verify this with his own eyes.
How could something so absurd be true?
The nearby doctor hurriedly protested. "That's impossible. Miss Yuko's body hasn't fully recovered yet."
"I feel fine alre— cough, cough." Yuko smiled, her calm expression faltering as she let out two uncontrollable coughs.
The doctor sighed. "Your lungs suffered severe frostbite. With our current medical knowledge, it cannot be completely treated. I assume this will affect your breathing techniques as well."
Michikatsu frowned. "What happened?"
Yuko shook her head. "I was tricked by that demon, that's all."
Those who awaken the Mark do not live past twenty-five.
With that knowledge in mind, Yuko didn't seem too concerned about lung damage.
Compared to the swordsmen who learn a breathing technique only to die horribly to demons shortly after, she was far, far luckier.
At the very least — she was still alive.
Returning alive from battle was already a blessing.
Seeing this, Michikatsu could not force her. "Rest well, then."
He turned to leave.
"Wait."
Yuko sat up on the bed.
The doctor panicked and moved to support her.
Yuko gently refused. "You understand my situation better than anyone, don't you?"
The doctor paused, then sighed. "I'll try to find a way to alleviate the lung damage. But please avoid strenuous activity."
"Thank you." Yuko smiled faintly before turning to her brother. "Brother, let's go to the training grounds."
Michikatsu frowned, not moving.
Yuko tilted her head. "What's wrong?"
"…"
He was silent for a long moment before speaking in a stiff, awkward tone:
"When… did you become this gentle?"
It gave him an odd, unsettling feeling — like the last kind words of someone nearing death.
"…"
A vein pulsed on Yuko's forehead as her lips twisted into a deadly smile.
"Oh? So Brother belongs to the type who feels uncomfortable unless someone scolds him?"
"If you told me earlier, I could've cursed you out all day long."
Even she got goosebumps from saying something like that — but as long as it disgusted Michikatsu, it was worth it.
He ignored her this time and left the infirmary.
Yuko took a deep breath.
Calm. Calm.
This damned jealous lemon… Today she would defeat him with a full set of techniques!
The "training grounds" Michikatsu referred to were not the Corps' public grounds — he disliked being watched.
He meant the back mountain behind headquarters.
The three siblings had often trained there.
Upon arriving, Yuko set down her Nichirin Blade and reached for a wooden sword.
"Use a real blade."
Michikatsu's voice cut her off. Yuko paused, then slowly drew her Nichirin Blade and faced her brother.
Her gaze lifted, meeting his as he unsheathed his own sword.
"Come."
The instant the word was spoken, two overlapping voices rang out:
"Moon Breathing, First Form: Dark Moon, Evening Palace!"
The blindingly fast iaijutsu clash rang out, steel crying against steel.
Michikatsu's pupils tightened as his arm — the one holding Yuko's blade at bay — trembled slightly.
She was matching his strength…?
A man's body was naturally stronger than a woman's.
That was an undeniable fact.
It was also the reason Michikatsu had never believed Yuko could truly stand on equal ground in the Demon Slayer Corps.
He had sparred with her before — and always defeated her with ease. He had never once felt this kind of pressure.
And she was using a breathing technique she wasn't even best at.
As though she had been reborn entirely.
"Moon Breathing, Second Form: Pearl Flower Moongazing!"
"Water Breathing, Fourth Form: Striking Tide!"
Each time, Yuko blocked Michikatsu's attacks.
Was Yoriichi not enough — even Yuko was surpassing him now?
Bitterness rose in his heart, and his swings grew increasingly erratic.
Yuko, with her greatly enhanced physique, met her brother's fierce attacks calmly.
She wasn't stupid. Though she had never read the manga or understood every detail about Tsugikuni Michikatsu…
Twenty years together had long been enough to understand his nature.
He was jealous — endlessly jealous of Yoriichi's talent.
He could accept being weaker than others, but never being surpassed by his own siblings.
Especially by his twin brother.
He envied the talents that belonged to his own family.
"Kh—!"
Yuko's breath faltered for a moment due to her lung injury — giving Michikatsu an opening.
"Moon Breathing, Sixth Form: Perpetual Night, Lonely Moon — Incessant!"
Several crescent blades shot toward Yuko in a rapid series of slashes.
The deadliest aspect of Moon Breathing was the countless crescent blades woven into each strike, covering an enormous area.
"Haa—"
Yuko calmly adjusted her breathing, releasing a faint white mist.
"Snow Breathing, First Form: Whirling Blizzard!"
A twisting white cyclone laced with icy wind shattered the incoming crescent attacks.
Michikatsu, unfamiliar with her Snow Breathing, failed to react in time and was pulled into the spiraling gale.
"Snow Breathing?!"
Suspended in midair, he was overwhelmed with shock.
Not only strength — she even created her own Breathing Style…
Didn't this mean that Yuko's talent was on par with his?
If he couldn't surpass even his own sister, how could he ever surpass that man?
The raging blizzard hammered at his body. Yuko had used the back of her blade — this was not a fight to the death.
The frustration of defeat mixed with seething jealousy made Michikatsu's body temperature spike and his pulse skyrocket.
"Moon Breathing, Fifth Form: Moon Spirit Calamitous Eddy!"
Spinning midair, Michikatsu sent out a massive vortex of crescent-edged slashes, blasting apart the blizzard.
The two techniques collided —
And canceled each other out completely.
---
+40 Chapters
(Currently at Chapter 54 on Ko-Fi.)
https:// ko-fi.com/rabi08