The method of demon hunting was simple and brutal. The demons' bodies would be frozen solid, then Shinobu would swiftly decapitate them with a single slash to the neck. But since it was already late at night, Tetsuya only took Shinobu out for a short hunt before they decided to head back to the Butterfly Mansion.
The Butterfly Mansion was Shinobu's home and also served as a recovery base for injured Demon Slayers. After her older sister's death, most of the healing work in the mansion fell to Shinobu, though there were other attendants who handled chores and looked after the wounded.
When they arrived, the three little assistants, Sumi Nakahara, Kiyo Terauchi, and Naho Takada, rushed out to greet them.
"Welcome back! Is anyone hurt?" the three small girls called out in perfect unison, their round, bead-like eyes wide with concern.
Shinobu smiled and shook her head. "No one is injured this time. We have other guests visiting."
The first one, of course, was Hancock, who had come here earlier because she couldn't stand being around so many men.
The three girls nodded and scampered off to attend to their own tasks.
Shinobu led Tetsuya to the backyard. There, they saw Hancock sitting quietly, gazing at a small black-haired girl with a ponytail and deep purple eyes.
A red butterfly rested in the palm of her hand. She stared at it in silence, her eyes emotionless, devoid of any spark or sign of life.
Shinobu looked at the girl with a complicated expression. "That's Kanao. Because of the harsh environment she grew up in, she became indecisive and quiet. She can't make decisions on her own."
"Can't make decisions for herself?"
Hancock, who had been silently observing Kanao, muttered to herself. This girl might have suffered a similarly dark past, perhaps even worse, resulting in PTSD-like symptoms.
Looking at Kanao, Tetsuya raised an eyebrow as an idea seemed to form in his mind. 'Maybe I can try it again?'
He immediately summoned his Zanpakutō.
"Mugen Saika."
To Shinobu and Hancock's shock, Mugen Saika dissolved into dark red particles that flowed into Tetsuya's eyes. A complex symbol then appeared in his pupils.
Tetsuya stepped forward.
The butterfly on Kanao's palm took flight. Her gaze followed it as it fluttered and landed on the tip of Tetsuya's finger, where it stayed motionless.
Kanao slowly lifted her head. Her empty, expressionless eyes met Tetsuya's now crimson gaze.
Shinobu and Hancock exchanged a silent glance. They had no idea what he was planning, but they chose to stay quiet and not interfere.
A red aura emerged around Tetsuya's body and gently touched Kanao's head. He asked softly,
"What do you think life is?"
Kanao stared at him, confused. Life? Like this butterfly, flying, doing something, that was life, right? Kanao didn't answer. No one was there to make the choice for her, and she didn't like making choices.
"Is it when something breathes, when it moves, when it's aware?"
Kanao stared into his red eyes and saw something she couldn't comprehend. She couldn't choose. She had no personal thoughts. She reached into her pocket to pull out her coin for a toss.
But Tetsuya spoke again.
"This butterfly is alive. Just like Shinobu—she is alive."
Hearing her name, Shinobu looked puzzled. It seemed like Tetsuya wasn't really talking to her, he was talking to himself. In truth, Tetsuya was inside Kanao's mind, directly hearing her thoughts.
'Like Shinobu… sensei? I don't understand…' Kanao blinked.
"If this butterfly dies, if it stops living, would you feel sad?"
'He's… talking to me?' Kanao looked at Tetsuya, then doubtfully at Shinobu behind him. If this butterfly was Shinobu, and it died, then yes, she would feel sad. She would be sad, but she wouldn't be able to express it clearly. She couldn't even cry.
Yet her mouth remained shut; no answer came out.
A flash of red light pulsed in Tetsuya's eyes.
The butterfly shattered into countless fragments.
'Sensei!'
He… had just torn "Shinobu" apart right in front of her eyes!
She saw the body sliced into pieces!
She watched it die, in that very instant!
Grief flooded her heart. Wordless emotions surged. The realization that it was Shinobu being torn apart by the man in front of her ignited rage in the heart of a girl who usually felt nothing.
No tears came.
She yanked out her sword. A flash of steel aimed straight for Tetsuya's neck.
"Kanao?!"
'Sensei's… voice?'
In an instant, the vision shattered.
Kanao saw her real sensei standing behind Tetsuya, worry, concern, and confusion etched across her face. Slightly resisting, Kanao realized her blade had been stopped mere millimeters from Tetsuya's neck. He was smiling faintly, preventing her from cutting any deeper.
"Life is when you feel something, when you still have emotions. Sadness, anger, jealousy, happiness… those are all signs that you're alive. Remember this feeling. You are not dead yet."
Tetsuya withdrew the red aura and straightened up slightly. The red butterfly fluttered once more on the tip of his finger, its wings brushing past Kanao's vision as it flew away.
Then Tetsuya turned and left, along with a bewildered Hancock, leaving Kanao frozen in place, staring at the departing butterfly.
…
"What did you do to that girl? Why did she suddenly turn aggressive and attack you?"
Hancock asked, still clearly confused. Shinobu was in the same state of bewilderment.
Kanao was not the type to attack anyone on a whim. She usually didn't even bother thinking about it.
Tetsuya chuckled.
"I was just trying to restore some rational thought by slowly shattering that emotional and mental void, while also influencing her senses and manipulating her visual perception so she saw me tearing Shinobu into a million pieces right in front of her."
"…" Hancock fell silent. She frowned slightly at how brutal the method was. Still, it seemed to have worked, and no real harm was done.
Shinobu blinked as realization dawned. Kanao had attacked because she witnessed "her" death, and in that moment, the girl had felt rage. The girl who had lost her emotions and refused to choose because of her traumatic past had become angry… for her sake. The realization filled Shinobu with relief and gratitude. She thanked Tetsuya sincerely.
"But… tearing me apart?"
It was undeniably cruel, even if it was just an illusion.
Shinobu looked at Tetsuya with grateful eyes, though a hint of sarcastic irritation flickered beneath the surface.
Tetsuya laughed.
Afterward, Shinobu led Tetsuya and Hancock to the rooms that had been prepared. Esdeath had already returned, having grown bored of "teaching" Sanemi Shinazugawa a few lessons. They all rested for the night. Tomorrow, they would carry out their plan, to finally put an end to the terror of demons.