Knowledge is power.
For the first time, Chika truly understood how literal that phrase could be.
To master the Sound Hashira's Score, one had to understand the fundamentals of rhythm and musical structure—only then could one translate the beat of combat into melody, perceiving the flow of battle as music itself.
"These books are your first step," Tengen said, handing her a stack of heavy volumes. "When you can understand every page, we'll start the practical training. Got it?"
"Yes, sir!!"
Clenching her fists, Chika gave herself a pep talk.
It's just studying. I survived nine years of mandatory education—I might fear it, but I can do it!
Taking a deep breath, she opened the first book. A few pages in, however, she froze.
Wait… this isn't as bad as I thought?
After finishing one page, she turned to the next, then closed her eyes to recall the previous one.
Every line, every word—perfectly remembered.
Chika's eyes widened. Her fusion with demon blood hadn't just strengthened her body—it had sharpened her mind.
Photographic memory…?
She chuckled softly. "So this is the kind of overpowered ability only novel protagonists get, huh?"
With a grin, she continued reading—page after page, faster and faster. From the side, Tengen could only stare.
Is… this supposed to be a flashy way to read?
He didn't think she was joking around. No—she was dead serious.
No wonder the Corps called her "The Miracle."
It wasn't just a nickname. Every impossible thing she'd done stacked up until the word itself became her identity.
Still, even a genius couldn't learn Score in one day. As dusk approached, Chika finally set the books down after finishing two and a half volumes. She thanked Tengen and promised to return tomorrow.
He waved her off casually but couldn't hide the spark of curiosity in his eyes. Something told him she really could master his art—maybe even faster than anyone he'd ever met.
He didn't see himself as a genius. Among the Hashira, he was the "normal" one.
The Mist Hashira had become a Pillar in two months.
The Stone Hashira was a literal monster in strength.
Even Rengoku had embodied perfection.
Tengen sighed, shaking his head as he watched Chika leave. "Man, even miracles need a break… Speaking of which, my wives haven't sent a letter in a while. Hope nothing's happened to them…"
Half a month passed.
Chika spent nearly all her waking hours at Tengen's residence. Her memory might've been flawless, but mastering rhythm required understanding, not just memorization.
Each day began with theory, continued with drills, and ended in exhaustion.
Then, one morning—
Her inner clock went off at dawn. Whether she'd been dreaming or not, she awoke right on schedule, stretching before stumbling toward the door like a zombie.
As she stepped out, someone else stirred.
From behind, Nezuko peeked out from under her blanket, puffing her cheeks in frustration as she watched Chika shuffle away.
'She's going to that man's house again…'
She'd only met Tengen a few times, but her "affection meter" for him was plummeting fast. Nobody steals her sister's time and gets away with it.
By now, Chika had completely mastered the theory of music and passed Tengen's written tests. What remained was combat practice—real, rhythm-infused dueling.
Outside Tengen's mansion, the training grounds had turned into a cratered wasteland. Between his twin Nichirin blades and explosive sound projectiles, the terrain looked like it had been shelled by artillery.
"My score is complete!!!"
"......"
"My score is complete again!!!"
"......"
"My score is complete again again!!!"
"......"
By noon, Chika collapsed onto the ground, drawing circles in the dirt with her finger, eyes lifeless.
Compared to her, Tengen could compose his Score ridiculously fast. The moment he completed it, his rhythm shifted entirely, resetting her synchronization every time.
She could have practiced with someone slower—like Rengoku, maybe—but that would've defeated the point. She wasn't here to take it easy. She was here to push herself past her limit.
If she couldn't activate her Score faster than Tengen, it would be useless in a real fight against an Upper Moon.
She clenched her fists. Still not enough. Gotta keep going.
Just as she was about to shout "Again!" she noticed Tengen staring off into the sky, lost in thought.
"What's wrong?" she asked.
"Ah, nothing major," he replied. "You know I've got three wives, right? They went to the Entertainment District to gather intel on a demon. Haven't sent word in a while, though. Starting to worry."
Chika blinked, realization dawning.
Right… timeline check. That means the Entertainment District arc is about to start.
Tengen's wives had gone undercover there to investigate—and the demon lurking in that district was none other than the Upper Moon Six.
She bit her lip. She didn't plan to interfere too much. Tanjiro and the others needed those battles for their growth.
But still… if things spiraled out of control, she'd have to step in.
Smiling faintly, she looked at him and said, "If you're that worried, let's just go check. I'll come with you—oh, and I'll bring my brother and the others too. If the demon isn't too strong, we'll let them handle it. Consider it training."