Dawn had barely broken when Akira stepped into the courtyard of the Butterfly Estate. The sky was still painted in shades of indigo and pale gold, the air crisp with early morning chill. Without ceremony, without audience, he drew his blade and began.
The Thirteenth Form flowed from him like a continuous current of fire and light. One motion bled seamlessly into the next, circular, relentless, refined beyond mortal strain. There was no wasted movement, no pause for breath—only rhythm.
Again.
And again.
And again.
Tanjiro stood at the edge of the courtyard, watching with wide, unblinking eyes. Nezuko stood beside him, equally transfixed, her fingers tightening slightly at her sides as she tried to follow the pattern of Akira's steps.
Mitsuri was not idle either.
A short distance away, she practiced Love Breathing, her blade tracing elegant arcs through the air. Each strike carried grace and whip-like flexibility, the ground cracking lightly beneath the force of her footwork. Her hair shimmered in the rising sun as she moved continuously, refusing to fall behind.
Shinobu and Kanae trained nearby as well, their movements quieter but no less precise. Shinobu's thrusts were exact, surgical, each step controlled. Kanae's stance remained fluid, balanced, almost serene.
Tanjiro swallowed. "That's… the Thirteenth Form?"
Nezuko nodded faintly, her eyes tracking Akira's feet rather than his blade.
Tanjiro inhaled deeply and stepped forward. "I'll try copying it."
He began with the first motion, but his form broke halfway through the transition. His shoulders tightened too early. His footing faltered.
Akira did not stop his sequence.
"Don't chase the flame," Akira said calmly mid-motion. "Become the rhythm that sustains it."
Tanjiro adjusted immediately, attempting to slow his breathing.
Nezuko glanced at Mitsuri instead.
Without hesitation, she shifted her stance and mimicked Mitsuri's movements instead of Akira's. Her feet mirrored the curved patterns of Love Breathing, testing flexibility over raw force.
Mitsuri noticed.
Her eyes lit up instantly.
"You're copying me?" she asked, barely containing her excitement. "Wait—no, adjust your wrist like this. Love Breathing needs softness before impact."
Nezuko tried again, and this time her blade curved more naturally.
Mitsuri gasped softly. "You can actually learn it…!"
Her expression sparkled with genuine joy.
"Finally," she murmured to herself. "Someone who can follow my breathing style."
Akira completed another full rotation of the Thirteenth Form before smoothly lowering his blade. His breathing was steady, not strained in the slightest.
Internally, he focused.
Great Sage, has analysis of Muzan's blood completed?
A familiar presence responded instantly.
{Analysis of Demon King's blood and Kamado family blood successful.}
{Creation of Anti-Demon antidote complete.}
Akira's lips curved faintly.
"Great Sage," he thought again, "is there really no way to achieve you at full power?"
The response was immediate.
{Notice! This world does not have energy to run Unique Skill on full power.}
{Unique Skill is operating on minimal access through physical energy.}
{Unique Skill will stop working as you grow.}
Akira's hand tightened slightly around his blade.
He had expected that answer.
Still, it felt heavier hearing it confirmed.
Great Sage had been there when he was alone. When there was no one to speak to, no one to understand the burden he carried. It had guided him, sharpened him, supported him.
Losing it would feel like losing a part of himself.
He exhaled slowly.
"I don't want to lose you," he thought quietly.
There was no emotional response from the skill.
Only silence.
He sheathed his blade and walked toward Tanjiro.
"Again," Akira instructed. "This time, don't imitate speed. Follow structure."
Tanjiro nodded, sweat dripping from his jaw. "Yes!"
Nezuko continued practicing beside Mitsuri, who now crouched slightly to adjust her posture.
"Love Breathing isn't about brute force," Mitsuri explained eagerly. "It's about channeling emotion into precision. You're doing well—don't stiffen."
Nezuko gave a determined nod and repeated the motion.
Shinobu approached, watching quietly. "She really is adapting quickly."
Kanae smiled softly. "They both are. He's teaching well."
After hours of training, the estate gathered for breakfast.
The meal was simple but filling. Tanjiro devoured his portion gratefully. Nezuko ate more quietly, though her eyes still flicked toward Mitsuri occasionally.
Akira finished early and stood.
"Shinobu. Kanae. You two come with me. I want to create something."
Shinobu's eyes immediately brightened. "Another poison?"
"Nope," Akira replied calmly. "Antidotes."
Shinobu blinked. "Antidotes?"
Kanae's expression sharpened slightly. "For what?"
Akira smiled faintly. "One that turns demons back to human."
Silence.
The air froze.
"Wait—what?" Shinobu's voice rose an octave. "You can make that?"
Kanae stepped forward. "That would be wonderful."
"We are going to create it," Akira said simply. "So ready—"
He didn't finish the sentence.
Shinobu and Kanae grabbed him simultaneously and dragged him toward the laboratory.
The work lasted for hours.
Glass clinked. Ink scratched across parchment. Shinobu adjusted compounds with razor focus, her earlier teasing replaced by intense concentration. Kanae recorded observations meticulously, ensuring no step was undocumented.
Akira guided the process calmly, using Great Sage's calculations as reference.
When the final solution stabilized in its vial, silence fell over the lab.
Shinobu's hands trembled slightly as she held it up to the light.
"This… changes everything," she whispered.
Kanae nodded slowly. "Demons could be reversed. Families restored."
Akira turned to Shinobu. "You wrote the recap, right? Create copies of them and send them to Master."
Shinobu nodded quickly, already organizing the papers. She handed the bundle to her crow.
Akira looked at it. "Tell Master to mass-produce those. And start using it."
He turned toward his own crow and handed over two carefully sealed antidote vials.
"Take those two antidotes and tell Master to send them to Lady Tamayo."
Both crows nodded sharply before taking flight toward the Ubuyashiki Estate.
The laboratory felt different now.
Lighter.
"Now our work as Hashira will be coming to an end," Akira said quietly. "With those antidotes, even normal slayers will be able to take care of demons."
Shinobu crossed her arms. "So what are you going to do?"
Akira thought for a moment.
"I'm going to open a big restaurant and a clinic. Mitsuri always wanted a restaurant. And you two need a clinic, right?"
Shinobu nodded instinctively—then froze.
"Wait. Does that mean—?"
Akira nodded once.
Shinobu jumped forward and hugged him tightly. "You serious idiot. You just decided this?"
He chuckled faintly. "I've been thinking about it."
"What about Mitsuri?" Kanae asked.
"Oh, I talked with her. No drama. She expected it."
As if summoned, Mitsuri stepped into the doorway.
"Yep," she confirmed cheerfully.
Then her tone shifted slightly.
"About Iguro. Can we talk with him? I really don't understand why he acted that way. He is one of the friends I made in my days as Demon Slayer."
Akira nodded slowly.
"I was irritated," he admitted. "Shocked by you suddenly coming in front of me as Hashira. And his hostility. I went overboard. I was going to apologize."
He looked down briefly.
"I don't hold grudges. But I do want to know if I did something wrong."
Mitsuri smiled softly.
Shinobu smirked. "Look at you. Mature and reasonable."
Kanae chuckled. "That's the Akira we know."
Mitsuri stepped closer and lightly nudged his shoulder. "You'll talk to him calmly?"
Akira sighed. "I will."
"And not fight?" Shinobu added pointedly.
"No promises," he replied dryly.
They laughed.
As they walked out of the laboratory together, sunlight filtering through the estate corridors, there was a new sense of direction.
Demons could be cured.
The war could end.
And perhaps, when it did, the Sun Hashira would finally lay down his blade—not in defeat, but in peace.