A few days passed peacefully after that incident.
Erika continued her training with Mitsuri as usual, but things had clearly changed.
With her improved control over her Device, Églantine, and the boost from Akira's Exp Overclock ability, her progress had accelerated tremendously.
she became stronger, faster than before.
Now, they could now safely confirm that Exp Overclock worked exactly as intended.
As for Akira's punishment, Erika really did turn him into her huge personal plushie.
In truth, she had no idea how to properly punish him. If it were her brother, she'd have probably broken a few bones and called it a day, but she couldn't bring herself to do that to Akira.
So after thinking for a while, she decided to be a bit selfish with his punishment. In the end, he was stuck inside the Pan-chan suit.
Still, Akira managed to master his own Breathing Style and maintain Total Concentration Breathing: Constant during that time. Thankfully, Erika at least let him leave the suit after a few days so he could train.
Of course, she continued using Pan-chan as her personal plushie during most of her free time.
Time passed peacefully like that until one day.
Akira was in the Butterfly Mansion's garden, kicking and punching a huge boulder as part of his training. He was focused with his breathing steady, when he suddenly heard a scream.
"I'm sorry! I'm sorry! Please stop!"
It was Tanjiro, sprinting through the courtyard like his life depended on it.
Behind him, a man in a Hyottoko mask chased furiously, waving a knife and shouting, "How dare you break my sword, you brat!"
Akira blinked and muttered, "Oh, it's already that time, huh?"
Moments later, Akira, Tanjiro, and Inosuke found themselves sitting inside a room with not one but two Hyottoko-masked swordsmiths, Haganezuka Hotaru and Kanamori.
Haganezuka was still fuming, lying down in a corner muttering darkly, while Kanamori did his best to keep things civil.
Haganezuka was lying there, still angry, while Kanamori was the one speaking to them. He was explaining about Haganezuka and how he had forged the katanas for Inosuke. When Inosuke took them into his hands, both blades had turned indigo.
Kanamori said, "The dull indigo-gray hue is actually pretty cool," and asked if the swords were good, since it was his first time forging blades for a dual wielder.
Inosuke didn't answer. He simply stood up, walked outside to the garden, grabbed a rock, and began chipping the edges of his blades.
All three people in the room, Tanjiro, Kanamori, and Haganezuka, were shocked, except for Akira, who had already seen this scene before.
Kanamori screamed, "I'LL KILL YOU, YOU BASTARD!"
while Tanjiro and Haganezuka tried their best to hold him back.
Akira, watching calmly, muttered, "Well, I understand he wanted serrated blades, but wouldn't doing that to a katana weaken it structurally?"
Soon, Inosuke did the same thing to his other blade, and Tanjiro and Haganezuka were again holding Kanamori back, who was screaming, "BASTARD! THAT'S IT, YOU'RE A DEAD MAN!"
A moment later, Inosuke finished "reforging" his weapons, both now crudely serrated.
Kanamori had to be physically restrained by Tanjiro and Haganezuka before he exploded into violence.
After the chaos subsided, Akira finally spoke up.
"Excuse me. About my sword."
Haganezuka looked at him. "Ah, you're the foreigner who requested a Nichirin blade?"
"That would be me," Akira replied.
He had made the request weeks ago, as part of his "cultural exchange" within the Demon Slayer Corps.
Haganezuka studied him silently, eyes glinting through his mask.
"You look like someone with potential. There's a good chance this sword will turn red, right?"
He then handed Akira a katana in a black sheath.
Akira received it, and Haganezuka urged him, saying, "Come on, hurry up and draw it. Nichirin swords are also known as color-changing swords; they change color depending on their bearer."
Akira slowly drew the katana from its sheath.
At first, it looked like any ordinary katana. Then, slowly, the blade began to shift in color, turning into a deep shade of elegant royal purple, similar to the color of his eyes.
Haganezuka tilted his head. "Hm. Not red… but not bad. A unique shade."
Akira stared at the blade for a moment, then muttered, "But I wanted black."
The room fell silent.
"…You wanted black?" Haganezuka repeated, bewildered.
"Well, yeah. It's my favorite color," Akira said with a sigh. "Oh well, whatever."
He walked outside, katana in hand. "Let's test it."
Tanjiro, Inosuke, and both swordsmiths followed curiously.
Akira faced the same boulder he had been training on earlier, took a deep breath, and activated his new Breathing Style.
In that instant, the purple blade began to glow, faint at first, then fiercely, until it burned like molten amethyst.
Everyone stared in shock.
"Why is it glowing!?" Haganezuka yelled.
But Akira didn't answer. He just brought the sword down in a casual swing.
And suddenly, the boulder was cut.
Just like that.
The cut was so smooth that the two halves slid apart silently before collapsing with a heavy thud.
Everyone was stunned. Sure, Tanjiro had done the same before, but Akira had done it casually, like it was nothing.
But then.
CRACK.
The sword splintered and shattered into countless glass-like fragments.
"MY SWORD!!!" Haganezuka's scream echoed through the mansion.
Akira looked at it and muttered, "Maybe I need a bigger sword?"
Everyone just stared at him.
But looking at the shattered blade that Haganezuka was crying over, Akira decided it would be better to go hand-to-hand for a while.
In the end, Akira didn't have a sword.
That night, the Butterfly Mansion was calm. The faint scent of wisteria drifted in through the open window, and the cicadas sang softly in the distance.
Inside their shared room, Erika sat on her bed, hugging the large Pan-chan plushie that currently had Akira stuffed inside it.
Her expression was relaxed but a little amused. "Honestly, Akira… how did your Nichirin Blade even explode?"
From inside the Pan-chan suit, Akira's muffled voice answered, "Maybe because I'm too powerful… or maybe because the breathing style I created is too powerful. In the end, it just wasn't strong enough to handle my strength."
Erika sighed and muttered, "Well, now how are we going to kill a demon?"
Akira said in a casual tone. "If a demon's unlucky enough to cross paths with us and doesn't die from your ribbons, we'll just deal with it using other methods."
Erika raised an eyebrow. "Other methods? What, did you develop a poison or something?"
Akira replied from inside the plush, "Just a small batch. Probably better than the ones people here are using. But I still need to run a few tests to see if it works properly."
As they spoke, Selena's voice suddenly echoed in both their minds, soft and clear through their telepathic link. "So, are we leaving tomorrow?"
Akira replied, "Yes. Tomorrow night would be better, then Erika can fly without getting spotted."
Erika let out a quiet sigh, hugging the plushie tighter.
Akira noticed it immediately. "What is it?" he asked.
Erika looked toward the moonlit window, her voice softer now. "We've spent almost a month here, after all… I think I'm going to miss everyone."
Akira was silent for a moment before replying gently, "Well, it's not a complete farewell. We're just going out for a while. It's my first time traveling with you, after all, so I think it'll be fun."
Erika smiled faintly at that, her blue eyes shimmering in the dim light. "That's right too," she said quietly, resting her head on Pan-chan's plush body.
Outside, the night wind stirred the curtains, and the faint glow of the moon filled the room with silver light, signaling the calm before their next journey began.
The next day, Akira and Erika were summoned for a meeting with Ubuyashiki Kagaya and the remaining Hashira present at the estate: Shinobu, Mitsuri, Gyomei, and Giyu.
The others were away on missions.
Kagaya greeted them with his usual calm, gentle smile. "So, are both of you about to set out?"
Akira nodded respectfully. "Yes. We've done our best in training here, so our next step is to face a demon directly. We'd also like to travel across this country while doing so."
"I see, then allow me to assist," Kagaya said kindly. "You have both earned not only my gratitude, but also my trust."
His voice carried the same serene authority that seemed to calm everyone in the room.
"From this day forward," Kagaya continued, "you may travel freely under the protection and cooperation of the Demon Slayer Corps. To aid your journeys, I shall grant you both a pair of wings and a place to rest beneath their shade."
With a subtle motion of his hand, two Kasugai Crows descended gracefully from above.
The first one, sleek and jet-black with intelligent and beautiful eyes, fluttered gently onto Erika's arm, its feathers glimmering faintly in the light.
The second one, a similar crow, but with a faint purple gleam running along its wings, also landed on Erika's other arm for some reason.
Kagaya smiled faintly. "These are Kasugai Crows. They are the voice of the Corps, connecting all our members across Japan. They will deliver missions, relay messages, and guide you safely along your path."
Akira blinked, glancing between the two crows perched on Erika. "Wait, why are both of them with her? Which one's mine?"
At that moment, the crow with the faint purple gleam flapped its wings and let out a loud caw. "CAW! CAW! Akira! Dangerous, don't blow up any more swords!"
Akira froze for a second, then sighed. "…Yeah, seems like we're going to get along well."
Erika couldn't help but chuckle softly, while even some of the Hashira in the room smiled at the scene.
The other crow, the one with beautiful eyes, tilted its head, then gave a slow shake, almost as if looking at both Akira and the loud crow with exasperation.
Its look seemed to say, "I'm surrounded by idiots."
It was a miracle how everyone in that room held back their laughter.
Before departing, Akira and Erika went around the Butterfly Mansion to meet everyone who had taken care of them, hoping to say their goodbyes properly.
Erika's first stop was with Mitsuri, who immediately hugged her tightly, tears welling up in her eyes.
"Erika-chan, take care of yourself, okay?" Mitsuri said, her voice trembling slightly.
Erika smiled softly and nodded. "I will. Thank you for everything, Mitsuri-san."
After that, the two of them went to meet everyone else: Shinobu, Aoi, the three little girls, and even Kanao.
Kanao, as always, stood quietly, her expression calm and unreadable. She took out her coin, flipped it into the air, caught it, and said, "All I did was follow Master's orders. There is no need for you to thank me. Sayonara."
Erika tilted her head, confused. "Wait… why did you toss…"
Before she could finish, Akira quickly stepped in and placed a hand on her shoulder. "We can't do that," he said firmly.
Erika blinked. "But…"
Akira shook his head. "No. Believe me, we can't. I'll explain later."
He then gently but decisively pulled Erika away before she could ask any more questions.
Their next visit was to Tanjiro and his group.
Tanjiro greeted them with his usual bright smile, though a hint of sadness lingered in his expression.
"Nezuko's still sleeping," he said. "It would've been nice if you could meet her."
Akira nodded. "Next time. I'm sure we'll meet soon."
Tanjiro smiled wider at that, his eyes filled with his usual determination. "Yeah, I'm sure of it."
That night, the two stood outside the Butterfly Mansion one last time.
The moon hung high in the clear sky, casting a gentle glow over the mansion's wisteria-lined courtyard.
Akira looked up at it and smiled faintly. "Well… till we meet again."
Erika turned around, seeing the people of the Butterfly Mansion gathered at the doorway to see them off. She raised her hand in a small wave. "Goodbye, everyone! Thank you for everything!"
Erika stepped closer, hugged Akira from behind, and spread her wings wide.
"Ready?" she whispered.
Akira smiled. "Always."
With one powerful flap, they soared into the night.
The wind rushed past them, cool and comforting, as the mansion grew smaller beneath their feet.
"Okay," Erika said over the rushing air, "but… which direction do we go?"
As if answering her question, the two Kasugai Crows appeared beside them, one jet black, the other glinting faintly purple under the moonlight.
Akira smiled and said, "Maybe they'll show us."
And so, guided by the crows, the two of them followed their wings into the starlit night, toward the next part of their journey.
Then, Selena's dry voice echoed telepathically in both their minds. "Why are you guys making this so emotional? We'll see them again in like a month or something."
Akira said seriously. "The tone's important, alright? Once I get into it, I can't just come out easily."