"Ehhh, Erika-chan, I heard you woke up, how… what happened? You don't look well rested," Kanroji Mitsuri, the Love Hashira, said as she entered the room. She looked at Erika, who indeed looked like she hadn't slept a wink last night.
Erika replied, "Well… I woke up and couldn't sleep last night."
"How could you not sleep? You need to rest!" Mitsuri scolded, then turned sharply. "Akira-kun, why didn't you take care of her well?"
Akira, who was sitting next to Erika's bed on a chair and happily eating the castella cake that was meant for Erika, looked up and said, "I don't know, I slept first. So I don't know why she didn't sleep well. I slept well, though."
Erika glared at him with deep resentment.
Not only had he basically used her like a plushy the whole night…
He was now eating her castella cake without even asking.
But she didn't say anything aloud.
Instead, Erika turned to Mitsuri. "Don't worry, Mitsuri-san. I already slept a long time before, so I just didn't go back to sleep after waking up, that's all."
"Good thing you're alright… I was really worried," Mitsuri said with a huge sigh of relief.
Akira, who had just finished the castella cake, suddenly remembered something and asked, "Oh yeah, Mitsuri-san, what about the thing I requested yesterday? Was it approved?"
"Oh! I completely forgot," Mitsuri said, clapping a hand to her cheek. "I originally came here to inform you about it, too. Yes, Oyakata-sama approved it."
"Really? That's great!" Akira said, genuinely excited.
Erika, who didn't know what they were talking about, asked, "What are you guys talking about?"
Akira explained, "Well, I asked them if they could teach me how to forge a sword. I wanted to visit the Swordsmith Village to learn it. Good thing it was approved."
Erika blinked. "Why do you want to learn sword-forging all of a sudden?"
Akira replied, "Well, in the last fight, I broke my twin katanas when I used Star Breathing, just after a single slash. So I want to make a sword that can handle Star Breathing."
"What about that Demon Slayer sword?" Erika asked.
"I can't use it seriously," Akira said. "It's already a bit chipped, too. Back then, all I could do was use it to buy time for you guys to cut off that demon's head, so I could use my katana to cut the head of the one I was fighting. And I can't keep on doing that in the future. That demon we fought is the weakest of the Upper Moons, and they're already tricky to kill. I'm sure the others are even harder to kill, too… so I need a better weapon to kill them."
Erika nodded. "I guess that makes sense. So when are we leaving?"
Akira asked, "I don't know. Mitsuri-san, do you know?"
Mitsuri said, "Well, we were waiting for Erika-chan to recover."
Erika quickly said, "I'm totally fine. Just a bit exhausted from using my powers, that's all. We can go anytime."
"Then how about tomorrow?" Mitsuri suggested. "I'm going there too, so we can all go together."
Akira nodded. "I'm okay with that. What about you, Erika?"
"I'm okay too," Erika replied.
"Alright then," Akira said, satisfied. "We leave tomorrow."
Mitsuri suddenly leaned in with curiosity sparkling in her eyes.
"So, about that Upper Moon you guys fought, can you tell me how strong they were? And how do you beat them? I'm really curious!"
Akira instantly perked up, practically vibrating with excitement. "Oh, you have no idea! Erika destroyed that Upper Moon, like, she didn't even let her get back up. She completely annihilated her!"
"Really?" Mitsuri gasped.
"Yes!" Akira nodded rapidly. "Oh, actually, it was recorded. Do you want to see that fight?"
"You can show me!?" Mitsuri asked, surprised.
Erika stiffened. "Wait, it's recorded?"
Akira said, "Yep. You know who recorded it, so we can watch it later."
Erika sighed. "I see… it was she-who-shall-not-be-named."
Selena telepathically snapped at both of them, "Can you not treat me like Voldemort?"
But neither of them reacted to her.
Akira then asked, "So, do you want to watch it? I can show it to you with my magic."
"W-Wait!" Erika stuttered, already feeling dread.
But Mitsuri leaned forward eagerly. "Really? Then please show it to me!"
Akira activated his system screen and played the video.
The recording began: a full display of Erika violently beating up Daki. Every slam, every stomp, every brutal movement.
Akira pointed excitedly. "See?! Isn't that cool?! Look how she grabbed her hair and just slammed her into the ground! And look—look how she stomped on her head! It's cool too! And you have to see how she grabbed her legs and just swung her around, it's so cool!"
Mitsuri nodded enthusiastically. "Ohhh, Erika-chan really beat her up!"
Erika, watching her own rampage for the first time, was mortified. "D-Did I really do all that…? Isn't that a bit too violent? And why does this idiot look so excited?!"
Selena's telepathic voice chimed in immediately.
"Well, my brother is a bit weird, so please don't expect any normal response from him. And look, he's really excited to show Mitsuri how cool you fight. I mean, look at his face. That's the look of a boy in his first love."
"SELENA!!" Erika screamed in her mind.
Selena giggled, "Hehe, I was just joking. But he really does look excited to watch you violently beating her up, right?"
"…I know," Erika replied mentally, "but I have very mixed feelings about this…"
After a while, Mitsuri finally left, saying she needed to prepare for tomorrow.
Erika then punished Akira for eating her castella cake, among other things.
"So, do you understand what you did wrong?" Erika asked coldly.
Akira was currently wrapped up in her ribbons, using her Blood Breathing: First Form — Crimson Thorn Prison.
Of course, she was using the non-lethal, illusionary form of her Device, where a Blazer summoned their weapon without real intent to harm. But Akira was still bound tightly, unable to move.
Akira tilted his head. "… What's wrong? Is it about that castella cake? I'm hungry, okay? I'll get you another one, what do you say?"
Erika's eye twitched.
"Not that. It's about what you did last night."
Akira blinked in confusion.
"What did I do?"
"You can't just hug a girl and fall asleep like that!" Erika snapped. "I couldn't even move because you were hugging me so tight!"
"But I didn't hug any girl," Akira replied innocently. "I was hugging you inside the Panchan costume. And you always hug me when I'm the one wearing it."
"This and that are different!" Erika shouted. "You can't do that without permission!"
"…So can I hug you if I get permission?" Akira asked seriously.
Erika froze, then turned bright red.
"W–What nonsense are you talking about!?"
Akira continued honestly, "Well, it's actually really comfortable hugging Panchan to sleep. I haven't slept that good in a long time, so I want to do it again."
Erika didn't answer.
Instead, she smiled.
And tightened the ribbons around him.
"Ah, wait, wait! Erika, I'm joking! I'm joking! Please forgive me!"
"No," Erika said sweetly. "You need to be punished."
And so Akira was very thoroughly punished
…until she was satisfied.
A day passed. Everyone was well rested, except for certain someone.
It's time for them to leave for the swordsmith village, but before leaving, Akira visited Shinobu, handing her a stack of notes and research papers, and experimental material he had created using his evolutionary abilities.
"This is all my research plans and materials for it," he said.
Shinobu blinked. "Research about… what?"
"A medicine that can turn a demon back into a human."
Shinobu's eyes widened. "You already figured it out?"
Akira shrugged casually. "I had the idea for a while. I just needed the blood of an Upper Rank. And now, with Nezuko's blood too, I'm sure we can create a demon cure."
Shinobu looked between the papers and Akira. "You're going to the Swordsmith Village… aren't you continuing this research with us?"
"I actually finished the research theoretically," Akira replied. "It's all in those notes."
"It's just theories, right? Without any real experimentation?"
"My theories will work 99.9 percent, so don't worry," Akira said confidently.
Shinobu couldn't deny it. After working with him closely, she already knew he was a genius, one who almost never made mistakes.
Akira continued, handing her another bundle. "And this is my research on poisons that can affect demons. Even Upper Ranks can be affected."
Shinobu skimmed through the formulas and chemical diagrams. She paused.
"…Are you sure this is meant to kill demons, not torture them?"
Akira shrugged again. "Well, I just wrote down everything that can work. How you use them is up to you."
Shinobu sighed. "I see. Thank you."
"Don't worry about it."
Just then, Aoi knocked on the door. "Shinobu-sama, Mitsuri-sama is here."
"We'll be right there," Shinobu replied. She turned to Akira. "It seems it's about time. We'll send you off."
So Akira, Erika, and the Butterfly Mansion girls gathered outside to see the group off. Mitsuri was already waiting near the entrance.
And for some reason, Tanjiro was there too, his Nezuko box on his back, completely ready to go.
Akira asked, "Tanjiro, you're coming with us too?"
Tanjiro nodded, looking embarrassed.
"I broke my sword in the fight when we beheaded that Obi demon. And Haganezuka-san sent me a letter saying he will not make me any more swords… so I'm going there to apologize to him."
"I see," Akira said. "Seems like we're all going there. It'll be fun like that anyway."
He then telepathically asked Selena, "Sister… don't you think Tanjiro is a bit weaker than he was in the anime around this time?"
Selena answered calmly, "Probably because Rengoku is alive. He didn't get the chance to 'set his heart ablaze.'"
Akira nodded. "Yeah… that makes sense."
Then he turned to Mitsuri.
"Mitsuri-san, do you know how to go there? Is it too far?"
Mitsuri shook her head.
"I don't know."
"…You don't?" Erika repeated, confused.
"No single person knows where it is," Mitsuri explained. "It's a really big secret place, after all."
"Then how will we get there?" Erika asked.
Mitsuri smiled mysteriously. "You'll see."
At that moment, a Kakushi woman dragging a cart approached them. She bowed politely. "Nice to meet you. As the Master granted approval, I shall be your guide this time. First, you need to cover your eyes and ears."
She handed each of them a blindfold and earplugs, plus a nose plug for Tanjiro.
As everyone from the Butterfly Mansion came out to say goodbye, the group climbed into the cart. The Kakushi woman tightened her grip on the handles…
…and began to pull.
Since the Swordsmith Village was one of the best-kept secrets, no single person knew its exact location.
Because of that, the journey turned into a relay, each Kakushi guiding them only part of the way before handing them off to another, and then another.
After what felt like a long, winding trip, the cart finally slowed.
A different Kakushi woman's voice spoke gently:
"We have finally arrived."
Akira and the others removed their blindfolds and were greeted by the sight of a village hidden deep in the mountains, quiet, isolated, and unlike anywhere they had ever seen.