The next morning, Erika woke up and, for one brief, fiery moment, almost chose violence. Seeing where exactly she slept the whole night.
Thankfully, Akira and Selena somehow managed to calm her down before things escalated, and the fact that Akira was still wearing the fluffy panda costume helped. A lot.
By the way, they'd officially named the costume Pan-chan, and it had somehow become a sensation in the Butterfly Mansion. The children adored it. Even the attendants giggled whenever Pan-chan appeared in the hallways.
Since the costume was combat-effective, Akira realized it could actually help with the rehabilitation training of the recovering Demon Slayers. Sure, it couldn't kill a demon, but it could take a lot of hits. That made it perfect for practice sessions.
So, that day, as Tanjiro and Inosuke were preparing for their rehabilitation training, they froze at the sight of what stood before them: a massive, fluffy panda.
Both stared in disbelief.
"...Huh?" Tanjiro blinked, utterly lost.
"WHAT IN THE HELL IS THAT!?" Inosuke shouted, pointing accusingly.
A muffled voice answered calmly from within the suit, "Morning. Are you ready for your beatdown?"
The courtyard fell silent. Even the breeze seemed to pause.
Then, slowly, Tanjiro stammered, "A-Akira-san?"
Inosuke added, "No way! Where's the real one!? Did a bear eat him!?"
From the sidelines, Aoi sighed deeply. "No, that is the real Akira-san."
Akira, still in full panda form, nodded, removing the panda head briefly to reveal his face before putting it back on. "Yep, it's me."
Tanjiro, still confused, asked, "Akira-san… what happened to you?"
"Nothing," Akira said casually. "This is just a panda costume I made."
Tanjiro tilted his head. "What's a panda?"
"It's probably a powerful monster!" Inosuke declared, snorting.
Akira chuckled. "No, it's just a type of bear from China. They're actually really docile."
He then clapped his fuzzy hands together. "Anyway! We're going to train with this today."
"Train… how?" Tanjiro asked.
Akira grinned under the mask. "Hehe. Try punching me and see."
Tanjiro hesitated. "…Punch you?"
Before he could act, Inosuke yelled, "I WILL CRUSH YOU, BEAR DEMON!" and charged at full speed.
Akira didn't even move to block. Inosuke's punch landed squarely on Pan-chan's plush belly, only to bounce off harmlessly. Inosuke froze in disbelief, staring at the unmoving panda.
Then, with one slow, exaggerated motion, Pan-chan swung an arm forward and smacked Inosuke, launching him backward with equal force.
Tanjiro and Aoi both gawked in shock.
Even the crows stopped cawing.
"Th-that was incredible…" Tanjiro whispered in awe.
Akira, still in full panda form, nodded proudly. "This is how we'll train. You can attack as much as you like without getting hurt, and I can practice defending and countering without injuring anyone. It's perfect!"
Tanjiro raised a tentative hand. "Uh… Akira-san…"
"Pan-chan," Akira corrected immediately. "When I'm wearing this costume, call me Pan-chan. Only when I'm wearing this costume, alright?"
Tanjiro tilted his head. "Eh? Why?"
Akira turned his head toward the horizon dramatically. "Because… sometimes punishments can be emotional, too."
Tanjiro blinked again, lost. "…Okay, Pan-chan-san. But you sent Inosuke flying just now, won't he get hurt?"
Akira waved a fuzzy paw. "No, the suit absorbs the impact. Even my counterattacks are soft."
Tanjiro frowned. "But… falling that far still hurts, right?"
"Well, it's a soft punch," Akira reasoned.
Inosuke, who had just gotten back up, screamed again. "I WILL CRUSH YOU, BANCHIN!"
"…It's Pan-chan," Akira corrected right before Inosuke charged again, only to be launched into the air a second time.
Akira turned toward Tanjiro. "So, are you going to try?"
Tanjiro took a deep breath. "I will!"
He dashed forward, striking as hard as he could, and was promptly sent flying in the same way.
Despite the repeated defeats, both Tanjiro and Inosuke continued their relentless attacks, but none of their strikes even dented Pan-chan's fluffy defense. Eventually, they collapsed in exhaustion, completely defeated.
After training ended, Akira handed Pan-chan to Aoi for laundry and went to continue his research on demons.
When he opened the door to the reading room, Shinobu was already there, smiling warmly. "Good morning, Akira-san."
"Morning," Akira replied.
"Is Erika-san already off training with Mitsuri-san?" Shinobu asked.
"Yeah," Akira nodded. "She left early this morning."
Indeed, Erika had gone out before sunrise, confident she'd finally found her path toward her own breathing technique.
Shinobu nodded, satisfied. "I also heard you played with the children while wearing a big bear costume. Thank you for that."
"Oh, that?" Akira waved it off. "I was just testing its endurance."
Shinobu chuckled softly. "Still, it made them smile. But may I ask… why fight while wearing that?"
"Well," Akira said, "it's a good training opportunity, right?"
"Perhaps," Shinobu replied thoughtfully. "But won't it affect your combat style?"
Akira thought for a moment. "Maybe, but I learn things faster than normal people. I can fix it even if it does."
Shinobu smiled. "If that's your decision, then I won't stop you. Oh, by the way, what you requested has arrived."
She gestured toward a small wooden box beside her.
Akira's eyes lit up. "Wait, is that what I think it is?"
"Yes," Shinobu replied. "A demon blood sample. It's not much. We can't bring a live demon into the estate, but this was the best we could get. If you need more, you'll have to test it outside."
Akira nodded. "This is enough for now. Oh, by the way, do you have a lab I can use?"
"There's a medical room with basic equipment," Shinobu said, leading him there.
It wasn't high-tech, but it would suffice.
He began studying the blood through the microscope, frowning slightly as he adjusted the focus.
The cells writhed under the lens, rapidly dividing and mutating.
"The mutation factor resembles aggressive metastatic cancer…" he murmured. "But the rate of change is insane."
As he continued, the sliding door opened softly.
"Um… Akira-san?" came a familiar voice.
Akira looked up to see Tanjiro stepping in, bowing politely. "Are you busy?"
"I'm free now," Akira replied. "What's up?"
Tanjiro walked closer, eyes filled with quiet determination. "I wanted to ask you something."
"Sure, what is it?"
Tanjiro hesitated briefly before saying, "You… know magic, right?"
Akira raised a brow. "Didn't I already show you some before?"
Tanjiro nodded. "You did. That's why… I need your help."
Akira said, "Sure, with what?"
Tanjiro took a seat and began explaining everything, from the night his family was slaughtered to Nezuko's transformation and her resistance to human blood.
Akira listened quietly, though he already knew most of it. Still, hearing it from Tanjiro himself confirmed the details of this world's timeline.
When Tanjiro finished, Akira asked calmly, "You want to turn her human again?"
Tanjiro nodded firmly. "Yes. More than anything. Can you… Use your magic to cure her?"
Akira smiled faintly. "Yes, it's possible."
Tanjiro's eyes widened. "Really!?"
"Of course," Akira said. "Her transformation is biological, not spiritual. I can probably reverse it with magic. But first, I need a sample of her blood."
He reached into his inventory and pulled out a sleek, modern syringe.
Tanjiro blinked. "What's that?"
"A syringe," Akira said casually. "I'll need you to get a small blood sample from your sister. Can you do that?"
Tanjiro nodded immediately. "Understood!"
He took the syringe, bowed deeply, and sprinted out of the room.
Akira stared after him for a moment, muttering under his breath, "He's running through a medical corridor with a needle… this can only go well."
A few minutes later, the door burst open again.
Tanjiro, flushed but grinning, held up the syringe proudly. "Akira-san, I got it!"
Akira blinked, genuinely impressed. "Already? That was… fast."
Still, Akira kept his promise and placed Nezuko's blood under the microscope. He examined it carefully and soon noticed something strange.
It was different from the blood of any other demon. Within it, he could see faint blue cells actively fighting and stabilizing the Muzan cells.
Akira then gestured for Tanjiro to come closer.
"Take a look at this," he said, adjusting the microscope.
First, he showed him a sample of normal human blood, its cells calm and steady.
Then, he replaced it with demon blood, the cells writhing violently, splitting and consuming everything around them.
"See the difference?" Akira asked.
Tanjiro nodded silently, eyes wide in curiosity.
Then Akira switched the slide once more. "Now, this is your sister's blood."
Tanjiro leaned in to observe, and his expression changed instantly. The sample pulsed with strange, faintly glowing blue cells intertwined among the darker Muzan-infected ones. The two types clashed, but instead of being overwhelmed, the blue cells seemed to stabilize the muzan cells.
Akira explained, "Her blood isn't like other demons'. It's actively changing and evolving. Those blue cells are stabilizing the corrupted ones."
Tanjiro blinked, astonished. "So… what does that mean?"
Akira crossed his arms, deep in thought. "It means your sister is somehow resisting Muzan's influence. Her body's fighting the infection from the inside."
"Resisting? But… how?"
Akira didn't answer immediately. He stared at the microscope for a long moment before suddenly saying, "Give me a drop of your blood."
Tanjiro blinked. "Mine?"
"Yeah. Just a drop."
Once he got the sample, Akira placed it under the lens and studied it carefully. After a moment, his expression shifted slightly in realization.
"It's just a hypothesis," he began, "but your blood… it has the same trace elements as Nezuko's. The same blue cells. But in a smaller amount and inactive, Whatever's keeping her stable might come from your family's bloodline itself."
Tanjiro looked surprised. "Something about my family…?"
Akira nodded. "Exactly. Think, do you remember anything special about your family, a unique ritual, or food, anything passed down through generations?"
Tanjiro frowned, thinking hard. Then his eyes lit up. "The Hinokami Kagura!"
Akira asked, "Hinokami Kagura?"
Tanjiro explained. "Yes, it's a dance our family used to perform every New Year's. He said it was a dance passed down through generations of our family. But recently, I learned it is similar to breathing style. Could that be related?"
Akira thought for a moment. "Unlikely… but I can't be sure without seeing it myself. Show it to me once you've recovered more, and maybe I can find the link."
Tanjiro nodded eagerly. "Yes, I will!"
"Good. And try to recall if there's anything else unique about your family," Akira added.
Tanjiro nodded again before hesitating. "Then… Akira-san, can you really turn Nezuko back into a human?"
Akira exhaled softly. "I could, but since her blood's already fighting Muzan's cells, interfering now could disrupt the process. I need more time to study it safely before I try anything."
Tanjiro bowed deeply, gratitude clear in his voice. "Thank you, Akira-san. I'll wait and I'll help however I can."
As Tanjiro left the room, Akira leaned back in his chair, watching the blood under the microscope one last time.
"That went well," Selena's voice echoed telepathically in his mind.
"Yeah," Akira replied. "And now, I can look deeper into Sun Breathing and find the Blue Spider Lily too."
"So you think that's what causes their resistance to sunlight?" Selena asked.
"Exactly. Those blue cells, there's a clear link. If Tanjiro knows where the Blue Spider Lily is, I can easily complete one of the quests." Akira said, leaning back.
There was a brief pause before Selena's tone turned mischievous. "You should be worrying about your current situation instead."
Akira blinked. "Current situation?"
"You put Pan-chan in the laundry," Selena said flatly. "Erika-chan will not be pleased."
Akira frowned. "She won't be that mad about that… right?"
"Not about the laundry," Selena replied. "But she's going to be furious when she learns you used it for fighting."
Akira froze. "…Oh no."
And, as Selena predicted, when Erika returned that night, she was not happy.
Akira did his best to explain himself, offering apologies and logical reasoning, but her glare said everything. It took a while, but she eventually calmed down… though she ended up drinking a lot more of his blood than usual before she did.
Lying there afterward, Akira sighed weakly. "Well… at least she's comfortable drinking my blood now."
Selena's amused voice chimed in his head. "You really don't value your life, do you, brother?"