Tanjiro was sent flying across the training grounds, knocked back by a powerful kick from a big panda, or rather, Akira wearing his Pan-chan costume.
This wasn't the same fluffy Pan-chan Erika used as a hug pillow.
This was Combat Pan-chan, reinforced and hardened specifically for training.
After Erika once threatened, "Don't you dare use Pan-chan for fighting or I'll kill you,"
So, Akira simply made a combat version so he could still spar safely.
It was early morning in the Swordsmith Village, sunlight just peeking between the rooftops. The air was crisp, and the distant echo of hammers striking metal blended with the sounds of their training.
Akira and Tanjiro were sparring as usual. Since Akira didn't want to hurt Tanjiro too much, he always used the Pan-chan suit when sparring with Tanjiro or members of Tanjiro's squad.
Tanjiro groaned, pushing himself up from the ground.
Akira watched calmly, big panda head tilting as he said, "You are strong, but not strong enough. I seriously don't think at this level you can fight an Upper Moon, much less Muzan."
Tanjiro grit his teeth, pushing himself up again. "I will try harder!"
He rushed at Akira with his wooden sword. Akira, unarmed, easily sidestepped the attack and tapped Tanjiro's hand, sending the blade flying.
"In a real fight, losing your blade means you die," Akira said.
Tanjiro quickly rolled, grabbed his wooden sword again, and charged with an overhead strike. Akira, still in the bulky Pan-chan suit, caught the wooden blade perfectly between his hands in a flawless shirahadori. He twisted slightly, then.
Crack.
The wooden blade snapped in two.
Then he kicked the shocked Tanjiro, sending him flying back to the ground.
Tanjiro looked stunned.
"H-how did you do that, Pan-chan-san?"
Akira shrugged inside the suit.
"I just read your movements and the timing of your attacks. It's not that hard."
Then he added,
"If I can do this, I'm pretty sure an Upper Moon demon can do it too. They could probably break your Nichirin blade as well."
Tanjiro swallowed. "Then… what should I do?"
"Your sword strikes need to be faster than they are now," Akira replied. "And you need to think of a way out of this situation, too. You froze when I caught your blade. If I were a demon, you would die."
Tanjiro breathed heavily but still tried to stand again.
But then a cheerful voice called out,
"That's it! Akira-kun won!"
Mitsuri stepped forward to stop the spar. She and Erika had been watching the whole time. Akira had basically appointed Mitsuri as a referee or something, while Erika simply watched quietly from the side.
Tanjiro let out a tired sigh.
"Akira-san is really strong… How can I get that strong, Akira-san?"
Akira shrugged casually.
"I don't know. I've been training since I was seven years old, so I'm strong because of that."
Mitsuri, who had been listening, leaned forward, encouragingly and cheerfully added, "Tanjiro-kun is very strong too! Especially for someone who only recently picked up the blade."
But Tanjiro shook his head with unshakable conviction.
"I have to become stronger… if I want to defeat Kibutsuji Muzan and turn my sister back into a human. So, Akira-san, can we go one more time?"
Akira sighed through the Pan-chan suit.
"I wish I could, but I need to train my swordsmithing skills if I want to make my blade."
Only yesterday, Akira had won the bet and learned forging. Now he had to practice if he wanted to build a strong sword.
Tanjiro's shoulders slumped. Even so, his conviction didn't waver, "I see… Then I'll train by myself."
Mitsuri, wanting to help him, suddenly brightened. "Actually, I might be able to help a little!"
Akira tilted his head. "But Mitsuri-san, didn't you say you had work to do?"
"I do! I'm still busy," she admitted, waving her hands. "But I know the solution to Tanjiro-kun's problem!"
Mitsuri pointed dramatically.
"There is a secret weapon in the village that can make you strong!"
Akira appeared surprised on the outside…
But inside?
"All according to my plan."
Soon, Mitsuri was guiding Tanjiro and the others into the forest behind the village. Akira and Erika tagged along, partially out of curiosity, partially because Akira knew exactly what was coming.
They reached a clearing… and there it stood.
A man with six arms.
No, an automaton with six arms, each holding a katana.
Ancient armor, half-cracked face, worn wood… yet still very much operable.
Mitsuri gestured proudly.
"This is the secret weapon I talked about… Yoriichi Type Zero."
Tanjiro and Erika froze, eyes widening in shock.
But Akira, he suddenly vanished, then reappeared right in front of the machine.
His eyes sparkled like a child discovering his first Gundam model.
"WOW, it's so cool!"
Erika sighed softly.
"He's fanboying again…"
Tanjiro blinked. "Fan… what?" He looked utterly confused.
Then a small boy wearing a Hyottoko mask stepped forward timidly.
"Um… hello. This is the Yoriichi Type Zero.
It's extremely old, but still operat…."
He didn't even get to finish when Akira grabbed his shoulders with both hands.
"When was it made? Who built it? What material are the joints?
How do the gear ratios work? What's its power source? Does it have multiple modes? Is the wood lacquered for moisture control? How do the six-arm synchronizing rods function? Can I see the schematics?"
Kotetsu's entire soul visibly shook.
"W–wha…!? S–slow down!! I… I don't even know half those words!!"
Akira's eyes gleamed.
"Can I take it apart?"
Kotetsu's soul left his body.
"WH…NO!! ABSOLUTELY NOT!! NO TAKING APART ANYTHING!!"
Akira leaned in closer.
"I'll put it back together."
Kotetsu leaned backward in terror.
"NOOOO!!"
Akira leaned in even closer.
"Just once? I promise I won't break anything."
"That makes it WORSE!!" Kotetsu squeaked.
Erika finally snapped.
With a flick of her wrist, her red ribbon wrapped around Akira, binding him completely.
Crimson Throne Prison.
He instantly became a muffled, wriggling cocoon.
"I'm sorry," Erika apologized. "He becomes like this when he sees a cool machine. He'll be normal soon."
Kotetsu stood there, frozen. "Eh… o-okay…"
Tanjiro, still staring at the machine doll, murmured, "This person… I think I've seen this person before."
Kotetsu shook his head immediately. "Eh? That's impossible! This battle doll was made by my ancestors during the Sengoku period. It was modeled after a swordsman named Yoriichi. You couldn't have met him."
"No," Tanjiro insisted, "I feel like I met him in my dreams."
Kotetsu nodded knowingly.
"Then it must have been an inherited memory."
Tanjiro tilted his head. "Inherited… memory?"
Kotetsu explained proudly, "Yes! We talk about it all the time in our village. It isn't just your physical form that gets passed on. Living creatures pass on their memories, too! What you saw must've been your ancestor's memory."
Tanjiro brightened. "Thank you for telling me. I'm Tanjiro."
"I'm Kotetsu," the boy replied.
Meanwhile, Erika, who is still holding wrapped-up Akira, asked, "Kotetsu, you said this is modeled after a real person, right? Then… why does it have six arms?"
Kotetsu puffed his chest a little. "According to my father, that swordsman was so powerful that they couldn't replicate his moves unless they gave the doll six arms."
Erika whispered under her breath, "Must have been a really powerful swordsman then…"
Akira tried to say something from inside the ribbon cocoon, but only muffled noises came out.
Mitsuri clapped brightly. "Enough talking! Let's start training! Tanjiro-kun, you're going to practice against the Type Zero today!"
Tanjiro straightened his back. "I'll do my best!"
Kotetsu nodded and began adjusting the machine doll, since this happened two months before, when it happened in the anime. Yurichi Type Zero is in a better condition than when Tanjiro met it in the anime, so Kotetsu didn't have much aversion to starting. After several clicks and wooden shifts, the six swords were replaced with six wooden clubs.
Then.
CLANG!!
Yoriichi Type Zero lunged forward at high speed, his six wooden arms shot forward at speed so fast it's hard to see with the naked eye.
CLACK—CLACK—CLACK—CLACK—CLACK—CLACK!!
Bamboo swords tore through the air with terrifying speed.
Tanjiro barely dodged one, then two; the third grazed his cheek.
Kotetsu puffed out his chest proudly.
"Of course it is! My ancestors built it to imitate a legendary swordsman!
Type Zero can move faster than most people can even see!"
On the sidelines, Akira, finally freed from Erika's ribbon cocoon, watched silently.
His eyes glowed faintly.
Every movement of the automaton was reflected in them.
Every joint rotation.
Every pressure shift.
Every micro-stall.
Every creak of ancient wood.
Akira had entered full analysis mode.
Meanwhile, Tanjiro struggled to survive the onslaught.
He inhaled sharply.
"Total Concentration!"
He lunged forward, trying to strike one of the doll's arms.
But he was too slow.
WHACK!!
A wooden club smashed into the dirt where Tanjiro's foot had been a moment ago.
He rolled aside, sweating heavily, but Yoriichi Type Zero didn't stop. It advanced relentlessly, giving him no time to breathe.
"It's keeping pressure on me constantly…
It doesn't get tired at all…" Tanjiro gasped.
Kotetsu nodded vigorously.
"That's right! It doesn't get hungry, thirsty, or sleepy!
It's the perfect training partner!"
Akira finally spoke.
"It's not perfect yet."
Kotetsu turned, confused.
"Huh? What do you mean?"
Akira answered without looking away from the machine.
"Its attack patterns loop.
Its pressure system has a reset interval.
And the joints slow down after long, continuous motion."
Kotetsu's eyes widened behind his mask.
"You… noticed all that already?!"
"It's not that hard," Akira said calmly. "It's an impressive machine…
But predictable."
Kotetsu nearly fainted.
After several minutes, the Type Zero abruptly halted, wood grinding to a stop.
Only then did Tanjiro collapse onto the dirt, panting like he'd fought a real demon.
"Hah… hah… It's amazing… but fighting it is like fighting six people at once…"
Kotetsu hurried to help him up.
"Yes! Exactly! Isn't it incredible!"
Akira stepped forward, looking at the machine, "Type Zero is amazing, yes, but it has limits. It's old. Some parts don't move smoothly anymore. It can't use breathing techniques. It can't follow complex commands. And it can't adapt to an enemy."
Kotetsu nodded. "Yeah, that's why it's only for training…"
Akira tilted his head slightly. "What do you think would happen if we fixed all its flaws?"
Tanjiro, who was still exhausted, suddenly froze, hearing this.
Not just him, both Kotetsu and Mitsuri also froze.
Erika stared at him. She had a feeling he would say this when she first saw this machine doll; it was inevitable.
The forest went silent.
If Yoriichi Type Zero's weaknesses were removed…
It would become the perfect weapon against demons.
Akira smiled. "Yes. If we fix it… We can create a machine army. One capable of destroying every demon."