In the deep woods, a clearing awaited.
As the day broke, this once deserted clearing, where no one dared to tread, now welcomed an unexpected visitor who had caused quite a stir here just yesterday.
*Ka-Ka!*
Under Kotetsu's control, Yoriichi Type Zero slowly entered the clearing and stood motionless, resembling a samurai awaiting orders from their lord.
Tanjirou and Kotetsu arrived early and were waiting for Riezel's arrival.
"He hasn't come yet?"
Kotetsu impatiently scanned the other end of the forest path, eagerly anticipating Riezel's arrival.
"He might not be here so soon."
Ready for combat with his sword in hand, Tanjirou answered, but upon seeing Kotetsu's impatience, he added.
"Afternoon..." Kotetsu couldn't hide his disappointment. "Do we really have to wait that long?"
Before Tanjirou could respond, he suddenly sniffed the air curiously, his nose twitching slightly.
"It seems Big Brother is here..."
Tanjirou remarked as his nose caught Riezel's scent.
"Really?" Kotetsu's spirits immediately lifted.
Before long, they saw Riezel slowly approaching from the end of the path.
Indeed, he had arrived as Tanjirou said.
Surprisingly, before beginning his training session with the Hashira, Riezel had made his way here first.
However, he wasn't alone.
A figure followed closely behind him, resembling a subordinate.
Upon seeing this figure, both Tanjirou and Kotetsu exchanged surprised looks.
"Yoriichi Type Zero?!" Kotetsu exclaimed in shock.
"Mr. Tsugikuni..." Tanjirou murmured, staring in disbelief at the figure.
Of course, Tanjirou wasn't addressing Riezel but rather the swordsman who shared a deep connection with his ancestors and left behind Sun Breathing and the hanafuda earrings to his family, the actual Tsugikuni Yoriichi.
Standing behind Riezel, the figure resembled Yoriichi Type Zero but lacked the mechanical appearance, appearing more akin to a living human—a swordsman with a gentle demeanor.
"Sorry for keeping you waiting."
Riezel greeted Tanjirou and Kotetsu with a wide grin.
Although he seemed to be in a good mood, neither Tanjirou nor Kotetsu noticed, their attention wholly captivated by the figure that stopped beside him.
"Wh-What's going on?"
Kotetsu was utterly confused.
"Big Brother?"
Tanjirou looked at Riezel, then glanced at the figure by his side, which closely resembled Yoriichi Type Zero, his eyes filled with disbelief.
"Let me introduce it to you. Its name is 'Yoriichi Type One'."
Riezel explained to Tanjirou and Kotetsu, who looked puzzled.
"Since the first-generation model is called Type Zero, I named this one 'Type One'. How is it? Not too bad, right?"
How could Tanjirou and Kotetsu not understand what he meant?
"Is it also a mechanical doll?" Tanjirou's face showed even more astonishment.
"No fucking way!" Kotetsu jumped up in shock.
His shock was understandable.
"You made a mechanical doll?! Did you make another Yoriichi Type Zero?! No way!" Kotetsu shouted repeatedly. "Even if you figured out my ancestor's creation methods, making another Yoriichi Type Zero overnight is impossible!"
Shortly afterward, he leaped directly toward Type One and began feeling around its body. As he touched it here and there, he discovered that Type One was quite different from Type Zero.
Firstly, its outer shell material was clearly different from Type Zero's wooden feel; it was more like steel—cold and hard.
Secondly, Type One didn't have six arms and six swords like Type Zero; it only had two hands and a pair of swords.
Thirdly, the humanoid appearance of Type One was also highly realistic, at first glance appearing completely humanlike, unlike Type Zero, where the lines and joints of the doll were visible on its face and joints.
In light of this, the appearance of Type One was identical to Yoriichi as seen by Riezel in his dream, except that Yoriichi only had one sword, while Type One had two swords.
Due to improvements in materials and performance by Riezel, Type One didn't need six arms and six swords like Type Zero to reproduce Yoriichi's swordsmanship, only two swords were enough.
As a result, compared to Type Zero, although Type One had improved performance, its combat power didn't increase much. It only went from barely entering Level 4 to roughly equivalent to the middle Level 4.
In terms of combat power, it was already on par with powerful Hashira like Kyoujurou, Sanemi, Tengen, Obanai, and Giyuu before using the Demon Slayer Mark, but it still fell short compared to the Upper Ranks.
However, the change in materials, by using metal inside and out, significantly increased its defensive power and resistance to attacks by an entire level.
In other words, Type One, born from Riezel's hands and modifications, had combat power equivalent to Level 4 while being specialized in 'END'.
In terms of END alone, Type One could match Level 5; even ordinary Level 4 opponents wouldn't leave a scratch on its surface.
In fact, such beings also existed in the dungeon of Danmachi.
It was the floor boss of the 17th Floor, a supersized monster, Goliath.
Goliath was classified as a Level 4 monster specializing in END. Its skin was so tough that it couldn't be broken without at least the attack from a Level 5 first-class adventurer or equipment of second class or higher.
Type One belonged to the same category as Goliath, just with a smaller size. Yet, despite being smaller, Type One was much faster and more agile than Goliath, which wasn't necessarily a bad thing.
It was the mechanical doll that Riezel himself created, based on Type Zero with some improvements.
"It can't be... It can't be..."
Kotetsu felt as if his worldview was shattering.
He couldn't believe that the most outstanding mechanical doll invented by his ancestor, crafted with a lifetime's effort, had not only been created overnight by someone else but also improved to be stronger.
For him, this wasn't something easy to accept!
"For you."
Riezel handed the old book back to Kotetsu.
"It has been very helpful to me. Thanks a lot."
"..."
Kotetsu looked bewildered at the book Riezel handed him.
After a moment of silence, Kotetsu reached out and took it.
"Can this also be used for training, Big Brother?"
On the other hand, since Tanjirou didn't have the same complex feelings as Kotetsu, upon knowing that Riezel had created another mechanical doll, he only felt excitement. He looked at Type One, which resembled a human samurai in appearance, feeling eager to try it out.
"Not just for training, but it can also be put into battle to fight demons." Riezel said calmly. "Don't worry, I'll fix Type Zero first."
Upon hearing this, Kotetsu regained his spirits.
"Can you fix it?" Kotetsu hurriedly asked.
"No problem." Riezel smiled at him. "I can even upgrade it if needed."
Since Riezel could use his magic to create Type One with higher performance than Type Zero, he naturally could use his magic to upgrade Type Zero to have the same performance as Type One.
"N-No need..." Kotetsu shook his head. "Just fixing it will be enough."
He was actually a bit afraid that Type Zero would be transformed by Riezel into something completely unrecognizable. After all, it was an heirloom left by his ancestor, the masterpiece of his family.
For this reason, rather than treating Type Zero as a combat mechanical doll, he actually saw it as a spiritual support and a symbol of his family.
It would have been fine if only minor improvements were made, but Riezel's modification was almost like creating a new and different mechanical doll, which frightened him.
As a result, he declined Riezel's offer.
"Okay." Riezel shrugged casually. "Just fix it directly then."
"What do you need me to do?" Kotetsu asked eagerly. "I have tools at home and a workshop. If you need anything, you can come over."
"No, none of those are necessary." Riezel shook his head. "We'll do it right here directly. Just wait for me."
With that, he walked over to the center of the clearing and approached Type Zero.
At the same time, Type One immediately followed him like an emotionless personal attendant.
It was yet another thing that shattered Kotetsu's worldview.
No choice.
A mechanical doll was, after all, just a doll—without the necessary controls, it wouldn't move at all.
However, Type One was clearly different.
It didn't need Riezel to control it, nor did it require any buttons or switches on its body. If he stopped, it stopped, if he walked, it walked—it was almost like it had a mind of its own.
'So this is the mechanical doll created by the master of the divine sword...?'
Kotetsu began to understand why the swordsmiths in the village, usually so full of themselves, had been so ecstatic upon seeing Riezel's sword.
Surely that sword was just like Type One, a creation that surpassed any human understanding or imagination.
With their skills, those swordsmiths could never have imagined why such a sword could exist in this world and must have seen it as a divine creation, a divine sword.
Now Kotetsu felt the same way.
He could hardly imagine why a mechanical doll like Type One could exist in this world, almost thinking Riezel had created life itself.
Unaware of Kotetsu's thoughts, Riezel observed Type Zero for a moment, then suddenly used the Transparent World.
'As expected, it's in here...'
Having confirmed something, Riezel reached out and grabbed Type Zero's head, giving it a firm twist.
*Snap!*
With a crisp sound, Type Zero's head was twisted off.
"AAAAAAHHHHHH—!"
Seeing this scene, Kotetsu touched his two cheeks and let out a scream of sheer terror.
Riezel extended his hand again, this time reaching into Type Zero's neck and through its body.
Before long, he pulled a sword out from inside Type Zero.