Yoriichi Type Zero, the existence of this battle-oriented mechanical doll, only came back to Riezel's memory after meeting Kotetsu.
Its presence wasn't imposing, but from its name alone, one could discern a connection to Tsugikuni Yoriichi.
In truth, the creator of this mechanical doll created it after Yoriichi, endowing it with strength far surpassing that of ordinary humans. Moreover, it had existed for a considerable time, spanning from the Sengoku period to the present day, easily over three hundred years.
Clearly, the fact that a mechanical doll could persist for over three centuries was truly remarkable in itself, emphasizing its exceptional nature.
It was thanks to Kotetsu's family, who had taken care of this mechanical doll since the Sengoku period, for over three hundred years up to the present day.
As Riezel thought about this mechanical doll, his interest was piqued, but he also felt a bit confused about Kotetsu's intentions.
"Why did you come to me?" Riezel asked with a puzzled tone.
In fact, Yoriichi Type Zero was quite old, nearly breaking down and beyond repair.
Unfortunately, by the time it reached Kotetsu's generation, the necessary skills and knowledge needed to maintain and repair it had been lost, so it wasn't unusual for him to seek someone to help him fix it.
However, the question remained—why didn't Kotetsu approach the highly skilled swordsmiths in the Swordsmith Village, but instead came to him?
Truly, this was something Riezel couldn't quite grasp.
However, Kotetsu's next words would answer his doubt.
"In the village, apart from my father, there's no one left who can repair Yoriichi Type Zero, including myself..."
As Kotetsu answered, there was a hint of reluctance in his tone.
A mechanical doll that had survived from the Sengoku period to the present surely harbored remarkable craftsmanship.
While the Swordsmith Village boasted many skilled swordsmiths, particularly the village chief who was arguably the world's best swordsmith, expertise in mechanical doll-making was scarce.
After all, this type of craftsmanship was already niche within the Swordsmith Village, almost forgotten and overlooked. Because of this, until now, only Kotetsu's father possessed the ability to maintain, care for, and repair Yoriichi Type Zero.
Sadly, Kotetsu's father had passed away, leaving Kotetsu as the last inheritor of this dwindling mechanical doll.
However, Kotetsu was merely a precocious child, lacking the ability to repair Yoriichi Type Zero, and didn't even possess the natural talent for swordsmithing. For this reason, in the original work, Yoriichi Type Zero remained damaged until the end.
Fortunately, at this time and this moment, Kotetsu saw hope in repairing Yoriichi Type Zero, which lay in Riezel.
"You're the master of the divine sword, right?"
Kotetsu asked with a hint of anticipation.
"Many in the village say the divine sword was actually made by you. Although some skilled swordsmiths led by the village chief deny this claim, stating they don't smell the scent of a blacksmith on you, I want to know, if you really did create the divine sword, can you also repair mechanical dolls?"
Upon hearing this, Riezel finally understood.
Needless to say, Kotetsu harbored a hopeful belief when he sought him out.
"You sure know how to beat a dead horse." Riezel chuckled and shook his head.
"So, um... can you?"
Kotetsu asked, not denying Riezel's words while looking nervously at him.
After a moment of contemplation, Riezel replied.
"Take me to see Yoriichi Type Zero first, then we'll decide."
"Alright!" Kotetsu readily agreed.
"Um, can I come along?" Tanjirou quickly raised his hand.
"Let's go." Riezel glanced at him with a smile. "Perhaps you will find something useful there."
After saying these mysterious words, he took the lead and walked ahead.
Seeing this, Tanjirou and Kotetsu hurried to catch up.
===
Under Kotetsu's guidance, Riezel and Tanjirou arrived at another stretch of mountain forest.
A clearing lay before them, seemingly designated for training purposes, though it appeared neglected from lack of recent use.
"It's right there."
Kotetsu stepped into the clearing, pointing toward a figure standing tall in the center.
Riezel looked up and immediately spotted the mechanical doll, a relic from the Sengoku period, still intact.
It was dressed in a kimono, resembling an ancient samurai, with its hair styled in a tall ponytail. It had the appearance of a human male, but its expression was stiff and robotic, revealing that beneath its exterior lay not supple flesh, but rigid mechanical parts.
It also had six arms, each equipped with a sword, resembling a demon from hell. Even standing motionless, it emanated a faint but eerie sense of dread.
"Is this Yoriichi Type Zero?"
Riezel examined Yoriichi Type Zero with interest.
Tanjirou also did the same.
"This doll..."
As Tanjirou stared at the mechanical doll's face, he felt a strange sense of familiarity.
Kotetsu stepped in to explain.
"This is Yoriichi Type Zero, a combat mechanical doll of my family. It was my ancestor's greatest creation during his lifetime, unmatched even today."
"According to my family records, Yoriichi Type Zero was modeled after an extremely powerful swordsman from the Sengoku period."
"The swordsman's incredible skill left a profound impact on my ancestor, inspiring him to create this mechanical doll."
Kotetsu's voice brimmed with pride.
"To replicate the swordsman's skills, my ancestor created Yoriichi Type Zero with multiple action modes, six arms, and six swords."
"Without these modifications, it's said that the doll wouldn't even possess a tenth of the swordsman's strength."
"Hence, Yoriichi Type Zero appears as a six-armed swordsman."
Kotetsu's words finally dawned on Tanjirou, usually dense and slow to react.
"Yoriichi Type Zero... Yoriichi...?"
Muttering this, Tanjirou looked at Riezel in surprise.
"Just as you suspected." Riezel nodded. "This mechanical doll is designed after Tsugikuni Yoriichi from the Sengoku period, the creator of Sun Breathing, who passed it down to you and me."
Upon hearing this, Tanjirou finally understood why the mechanical doll seemed so familiar to him.
After all, this was the great ancestor who had once befriended and saved his own ancestors, leaving behind the legacy of Sun Breathing for his family. Furthermore, the blood flowing within him told him that the person with that appearance was a great benefactor to his family.
One could even say Yoriichi was his family's master (sensei) and the master of his family through generations since the Sengoku period.
"..."
Tanjirou fell silent for a while, then bowed respectfully toward Yoriichi Type Zero.
Riezel, however, didn't share Tanjirou's deep emotions.
His connection with Yoriichi was not as profound as Yoriichi's connection with Tanjirou's family, so he simply continued to examine Yoriichi Type Zero, vaguely recognizing the figure of the swordsman who had demonstrated Sun Breathing to him in his dream.
Eventually, Riezel turned to Kotetsu and threw out a question.
"It should still be functional, right?"
"It should be..." Kotetsu nodded hesitantly. "But Yoriichi Type Zero is quite old now. It can move, but if it's put into combat again, it might break down immediately."
"If that's the case, there's nothing we can do." Riezel glanced back at the mechanical doll. "We need to see how much it can move before deciding whether we can repair it. If it breaks before then, it's just its fate."
Although his statement saddened Kotetsu, it was also the truth.
"Okay, I'll make it move."
Kotetsu took a key from his pocket, approached Yoriichi Type Zero, and inserted it into a hole in its body.
He then twisted the key, activating it.
*Ka-Ka!*
In the next moment, the sound of metal parts being activated echoed from within Yoriichi Type Zero.
As its eyes lit up slightly as if infused with life, it raised its head.
Seeing this, Kotetsu hurried back.
At the same time, Riezel suddenly grabbed Tanjirou by the arm.
"Eh?"
Tanjirou was taken aback.
"Big Brother?"
His voice conveyed both confusion and a hint of unease as if sensing something ominous.
"You go and give it a try."
Sure enough, as Riezel heartlessly said this, he threw Tanjirou toward Yoriichi Type Zero without hesitation.
"EEEHHHH—?!!!"
Tanjirou immediately let out a series of screams as he was thrown right in front of Yoriichi Type Zero.
*Swish!*
Seeing its target, Yoriichi Type Zero instantly sprang into action.
It extended its six arms and raised its six swords before dashing toward Tanjirou with astonishing speed.
"Wa-Wait?!"
Tanjirou exclaimed in shock, quickly drawing his own sword.
*DING!*
In the next moment, their swords clashed, producing a crisp sound of impact and sparks flying. In the nick of time, Tanjirou hastily raised his sword, blocking the lightning-fast strike coming toward him.
However, Yoriichi Type Zero's other five arms and swords also moved, like a storm, slashing out with a flurry of sword lights, attacking Tanjirou like a torrential downpour.
*Clang!* *Cling!* *Clang!* *Cling!*
*Clang!* *Cling!* *Clang!* *Cling!*
For a moment, the sounds of swords colliding echoed fiercely in the empty clearing.
Yoriichi Type Zero seemed possessed by a god of war, its six swords turning into blades of minced meat, slashing out flashes of sword light, cutting out slashes with incredible speed and high attack frequency, forcing Tanjirou to barely defend himself.
Seeing this scene, Riezel's eyes grew brighter and brighter.
'Heh, even though it's almost falling apart, it still has this kind of strength?'
Looking intently at Yoriichi Type Zero, Riezel made his judgment.
Yoriichi Type Zero should have combat power equivalent to Level 4.
Clearly, this was essentially the combat power of a Hashira, yet it appeared in the form of a mere doll.
'Interesting...'
Riezel was interested in this mechanical doll—or rather, he was interested in acquiring the technology to create it.