Isekai Adventure in the Dimensional Cube

Thus, Reiger was invited by Rengoku Kyoujurou and stayed at the Rengoku residence.

The Rengoku residence, generation upon generation a family of Ghost Hunters, is essentially top secret, with connections to the Demon Slayer Corps that have withstood the test of time, earning the deep trust of the Ubuyashiki family. Hence, the distance between the Rengoku residence and the Ubuyashiki estate was not far, even situated within the same town.

Reiger began to suspect that the town was specifically intended for Ghost Hunters and those greatly associated with them since several Pillars also entered the area after their dispersal, disappearing without a trace, likely having their own homes here.

If that was indeed the case, then the wealth of the Ubuyashiki family must be even greater than Reiger had imagined, to build an entire town for habitation, showcasing their significant financial strength.

The mansion of the Rengoku family was also impressive, an historical estate, though not as grand as the Ubuyashiki's, it was still much larger than the typical household.

After moving in, Reiger heard Kyoujurou mention,

"My father and younger brother also live here, though my father is semi-retired at the moment, and my brother is not yet a Ghost Hunter, so I won't introduce them to you for the time being. Just make yourself at home here. If you want to train, you can use the courtyard—it's spacious enough!"

Kyoujurou took Reiger on a brief tour of the Rengoku residence, gave him an overview of the place, and then arranged a room for him.

During this time, Reiger also encountered the main trio, who for some reason were enthusiastically engaged in some incomprehensible training.

"Hahaha! Let's have a showdown, master of the land!"

Inosuke excitedly chased after a... humanoid locomotive?

"Why do I have to be some master of the land?!"

Zenitsu was dressed in a locomotive-shaped costume, roaring with rage, yet simultaneously fleeing in panic from Inosuke's chase.

"334...335...336...337..."

Meanwhile, Tanjirou was doing push-ups, seemingly building his strength, sweating profusely with his inseparable wooden box on his back for added weight.

The trio was creating a ruckus in the courtyard, lively to the point that Reiger and Kyoujurou stood watching for quite a while.

"...Maybe we shouldn't disturb them?"

Reiger suggested.

"Yes!"

Kyoujurou nodded seriously.

In this way, Reiger settled temporarily at the Rengoku residence.

The movement at the Ubuyashiki household was swift as well, or rather, they placed great importance on the matters Reiger had proposed. The following day, they sent over the items Reiger needed.

"Here are the compiled volumes of the five fundamental breathing techniques."

Kyoujurou brought over five books that had been specially compiled, handing them to Reiger.

The books were not thick, each of a medium size, yet they represented the foundation of the Demon Slayer Corps.

The covers of the books varied in color according to their content.

The Breath of Flames was red.

The Breath of Water was blue.

The Breath of Rocks was grey.

The Breath of Wind was green.

The Breath of Thunder was gold.

The five books, each with a different cover color, were displayed before Reiger in a row, and indeed, they looked rather imposing.

"These five books are the latest versions, specially organized and recompiled, with a lot of insights from experts added. For example, the Breath of Flames includes the understanding and explanations added by generations of Flame Pillars from our Rengoku family!"

Kyoujurou said with a smile to Reiger.

"Though I can't arrange face-to-face guidance with experts of the various breathing techniques for you, if you have any questions about the Breath of Flames, you can ask me!"

Direct guidance from a Flame Pillar was undoubtedly a precious opportunity for any swordsman.

"Alright, thank you,"

Reiger did not refuse on the spot and agreed right away.

"Is there anything else you need us to do?" Kyoujurou asked loudly. "The lord has ordered us to meet your requests as much as possible!"

Upon hearing this, Reiger thought for a moment and then made a request.

"Could you prepare Crimson Sand Iron and Crimson Ore for me?"

Naturally, Reiger was referring to the metallic minerals used to craft the Sun Wheel Blade.

"Oh?" Kyoujurou Rengoku's eyes lit up as he said, "Do you need a Sun Wheel Blade?"

"I might," Reiger replied with a smile. "After all, I don't have one yet, and it would be more fitting to use the Sun Wheel Blade when performing the Sun Breathing techniques."

In this world, swords and blades are actually the same kind of weapon, otherwise the various "sword techniques" or "sword forms" of the breathing methods wouldn't be called as such.

The difference between the Sun Wheel Blade and the swords Reiger usually used was that the former had an edge on only one side with the other being the blade's spine, and the blade had a curve, suited for heavy chopping, while the latter had edges on both sides, a straight blade body, and favored agility.

Either type could be used to execute sword techniques, but there were some differences between the two.

All the forms of the Sun Breathing were performed based on the standard style of the Sun Wheel Blade. If Reiger wanted to use another weapon to perform them, he would probably have to make some adjustments.

Right now, Reiger had no such intention; he simply thought about whether he could pair himself with a Sun Wheel Blade, which would be quite useful when dealing with demons anyway.

Without a Sun Wheel Blade, he would have to use decomposition magic to kill demons. Now, wanting to study breathing techniques more thoroughly, Reiger had decided to temporarily stop using magic for combat.

Given this, obtaining a Sun Wheel Blade seemed quite necessary.

"How about we forge your Sun Wheel Blade?" Kyoujurou Rengoku, now interested in the matter, enthusiatically said, "Our Demon Slayer Corps has swordsmiths working in secret to assist in the forging of Sun Wheel Blades. Their craftsmanship is superb; they will definitely create a Sun Wheel Blade that will satisfy you!"

This was not a matter of Kyoujurou Rengoku boasting about his own.

The Demon Slayer Corps indeed had a collaboration with a clan of swordsmiths from a place called Swordsmith Village, and their relationship was very close.

Almost everyone in Swordsmith Village was a swordsmith, not only responsible for forging and maintaining all the Sun Wheel Blades for the Demon Slayer Corps, but also the swordsmiths there had vested a lot of passion and a sense of mission in forging blades. Generation after generation spent their lives researching and creating Sun Wheel Blades, improving their forging skills year by year, undoubtedly making them elite in the field of swords crafting.

Each member of the Demon Slayer Corps had a swordsmith from the village dedicated to forging their individual Sun Wheel Blades. To prevent demon attacks, the location of Swordsmith Village was also extremely secretive, and even the members of the Demon Slayer Corps hardly knew its exact location. Entering the village even required being blindfolded and having one's nose plugged, with several people responsible for escorting and crows used to guide in stages. The order of the paths, the guide crows, and the escort personnel were also frequently changed, making the secrecy as high as that of the Ubuyashiki family estate, the headquarters of the Demon Slayer Corps.

It could be said that there was no blacksmith more skilled in forging Sun Wheel Blades than the swordsmiths of Swordsmith Village, with even the Pillars' blades being created there, making it worthy of Kyoujurou Rengoku's pride and recommendation.

However, Reiger did not plan to let the swordsmiths of Swordsmith Village forge his blade.

"Just help me prepare the ores. I have my own ideas," Reiger said.

There was no helping it, as the Sun Wheel Blades of this world were not considered very special weapons.

Be it hardness, strength, or even sharpness and durability, the Sun Wheel Blade could only be considered a category of average weapons, nowhere near the standard of "special armaments" from the Earth Mistake World.

Which is to say, a Sun Wheel Blade couldn't even be counted as a third-grade armament, but rather it was just a superior and more outstanding weapon among ordinary armaments.

The reason it could harm demons was not due to the blade's performance itself but the characteristics of the forging materials.

The ability to emit energy like sunlight was quite effective against demons, but for any other beings, that was completely useless.

For Reiger, such a weapon was naturally not suitable.

Even without using the "Wind Spirit Swift Walk" augmentation, should Reiger fight seriously with his strength and level, there was a very good chance that the Sun Wheel Blade would break.

Tanjirou's blade was cut during the encounter with the Lower Rank Five demon, and Reiger didn't want to use such a brittle sword.

The swordsmiths of Swordsmith Village might be quite skilled, but after all, they were regular people, unlike the Advanced Forgers of the Earth Mistake World, each possessing the 'forging' development ability, enabling them to imbue forged weapons with special properties and process special materials. The weapons they created could even slice through the hard exteriors of floor bosses that were as tough as steel.

If the Sun Wheel Blade were left to be forged by the swordsmiths of Swordsmith Village, what would result would only be a superior blade, not even brushing the edge of a special weapon.

For Reiger, who possessed first and second-grade indestructible armaments, this was unquestionably not a good blade.

In light of that, Reiger's idea was to forge the blade himself.

"Although I don't have the 'forging' development ability, nor do I know how to forge swords, I do have magic, right?"

Reiger had already learned construction magic from Yuri. While he couldn't craft magic or alchemical items, he was still capable of forging weapons.

Of course, the weapons he refined weren't magical weapons, just ordinary ones.

However, with Reiger's current level, his accumulated 'Magic Power,' plus the assistance of the 'Magic Guidance' development ability, the magic that he would cast, in terms of power and effect, would certainly far surpass that of an average Construction Mage.

Therefore, Reiger thought...

"If I use decomposition magic to break down a large amount of crimson sand iron and crimson ore, removing all impurities and leaving only the essence, then the quality of these two ores would meet the standard for special materials."

"Then, using construction magic, I can fuse the essence of the two ores with the Hermit's Blade to create a Sun Wheel Blade. Wouldn't the quality of this Sun Wheel Blade be unlikely to be any less?"

"By then, at worst, I should be able to possess a second-grade indestructible Sun Wheel Blade."

That was Reiger's thought.

If he was going to use a Sun Wheel Blade, he wanted the best.

A Blade that surpassed the understanding of everyone in this world, one exclusively for Reiger himself— the Sun Wheel Blade!