Isekai Adventure in the Dimensional Cube

If the emergence of breathing techniques gave humanity the power to confront demons head-on, the abilities of the set of three granted these humans even greater strength, enabling them to stand toe-to-toe with even the strong among the demons as a high-end battle force.

Whether it was the Demon Slayer Marks or the Transparent World, the appearance of either significantly enhanced the strength of humans.

Even the Nichirin Blade, though useless against non-demon entities, held immense lethality against demons.

Therefore, within the ranks of the Demon Slayer Corps' Pillars, with the exception of one individual, the rest needed to awaken at least one ability to possess the power to directly contend with the Upper Rank demons.

"Is that so?"

When the Pillars learned of this, they were greatly shocked.

Helpless, the traditions of the Demon Slayer Corps had been interrupted and lost many times throughout history, rendering their knowledge of the Demon Slayer Marks, Nichirin Blades, and the Transparent World rudimentary at best.

Only Ubuyashiki Kagaya coughed a few times before saying something.

"Concerning Nichirin Blades and the Transparent World, we might set those aside, but in the family history passed down through the Ubuyashiki clan, I have seen records related to the Demon Slayer Marks."

Ubuyashiki Kagaya revealed this piece of information.

"Legend has it that during the warring states period, several original breathing technique swordsmen, who pushed Kibutsuji Muzan into dire straits numerous times, all bore markings similar to demon patterns on their bodies, which most likely were the Demon Slayer Marks," he said.

Upon hearing this, Reiger curled his lips in a smile.

"Forcing Kibutsuji Muzan into a desperate situation?" Reiger was somewhat sceptical of this claim, but he did not correct it and instead said, "That indeed would be the Demon Slayer Marks. Swordsmen who have awakened the Marks are significantly stronger than ordinary swordsmen, so whether they forced Kibutsuji Muzan into a desperate situation, I do not know, but it's undeniable that they certainly had the power to push an Upper Rank demon into a corner."

Upon this revelation, many Pillars became restless.

"Tsukiguni Yoriichi, you're so strong because you've awakened the Demon Slayer Marks and accessed the Transparent World, awakening those three abilities you've mentioned, right?" Rengoku Kyoujurou loudly voiced such a question, lighting a fire in the eyes of the assembled Pillars.

If Reiger was so powerful because of these three abilities, did that mean they too could become as strong as him if they also possessed these abilities?

This thought appeared in the minds of several Pillars and became unstoppable.

Yet Reiger continued to throw cold water on their enthusiasm.

"I have indeed accessed the Transparent World, but only the Transparent World; I have not awakened neither the Demon Slayer Marks nor the Nichirin Blades," he clarified.

Reiger's admission startled everyone.

"You're so strong with just one ability?" Kanroji Mitsuri covered her mouth in disbelief.

"No, my strength is not related to how many abilities I've awakened," Reiger shook his head and said, "While the Demon Slayer Marks and Nichirin Blades are indeed impressive, to me, they are just that, impressive. Specifically, the Marks, once awakened, have a terrifying side effect. Although I know how to unlock them, I do not intend to do so."

"Side effect?" Shinazugawa Sanemi seemed particularly concerned and pressed, "What kind of side effect?"

Reiger glanced at him and then calmly explained.

"The Demon Slayer Marks are an ability that enhances one's strength by overextending their own life potential."

"In other words, once you awaken the Marks, it shortens your lifespan."

"All those who awakened the Demon Slayer Marks, in the end, nearly none have lived past the age of 25."

The moment these words were spoken, everyone fell silent.

It was because of this side effect that Reiger had no intention to awaken the Demon Slayer Marks.

In his eyes, while the Marks were valuable, that was all they were.

Even the weakest Pillar within the Demon Slayer Corps possessed the equivalent strength of at least a Level 4 Lower Rank, and the weakest of the Upper Rank demons in the Twelve Kizuki were roughly equivalent to a Level 4 Upper Rank.

If the Pillars awakened the Demon Slayer Marks, even the weakest among them would have the power to directly contest the weakest of the Upper Rank demons. This may seem impressive, but how remarkable is it to boost a Level 4 Lower Rank to a Level 4 Upper Rank?

In this world, the Demon Slayer Marks are definitely a strong ability, but in Reiger's case, they seemed quite average.

With an exceptional magic spell like "Wind Spirit Swift Walk" that allowed one to challenge beyond their level, an ability that only allowed for a half rank challenge was unremarkable, especially if it came with side effects. Without side effects, it might be worth exploring, but with them, it's better left alone.

Bearing such considerations, Reiger never contemplated awakening the Demon Slayer Marks from the beginning.

As for the Nichirin Blades, he had some interest at first, but now, with the "Sun Wheel Blade Opener" at his disposal, this ability also became redundant.

Undoubtedly, the special attack capability of the "Sun Wheel Blade Opener" surpasses the Nichirin Blades' lethality against demons. Not to mention, Reiger's exclusive Sun Wheel Blade hermit also had significant damaging effects on demons, and the original breathing technique of Sun Breathing was also capable of restraining demons like sunlight. An example is Reiger's previously used "Sun Halo Dragon: Head Dance," which could temporarily suppress a demon's regenerative abilities and cause them agonizing pain.

Therefore, the Nichirin Blades were also no longer significant for Reiger.

Of the three-piece set, only the Transparent World had a noticeable effect on Reiger; the other two either had side effects he could not accept or had already become irrelevant.

Hence, Reiger had no plans to awaken the Demon Slayer Marks or delve into the Nichirin Blades, as the Transparent World alone was sufficient.

Naturally, for the Pillars, it was a different matter altogether.

"If we awaken the Demon Slayer Marks and those three abilities, does that mean we can take down the Upper Ranks?" Kochou Shinobu spoke on behalf of all Pillars, seeking final confirmation.

To this, Reiger provided a straightforward response.

"Leaving aside the strongest of the Upper Ranks, Yoriichi, who is on a different level from the rest, as for the remaining Upper Ranks, if you could utilize all three abilities, you would have at least a fighting chance to defeat them on your own."

In Reiger's view, the strength of the pillars could roughly be divided into three tiers.

First were the Insect Pillar Kochou Shinobu, Love Pillar Kanroji Mitsuri, and Mist Pillar Tokitou Muichirou. These three were the relatively younger successors among the pillars and were comparatively weaker, occupying the lowest level in the hierarchy, equivalent to a lower Tier 4.

Then came the Flame Pillar Rengoku Kyoujurou, Water Pillar Tomioka Giyuu, Wind Pillar Shinazugawa Sanemi, Sound Pillar Uzui Tengen, and Serpent Pillar Iguro Obanai. These five were the mainstay of the pillars, with relatively stronger abilities, equivalent to the mid-level Tier 4.

The last was the Rock Pillar, Himejima Gyoumei.

Reiger glanced at the monk who had been praying silently with his hands together, tears streaming down his face.

This was the oldest member of the Demon Slayer Corps, now 27 years old.

But it was precisely because he was the oldest that his strength was also the greatest.

The strongest of the Twelve Kizuki was Upper Moon One, and the strongest in the Demon Slayer Corps was this Rock Pillar, Himejima Gyoumei.

His strength was roughly equivalent to the high Tier 4, and he was the only one among the current nine pillars who could directly contend with an Upper Moon demon.

But a high Tier 4 was also the lowest rank among the Upper Moon demons.

For instance, Upper Moon Six, Gyuutarou, was probably at the high Tier 4 level.

And Gyokko, Upper Moon Five, was about the same.

Even Hantengu, Upper Moon Four, though his abilities were a bit tricky, Himejima Gyoumei would not perform too poorly against him as long as he knew how to counter him.

Even against Upper Moon Three, Akaza, Himejima Gyoumei could hold his own in a fight without being overwhelmed.

Unfortunately, that was probably his limit.

Above that, without activating any one of the three parts of his set, Himejima Gyoumei would find it very difficult to win.

Especially against Upper Moon One, that guy was on another level entirely, and Reiger even suspected he had strength equivalent to Tier 5. Himejima Gyoumei, even with all three parts of his set activated, would not stand a chance fighting alone.

Besides Upper Moon One, as long as the pillars could awaken all three types of abilities, even if they faced the others alone, they would have some chance of winning.

Particularly for Himejima Gyoumei, if he activated his Mark, opened the Transparent World, and awakened his Bright Red Blade, he would at least be at the ultimate level of Tier 4, or even halfway to Tier 5.

In such a state, facing Upper Moon Two alone, he would have a great chance of victory.

With such a clear answer from Reiger, the pillars looked at one another.

"Hmm," the Sound Pillar, holding his forehead, said, "If that's the case, what we need to do must already be glaringly obvious, right?"

Then, the eyes of the pillars ignited with flames.

Seeing this, Reiger knew.

These people were truly ready to go all out.

"You know how to activate those three abilities, don't you?" Iguro Obanai looked at Reiger, his voice grave. "Tell us."

The meaning of his words was clear.

The side effects of the Mark, all the pillars present were willing to bear.

"As long as we can kill the Upper Moon demons and Kibutsuji Muzan, dying immediately wouldn't be a problem, let alone living to 25."

Shinazugawa Sanemi's eyes glowed fiercely.

"Exactly!"

Rengoku Kyoujurou, with his arms crossed, had his usual wide smile on his face.

"Amitabha."

Himejima Gyoumei chanted the Buddha's name again, with tears flowing more violently than before.

Kochou Shinobu, Kanroji Mitsuri, Tomioka Giyuu, Tokitou Muichirou, and others silently expressed their resolution; even Kanroji Mitsuri, who appeared the most delicate, was determined.

Seeing the pillars with a resolute acceptance of death in their eyes, Reiger stopped talking.

He understood, talking anymore was pointless.

"If you really aren't afraid of death, I can accommodate you."

Reiger's indifferent words seemed rather heartless.

Yet even so, many cast grateful looks at Reiger, bowing their heads to him.

Ubuyashiki Kagaya watched it all silently without intervening, and he didn't say much else, just announced one thing.

"Effective immediately, the Demon Slayer Corps will establish the position of Chief-in-Command, to be held by Tsukiguni Yoriichi."

"The rank of Chief-in-Command stands above the pillars and is equal to mine."

"All of you are to follow the orders of Chief-in-Command Tsukiguni Yoriichi and prepare for the ultimate battle against the demons."

To this, the pillars had only one response.

"Yes!"