Chapter 639: Limitation of Breathing Styles

Seeing Ais’s fierce determination, Riezel couldn’t help but chuckle softly.

"Hey, Ais, you wanna learn it?" Riezel asked to make sure.

"Un!" Ais immediately nodded without a trace of hesitation.

In her eyes, that so-called

Wind Breathing

seemed tailor-made for her, so she naturally had no reason not to want to learn it.

Not only would the power of

Ariel

increase while its burden on her body decreased, but it would also allow her to unleash that kind of swordsmanship capable of sending out raging wind slashes.

She clearly understood that once she mastered Riezel’s

Wind Breathing

, her strength would rise to an entirely new level.

For her, strength meant everything.

For that reason alone, she simply couldn’t refuse to learn

Wind Breathing.

"Alright, I’ll teach you." Riezel nodded with a smile.

In the first place, the reason he had demonstrated

Wind Breathing

was precisely to help Ais grow stronger.

Back when he was still weak, Ais had generously guided him, teaching him her magic, swordsmanship, and even sparring with him. Now that he had grown, it was only natural that he returned the favor by helping her become stronger.

Becoming powerful was always Ais’s wish, her obsession.

Understanding this, Riezel naturally didn’t hesitate now that he had the ability to help her.

In that moment, Tiona raised her hand eagerly.

"Me, me, me! I wanna learn too!"

Tiona’s loud declaration made several others nearby show similar sparks of interest.

Unfortunately for them, Riezel didn’t agree.

"You guys better sit this one out. It’s not worth it."

Upon hearing this, Tiona was the first to complain.

"Why can you teach Ais but not me?" Tiona complained with a pout. "It’s unfair! You two get to grow stronger together secretly!"

"Yeah." Tione crossed her arms and nodded in agreement. "If only the two of you keep getting stronger, even we’ll start getting jealous, y’know?"

After witnessing Riezel suppress Ais, who had already reached Level 6, while he himself was still Level 5, even the amazoness twins and the other First-Class Adventurers of the familia had to admit that Riezel was now stronger than them—and not just by a small margin.

Such a fact made Tiona anxious and Tione slightly bitter, while Bete just glared at Riezel, looking as if someone had stolen his prey.

If they ever found out that Riezel had actually been holding back, that what he showed earlier wasn’t even one-tenth of his true strength, they’d probably rampage on the spot.

Riezel could only shake his head helplessly before addressing everyone.

"It’s not that I don’t wanna teach you. It’s just... it really wouldn’t be worth it."

From the perspective of this world,

Breathing Styles

were indeed unique—but only that, unique.

In the first place, they were created so that ordinary humans could temporarily gain enough power to fight demons, which fundamentally limited their effectiveness.

It should be noted that the world of

Demon Slayer

was not a world of high mystery or immense power. Compared to the world of

Danmachi

, it was on a completely different scale.

A cheat-like being such as Tsugikuni Yoriichi, if born in the world of

Danmachi

and granted a Falna, would have reached Level 5 or higher in just a few months, becoming a First-Class Adventurer like Riezel or the protagonist—his basic abilities might have even broken their limits, reaching SS-rank or SSS-rank.

But in the world of

Demon Slayer

, Yoriichi lived over eighty years and only achieved a power roughly equivalent to a peak Level 6. If not for encountering Riezel and drawing inspiration from the evolved

Sun Breathing

within Riezel’s body, his power might never have even reached Level 7.

Needless to say, that alone showed the clear limits of

Breathing Styles

, especially for adventurers blessed with Falna.

Every level up for an adventurer represented an evolution of life itself.

Their very body evolved.

Their potential expanded even further.

Each level up was a step toward godhood—the higher one climbed, the closer one came to the gods.

At Finn and Tiona’s level, even if

Breathing Styles

still had some effect, it would soon fade away since they had already transcended mortal limits.

How could beings whose lungs and hearts were already superhuman grow stronger just by inhaling more air?

Was it realistic to think they could boost their already monstrous bodies that way?

Not at all.

Besides, adventurers in this world were different.

Having Falna, they could grow stronger simply by honing their abilities and gaining experience in battle.

As long as they achieved great feats and got high-rank excelia, they could level up, causing their power to skyrocket instantly, so spending time to master something that would soon lose effectiveness simply wasn’t practical.

Considering all this, Riezel had decided not to teach

Breathing Styles

to his other familia members, especially not to the First-Class Adventurers like Finn and the others.

After years of battling through the Dungeon and fighting countless monsters, their combat systems were already fully established. Unlike Lizbeth in her early days, they weren’t suitable for suddenly learning an entirely different style.

If the

Breathing Style

were overwhelmingly powerful, it might have been worth it, but since its effects would fade, it simply wasn’t worth their effort.

Only Ais was different because she was a swordswoman who could more easily adapt to new swordsmanship, and as the wielder of

Ariel

, her affinity with

Wind Breathing

was exceptionally high—perhaps even higher than Riezel’s.

For her,

Wind Breathing

might not boost her strength much on its own, but in combination with

Ariel

, it would create a synergistic effect of tremendous value.

Even as she continued to level up, it would remain useful to her.

Needless to say, the stronger she became, the more powerful

Ariel

would grow—and paired with

Wind Breathing

,

Ariel

would become more efficient while placing less strain on her body.

In other words, she would continue to benefit from it indefinitely, and that benefit might even surpass what

Sun Breathing

offered to Riezel.

He had, after all, already noticed that as his level increased, the power boost granted by his evolved

Sun Breathing

gradually diminished.

Before reaching Level 7, each use of

Sun Breathing

granted him a combat power boost equivalent to an entire level, but after Level 7, that stable leap vanished—the increase became noticeably smaller.

Once he leveled up again,

Sun Breathing

would likely only boost his combat ability by half a level, and two levels later, only by a fraction.

Even so,

Sun Breathing

would never lose its usefulness entirely because, unlike other

Breathing Styles

, it infused magical energy into the bloodstream.

As long as Riezel didn’t lose his control over his original magical energy after the damage to his Gate,

Sun Breathing

would always enhance his close-combat capabilities to some degree—no matter his level.

However, its improvement would no longer be as striking or overwhelming as before.

By then,

Wind Breathing

might even prove more beneficial to him than

Sun Breathing

—especially since it could be combined with

Ariel

, allowing both him and Ais to draw continuous benefits from it.

Such was the inherent limitation of

Breathing Styles

.

Riezel had tried to refine them further, but their potential simply had its bounds.

Fortunately, each

Breathing Style

still had its unique characteristics.

Moon Breathing’s

immense attack speed and range could turn Riezel’s slashes into devastating AOE strikes.

Thunder Breathing’s

speed and explosive power made his blows almost impossible to react to.

Sun Breathing’s

purifying force remained a lethal weapon against demons and other evil foes.

For this reason, for Riezel,

Breathing Styles

would never become entirely obsolete—at the very least, their various sword forms were undeniably effective.

Especially the thirteenth sword form of

Sun Breathing—Blooming Radiance

.

It was his ultimate technique—a finishing strike that drained all his strength, comparable to a Servant’s

Noble Phantasm.

Not only did the stronger he became, the deadlier the strike grew, but it would also never lose its power.

For this reason, he continued to use

Breathing Styles

as the foundation of his combat system.

At this point, what he valued most about them was not their ability to strengthen the body, but their versatility—the variety of techniques and traits they could develop.

In short, within the familia, only Ais was truly suited to learning a

Breathing Style

, while the rest were not.

After hearing Riezel’s explanation, everyone finally nodded in understanding.

"So basically, this swordsmanship works best for swordsmen who have enchant-type magic?" Finn summarized the idea.

He wasn’t wrong.

Since

Wind Breathing

could be used in tandem with

Ariel

, then naturally

Flame Breathing, Stone Breathing, Water Breathing, and Thunder Breathing

could also be paired with enchant-type magic spells of their corresponding attributes.

However...

"While other enchant-type magic can be used that way, I don’t think any of them would ever match the compatibility that Ais and I have with

Ariel

."

Riezel believed that although enchant-type magic wasn’t exactly rare in Orario and many people possessed it, an exceptional enchant-type magic like

Ariel

was absolutely one of a kind.

A magic with an ultra-short chant—just a single verse—capable of granting effects strong enough to let someone challenge enemies far above their level, besides

Ariel

, how many such magic spells had ever appeared in the original story?

Finn’s own magic,

Hell Finegas

, might count as one, but its side effects were far too severe.

Other magic spells were similar—either the activation requirements were too strict, or the backlash too heavy.

Truly overpowered enchant-type magic spells that surpassed

Ariel

were practically nonexistent, especially within that specific category of magic.

In other words, even if other enchant-type magic spells of different attributes existed, their power would never come close to what

Ariel

could achieve when combined with

Wind Breathing.

"As for whether the user has to be a swordsman—that doesn’t really matter." Riezel continued.

Even someone who wasn’t a swordsman could use a

Breathing Style

—it would just take them much longer to adjust to it.

For example, Himejima Gyomei’s Nichirin Sword had long since gone beyond what could be called a sword, since the combination of a spiked flail and a massive axe made one wonder if it could even still be considered a sword.

As Riezel pondered that, he noticed Finn, Riveria, and Gareth all turn their gazes toward one particular person.

"So even if one isn’t a swordsman, as long as they can use enchant-type magic... it’s possible, right?" Finn said meaningfully, causing the person being stared at to scowl in irritation.

"What the hell are you trying to say?" Bete glared at Finn, his tone as rough as ever—even toward the familia’s captain.

"Why don’t you give it a try, brat?" Gareth said lazily, his grin half-mocking.

"Tch." Bete clicked his tongue in annoyance and spat back without hesitation. "I’ve already got these legs, that’s all I need! Who the hell wants some dumb magic or weird breathing crap anyway?"

With that, he turned around and walked off, leaving the others behind.

Several members exchanged puzzled looks, clearly unsure what that exchange had been about.

"Still the same as always." Gareth sighed and gave a wry smile. "Forget it, just let him be."

Finn nodded slightly, saying nothing more.

"Uuugh, it’s still so frustrating!" Tiona pouted, crossing her arms as she complained. "Now Ais has surpassed me—and Riezel’s even surpassed her!"

"Just be glad he’s in our familia..." Tione said with a serious face and a sigh. "If he belonged to another familia, we’d have to watch our backs walking at night."

Such a remark drew a few awkward laughs from the others—none of them denied it.

It was obvious that the possibility wasn’t entirely a joke.

"In any case, it’s good that Riezel and Ais are getting stronger."

Riveria was the one who finally concluded the matter—her words made everyone nod in agreement, bringing the discussion to an end.

However, the way they all looked at Riezel had clearly changed.

Now, the young man standing before them was no longer just a recently promoted Level 5 rookie—he was someone capable of crossing the gap between levels and defeating a Level 6.

Realizing this, Riezel’s position within their hearts had risen once again, placing him just beneath the familia’s three top executives.

"Haaa... Haaa... Haaa..."

Suddenly, Loki came running out of the manor, panting heavily.

"You—! You guys couldn’t wait for me before starting the damn conversation?!"

Loki’s outburst made everyone burst out laughing.

Unknowingly, the sun had begun to sink, and evening draped the Twilight Manor in a true shroud of dusk.

As this sight fell upon Riezel’s eyes, it stirred a deep sense of nostalgia within him.

===

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