Marilyn's shock didn't catch Riezel's attention.
At this moment, Riezel simply watched Yuri, who looked quite upset, before suddenly reaching out to pat her on the head.
"What do you want me to say?" Riezel asked with a faint smile. "Should I brag about how amazing I am?"
His reasoning was somewhat similar to what he had said in front of Yuri when he first revealed his swordsmanship abilities after defeating the Shadow Knights with Ain and Ian.
Yuri's frustration immediately vanished as she stared at Riezel, who smiled and patted her head without warning.
It took her a moment to react.
"Don't treat me like a kid!"
Yuri quickly swatted Riezel's hand away with an annoyed look, but if one looked closely, one would notice a hint of red on her cheeks.
However, his playful gesture seemed to make her lose her mood to confront him.
Not responding to her words, Riezel merely smiled faintly.
What Yuri didn't know was that Riezel was actually still holding back. After all, in his match against Albert, he had used Thunder Breathing, not Sun Breathing.
Regarding this, there was a world of difference between the two.
Sun Breathing had evolved into a completely different realm, giving Riezel a stable combat power that crossed a level, making him nearly invincible even against Level 7 opponents.
Thunder Breathing, though unique, couldn't compare to the evolved Sun Breathing.
However, if that was the case, why did Riezel choose to use Thunder Breathing and not other breathing styles?
Simple.
It was simply because Riezel had a special fondness for Thunder Breathing.
In truth, not only had he mastered the five fundamental breathing styles with the help of the Ubuyashiki family, but he had also mastered the derivative breathing styles from the Hashira during their two months of training together.
Whether it was Sound Breathing, Mist Breathing, Serpent Breathing, Insect Breathing, or even Love Breathing, he had mastered these derivative styles during his training with the Hashira.
For Riezel, who had managed to grasp Flame Breathing by merely observing Kyoujurou's breathing during their first meeting in the Mugen Train, this wasn't particularly difficult. He even mastered Moon Breathing just by observing it during his battle with Kokushibou.
If this fact were known to everyone in the Demon Slayer Corps, it would surely drop a lot of jaws.
Ultimately, Riezel had nearly mastered all the breathing styles from the world of Demon Slayer, except for Flower Breathing and Beast Breathing, which he had not yet seen in person.
Among all these breathing styles, Sun Breathing was undoubtedly the most useful for him, closely followed by Wind Breathing, which could be used in Fast Attack Mode with Ariel.
While the other breathing styles didn't have as much impact because they couldn't be applied to any attack modes, Thunder Breathing was undoubtedly his favorite.
Thunder Breathing was, after all, the second most challenging breathing style after Sun Breathing and had the strongest speed and explosive power of all breathing styles, making it a preferred choice for both killing and quick strikes.
It was evident from how he developed Blooming Radiance, a new thirteenth form of Sun Breathing. Much like Thunder Breathing's first form, Thunderclap and Flash, Blooming Radiance was also an Iai technique, though they were not identical.
For this reason, he even attempted to evolve Thunder Breathing just as he had evolved Sun Breathing.
Unfortunately, he failed.
He realized that Thunder Breathing and Sun Breathing were completely different.
One should know that the main reason Sun Breathing could evolve and transform was its incredible versatility and adaptability.
As the origin and ancestor of all breathing styles, the five fundamental breathing styles derived from Sun Breathing, while the remaining derivative breathing styles further evolved from these breathing styles, all ultimately traceable back to Sun Breathing.
Even Moon Breathing was a derivative of Sun Breathing, proving that Sun Breathing was all-encompassing and had extremely high versatility and adaptability.
Unlike other breathing styles, which focused on enhancing specific aspects, Sun Breathing offered a comprehensive boost to overall abilities.
Needless to say, such versatility, adaptability, and comprehensive nature allowed Sun Breathing to evolve into a divine swordsmanship capable of strengthening the human body in every aspect.
Other breathing styles, however, fall short.
For example, since Thunder Breathing emphasized speed and explosive power, with other aspects being less important, it couldn't integrate with the Akasha Continent's breathing technique like Sun Breathing, which achieved an all-around enhancement effect. Coupled with its lack of versatility and adaptability, it made improvement or reshaping difficult.
As a result, among the breathing styles he mastered, only Sun Breathing could evolve and transform as he envisioned, while the other breathing styles could not.
Understanding this, Riezel felt regret more than once.
Regardless, in his current situation and needs, Thunder Breathing still proved useful.
'Indeed, demonstrating strength is the best way to deter petty threats, but if you show all your strength and don't keep any cards up your sleeve, you'll eventually suffer.'
Riezel's heart was as clear as a mirror as he thought this.
Facing his current situation, where countless people were eyeing him, he knew he needed to show enough power to make them wary but also not reveal his full capabilities to avoid being targeted.
Because of this, Riezel kept a few tricks up his sleeve, hiding his true power.
For him, even without using Sun Breathing in Strong Attack Mode or Wind Breathing in Fast Attack Mode, he could easily handle someone claiming to be the best swordsman just under Sword Saint.
Under normal circumstances, he could already dominate Level 6 opponents, so even against Albert, who had reached the limit of Level 6 and could be considered a half-step to Level 7, he would still have the upper hand.
For this reason, when he used a breathing style to enhance his power, even a standard breathing style without evolution could help him reach the power of Level 7 and effortlessly defeat Albert.
Level 7, even if just barely, was the genuine realm of Sword Saint, enough to deal with an ordinary Sword Saint, let alone someone who was still a step away.
Moreover, with Riezel using Thunder Breathing, the strongest in speed and explosive power among all breathing styles, merely using its first form, which was the same as the Blooming Radiance, the strike he unleashed at that moment would be hard for ordinary Sword Saints to block.
In this way, the result was as expected.
Albert Borley, the so-called best swordsman just under Sword Saint, faced a devastating defeat. If it had been a life-and-death battle, he would have been killed in an instant without even realizing it.
Demonstrating such a level of power was enough to intimidate petty threats.
Riezel had already planned this thoroughly.
'In the future, I'll use Thunder Breathing in front of others and hide my true power. If someone thinks that's all I have and targets me, I'll give them a big surprise.'
With this thought, Riezel suddenly remembered Zenitsu.
As a swordsman who only knew the first form of Thunder Breathing, Zenitsu appeared to be a hopeless case but was, in truth, a master practitioner of Thunder Breathing.
In the original work, Zenitsu perfected the first form and developed even stronger techniques based on it.
They were 'First Form - Thunderclap and Flash - Godspeed' and 'Seventh Form - Flaming Thunder God', the two techniques Zenitsu created based on his understanding of Thunder Breathing's first form.
Godspeed was the ultimate move of Thunderclap and Flash, the fastest strike, the fastest slash.
Flaming Thunder God, on the other hand, could achieve speeds even Upper Ranks couldn't catch, allowing Zenitsu, who wasn't even a Hashira and had none of the three abilities—the Demon Slayer Mark, the Bright Red Nichirin Sword, and the Transparent World—to decapitate his senior brother, who had become an Upper Rank.
Riezel thought these two techniques had a lot of potential and were similar in essence to his Blooming Radiance.
'Maybe if I develop them further, I might find some inspiration to improve Blooming Radiance.'
Indeed, Riezel was thinking about improving Blooming Radiance.
Meanwhile, Yuri, who was unaware of all this, was still in awe of the stunning lightning bolt Riezel had created, not realizing that it wasn't even his true strength.
However, there was one thing she did know.
"Is the swordsmanship you used a Special Swordsmanship?" Yuri asked seriously. "So, you already know and have learned a Special Swordsmanship?"
She had been trying every possible way to give this troublemaker access to her family library, only to find out he didn't need it at all.
Special Swordsmanship was, after all, something even the Frenzel family didn't possess.
"Well, I guess so..."
With such a casual answer, Riezel didn't explain much further.
In the eyes of the people of this world, Thunder Breathing could indeed be considered a type of Special Swordsmanship.
Special Swordsmanship was a form of swordsmanship that allowed a swordsman to develop unique abilities—some could summon wind, while others could control fire, performing feats similar to magic.
Since Thunder Breathing used the power of lightning, it was seen as a type of Special Swordsmanship.
However, unlike the genuine Special Swordsmanship of this world, Thunder Breathing didn't permanently enhance the body and only provided temporary effects.
For this complicated reason, Riezel didn't intend to clarify further.
"Anyway, with this, things are settled..." Riezel said calmly. "Although I can't say I'm completely safe, it should help prevent some underhanded tricks, right?"
At his words, Yuri paused for a moment before suddenly smiling.
"I can't guarantee there won't be any underhanded tricks, but I can guarantee that you'll have something to do next."
"What?" Riezel asked with a confused expression.
Perhaps out of spite, she kept him in suspense.
"You'll find out soon enough."
With that, Yuri turned and got into the carriage.
Marilyn, still shocked, gave Riezel a peculiar look before following her master into the carriage.
Still standing in place, Riezel was lost in thought.
'What did she mean by that?'
Not understanding Yuri's meaning, Riezel shook his head before getting into the carriage as well.
It wasn't until later that he realized he indeed had something to do next.
However, whether it was a good or bad thing was up to everyone's interpretation.