Amidst the storm of impacts, Riezel was directly blasted to pieces by Muzan's seventeen whips, capable of destroying terrain and buildings alike, leaving no trace behind.
However, a figure suddenly appeared silently like flickering sun flames behind Muzan.
"Sun Breathing - Fourth Form - Fake Rainbow."
Riezel drew his sword that radiated intense heat, slicing through the void straight toward Muzan's back.
However, his slash ended up cutting through empty air.
With astonishing speed, Muzan evaded Riezel's slash aimed at his back, darting away like a bullet, his seventeen whips still in motion.
"Hmm?"
Riezel raised an eyebrow, somewhat surprised.
His surprise was not without reason.
Previously, whether facing Akaza, Hantengu, Gyokko, Gyuutarou, Daki, or even Kokushibou, whenever he drew his sword and launched a slashing attack, none of them could react in time or evade effectively.
Truthfully, it really couldn't be helped.
Not only did Riezel's strength surpass them by too much, but even when he wasn't in fast attack mode, his speed wasn't something these so-called Upper Ranks could react to.
Even when Riezel first arrived in this world, before he had evolved Sun Breathing and during his encounter with Akaza, he already possessed strength equivalent to Level 6, which was two levels higher than Akaza's Level 4, making it effortless to defeat him.
And now, having successfully evolved Sun Breathing and possessing strength equivalent to lower-middle Level 7 in strong attack mode, the Upper Ranks were even further below him—three levels in difference.
Even Upper One Kokushibou was two levels lower than him, making it very easy to defeat him.
However, Muzan was undoubtedly different.
"It seems your strength has indeed grown considerably compared to when you faced Tsugikuni Yoriichi back then, huh..." Riezel remarked calmly.
"Do you think I am still the me from over three hundred years ago?" Muzan said coldly. "Since then, I've consumed countless humans, far beyond your imagination."
Even if he ate only one human every few days over three hundred years, the number of humans he consumed was still astonishing. Not to mention, for this battle, he had slaughtered an entire town, capturing thousands of humans to nourish himself, significantly enhancing his strength once again.
As a result, the current him was indeed much stronger than when he first encountered Yoriichi. Otherwise, if Yoriichi could defeat him in an instant, Riezel should have been able to as well.
In this situation, Riezel could already be certain.
Muzan undoubtedly possessed strength equivalent to Level 6, and not just any Level 6, but at least on the higher end of Level 6.
In the original work, even weakened by Tamayo's drug, Muzan could handle Tanjirou, Gyoumei, Sanemi, Obanai, Giyuu, and Mitsuri with ease, displaying strength surpassing that of Kokushibou, who was equivalent to Level 5.
All of this made Riezel suspect that Muzan might have been Level 6 in his prime.
Whether Muzan was truly Level 6 before, Riezel wasn't sure, but at this moment, Muzan definitely had the strength of Level 6, or else Muzan wouldn't have been able to dodge his slash.
However—
"Even if you get stronger, so what?" Riezel raised his sword. "Dodging one strike is one thing, but how will you dodge the next?"
With these words, flames erupted beneath Riezel's feet, engulfing his entire body and transforming him into a blazing figure, charging toward Muzan.
"Sun Breathing - Seventh Form - Sunflower Thrust."
Originally, this sword form was designed to launch a thrust attack toward an opponent above oneself, enveloping the sword with a ring of flames that inflicted multiple piercing wounds and burns on the opponent.
However, after mastering all the sword forms of Sun Breathing, Riezel could now launch this sword form against an opponent in a horizontal position.
Soon, the flames swirling around Riezel twisted into a cone shape, piercing toward Muzan.
"?!!!"
Seeing this, Muzan's pupils contracted before he immediately raised both hands, transforming his arms into flesh whips to meet the attack.
*Pu-chi!*
As the cone-like thrust struck the whips, it pierced them directly and skewered them on the spot.
"Ugh!"
Muzan groaned, then swung another whip, booming toward Riezel who transformed into a cone of fire.
*BOOOM!*
Dust and smoke accompanied the roar, generating a fierce airflow that tore up the ground.
However, Riezel had already leaped high into the air, evading Muzan's counterattack.
Without delay, Riezel spun his sword, reigniting the flames.
"Sun Breathing - Tenth Form - Beneficent Radiance."
In mid-air, Riezel swung his sword directly at Muzan, unleashing a spiral slash from top to bottom that unfolded like a red lotus flower, entwined with intense flames like the sun.
It not only severed Muzan's other whips but also cut through and incinerated several hastily raised thin whips that he used to defend himself.
In the end, Muzan lost both arms and several thin whips at once.
"GET LOST!"
With veins bulging on his face, Muzan was completely enraged, his eyes full of nothing but blood, roaring at Riezel.
*BOOOM!*
Immediately afterward, a tremendous shockwave suddenly erupted from Muzan.
Accompanied by falling thunder and lightning, hurricanes, and explosions, the shockwave indiscriminately bombarded all directions.
As the shockwave spread, it destroyed everything around, particularly the ground, suffering from an all-around ravage, not just simple inch-by-inch fractures, but directly presenting a catastrophic collapse, causing the upper half of the cliff-like structure to explode and shatter.
"Tch!"
Riezel, who was close at hand, could not avoid this indiscriminate bombing aimed at everything, only able to slash at the oncoming shockwave.
"Sun Breathing - Second Form - Clear Blue Sky."
*BOOOM!*
A vertically circular slash resembling the outline of the sun caused flames to flutter, enveloping Riezel and colliding with the oncoming shockwave, causing bursts of explosions.
However, the shockwave seemed not only to have extremely powerful physical destructive power but also to affect the human body, causing chaos in the nervous system, leading to spasms that immobilized and even killed those affected.
Riezel's shoulder was accidentally grazed by a lightning bolt carried by the shockwave, instantly causing stiffness on it.
'Blood Demon Art?'
Riezel recognized this move.
It was Muzan's Blood Demon Art—his trump card and most powerful attack.
Although the name of his Blood Demon Art wasn't mentioned in the original work, this move had been used several times to turn the tables, almost resulting in the deaths of the protagonist and the Hashira attacking him.
'His attacks, whether those arm whips, thin whips, or this Blood Demon Art, all have an instantaneous deadly effect.'
Riezel rode the recoil of the flames, leaping down from the cliff-like structure that had turned into ruins.
*BANG!*
At the same time, Muzan burst out from the shockwave, wielding the remaining dozen or so thin whips like a frenzied spider, crushing debris underfoot as he swiftly descended.
"GIVE ME THE BLUE SPIDER LILY!"
Muzan's face had completely transformed, veins bulging like thick blood vessels, making him look like a genuine demon crawled out from hell.
"If you want it, then you'll have to take it."
Responding calmly, Riezel's feet landed on the surface of the structure, sliding down frictionally, while his sword suddenly slashed out.
*Clang!*
Like a tolling bell, the burning sword clashed with the deadly bladed thin whips, sparking flames like fireworks.
*Clang!* *Cling!* *Clang!* *Cling!*
In resounding clashes, Riezel and Muzan engaged in intense combat—one sliding down while the other sprinted up the structure's surface, their sword and whips colliding repeatedly.
Muzan used eight thin whips connected to his lower body, each whip's attack power and speed far surpassing those from his upper body and arms—each swing caused sonic booms, damaging the structure's surface.
In contrast, Riezel's sword swings were equally swift, leaving blazing slashes in the air like dazzling meteors or fleeting flames, each one aimed at Muzan, causing explosions of flames that burned everything in their path.
They fought from the top to the base of the structure, and then from the base returned to the top, leaving destruction in their wake as flames and sonic booms shattered everything.
*Rumble!*
Before long, the colossal cliff-like structure collapsed with a thunderous roar, turning into countless massive stone fragments raining down.
Without a doubt, this scene resembled a mountain collapse.
"Sun Breathing - Eleventh Form - Sun Halo Dragon Head Dance."
Eventually, Riezel countered, charging forward with his sword, his whole body dancing like a fire dragon, unleashing a rapid barrage of slashing attacks at Muzan who was beneath the falling stone fragments.
*Sizzle* *Sizzle* *Sizzle*
As if a fire dragon danced around him, scorching slashes landed on Muzan, who couldn't react in time—flames burned into his body, leaving fiery blade wounds.
"AAAAARGHHH—!"
After all these clashes, the intense pain from the burning flames in his wounds finally drove Muzan to scream in agony.
"Sun Breathing - First Form - Dance!"
In the next second, Riezel suddenly spun around and, with a sweeping slash, the blade of flames struck Muzan's neck.
*Pu-chi!*
Amidst the tearing sound, Muzan's head was severed.