As time passed, the apocalyptic scene inside the underground chamber grew even more intense. The barrier separating the inside and outside wavered dangerously, looking as though it might collapse at any moment.
Leo's power was steadily pushing past what the barrier could withstand.
Yet despite releasing such overwhelming force, Leo's expression only grew heavier. The look in his eyes as he watched Miyamoto Musashi changed.
At first glance, it seemed like the entire battlefield had become his domain—filled with the calamities he unleashed. Any one of them could have ravaged the world outside. But none of these disasters, no matter how terrifying, managed to harm the lone swordswoman blooming at the center like an eternal celestial flower.
Miyamoto Musashi simply swung her blades freely within the storm of destruction, her swordsmanship flowing without restraint. Every calamity that crashed down on her was split apart by her seemingly plain, unadorned dual blades—never once reaching her body.
A roaring blaze—cut cleanly in half.
A surging flood—cut cleanly in half.
Lightning falling from the heavens—cut cleanly in half.
A storm fierce enough to blow everything away—cut cleanly in half.
Even the rising sand pillars from the earth and the glacial surges from every direction were severed one after another, none spared.
She looked like a frail, delicate swordswoman, while her opponent was nature transformed into calamity itself. Anyone would think such a battle was hopelessly one-sided. Humans couldn't possibly challenge nature.
And yet, this swordswoman completely overturned that belief with her blades—declaring to the world that humans could overcome nature, overcome disaster.
Soon, the brilliance of her sword eclipsed the calamities themselves—like a blade sharp enough to slice apart the apocalypse. It inspired awe and fear in equal measure.
"As expected… someone who can serve as a Maou's servant—no matter how unreliable they look—couldn't possibly be weak."
Leo had mostly confirmed it. Miyamoto Musashi's strength placed her firmly at the pinnacle of Ultimate-Class Devil level—equivalent to a ten-winged devil, ten-winged angel, or ten-winged fallen angel.
A ten-winged entity was cadre-class within the three factions—top-tier combat power.
And Musashi stood at the absolute peak of that level, a being only a single step away from Maou-Class.
He probably wasn't a match for her at all.
Realizing this, Leo let out a long breath.
"My final strike."
His voice echoed through the battlefield.
"The next attack will be the strongest strike I can unleash right now!"
If this strike couldn't win, then for Leo, the result was no different from losing outright.
"Here I come!"
Before Musashi could respond, Leo gathered every bit of his demonic power and poured it into the coming attack. The power of Zenith Tempest exploded outward.
The storm clouds above descended, lightning surging wildly within them. Flames from every direction converged around Leo.
The ground rose. The air hummed violently. Phenomena that should never coexist appeared one after another.
Thunderstorms, hurricanes, floods, sandstorms, blizzards, falling fire from the sky—every type of extreme weather manifested inside the underground chamber. Under Leo's control, they took on monstrous forms.
The falling fire became an immortal phoenix wreathed in flames. The flood rose into a giant water dragon. Windstorms, thunderstorms, sandstorms, and blizzards twisted into ferocious beasts that roared across the mansion.
The nightmarish scene left Asuna breathless, and even Miyamoto Musashi narrowed her eyes with a faint smile.
"In that case, I'll use my strongest strike as well."
The pressure she had been gathering since the start of the fight erupted.
She slowly raised her blade, releasing a suffocating force. Behind her, a towering Niō statue materialized, standing like an immovable guardian.
It was a manifestation formed purely from sword pressure.
Historically, after achieving fame, Miyamoto Musashi devoted herself to the worship of Tenman Ōmikami. The Niō statue was essentially her guardian deity, a natural symbol born when her swordsmanship reached its final destination.
"One stroke, three bows—breaking through infinity to reach zero."
The blade she lifted gathered a massive amount of demonic power. The sword became pure light, extending endlessly.
"This is my void-path, my entire life."
Her declaration drowned out the roars of Leo's calamity beasts, echoing through the chamber.
"Draw, flash, strike—let's go!"
Her blade fell. The Niō statue behind her swung in unison, cleaving toward Leo.
It was a strike that could split the world itself, reducing everything to nothing.
When it fell, Leo and Asuna saw only a single line of light dividing the world into two halves—those halves beginning to slip out of alignment.
The calamity beasts charging around Leo touched that boundary—and without making so much as a sound, they split along the shifting seam of reality and vanished.
"————"
Time itself seemed to stop. All the thunder and roaring that had filled the chamber disappeared.
Leo and Musashi remained where they were—one in the sky, one on the ground. One with wings spread, one with a blade raised. They simply looked at each other. One silent. One smiling.
Then Leo lifted his gaze from Musashi and looked across the underground chamber.
The once-devastated chamber now had a bottomless chasm in the center, splitting the entire underground space nearly in half.
The barrier enclosing the chamber had vanished without a trace—cleaved apart silently, as though it never existed.
"…All right."
Leo stood quietly for a moment, then let out a wry laugh. He folded his wings and descended to the ground.
"I lost."
The moment he admitted defeat, the frozen world seemed to resume moving. The suffocating tension filling the chamber dispersed instantly.
"Thank you for the match, Leo-sama."
Musashi sheathed both blades and walked toward him with a refreshed, satisfied expression.
"Ah, it's been so long since I had such an enjoyable fight. I knew I wasn't mistaken about you, Leo-sama. You really are a worthy opponent."
Miyamoto Musashi, the warrior, looked completely fulfilled.
"You were both amazing!" Asuna finally rushed over, unusually excited. "I didn't know devils could be this strong! That was incredible!"
She wasn't someone who worshiped power. But seeing the battle had stirred something inside her—something she hadn't known existed.
In truth, it was simply human nature.
Just as people felt awe before towering mountains or an endless sea, what she felt now was the same.
Until now, she had been nothing more than an ordinary human. She'd lost consciousness after being attacked by a Stray Devil, only to wake up as a devil—and she had barely seen any devil powers since then.
This was the first supernatural battle she had ever witnessed. Her emotions couldn't help but swing wildly.
"This is nothing. If you work hard, you may reach this realm yourself one day."
Musashi encouraged her with a smile, and it was clear she wasn't just being polite.
In her view, Asuna truly had the potential to reach this level.
Whether she could bring out that potential depended on her own effort.
"And you, Leo-sama—you should be able to surpass me easily in the future, right?" Musashi's eyes sparkled as she spoke. "I never expected the legendary Zenith Tempest to appear in your hands. If Serafall-sama… my master learns of this, she'll be shocked."
Forget her master—if the devils of the Underworld learned this, it would shake their entire world.
The second-strongest Longinus appearing in the once-fallen heir of the Eligos family? If that leaked, the high command of all three factions would be thrown into chaos.
Without exaggeration, Leo—with this Longinus—had the potential to influence the balance of the three forces in the future.
And once exposed, every faction, devils included, would be forced to take action.
"For now, please keep this a secret." Leo said to Musashi. "I'm not ready to reveal it yet."
"Understood. I'll keep this quiet." Musashi agreed without hesitation. "As long as I'm still eating and staying here, I won't reveal anything on my own."
In other words, once she left the mansion and returned to the Underworld, she likely couldn't hide it anymore.
After all, she had to report her mission to her master.
So Musashi could only keep this secret for that long.
"That's enough."
Leo didn't intend to hide it forever. He just needed more time—to grow stronger, to ensure that when the truth came out, he could control the situation.
With that in mind, he asked Musashi a question.
"In your view… how strong am I right now?"