The vast underground training hall thundered with explosions as demonic power surged through the air. The roaring energy rippled against the protective barriers, activating them in shimmering waves of light.
Booms echoed one after another. Blasts of raw demonic power streaked across the space—sometimes exploding like shells, sometimes weaving into intersecting beams, sometimes spinning out of control as chaotic orbs, and sometimes scattering into a storm of tiny arrows. The variety was dazzling.
Leo stood at the center, eyes focused, channeling his demonic power with precision. In his mind, he pictured countless scenes of destruction—then molded his power into cannon fire, arrows, beams, and massive bursts, unleashing them in turn.
The power of a High-Class Devil was nothing short of terrifying. A casual blast could flatten skyscrapers or carve out craters like meteor impacts. At full strength, a single strike could level an entire mountain. Few modern weapons could compare—if not quite nuclear-level, it was still among the most destructive forces beneath it.
If not for the training ground's powerful enchantments and reinforced construction, every brick and tile forged from special materials, Leo's reckless outpouring of energy would have turned the whole estate into scorched earth within seconds.
And yet, despite that frightening display of power, Leo didn't look the least bit satisfied.
"So this is all it takes to reach the level of a High-Class Devil… and I'm still so far from the next stage."
Feeling the rapid depletion of his demonic power, Leo sighed softly.
The hierarchy of devils was divided into five ranks: Low-Class Devil, Mid-Class Devil, High-Class Devil, Ultimate-Class Devil, and Maou.
A Low-Class Devil usually bore two wings, corresponding to two-winged angels and fallen angels.
A Mid-Class Devil typically had four wings.
By that pattern, a High-Class Devil had six, an Ultimate-Class Devil had eight or ten, and a Maou stood at the peak with twelve. Angels and fallen angels followed the same structure.
In general, the more wings one possessed, the higher the rank and the greater the strength—but that wasn't absolute.
Take Leo, for instance. He only had two wings, yet his power had already reached the High-Class Devil level, far surpassing what his rank would normally allow. It was a common flaw among young devils who grew too fast for their own good.
When your strength grew faster than your rank could evolve, imbalance followed. It wasn't unique to Leo—Sona was the same way.
Still, Leo's "rapid growth" wasn't really fast at all.
Thanks to the pureblood devil lineage flowing in half of his veins, he was born with demonic power far beyond that of a Low-Class Devil. When he began training at three years old, he was already considered among the best of the Mid-Class Devils. Even so, it had taken him fifteen long years to finally ascend to the High-Class rank—a pace that, in truth, was rather slow.
Sona had once comforted him about that…
"Devils live for a very long time. Even the lowest among us can survive for thousands, even tens of thousands of years. Yet most will never reach the High-Class level. You and I, born with pureblood power and reaching this level in barely over a decade—that alone is something others envy."
She wasn't wrong. Compared to a lifespan stretching tens of thousands of years, a decade or two was like infancy.
Reaching High-Class at his age was a privilege reserved almost exclusively for pureblood devils. The rest—half-bloods, mixed-bloods, and reincarnated devils from other races—might never even glimpse this realm in their entire lives. By all accounts, Leo was lucky.
But he still wasn't satisfied.
He knew just how terrifying the strongest beings in this world truly were—and how much strength he would need to face the crises that lay ahead.
High-Class Devil? That was just the entry ticket for what was coming. Sometimes, not even enough to get through the door.
In the eyes of true powerhouses, a so-called High-Class Devil was no more than an insect.
Even an eight-winged Ultimate-Class Devil could crush a High-Class Devil with one hand—never mind the Maou-Class, or those beyond even that.
The devil hierarchy was strict, and the gap between each level was enormous.
Take, for example, one of the future Heavenly Dragons—the Red Dragon Emperor. When he was still a Low-Class Devil, he could use his Sacred Gear to double his power every ten seconds. After just two minutes, his strength multiplied by 8,190 times… and even that only let him deliver a blow comparable to a High-Class Devil. That alone showed how vast the gap was—like an ant trying to fight an elephant. Two ranks apart might as well be an unbridgeable chasm.
Likewise, even a newly ascended eight-winged Ultimate-Class Devil would be a hundred times stronger than Leo. And if the opponent was a ten-winged one? That was another rank higher—another impossible gulf.
At Leo's current pace, breaking through to the Ultimate-Class level might take hundreds, maybe even thousands of years.
But within a few short years, the entire underworld would be thrown into chaos—and even Ultimate-Class strength might not be enough to survive.
So how could he possibly be satisfied with what he had now?
"...Haa."
Drawing his drained demonic power back into his body, Leo exhaled quietly and murmured to himself.
"I can't keep growing this way. The old methods won't cut it anymore."
No—if he wanted to get stronger, he'd have to rely on the Evil Pieces. On gathering powerful, talented servants who could help him grow.
At least, for Leo, that was the only path forward.
"Training can wait."
He retracted his devil wings, landed lightly on the ground, and turned toward the exit.
Right now, his priority lay elsewhere—with that cold, distant underclassman.
Sobu High, Class 3-C.
Just before the bell rang, Leo strolled into the classroom with his usual relaxed gait, greeted by a chorus of voices.
"Good afternoon, Leo."
"Good afternoon, Eligos."
"Good afternoon, Eligos-san."
The girls, who had been chatting in small groups, instantly lit up at his arrival. Their greetings came all at once, warm and enthusiastic.
"Hey there, everyone~"
Leo smiled brightly as he replied, his easy charm making several girls blush on the spot.
The boys, however, grumbled under their breath.
"Why does a guy get to smile that good?"
That radiant grin of his carried an effortless magnetism, almost intoxicating. Even the boys found it hard not to react—it was as if that blinding light exposed their darker thoughts, leaving them uneasy and conflicted.
If only they knew.
That dazzling smile belonged to someone who, beneath the surface, was a devil—one who represented everything dark and twisted in human imagination.
But even as a devil, Leo was the heir to a pureblood noble line. The Eligos House might be nearly extinct, yet the centuries of aristocratic grace still clung to him. His looks alone were enough to make him nearly flawless.
Of course, there was always someone who remained completely unmoved.
Sitting by the window, a girl quietly read a book, seemingly lost in her own world.
She was stunning—no less beautiful than Yukino herself. Her long black hair fell straight down her back, accented by a white headband. Tall and elegantly curved, her every motion carried a gentle refinement. Even sitting still, she drew the admiration of half the class without trying.
Watching her, Leo's lips curved into a faint smile. He walked over and took the seat beside her.
"Good afternoon. Still radiating that literary charm as always, Utaha-san."
Leo greeted her cheerfully.
"Good afternoon to you too. And you're still as impossibly self-absorbed as ever, Leo-san."
Utaha looked up from her book, her dark red eyes glinting as she delivered that sharp line—words as poised and cutting as her elegance.