Leo's manor — underground training chamber.
When daylight began to push away the remnants of night, Leo was already training in the basement.
It was Saturday. No school. Instead of waking up, having breakfast, and heading to Sobu High like usual, he had gone straight to the underground training room the moment he opened his eyes.
"Rumble—"
Thunderous echoes shook the ceiling as thick, stormy clouds spiraled into existence overhead. Lightning crackled within them, making the air heavy and oppressive, like a storm about to burst.
Leo stood beneath the swirling clouds, three pairs of devil wings unfurled behind him. A fierce aura burned off his body as demonic power surged upward into the man-made sky, calling bolt after bolt of lightning down like a torrential downpour.
But none of the lightning struck the ground.
As if guided by an invisible force, every bolt veered mid-fall and converged around Leo, condensing into bright, pulsing spheres of electricity.
Spherical lightning danced around him—above, below, weaving through the chamber with dazzling brilliance, like the living servants of a storm god.
"Again."
Feeling he still had energy to spare, Leo urged Zenith Tempest forward and activated its second attribute—fire.
In an instant, waves of scorching flames erupted like a series of explosions. Under Leo's control, the fire gathered just like the lightning, shaping itself into blazing fireballs that orbited beside the crackling spheres of lightning.
Blue-white lightning. Crimson fire.
The entire underground chamber was drowned in those two colors.
"Boom!"
A lightning sphere collided with a fireball, detonating in midair.
"Boom!" "Boom!" "Boom!" "Boom!" "Boom!"…
The explosion triggered a chain reaction. One after another, lightning spheres and fireballs slammed into each other, unleashing a storm of continuous, deafening blasts.
Fire and lightning exploded everywhere, lighting the chamber in a chaotic festival of destruction.
"Ha…"
Only when every sphere had clashed and vanished did Leo exhale, a satisfied smile on his lips.
"Zenith Tempest really is a Sacred Gear with endless potential. Just inheriting the past users' memories—just making my usage more versatile and refined—was enough to boost its power by several tiers. It's unbelievable."
As he grew more skilled with Zenith Tempest, his understanding of the world's second-strongest Longinus deepened.
To Leo, the Sacred Gear wasn't even close to reaching its Balance Breaker form yet. His mastery was far from perfect. And still, its current power could already threaten opponents one or two tiers above him—absurd strength for something a human could theoretically wield.
"No wonder everyone questions why God would create something like this. Normal Sacred Gears aside, a Longinus really can overturn the balance of the world. Saying it can kill gods and Maou isn't an exaggeration. Hard to believe God made something that could threaten even Him."
Next to Zenith Tempest, the devil abilities that had shocked Sona Sitri and Sharon Holygrail seemed trivial—completely overshadowed.
Of course, without his current level of demonic power, he wouldn't be able to wield Zenith Tempest so freely.
Sacred Gears typically consumed stamina, which was why humans could use them. But beings with supernatural power could substitute that stamina with their own energy.
Leo was one such being—his demonic power was so vast it completely replaced stamina as fuel. And the stronger the energy he poured in, the stronger the Sacred Gear became. Longer-lasting. More destructive.
Unlike that Red Dragon Emperor, whose infinite boosting ability was wasted because he could barely handle it. A truly tragic case of wasted potential.
Leo's near–High-Class Devil–limit power was one of the main reasons Zenith Tempest could already unleash such terrifying force.
"If my next servants give me another boost in Sacred Gear compatibility… two more with mid-tier potential might be enough to bring Zenith Tempest to its peak."
"If I find one with high potential, even one might do."
"Then I can move on to the next stage—reaching Balance Breaker."
Balance Breaker was the true culmination of a Sacred Gear. The power capable of distorting the balance of the world.
A user before Balance Breaker and a user after it were not even in the same category. Even without activating Balance Breaker, a post-Balance Breaker user could easily overwhelm an ordinary one.
Reaching Balance Breaker with Zenith Tempest… Leo estimated he could at least stand against a Maou-Class existence.
"Shame good servants are so rare."
Leo folded away his devil wings and landed with a sigh.
Forget high-potential servants—he barely had leads on even mid-potential ones.
Sona Sitri had been right. Sobu High was a school overflowing with hidden talent. Aside from Yukino, there were probably one or two more Sacred Gear users who hadn't awakened yet.
Sacred Gear users were extremely rare. Having multiple unawakened ones in a single school was almost absurd.
That was why Leo still chose to attend Sobu High.
Otherwise, he would've already considered returning to the Underworld to rebuild the Eligos territory, abandoned for who knew how many years.
"Maybe it's time to speed things up."
Thinking about the promising candidate he'd been watching, Leo felt a spark of anticipation.
"Are you done?"
Yukino arrived while he was lost in thought, walking toward him.
"More or less." Leo snapped out of his thoughts and nodded. "You coming to train too?"
"I'll come after lunch." Yukino explained her schedule, then added, "I came to tell you—your new servant woke up."
"Want to go see her?"
Leo raised a brow and turned toward the exit.
"Let's go welcome our new teammate."
...
On the manor's third floor, inside a room different from the one Yukino had used but equally extravagant, a girl sat on the bed, staring blankly out the window.
Leo and Yukino stepped inside quietly, subconsciously softening their movements.
Even so, the girl sensed their presence and turned toward the door.
Chestnut-colored hair shifted with her movement. Then Leo saw her hazel eyes—not particularly bright, but carrying a warm kind of clarity.
"You are…?"
The girl froze for a second, likely struck by Leo's unnaturally attractive appearance. Her voice was soft and clear when she spoke.
Leo didn't answer immediately. Instead, he walked in with Yukino, pulled a chair over, and sat by the bedside.
"How do you feel?" Leo met her eyes, smiling lightly. "Anything hurt?"
"Um…" She hesitated, then decided to answer honestly. "It doesn't hurt, but… I feel really sleepy. And sunlight feels uncomfortable."
Yukino couldn't help nodding along.
She remembered her own awakening clearly—no pain, but her body had felt strange, sluggish during the day, and sunlight had been unpleasant.
Now she had adapted, and it was the newcomer's turn to walk the same path.
Yukino felt a small, complicated sense of nostalgia.
Did that make her a senpai now?
Maybe she could talk to the girl later, explain how she got through her own early days.
"This is normal. Nothing to worry about." Leo didn't reveal the whole truth yet. He simply smiled. "Once you get used to it, you'll feel stronger—better than before."
Yukino quietly rolled her eyes at the chuunibyou-like line.
The girl, however, leaned forward eagerly.
"Did you save me?" she asked. "This doesn't look like a hospital. Is this some kind of private treatment facility?"
"Not at all." Leo still didn't answer her core question. "This is my home. You're in one of my rooms—not in a hospital or private clinic."
"Y-your home?" She blinked, startled, then tensed slightly. "Then you are…?"
"My name is Leo Eligos. Third-year at Sobu High." He decided there was no need to keep teasing her. "Just call me Leo."
"Leo-san." She didn't drop the honorific, greeting him politely before introducing herself. "I'm Yuuki Asuna. I live in Setagaya Ward, Tokyo, and I'm currently a second-year student at a private academy there."
She didn't mention the school name—it wasn't relevant, and someone living in Chiba Prefecture likely wouldn't know it anyway.
Still, she had revealed her full name and location. Cautious but trusting.
Even if he had ill intent, anyone who knew the Yuuki family would think twice.
"Yuuki, huh?"
Leo looked at the familiar yet unfamiliar girl and let out a soft sigh.
"Quite the famous name."