Leo's mansion, underground training room...
As dawn broke and daylight replaced the darkness illuminating the land, Leo was training in the basement.
Today was Saturday, and there was no school, so Leo, unlike his usual routine, didn't prepare breakfast and head to school after waking up; instead, he went straight to the basement.
"Rumble—"
The basement ceiling swirled with thick, dark clouds like a vortex amidst thunderous roars, streaks of lightning flashing within them, making the entire basement's atmosphere as oppressive as before a storm.
Leo, with three pairs of demon wings spread, stood beneath the dark clouds, terrifying aura burning around him, magic power pouring into the sky like a torrent, causing bolts of thunder to fall like heavy rain.
However, the falling lightning didn't directly strike the ground; instead, as if guided by an invisible force, it all gathered around Leo, transforming into dazzling balls of lightning.
The spherical lightning danced up and down around Leo, incredibly mesmerizing, as if obeying the command of the Lord of Thunder, moving back and forth through the entire basement space with unparalleled agility.
"Again!"
Leo felt he still had energy, so he immediately activated Blazing Heaven Thunder Prison, triggering its second attribute—fire.
Instantly, endless flames appeared out of thin air, bursting forth like an explosion, yet under Leo's control, they, like the lightning, converged around him, turning into fireballs.
Lightning balls and fireballs intertwined, making blue-white and crimson the dominant colors of the entire basement.
"Bang!"
The next moment, a lightning ball and a fireball suddenly collided, causing a roar.
"Bang!" "Bang!" "Bang!" "Bang!" "Bang!"...
As if triggering a chain reaction, the lightning balls and fireballs flying in mid-air immediately went wild, colliding with each other one by one, creating an unending series of roars.
Flashes of fire and lightning instantly appeared in all directions, making the space around Leo seem like an explosion feast, with roars everywhere, and fire and lightning everywhere.
"Hoo..."
Only when all the lightning balls and fireballs had collided and disappeared one by one in mid-air did Leo exhale a breath and smile.
"Blazing Heaven Thunder Prison is indeed a Sacred Gear with endless potential. I merely gained the usage memories of past wielders, and my application methods became more varied and proficient, yet the power of this Sacred Gear has risen by several levels, which is simply incredible."
As his proficiency with Blazing Heaven Thunder Prison grew, Leo gradually gained a whole new understanding of the power of this second-ranked god-slaying tool in the world.
In his opinion, Blazing Heaven Thunder Prison hasn't even reached the realm of Balance Breaker yet, and his mastery over it isn't at its peak. Yet, even so, the power of this Sacred Gear is enough to threaten beings one or two levels higher than Leo, with a power so immense that it's hard to imagine it's something humans can possess.
"No wonder so many people are puzzled as to why God would create such a thing. Leaving aside ordinary Sacred Gears, god-slaying tools truly have the ability to disrupt the world's balance, and being able to eliminate Gods and Demon Lords is not an exaggeration, making it hard to believe that God would create such a power that could threaten himself."
Compared to Blazing Heaven Thunder Prison, Leo's demonic abilities, which surprised Sona Sitri and Saron, were nothing; they could even be called insignificant.
Of course, if Leo didn't have his current magic power, it would probably be difficult for him to use the power of Blazing Heaven Thunder Prison so freely, right?
After all, the most basic consumption for using a Sacred Gear is stamina, which is why humans can use this power, but if one masters extraordinary power, those powers can also be used as a substitute for consumption.
This is exactly Leo's situation; his magic power is so strong that it can completely replace stamina as the consumption for using a Sacred Gear. The stronger his magic output, the greater the power of the Sacred Gear, and the longer its sustained use, unlike the Red Dragon Emperor, who, despite possessing the power to endlessly strengthen himself, can barely utilize it due to his own insufficient abilities, which is simply a waste of natural resources.
Therefore, Leo's power, which is close to the limit of a High-Class Devil, is also one of the main factors allowing Blazing Heaven Thunder Prison to exert its current power. This is the foundation for using a Sacred Gear, and naturally, the stronger, the better.
"If I can still get feedback on Sacred Gear proficiency when recruiting new Retainers in the future, then two Retainers with medium potential should be enough for me to maximize the power of Blazing Heaven Thunder Prison."
"If it's a Retainer with high potential, even one might be enough."
"Then, I can proceed to the next stage and start figuring out how to reach Balance Breaker."
Balance Breaker is the ultimate realm of a Sacred Gear, a power truly capable of disrupting the world's balance.
A Sacred Gear Holder before reaching Balance Breaker and a Sacred Gear Holder after reaching Balance Breaker are completely on different levels; the latter, even without using their Balance Breaker ability, could probably suppress the former, even engaging in a stylish beatdown.
And once Blazing Heaven Thunder Prison's Balance Breaker is achieved, Leo's strength will at least be able to contend with a Demon Lord-level existence.
"Unfortunately, excellent Retainers are rare."
Leo folded his wings, landed on the ground, and sighed with emotion.
Let alone Retainers with high potential, even for those with medium potential, Leo currently only knows of one more person.
Sona Sitri was indeed correct; Sobu High School is a very promising school. Besides Yukinoshita Yukino, there are probably one or two other Sacred Gear Holders hidden there, none of whom have awakened yet.
Sacred Gear Holders are rare existences, yet Sobu High School contains multiple such hidden talents, which is truly incredible.
This is also why Leo still insists on attending Sobu High School; otherwise, he would have long been considering returning to the Underworld to develop the Erigor Family's territory, which has been neglected for who knows how many years.
"Perhaps I should speed things up a bit."
Thinking of the potential stock he had been in contact with, Leo felt a bit restless.
"Are you done?"
Yukinoshita Yukino came into the basement while Leo was deep in thought, walking towards him.
"Mostly," Leo came back to his senses, nodded at Yukinoshita Yukino, and said, "Are you going to train too?"
"I'll come after lunch," Yukinoshita Yukino revealed her schedule and added, "I came to tell you that your new Retainer has woken up."
"Do you want to go see her?"
Upon hearing this, Leo raised an eyebrow and turned around.
"Let's go, let's welcome our new companion."
...On the third floor of the mansion, in a room different from the type Yukinoshita Yukino had used before, yet equally luxurious, the girl sat on the bed, looking at the scenery outside the window, lost in thought for a long time.
Leo brought Yukinoshita Yukino here, and seeing this scene, he unconsciously lightened his steps and movements.
But the girl seemed to have noticed Leo and Yukinoshita Yukino's arrival anyway, turning her head to look at the doorway.
Her chestnut-colored long hair swayed with the girl's movement, and then Leo saw a pair of hazel eyes, not particularly bright, yet full of a unique radiance.
"You are...?"
The girl was also momentarily stunned by Leo's striking appearance, then spoke in confusion, her voice clear and gentle.
Leo didn't answer the girl's question. Instead, he and the silent Yukinoshita Yukino walked into the room, came to the bed, and pulled up a chair to sit down.
"How do you feel?" Leo met the girl's beautiful big eyes with his gaze, smiling as he spoke, "Does anything hurt?"
"Um..." The girl hesitated for a moment, then decided to tell the truth, saying softly, "It doesn't hurt, but I feel very sleepy, and the sunlight doesn't feel very comfortable."
Hearing this, Yukinoshita Yukino couldn't help but show a look of understanding.
She recalled that when she had just been reincarnated as a demon, she felt the same way—no pain, but her body felt strange, she had little energy during the day, and she was averse to sunlight.
Now that she had endured it, it was the newcomer's turn to follow her old path, which made Yukinoshita Yukino quite reflective.
She was, after all, a senior now, wasn't she?
Later, she could chat with this Yuuki Family young lady and let her know that she had gone through the same experience.
"This is normal, you don't need to worry," Leo didn't immediately reveal everything, continuing with a smile, "Once you get used to it, you'll feel that you've not only gotten better but also stronger."
This somewhat chuunibyou statement made Yukinoshita Yukino unconsciously curl her lips.
The girl, on the other hand, asked eagerly.
"Did you save me?" The girl, eager to know her current situation, asked, "This doesn't seem to be a hospital; is it some private sanatorium?"
"Neither, actually," Leo still didn't answer the girl's most pressing question, saying with a smile, "This is my home, and you are currently in one of the rooms in my house, not some private sanatorium."
"Your, your home?" The girl was a little surprised, and a little unnaturally wary, saying, "Then you are...?"
"My name is Leo Erigid, a third-year student at Sobu High School," Leo no longer kept her in suspense, saying, "You can just call me Leo."
"Mr. Leo," The girl didn't comply, greeting him very respectfully before introducing herself, "I am Yuuki Asuna, living in Setagaya Ward, Tokyo, and currently a second-year student at a private aristocratic school there."
She didn't reveal the school's name because she felt it wasn't necessary.
After all, she lived in Tokyo, and this was Chiba; even if she mentioned the school's name, the other party might not know it.
But the girl still revealed her name and address, which showed that despite her wariness, she still chose to believe that Leo had no ill intentions towards her.
Even if he did, hearing her surname should make him hesitate a bit, right?
"Yuuki, huh?"
Leo looked at the girl before him, who seemed both familiar and unfamiliar, and sighed.
"Indeed, it's a famous name."
You can visit my Patreon to read more chapters of the book.
patreon.com/02Fanworks