The Second Life of Demon King

Episode 4: The Mysterious Magic Teacher

The evening sky burned with golden hues as a black carriage came to a stop in front of the Ackerman manor. The air carried the lingering scent of morning rain, creating a cool atmosphere that contrasted with the tension creeping into Isaac’s heart.

From within the carriage, a tall man clad in a deep blue robe stepped out with graceful movements. Orland, a man known as one of the most respected mages in the kingdom, walked with an air of authority. His eyes—sharp blue like eternal ice—swept the surroundings with the calmness of someone who had seen much in life.

Isaac, sitting in the back garden with his older brother, observed from afar.

"A Magister? Father is really serious about this…"

He had assumed that the magic instructor sent to him would be an ordinary mage. But seeing Orland, who carried an almost undetectable aura, immediately put his instincts on high alert.

Orland stepped into the main hall, welcomed by the Ackerman family. Soon, Isaac was summoned to meet his new teacher.

Standing before Orland, the man studied him long and deep, as if searching for something hidden behind his eyes.

"You are Isaac Ackerman?" Orland asked, his voice deep and commanding.

Isaac maintained a neutral expression and nodded. "Yes, sir."

The man narrowed his eyes slightly, then gave a faint smile.

"I expect great things from you, young man."

However, Isaac sensed something else in the man's gaze—not expectation, but suspicion.

The First Lesson.

In the family's training room, the marble floor gleamed under the magical glow of crystal lamps. Shelves were filled with spellbooks, while embedded magic circles in the floor glowed faintly.

Isaac stood in the center of the room, facing Orland, who held a long staff adorned with a blue gemstone.

"Human magic is unlike anything you've imagined," Orland began, swinging his staff in the air. Immediately, glowing golden symbols appeared, forming a complex magic formation. "Spells are not just about power but also precision and understanding."

Isaac watched carefully.

"Human magic is more technical compared to demon magic. They rely on catalysts and written incantations to stabilize mana control."

Orland continued, "Now, try to focus your mana. Feel its flow."

Isaac raised his hand, pretending to struggle. He deliberately furrowed his brow and took a deep breath as if trying to grasp the instructions.

Orland observed him keenly.

"Interesting…" he murmured.

Isaac pretended not to hear the comment. He purposely concealed his extraordinary talent, yet he still felt Orland’s piercing gaze, as if the man knew something he wasn’t supposed to.

After several days of lessons with Orland, Isaac became more convinced that the man was not just an ordinary mage. He suspected something—and that made Isaac uneasy.

One night, under the dim glow of the moon, Isaac decided to sneak into the family library.

Dark hallways led to a vast room lined with towering bookshelves filled with ancient texts. Small candles flickered with dim light, casting long shadows on the stone walls.

He carefully scanned the shelves, his fingers brushing against the book spines, searching for something… missing.

"Something's not right."

Basic magic books were there, but when he tried to find more advanced texts…

Empty.

"This is strange. There should be more books here."

Several empty spaces on the shelves were conspicuous, as if someone had deliberately removed certain knowledge.

Isaac narrowed his eyes.

"Is my family hiding something from me?"

Curiosity drove him to search further. His fingers traced the wooden wall behind the shelves, tapping lightly to find any hidden gaps—

Tok. Tok.

A hollow sound.

Isaac smirked.

"Interesting."

He pressed against that part of the wall, and a mechanism shifted with a faint creak. The bookshelf slowly moved aside, revealing a hidden passage behind it.

The air inside was cold and damp, carrying the scent of old paper and stone. Without hesitation, he stepped inside, letting the darkness swallow him.

However, just as he took a few steps—

"I didn't expect you to find this place so quickly."

Isaac froze.

That voice… deep and calm, with a tone that was almost amused.

He turned around slowly, and there—standing at the entrance of the passage with a mysterious expression—was Orland.

The man’s blue eyes glowed under the candlelight.

Isaac remained composed, but in his mind, alarms blared.

"So he's really been watching me… Since when?"

Orland stepped forward, his hands clasped behind his back.

"You know, Isaac…" he said casually, "very few people realize that this library holds secrets."

Isaac concealed his surprise. He met the man’s gaze with a blank expression.

"And how do you know about this passage, sir?" he asked, attempting to turn the tables.

Orland smirked faintly.

"That's not the question you should be asking, kid."

Before Isaac could say more, Orland flicked his hand, and glowing magic symbols appeared in the air. In an instant, the air around Isaac grew heavy.

"He's trying to trap me with magic!"

But before Orland could complete his spell, Isaac moved.

With a speed unnatural for someone his age, he leaped back, taking cover behind the shelves, quickly devising a strategy.

"I can't reveal my true power… But I also can't let myself get caught."

Orland remained standing where he was, showing no signs of attacking further.

Instead, the man smiled, his eyes gleaming as if

he had just found a fascinating puzzle to solve.

"Interesting…" he murmured softly, as if Isaac had only made him even more curious.

Isaac barely had time to react when a large hand firmly gripped his shoulder. He was yanked backward, forced to turn and face Duke Reinhardt Ackerman—his own father.

The man's gaze was cold and sharp, like a drawn sword under the moonlight. His posture was upright, his expression stern and unreadable, and his piercing eyes carried enough weight to freeze anyone in place.

"Isaac." His voice was deep, almost like the rumble of an approaching storm. "What are you doing here?"

Isaac swallowed, but he couldn't show weakness. He met his father’s gaze, trying to maintain a relaxed expression.

"Just reading," he replied briefly, though it was clear that wouldn’t be convincing.

Reinhardt let out a quiet scoff, then glanced at the open bookshelf and the hidden passage behind it. His jaw tightened.

"You’re not supposed to be here."

Isaac felt the grip on his shoulder tighten as if his father was restraining himself from dragging him out immediately.

"What is this?" Isaac finally asked, breaking the heavy silence. "Why is there a secret passage in the family library? And why are so many books missing?"

Reinhardt exhaled sharply before releasing his grip with a rough motion. He stared at his son for a long moment before finally speaking, his voice lower but still full of authority.

"There are things you're not ready to know yet."

Isaac clenched his teeth. That answer was too vague. Too suspicious.

"I'm not a child anymore."

Reinhardt’s gaze sharpened. "You're still a child."

Tension filled the air between them. Isaac could sense a subtle magical pressure radiating from his father’s body. He knew Reinhardt wasn’t just an ordinary duke—he was also an exceptionally powerful mage.

After a long silence, Reinhardt spoke again, this time with a quieter tone.

"Our family... has a history far greater than it seems, Isaac. But if you dig too fast, you may not like what you find."

There was something strange in his father’s voice—not just a warning, but also fear.

Isaac clenched his fists.

"Then let me know," he said, his voice full of determination. "I want to understand who I really am."

Reinhardt was silent for a moment before slowly shaking his head.

"Not yet."

Then, without giving Isaac a chance to respond, he turned and walked away.

Isaac remained standing, watching his father’s back disappear into the darkness of the passage.

An unsatisfying answer.

But not a complete rejection either.

Isaac took a deep breath. If his family wouldn’t tell him, then he would find the answers himself.

After the incident in the library, Isaac became even more determined to strengthen himself.

He realized that despite having the experience of a Demon Overlord in his past life, his current human body had significant limitations.

A human's mana core was too small.

Too weak.

But that didn’t mean he couldn’t overcome it.

In his private training chamber, Isaac sat cross-legged on the cold stone floor. Moonlight streamed through the cracks in the window, casting a faint glow across the room.

He closed his eyes, focusing on the circulation of mana within his body.

"If I can’t store a lot of mana... then I just need to make it flow more efficiently."

Using a technique he had developed himself, he began reorganizing the flow of mana in his body, ensuring that no energy was wasted.

Sweat trickled down his temple.

His breathing grew heavier.

Every second felt like a battle against his own body's limits.

But when he finally opened his eyes, he could feel the change.

The mana in his body now flowed more smoothly, no longer hindered by the natural constraints of a human.

"It worked."

Isaac smirked slightly. Now, it was time to test it.

Far from anyone’s watchful eyes, Isaac stood in the manor’s back garden. The night was silent, filled only with the sound of wind rustling the leaves.

He raised his hand, slowly gathering mana into his palm.

A small flicker of fire appeared, then grew into a tiny flame dancing above his skin.

Isaac smiled in satisfaction.

But in that instant, a sharp dizziness stabbed through his head.

His body wavered, his legs weakened, and the world around him spun.

"Damn... I used too much mana."

His heart pounded as he struggled to steady himself, but his breath came in ragged gasps. The flame in his hand vanished instantly, but the exhaustion that followed was far worse than he had anticipated.

He fell to his knees, his hands gripping the damp earth to keep himself from collapsing entirely.

His body wasn’t ready for large-scale magic yet.

Isaac clenched his fist.

Frustration.

He knew the theory and techniques, but his physical form still couldn’t keep up.

"I need more time..."

Then, suddenly—

Footsteps echoed behind him.

Isaac immediately turned, despite his weakened state.

In the shadows beneath the trees, someone stood watching.

And a familiar voice cut through the air.

"I suspected as much."

Magister Orland.

The man's gaze was filled with curiosity.

Isaac swallowed hard, his mind racing.

"How much did he see?"

Orland stepped forward, his blue eyes gleaming in the dim light.

"A child shouldn’t be able to do that… unless they have extraordinary talent or…" Orland paused briefly, then smirked. "...something else."

Isaac tensed.

Orland knew something.

And that night, under the pale glow of the moon, Isaac realized—he could no longer hide himself completely.