The Strongest Demon Lord Reincarnated as a Commoner

The ridicule followed Leo like a shadow.

As the new students were guided through the grand, echoing halls of Aethelgard towards their designated dormitories, whispers and snickers trailed in his wake.

"That's him! The 'Orb-Breaker'!"

"I heard he's the first student in history to register a zero."

"My father told me commoners have diluted blood. Guess he was right."

"Pathetic. He'll be expelled within a week."

Leo ignored them all, his expression a mask of bored indifference. He had endured millennia of cosmic warfare and the deafening silence of absolute solitude; the idle chatter of children was less than background noise to him. His only concern was the administrative headache he had caused. Bureaucracy, Azeros's slumbering consciousness grumbled, the one force in the universe more tedious than omnipotence.

The dormitories were segregated by social standing, a fact that surprised Leo not at all. The nobles were assigned to the opulent Azure Spire, a tower that seemed to be woven from glass and moonlight. The merchant-class students went to the comfortable Garnet Hall. And the commoners, the scholarship students, were led to a sturdy but stark stone building at the edge of the campus known simply as the 'East Barracks'.

"This is it," the guide, a bored-looking second-year, announced, gesturing to a plain wooden door. "Find a vacant room. Rules are on the notice board. Don't cause trouble for the nobles. Good luck."

With that, he was gone, leaving the handful of commoner students to fend for themselves.

Leo found an empty room at the far end of the hall. It was small and spartan: a hard-looking bed, a rickety wooden desk, and a small wardrobe. A single window looked out not upon the beautiful campus, but towards the dense, dark woods that bordered the academy grounds.

Perfect, Leo thought. It was quiet. Secluded. Minimal chance of unwanted interaction.

He dropped his small bag on the floor and collapsed onto the bed, which groaned in protest. He closed his eyes, intending to spend the rest of the day in a state of semi-conscious oblivion. The world, however, had other plans.

A timid knock came from his door.

Leo let out an almost inaudible sigh of irritation. He didn't move. Perhaps if he ignored it, it would go away.

The knock came again, softer this time, more hesitant. It was followed by a small, trembling voice.

"U-um... excuse me? Is anyone in there?"

Recognizing the voice would require effort, so Leo remained silent. The doorknob rattled. He had forgotten to lock it. The door creaked open, and a head of shimmering, silver hair peeked inside.

It was the shy girl from the carriage. The one he had vaguely registered as being the target of some low-grade bullying. Her name, he recalled from the proctor's announcements, was Luna Brightwood. Her eyes, the color of amethysts, widened in fear when she saw him lying on the bed.

"Oh! I'm so, so sorry!" she squeaked, immediately trying to pull the door shut. "I thought this room was empty! I'll leave right away!"

"It's fine," Leo said, his voice flat. He didn't sit up. "What do you want?"

His bluntness seemed to startle her. She clutched the hem of her simple tunic, her knuckles white. "I... I just... I wanted to thank you."

This managed to pique a sliver of Leo's interest. He cracked open an eye. "For what?"

"In the line... for the test," she stammered, looking at the floor. "That noble, Marcus... he was about to start on me next. But then... then he got distracted by you. So... thank you."

Leo processed this. He had inadvertently helped her by becoming a more prominent target for ridicule. It was a chain of events so mundanely ironic that it was almost amusing.

"Don't mention it," he said, closing his eye again. "It wasn't intentional."

"Still!" she insisted, taking a hesitant step into the room. "And... I don't believe what they're saying. About you having zero magic."

"Why not?"

"Because..." She looked up, and for the first time, he saw a spark of defiance in her timid eyes. "When you put your hand on the orb, I felt it. Just for a second. It wasn't like the others. It wasn't a push... it was like... like the whole world went quiet."

Leo's mind, the ancient super-processor that was Azeros, went on high alert. This girl, this seemingly insignificant, shy commoner... had sensed him? Not his power, no, that was impossible. But she had sensed the effect of his suppression—the absolute nullification of ambient energy in his immediate vicinity. Her innate magical sensitivity was astronomical. Far greater than the "Grade 7" noble or even the fiery duchess.

Interesting, he thought. A genuine flicker of academic curiosity.

"You're imagining things," he said out loud, his tone dismissive. He needed her to drop it. A person with that level of sensitivity was a liability to his quiet life.

Luna flinched as if struck. Her brief moment of confidence crumbled. "Oh. Y-yes... of course. I'm sorry to have bothered you." She bowed quickly and scurried out, pulling the door shut behind her with a soft click.

Leo listened to her footsteps retreat down the hall. For the first time since his reincarnation, he felt a sliver of something other than boredom or irritation. It was a complex, unfamiliar mix of surprise and... something else. Pity, perhaps? The girl was a diamond buried in mud, and the world would likely crush her for it.

Not my problem, he decided, and let sleep claim him.

The next day, the true academy life began. First on the schedule: "Basic Mana Theory" with Ms. Isabella Croft.

Leo ambled into the lecture hall and chose a seat in the back corner, the traditional sanctuary of the unmotivated. The hall was already buzzing. Marcus von Adler was loudly recounting the tale of the "Orb-Breaker," embellishing it with every telling. Elara von Valerius sat in the front row, radiating an aura of cold perfection. Luna Brightwood was huddled in a corner by herself, looking as though she wished the floor would swallow her.

The door snapped open, and a sharp silence fell as Ms. Croft strode in. She was a strikingly beautiful woman in her late twenties, with her dark hair pulled back into a severe bun and sharp, intelligent eyes behind a pair of spectacles. She carried an air of no-nonsense authority that instantly commanded respect.

"Welcome to Basic Mana Theory," she began, her voice crisp and clear. "Here, you will learn the fundamental laws that govern the very fabric of our world. Magic is not an art; it is a science. It has rules. It has limits. Those who ignore them meet disastrous ends."

Her gaze swept across the room, lingering for a half-second longer on Leo. It was a look of professional disapproval. She had read the proctor's report.

The lecture began. Ms. Croft was a brilliant teacher—concise, logical, and thorough. She spoke of mana circulation, atmospheric density, and elemental conversion formulas.

Most students were scribbling notes furiously. Elara looked engaged. Marcus looked bored.

Leo was fighting to stay awake. These "fundamental laws" were, to him, like a child's crayon drawing of the cosmos. He had written the real laws. He had broken them. He had rewritten them again for sport. He could feel the infinitesimally small flaws in every equation she presented, the exceptions to every rule she declared absolute.

"Now," Ms. Croft said, turning from the blackboard. "Let's discuss a practical application. The 'Flare' cantrip. It is the simplest manifestation of raw mana. Who can tell me the primary limiting factor in the Flare's brightness?"

Elara's hand shot up. "The caster's Mana Output Rate, ma'am. Governed by their core's purity and their personal circulation efficiency."

"Correct, Ms. Valerius," Ms. Croft nodded, a hint of approval in her tone. "It is a direct, linear relationship. More output equals a brighter flare. It is a fundamental law. The energy you put in is the light you get out."

She then decided to make an example. Her eyes scanned the room and landed squarely on the student whose very presence was an affront to magical science.

"Mr. Vance."

Leo blinked, pulling himself from the brink of sleep. "Yes?"

"Please, stand and demonstrate a Flare cantrip for the class."

A wave of snickers rippled through the hall. It was a cruel, targeted move. Asking the boy with zero aptitude to perform a magic spell.

Leo stood up slowly. "I'm not sure I can." It was the truth. Creating something so pathetically small, so constrained by false rules, was infinitely harder for him than unmaking a star.

"Try," Ms. Croft insisted, her tone leaving no room for argument.

Leo sighed. Fine. He held out his hand. He remembered the diagram from the textbook she had referenced. He focused his mind, not on his own power, but on the ambient mana floating in the air of the classroom—the free-roaming energy that every mage drew upon.

Instead of forcing his own energy out, he simply... gave the ambient mana a nudge. A suggestion. A gentle rearrangement of local reality.

'You want to be a small light,' he thought at the particles. 'Right here. In my palm.'

And the mana obeyed.

A small, gentle light bloomed in his palm. It wasn't bright. It wasn't impressive. It was a soft, warm, golden glow, about as luminous as a candle flame.

The classroom fell silent.

Ms. Croft's eyes widened behind her glasses. Marcus's jaw hung open. It was magic. Undeniable, albeit pitifully weak, magic. From the boy with zero aptitude. It contradicted the test. It contradicted everything.

"H-How...?" Ms. Croft stammered, her professional composure cracking for the first time. "The test... it showed you have no core output. It should be impossible."

Leo looked at the gentle light in his hand, then back at her, and offered the most logical, infuriatingly simple explanation he could think of.

"You said magic is science," he stated, his voice flat. "And science is about efficiency. Why would I use my own energy when there's so much of it just floating around for free?"

He extinguished the light and sat down.

The silence in the room was now of a different kind. It was not mockery. It was profound, utter confusion. What he said was so simple, so logical, yet it flew in the face of centuries of magical doctrine. Mages used their own internal mana. That was how it worked. Using ambient mana directly was like trying to build a castle out of fog—theoretically possible, but practically insane. It required a level of control that even Archmages didn't possess.

Ms. Croft stared at him, her mind racing. Was he a once-in-a-generation genius who had instinctively grasped a new form of magic? Or was he an idiot who had stumbled upon a dangerous fluke he couldn't replicate?

Elara von Valerius watched him, her emerald eyes narrowed in thought. The humiliation of the "Orb-Breaker" had been replaced by a vexing puzzle. His logic was absurd, yet she had seen the result with her own eyes. For the first time in her life, a commoner had presented her with a problem she couldn't immediately solve.

And in her seat, Luna Brightwood looked at Leo not with fear or pity, but with a dawning awe. He hadn't just proven them wrong. He had done it calmly, logically, and without a trace of arrogance. He was... different.

Leo, oblivious to the paradigm shift he had just triggered, leaned back in his chair, hoping he had now satisfied the teacher's curiosity and could be left alone for the remainder of the class.

He just wanted a nap.

But in the world of Aethelgard, the lazy commoner had just taken his second, calamitous step out of the shadows. And the consequences were already beginning to ripple.