I Was Mistaken as a Genius Mage in a Game

Behind the heavily armored guards, whose armor was soaked with the scent of blood, a massive bolt of lightning suddenly struck down.

Even though the lightning had erupted from behind them, its brilliance was so intense that the guards facing forward were momentarily blinded.

"......"

Hans, the captain of the guards, who had been standing at the very rear delivering his final speech, turned his now-recovering gaze toward the point where the lightning had struck, his face frozen in shock.

There, standing in that very spot, was the white-haired boy to whom he had given bread.

Dressed in rags barely distinguishable from tattered cloth, the boy had taken the full force of the lightning strike with his bare body—yet his limbs remained perfectly intact.

…No, it wasn’t just that his limbs were intact.

His entire body was radiating a blue light.

And with every step he took, small bolts of lightning burst forth, scorching the ground beneath him.

"Would you kindly step aside?"

The boy spoke in a calm and composed voice as he slowly walked toward the center of the battlefield.

Not a single guard dared to block his path.

His expression was serene, almost like that of a sage who had transcended all things—cold and unshaken.

The air currents around him trembled with each of his small steps. The dark clouds that blanketed the sky rumbled ominously, as if they could release another bolt of lightning at any moment.

"It’s something I’ve always wanted to try."

With those cryptic words, which neither Hans nor the other guards could comprehend, the boy continued his dignified march toward the heart of the battlefield.

"…Are you a mage?"

Hans, still in shock, absentmindedly asked while staring at the boy’s back.

"Well, for now, I suppose I am."

The boy leisurely replied, running his hands through his hair, which kept rising due to the static electricity.

"Who are you? There's no way a mage resides in this small town."

From the midst of the mutants, a demon slowly emerged from the mass of flesh and gazed at the boy.

The demon, with skin shifting between green and red hues, could not conceal his bewilderment as he observed the boy.

"Where did you come from…? The reinforcements shouldn’t be arriving for several more days."

The demon’s words were accurate. Just an hour or two ago, there hadn’t been a single mage in this city.

"That’s something I’m curious about as well. I was just born a moment ago, and here I am in this city."

The boy’s voice was cold and detached, making it clear he had no intention of explaining himself further.

"Is that supposed to be a joke? It’s not very funny."

"…I actually meant it quite sincerely."

Realizing he wouldn’t be able to extract any useful information from the boy, the demon abandoned the attempt. The boy clearly had no interest in engaging in proper conversation.

Instead, the demon quietly began to observe him.

The boy was young. At most, he appeared to be around sixteen or seventeen.

‘At his age, there’s no way he received proper training from a magic tower. He’d barely qualify as an apprentice… And judging by his ragged appearance, he’s clearly one of the vagabonds from the streets.’

From what the demon knew, vagabonds were usually too unintelligent to even learn how to read, let alone practice magic.

"…This is strange."

And yet, the boy before him unmistakably possessed the power to wield lightning magic.

A mysterious sense of unease crept through the demon’s red skin.

Narrowing his eyes, the demon activated his innate ability to perceive magical energy and examined the amount of mana within the boy’s body. He needed to identify the source of this anomaly.

‘His mana level isn’t particularly extraordinary…’

The boy’s mana reserves were comparable to those of a mid-tier mage, roughly at the level of a 4th-circle practitioner.

Given his age and status, that was certainly impressive, but it was far from sufficient to take on the demon and his army of mutants alone.

‘…However.’

Boom!

A colossal bolt of lightning struck the ground beside the boy from the dark clouds above.

The 1-billion-volt energy arced through the ionized air, carving a massive crater into the blood-soaked earth.

Despite the lightning striking mere inches from where he stood, the boy showed not the slightest hint of surprise.

In his blue eyes, there was an unexplainable madness—an obsession—that made it clear he had no intention of letting the demon leave alive.

‘Considering his mana reserves, the precision of his magic is absurdly high. On top of that, his fighting spirit is far beyond what’s normal for someone his age. There are too many anomalies for him to be just a regular 4th-circle mage.’

Feeling the tension of an irregularity that defied all his prior knowledge, the demon took a deep breath and carefully adjusted his stance.

"Let’s see how capable you are."

Scanning the countless mutants surrounding him, the demon raised a finger toward the lone, white-haired boy.

"Kill…"

"Mom! M-Mom! Moooooom!"

"Estella watches over me, grant these souls salvation…!"

"Ki-Kill. Kill. Kill… Kill me…!"

With staggering, unstable steps, the mutants forcefully pushed off the ground and charged toward the boy.

Every single one of them had lost their human form.

Those who had lost their arms and replaced them with sharp blades, those whose heads had been compressed horizontally as if by a hydraulic press, those who had lost all their bones and now moved like amorphous masses of flesh.

They all retained a faint consciousness.

The cunning demons who transformed intelligent beings like humans and elves into mutants deliberately left traces of their minds intact.

They knew all too well that the screams of mutants would plant hesitation in the hearts of their enemies.

The boy’s frozen expression twisted slightly. A visceral disgust, inevitable for any human, welled up from deep within him.

Crackle...!

Raising his left arm carefully, he prepared to end their suffering as painlessly as possible.

A thin, razor-sharp flash of light descended upon the battlefield, instantly reducing all the charging mutants to white ash.

"…This is beyond reason."

The demon, watching his carefully crafted mutants be reduced to ash in a single blow, came to a conclusion.

"…No matter how I think about it, you must be hiding your true mana reserves."

The precision and power of the magic the boy had displayed were unfathomable for a mere 4th-circle mage.

Moreover, the boy had been staring at the demon with piercing eyes, as if already certain of his victory.

His gaze held an intensity beyond mere determination.

It was an unsettling mixture of madness, obsession, and deep-seated hatred.

‘Most young mages would be terrified at the sight of demons and mutants. But those eyes… They resemble the gaze of a predator hunting its prey.’

Dangerous.

Through careful observation and instinct, the demon realized that this boy was not someone he could handle alone.

"There’s nothing more to see. I need to retreat."

Without hesitation, the demon chose to flee. No demon was foolish enough to provoke an opponent whose strength was beyond comprehension.

Having made his decision, he unfurled the wings hidden on his back. As he took to the air, he gestured toward his army, sending countless mutants charging at the boy.

It was a waste to lose his forces like this, but survival was far more valuable.

Mutants could always be created again.

A creature with the fused bodies of a boar and a stag, boasting eight legs. Another, a fusion of a human and a dwarf, with four eyes. Each mutant was different, but all exuded toxic substances from their bodies.

The stag’s razor-sharp claws secreted an acid potent enough to melt flesh upon contact. The dwarf’s thick tendons emitted a paralyzing gas. The exposed intestines of the human mutant leaked a stench so foul it defied description.

A writhing mass of grotesque flesh, they stumbled, trampled over each other, and tumbled forward in a chaotic wave—a tsunami of flesh surging toward the boy.

The boy.

He stood still before the grotesque tide and simply flicked his fingers.

Snap.

That was the only sound heard on the battlefield.

Immediately after.

A blinding flash, far beyond anything seen before, erupted across the battlefield.

The single strand of electricity released from the boy’s fingertip met the tsunami of flesh and scattered outward, consuming everything in its path.

The airborne demon, unable to counter the attack, was swallowed by the white lightning and vanished without a trace.

The mutants charging at the boy were likewise engulfed in a massive surge of electrical energy, reduced to white ash in an instant.

In less than a second, the battlefield, once overrun by thousands of writhing monstrosities, had been cleansed.

At that moment, the black clouds overhead parted slightly, allowing faint sunlight to seep through.

The enormous pile of flesh, now burned away, left behind a thick layer of ash that blanketed the battlefield like fog.

The overwhelming shockwave temporarily blinded and deafened most of the guards standing on the battlefield.

It took them a long time to regain their senses.

"……"

When their vision finally returned, the guards gazed at the silent battlefield, unable to believe their eyes.

The once blood-soaked battlefield had been wiped clean, turned pure white by a single burst of light.

And at the center of it all stood a lone boy, his entire body crackling with electricity.

No blood. No flesh. No remnants of battle remained—only a vast expanse of scorched earth.

Like a celestial being descending from the heavens, the boy turned away from the purified battlefield and slowly walked toward the city’s guards.

"…E-Estella has delivered us!"

A guard with a broken leg shouted in a trembling voice.

The other guards, still staring in awe at the white battlefield, instinctively clasped their hands in prayer, offering thanks to their deity.

To them, the boy had become nothing less than an apostle of god.

And who could blame them?

The boy, who had jokingly introduced himself as having been "born in this city just now," had suddenly appeared like a savior and rescued the city from its crisis.

Fatigue from battle, the relief of survival, and the sheer exhilaration of seeing the accursed demon slain all swirled chaotically in their minds. It was only natural that they mistook the boy for an apostle of god.

"…Well, giving thanks to the gods is nice and all, but shouldn’t you be thanking me first?"

"Ah! Ah, my apologies, Mage! I was so overwhelmed!"

The guard who had first prayed to the gods finally snapped back to his senses and bowed deeply to the boy.

"That aside, you must have had your reasons. For a mage of your caliber to be wandering around a border city like Strathus, dressed as a vagabond…"

"……"

The boy remained silent, maintaining a mysterious expression. He couldn’t exactly explain that he had started as a vagabond just to increase his critical hit rate, only for things to escalate to this point.

"I won’t ask further. We cannot trouble the hero who saved our city. We may not have much, but we’ll offer you the best meal we can. Please, come inside."

"That’s right! If not for you, we would never get to enjoy a meal again anyway! Eat to your heart’s content and put some meat on those bones!"

"Yes! Thanks to you, we get to live another day! While you’re at it, how about wiping out all the demons in this region?"

The guards, raising their bandaged arms high, cheered and welcomed the boy enthusiastically.

Feeling somewhat pleased, the boy let a faint smile slip onto his otherwise cold expression.

"Come inside! There’s even some alcohol left for you, Mage, though not much…"

A lieutenant beside Hans grinned as he approached the boy. The boy, smiling in return, reached out to shake the offered hand—

Thud.

"……?"

"Mage?"

The boy’s body collapsed forward, entirely devoid of strength.

Five minutes had passed far quicker than he had expected.

***

Deep within a dark, blood-soaked cave, where flesh and viscera dripped onto the floor, the agonized wails of those who had not yet fully transformed into mutants echoed throughout.

And even deeper within—damp, filthy, and foul—a demon with long horns and pitch-black skin sat upon a grotesque throne of stitched-together flesh.

"Impressive."

Maltiel, the highest-ranking demon lord, murmured in admiration as he observed the white-haired boy and the overwhelming surge of power he had unleashed, displayed upon a magical screen.

"A formidable mage."

"We never expected such a mage to be in that city. It seems reinforcements have arrived."

Two demons, bowing on either side of Maltiel, added their comments as they watched the screen.

"And he’s young, too. If we leave him unchecked, he will become a major obstacle in the future."

Maltiel smirked darkly, nodding in agreement with his subordinates.

"Prepare the army. A monster’s seed must be uprooted before it grows."

"A wise decision, my lord. Who shall we send? Vinverde is already prepared… and Beluda will soon return from his mission."

"I will go myself."

"…You mean you will personally handle this, Lord Maltiel?"

His subordinates showed slight surprise at his declaration.

"Yes. That mage only used a single spell. Moreover, he incinerated my minions and all those mutants in ‘one strike.’ It doesn’t take much thought to realize what that implies."

"…Are you saying that wasn’t his full power?"

"7th-circle. By my estimate, that monster is already at that level. Considering his age… it won’t be long before he reaches the 9th-circle."

With an unsettling grin, Maltiel rose from his grotesque throne, clearly anticipating his rare excursion.

"Furthermore… That boy has dangerous eyes. The kind of eyes that belong to a human destined to become a true monster."

As Maltiel took a step forward, rotting chunks of flesh peeled from his throne and splattered onto the cave floor.

"A monster’s seed must be eradicated before it fully blooms, don’t you think?"