After Crushing the Final Boss, I Got Infinite Mana and Returned to Earth ～With Cheat-Level Power, I’ll Rule Both the Game World and the Real World～ - Chapter 01: After Crushing the Mastermind, I Got Infinite Magic

Chapter 01: After Crushing the Mastermind, I Got Infinite Magic

“Mm, just a little more and… whoa!!”

While reaching for a book on the top shelf, my foot slipped off the ladder.

BAM!!

My head slammed against the floor with brutal force, and blood gushed out in a flood.

Through the haze of pain, memories that didn’t belong to me suddenly surged into my mind.

“…Huh? Did I just… reincarnate?”

What came rushing back were memories of my previous life.

That of a shut-in high schooler who lived for nothing but video games.

And in that instant, I realized something terrifying.

The world I was in right now—

It was the very game I had once played to death in my past life: Final Stories.

And even worse, I wasn’t just some faceless NPC.

Nope.

I was a character tied directly to the main storyline.

Not the hero.

Not even close.

I was the villain fated to block the hero’s path—

The 8th Prince of the Magiluke Kingdom, Georg von Magiluke.

“Your Highness, I heard a loud crash—Your Highness!? That injury…!”

“Ah, sorry. I slipped off the ladder.”

My personal maid, who served as my close attendant, came rushing in at the noise.

Her eyes went wide at the sight of blood pouring from my head.

But when she noticed the object I had been reaching for, she let out a heavy sigh.

The book in question—

A massive tome brimming with arcane knowledge.

With a calm but firm tone, she gently tried to draw me away from it.

“Your Highness Georg… forgive me for saying this, but since you cannot use magic, perhaps you should refrain from digging through grimoires?”

Right.

That was the cruel truth.

I couldn’t use magic—because I didn’t have any magic power.

And that was exactly why I, Georg, would eventually end up as the final boss.

Born a prince yet incapable of wielding the magic that royalty and nobility were expected to master, I grew up scorned and shunned by both my parents and siblings.

Naturally… my personality twisted beyond repair.

And then, one day, I was destined to open the forbidden book hidden deep beneath the royal castle of Magiluke.

There, I would form a contract with the sealed Evil Dragon, gaining overwhelming magical power.

That event was set to occur when I turned fifteen—three years from now.

With that power in hand, Georg would slaughter the family who had despised him, declare war on the world, and seek global conquest by bending both humans and monsters to his will.

But in the end, he would be defeated by the chosen Hero—the protagonist—blessed by the goddess with the mission of slaying the Evil Dragon.

As his final act, Georg would beg the dragon for more power.

Instead, the beast would hijack his body, using him merely as a vessel to resurrect itself.

Classic.

A pitiful pawn, used by the true mastermind and discarded with a miserable death.

Even knowing it was my role, I couldn’t help but feel sorry for myself.

…Anyway, reminiscing about the game’s settings could wait.

For now, I should just nod along to my maid’s advice.

“Yeah, you’re right. No point wasting time. Maybe I should find a more meaningful hobby instead.”

“Eh? Y-You’re really giving up? But you always wanted to use magic so badly…”

“Of course I’m giving up. No matter how many grimoires I dig through, it’s useless without magic power. And there’s no such thing as spellcasting without magic, right?”

I knew the rules of this world all too well, thanks to how much I had played the game.

Magic without mana? Impossible. That was an unbreakable law here.

Sure, the game had special items scattered around the world that boosted the Hero’s stats—but those were strictly Hero-only.

Since I wasn’t the protagonist, those items might as well not exist for me.

My maid looked stunned. Clearly, she hadn’t expected me to nod so easily and let go of my obsession with magic.

But honestly, leaving that forbidden grimoire sealed in the underground archive still worried me.

If anyone else got their hands on it, things would play out exactly like the original scenario—ending in disaster for the world.

If the Hero defeated the Evil Dragon, fine, everything would be solved.

But if he failed? It would be chaos.

And me, powerless Georg? I’d be one of the first to die.

I wasn’t planning on dying anytime soon—so I needed a countermeasure.

“I’ll take a quick trip down to the underground library.”

“Y-Your Highness Georg!? You’ve injured your head—you must rest in your room!!”

“I already had it treated. I’ll be fine.”

I made my way down to the underground library of the Magiluke Kingdom, where the forbidden grimoire was kept.

Just as I was about to enter, the guards stationed at the door muttered under their breath.

“Back to digging through grimoires even though he’s got no mana? The useless prince just doesn’t know when to quit.”

“Hey, quiet. He might hear you.”

“Who cares if he does? Nobody’s gonna stick up for the only prince without succession rights. No one’s dumb enough to defend deadweight.”

…Wow. Harsh.

Well, not that they were wrong. It was true—I had no allies. Not among my parents. Not among my siblings.

Ignoring the whispers, I walked straight past them and headed deeper into the archive.

The underground library was a special chamber built by the very first king of Magiluke, designed to preserve every kind of grimoire.

Here, books never rotted from damp air or got eaten by insects.

Over two thousand years, the collection had grown into a massive treasure trove of magical knowledge.

And somewhere within this sea of tomes was the forbidden grimoire.

In the game, Georg must have spent countless hours combing through these shelves, desperately searching for a way to use magic despite having no mana.

That was probably how he stumbled across the book sealing the Evil Dragon.

And then it happened.

“—”

“…Huh?”

A voice suddenly echoed inside my head.

It was eerie, bone-chilling, and made my skin crawl.

Guided by that voice, I wandered deeper and deeper until I found myself standing before a certain bookshelf.

“You there… do you desire power?”

“Hm?”

“If you crave power, I shall grant it. Take me in your hands, open my pages, and I will bestow upon you overwhelming magic.”

Found it.

The forbidden grimoire that sealed the Evil Dragon.

I pulled it from the shelf, ignored the voice, and carried it back to my room.

“H-Hey, why have you not opened me yet?”

“…”

“Why do you ignore me? It is not as though you cannot hear my voice, is it?”

“…I can hear you just fine.”

“Ah! Then why ignore me!?”

“This is the royal castle. Who knows who might be watching? If someone sees me talking to a book, they’ll think I’ve lost it.”

“…Hmm. Fair point.”

I tossed out that half-baked excuse, which was enough to shut the dragon up until I reached my room.

Sure, I had no claim to the throne since I couldn’t use magic, but I was still a prince.

My quarters had at least the bare essentials.

I lit the fireplace.

Then, without hesitation, tossed the grimoire straight into the flames.

“Wha—!? H-Hey!! Hot, hot!! What are you doing!? What the hell are you doing!?”

“Good paper, huh? Burns really well.”

“Y-You fool!! Do you even realize what you’re doing!?”

“Yeah. Just burning the book that sealed the Evil Dragon.”

“!? H-How do you know my true identity!?”

Saying “I remembered my past life” wouldn’t convince anyone, so I kept my mouth shut.

As I watched the forbidden book crumble to ash, the Evil Dragon still refused to give up and kept trying to tempt me.

“Wait, wait!! If you form a contract with me, you’ll gain immeasurable magic power! I’ve been watching you all this time!! Don’t you want revenge on those fools who scorned you, who looked down on you just because you couldn’t use magic!?”

“Actually, I lost interest in magic a few minutes ago. You’re a little late.”

“Wha—hot, hot! Damn it!! There’s barely half of me left!? A-Alright, fine!! I’ll give you not just overwhelming magic, but also my full knowledge of sorcery!! With that, revenge and even world domination won’t just be a dream!!”

If I accepted, I’d probably gain even greater power than the Georg in the game.

Not a bad offer. But still—

“How should I put this…?”

“W-What is it!? Have you finally decided to make a contract with me!? Then hurry, put out the fire—”

“Looking down on someone who should be leagues above me, then crushing them with one-sided violence… I have to say, it feels pretty damn good.”

“Y-You… you’re a twisted bastard, aren’t you!?”

And so, I was called rotten by the very mastermind himself.

How terribly unjust.

“I’ll never forgive you!! If I weren’t sealed in this book, I’d crush you into tiny little bits and stomp you flat!!”

“Your vocabulary sounds so outdated… is that because you’ve been sealed for centuries?”

“G-Gwaaaaaaaaaaaaaaaaaaaaaaahhhhhhhhhh!!!”

At last, the forbidden grimoire burned to ash, and the Evil Dragon let out its final death scream.

Mission complete.

No one would ever open the book again, and the dragon’s seal would never be broken.

The world would keep going just as it always had.

A happy ending, right?

It was late, so I crawled into bed, pulled the blanket over myself, and decided to sleep.

Figuring out how to live as Georg could wait until tomorrow—thinking about it tonight was too much hassle.

I don’t know how long I’d been dozing when I suddenly felt someone shaking me.

“Hey, you. Wake up. Hey!! Wake up!!”

“Mm… who’s there…?”

“It’s me!! The Evil Dragon, Diabel!!”

I opened my eyes.

Floating in the air, flapping its wings, was a tiny dragon covered in jet-black scales.

Its round little belly stuck out just enough to make it look completely non-threatening.

Honestly… it was kind of cute. Like a plush toy.

“Um… who exactly are you?”

“I’m the dragon sealed inside the book you burned!! Surely you figured that much out!?”

“Ah, right. Diabel—that was the Evil Dragon’s name. …Still, you’re awfully tiny, aren’t you? The Evil Dragon I know was supposed to be bigger than a castle.”

“I had to leave all my infinite magic inside the grimoire in order to escape the seal. As I am now, I’m weaker than the puniest slime.”

So the terrifying, final-boss Evil Dragon… was now weaker than a slime.

Even if I was the cause, the situation was just too funny.

“Hey, you. What’s with that smirk?”

“Oh, just thinking you look like a cute mascot.”

“Y-You dare say that with a straight face!? …Bah, whatever. More importantly—you, return my magic.”

“Magic? I don’t have any magic.”

“Not yours—mine.”

With that, Diabel poked my chest with the tip of his tail.

“When the forbidden book holding my power burned to ash, all the magic inside was absorbed by you—the one who set it alight!!”

“…I absorbed your magic? Uh, is that… safe for me?”

“Ordinarily, no. A normal human’s own mana would clash against mine and kill them instantly. But you… you’re different. You had no magic of your own. That’s why my power could settle inside you without issue.”

After hearing all that, something finally clicked in my head.

With the exception of me, every living being in this world carried at least some amount of magic power.

So if an ordinary human tried to contract with Diabel and wield his power, their own mana would reject it and they’d just keel over and die.

Which meant… I was the only one who could ever form a contract with him.

In other words, burning the forbidden book hadn’t been all that meaningful.

After all, as long as I ignored the book, nothing would’ve happened anyway.

So yeah—totally pointless.

Maybe that was why, in the game, Diabel targeted Georg in the first place—because he was born without any magic of his own.

And then another thought struck me.

Right now, Diabel’s magic was flowing inside me.

Which meant… maybe I could actually use magic now.

I had planned to give up on it, just like my maid had told me to.

But that was only because I’d been born without mana.

If I had mana now, then the story was completely different.

Time to test it.

“—Torch.”

I cast the spell—just a beginner fire magic that was supposed to create a tiny spark on my fingertip.

Beginner spells were the simplest kind—say the right words, and they worked. No complicated technique required.

Or at least, that’s how it was supposed to be.

The moment I finished the chant, a corrupt, swirling power erupted from my fingertip, and a massive magic array spread out before me.

A terrible feeling hit me, and I tried to cancel the spell—

But beginner magic was too easy to trigger, the casting time too short. I couldn’t stop it—

BOOOOOOOOM!!!

A blast thundered out so loud it could have ruptured eardrums, and a searing flash forced me to shield my face.

When my sight and hearing finally returned, the scene before me made my jaw drop.

“Whoa, what a view.”

“Y-You—your first comment is that!?”

There was a giant hole ripped clean through my room.

Looking out, I saw part of the royal capital scorched black by my little “Torch.”

The ground along the spell’s path had melted into glass; buildings and people alike had vanished—most likely vaporized. Screams rang out from every direction, and the entire city had plunged into chaos.

What a disaster.

All I had done was burn a single book, and somehow I’d ended up with power beyond human.

“Y-You… what now? You just slaughtered a ton of your own people, didn’t you!?”

“True, this is a bit of a problem… But with this magic power, I feel like I can do anything. Why don’t I try rewinding time—for everyone except us?”

“…What?”

Magic depended on quantity, quality, and knowledge—but above all, it relied on imagination.

According to an old grimoire, with enough imagination, you could cast spells even without a deep grasp of theory.

Of course, the mana cost would be insane…

But with Diabel’s infinite magic, it wasn’t impossible.

I pictured it like rewinding a TV recording. And just like that—

Amazing.

The people and buildings that had been vaporized were restored.

Even the wall of my room, blown apart earlier, was completely back to normal.

“Magnificent. This overwhelming strength… this feeling of being all-powerful. Using such power is pure fun.”

“…I think my infinite magic ended up in literally the worst possible human.”

“Fwahaha. I wonder what I’ll do tomorrow.”

And so, I became the one who held infinite magic.

―――――――――――――――――――――

[Afterword]

A Random Tidbit

This story was actually born from a silly setting idea I scribbled in a notebook, then shoved into the back of my desk and completely forgot about. Yeah, that happened.

If it made you laugh, toss me those ★s.

If you thought, “Seems fun,” “The Evil Dragon’s way too pitiful,” or “I cracked up,” then please drop a comment, bookmark, ★ rating, or review!