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 13: Practicing Magic in Some State in America

Chapter 13: Practicing Magic in Some State in America

Now then, let’s talk about what happened after I dealt with the Goblin Emperor.

Once their leader was gone, the goblins were swiftly wiped out by the adventurers. They might have been a little sharper than wild animals, but in the end, goblins were still goblins. Against a proper band of adventurers, they never stood a chance.

Oh, and about those young girls the goblins had kidnapped—every single one of them was rescued alive from their den.

By “alive,” I mean they kept their lives. Sadly, the things they’d been put through were awful beyond words. All we could do was pray that, given time, their hearts would heal.

The village itself had taken heavy damage, but when they requested help from the kingdom, for some reason they received far more aid than expected.

Rebuilding would take years, but little by little, life would return to normal.

The real chaos began once we returned to the Adventurers’ Guild.

“Promote Minato out of 10th class already!!”

“Yeah, seriously!! If someone like him stays a rookie, what does that make the rest of us!?”

“Demote Garf if you have to—just make Minato a 1st-class adventurer!!”

“Hey, the hell!? Don’t go dropping my rank just to boost his!!”

“Ah, Garf threw the first punch!! Look, he’s the one who deserves to be shoved down to 10th class!!”

“Brawl!! It’s a brawl!!”

So, after the goblin extermination, the adventurers who’d fought alongside me all started yelling for the guild to raise my rank—and it somehow escalated into a full-on barroom-style brawl right there inside the guild.

But really, there was no way they could just promote some guy who’d only registered as an adventurer that very same day.

In the end, the capital branch had no idea what to do. They just punted the whole mess up to guild headquarters and were now waiting for a reply about my rank.

“Ehh!? Onii-chan saved an entire village and you still don’t get a promotion!? That’s totally unfair!!”

“I don’t particularly care about rank, so it’s fine.”

“No, no, it’s not fine!! Just blast Adventurers’ Guild HQ with a giant beam already!!”

Aoi was coming up with some seriously dangerous suggestions.

Well, the guild’s headache wasn’t mine, so the next day I just went home.

And then, to start teaching Aoi and Saori magic, I teleported us straight to a deserted wasteland.

“By the way, Onii-chan, where even are we?”

“Some random state in America. Saw it on TV. Perfect place to practice magic without anyone noticing.”

“…Doesn’t this count as illegal entry?”

“As the saying goes—if no one finds out, it’s not a crime.”

“Ufufu, Minato-kun, you really are such a bad boy.”

Without wasting any time, I poured some of my mana into the two of them and began teaching them the chants for beginner spells.

““—Torch!!””

“Hmm, beginner magic looks just right.”

“Fufufu, of course!! I’ve been doing image training in my head since yesterday!!”

Aoi had clearly been waiting for this day forever.

From there, both she and Saori quickly got the hang of controlling their mana, and before long they were firing off basic spells like it was nothing.

At this pace, they’d probably be hurling advanced magic in a month.

“Oh, right!! Onii-chan!! I came up with a killer spell!!”

“A killer spell?”

“You said magic can be cast just by imagining it, right? That’s what you call Original Magic!!”

“Yes, that’s correct.”

“Okay, then watch closely—because I’m about to show you!! —Crimson Immortal Death!!”

The very next moment, a sinister surge of mana burst out of Aoi’s body.

Two eerie crimson shadows rose up on either side of her, and she stretched both hands toward the sky.

Then—countless scarlet flowers bloomed across the heavens.

They scattered at once, petals raining down in a gorgeous crimson shower.

But the instant those petals touched the ground—BOOM!! A deafening blast tore through the wasteland, the kind that made you want to clap your hands over your ears.

Blinding flashes followed, so bright you’d reflexively shield your eyes.

The scene looked exactly like a massive carpet bombing, ripping everything apart in a wide radius and kicking up a colossal cloud of dust.

“Ohh, incredible. The power and range are already beyond advanced-level magic.”

“Hehe, see that!? With this, we could head to the other world right now—”

“No. The condition is that you master advanced magic first, so it’s still a no.”

“Mouu!! Onii-chan, you stubborn mule!! Fine then!! I’ll just blitz through advanced magic super fast anyway!!”

Still sulking, Aoi immediately went back to practicing mid-level spells with fiery determination.

I glanced over at Diabel.

He’d declared he was going to spend the whole day bingeing anime, but in the end, he said being alone felt lonely and tagged along.

And yet—right after seeing Aoi’s spell, Diabel was trembling all over.

“Diabel, what’s wrong?”

“…T-That magic… i-it might even be able to slay me, even if I were fully restored.”

“…What?”

The words slipped out before I could stop them.

Diabel was the ultimate last boss of Final Stories, the strongest of the strong. The idea that he could be one-shotted by one of Aoi’s chuunibyou spells was just way too absurd.

“It did look like a powerful spell, sure, but…”

“The true terror lies elsewhere. That magic carries an absolute effect—to erase even immortal beings like myself without question.”

“…I see. Well, considering how much Aoi dotes on you, I doubt you’ll have to worry… unless something really extreme happens.”

“…Hmph. Perhaps you’re right.”

Diabel muttered under his breath, “Best not to go against Aoi…”

For my little sister to be the one casually taming a world-ending evil dragon without even realizing it—yeah, that was something else.

And then… my mother went and proved she was on a whole different level.

“Alright, now it’s Mama’s turn!! —Summon Harem!!”

Saori’s Original Magic was nothing less than pure desire made manifest.

Out of thin air, more than a dozen beautiful girls materialized.

Different faces, different figures, different personalities—yet they all had the same strange, doll-like aura. They were undeniably cute… but the uncanny uniformity made them just a bit unsettling.

“Kyaa!! They’re all so adorable!! Each one is the embodiment of my ideals!! Tonight marks the end of my lonely nights forever!!”

“Onii-chan…”

“Yeah?”

“…Watching my own mom surround herself with a harem of cute girls is… kinda rough.”

“…Yeah, I can’t disagree.”

Why she’d come up with a spell to summon beautiful girls… better not to ask.

There had to be things hidden in an adult woman’s heart that neither Aoi nor I could ever hope to understand.

“Hey, hey, Onii-chan. Don’t you have any Original Magic too?”

“I do, actually. Time manipulation magic, memory-reading magic…”

“Ehh? That’s so plain. Don’t you have something flashier? Like, oh I dunno, the one from that notebook you hid in your desk—the one called Ultimate Nova Explo—”

I instantly clamped a hand on Aoi’s shoulder and, with the brightest, friendliest smile I could muster, cut her off mid-sentence.

“Aoi, everyone has parts of their past they don’t want touched. If you dig into them carelessly, you’ll only end up making enemies. So please be careful, alright?”

“A-Ah, yes.”

“You’ve always been such an obedient, good girl. As your brother, I couldn’t be prouder.”

“Onii-chan… you’re scary…”

Aoi shivered from head to toe.

And so, both Aoi and Saori managed to master mid-level magic that very same day, and by evening we were back in Japan.

Honestly, I hadn’t expected them to level up that far in just a single day.

Then came the next morning.

While Diabel was watching the morning news, the screen suddenly switched to coverage of the very same state in America we’d used yesterday as our magic training ground.

“According to the U.S. Department of Defense, traces of multiple mysterious explosions were discovered, raising suspicions of a possible stealth missile strike from another nation. However, there are also theories suggesting the work of domestic terrorist groups… and among certain enthusiasts, even speculation of an alien attack—”

“…Georg, what are you going to do about this? Thanks to you, my Sunday morning got preempted by a breaking news special. This is on you.”

“Looks like we’ll have to put magic training on hold for a while.”

That entire day, Diabel sulked in a foul mood.

―――――――――――――――――――――

[Afterword]

A Random Tidbit

Original Magic: Ultimate Nova

A forbidden spell recorded in the Book of Dark History, shared by both the author and Minato Suzuki.

Effect: obliterates multiple universes in a single shot.

Downside: the enemy dies. You also die.

If reading this afterword gave you a sudden stabbing pain in your chest, drop those ★s.

And if your thoughts were something like, “That’s way too busted, being able to one-shot full-power Diabel,” “Saori’s magic was just raw, unfiltered thirst lol,” or “Yeah, no wonder this made international news,” —then don’t forget to leave a comment, bookmark, ★rating, or review!