The Duke's Secret Vault

The carriage from Earth had jolted so badly it bruised your ass, but this world's carriage, enchanted with magic, felt utterly smooth—no bumps at all. More comfortable than a car loaded with every modern tech gadget. It really drove home how puny science is compared to magic.

"Whoa—the scenery outside is flying by!"

"Oh, right! I steamed some potatoes for a snack. Want some?"

"Check this out! Even over these ruts, it doesn't shake a bit!"

While the whole group sat in tense silence, lips sealed, Noah bounced around oblivious to the mood. Munching on the steamed potatoes she passed out, I gazed out the window. It wasn't whizzing by that fast, but to a country girl who'd never even ridden a horse ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠her whole life, the landscape seemed to transform in an instant.

"Where are we headed, anyway?"

I muttered while staring out the window, and Stella crossed her arms, shooting me a look.

"You don't even know that?"

"No one told me."

"...Your homeroom teacher must be slacking off big time."

As she said it, Stella muttered something under her breath, too quiet to catch. I tilted my head and asked again.

"Where?"

"...The Iritz Duchy."

"...No way."

"I-It's not like that!"

I hadn't even finished my thought, but she jumped like she'd been burned, snapping defensively. Still, who wouldn't suspect? A carriage carrying Stella Iritz just happens to be heading to the Iritz Duchy.

"So this is just a coincidence?"

"...I said I wanted to ride this carriage, so maybe they accommodated me out of courtesy."

"Courtesy, huh."

The Iritz Duchy. Stella Iritz's family home. We were heading straight to her territory.

"Hey."

"...What."

"You still haven't given me that heirloom, right?"

Her face drained of color at my words. Time to collect in person on this trip.

Earth is round. This world is too. Which means demons don't come from just one direction—they can pop up from everywhere.

The Iritz Duchy was the noble house tasked with guarding the Empire's south, backed by dozens of vassal families. Naturally, their prestige was unmatched in the region.

"Huuuuge..."

Noah gaped at the Iritz family estate, letting out an awed squeal. Honestly, even I couldn't suppress the ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠overwhelming thrill bubbling up inside.

Damn, that's sick.

For a modern guy used to skyscrapers, no—this scale of wasteful grandeur hit even harder because of it. How much would all this cost? If they planted fields instead of flowers and trees in that garden, how many tens of thousands could they feed?

Lost in such random thoughts while waiting, the carriage finally cleared entry protocols and rolled inside. It moved faster than a brisk walk, yet it still took over thirty minutes to reach the main house. Noah burst into another gasp of amazement.

"Your house is insanely big!"

"Hmph, it's nothing special. Actually pretty modest for a ducal house."

Stella puffed out her chest proudly. As if she'd built the place herself. To tease her, I tossed out a half-joking line.

"Stella, I love you. Marry me."

"W-What...?"

She froze, face flushing crimson. Seeing that, I panicked instead, breaking into a cold sweat.

"It was a joke... Don't take it that seriously."

"...Let's go inside."

Stella bolted without a word, cheeks still pink—pissed at the prank confession, probably. Hurrying after her, we were greeted at the gate by a swarm of maids and butlers who'd been alerted, all bowing in unison.

"“Welcome home, miss.”"

"I'm back."

Stella breezed past like it was routine, but commoner Noah and I stood stunned.

"Whoa, whoaaa..."

"Why are there so many maids..."

"W-We have this many at our place too..."

I ignored Dinua Erebos's senior's weak protest and followed Stella to the lord's office.

The lord: master of this estate and territory. Father of Stella Iritz.

Knock knock.Stella rapped on the office door and waited.

"What is it?"

"Father, it's me. ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠Stella."

"...Enter."

She eased the door open carefully. The moment I stepped in, a wave of heat made me stagger back. But since the other two waltzed right in unfazed, I figured it was my imagination and followed.

Surprisingly, Stella's father wasn't red-haired. Bright golden blond with fierce blood-red eyes. A muscular build that screamed he could bench-press 500 without breaking a sweat. Scars and wrinkles half-hid his handsome features, twisting them into something ferocious.

"It's been a while, Father."

"So it has."

Stella gave a casual greeting. Given her usual attitude, you'd think she was spoiled rotten, but her father remained impassive even toward her. He scanned us briefly, then fixed his gaze on me for an eternity—like he was boring holes through me. Finally, he closed and opened his eyes, introducing himself.

"Patriarch of the Iritz Duchy, Hypnos Iritz."

"N-Nice to meet you. Dinua Erebos of the Erebos Marquisate."

"N-Noah..."

As Dinua and Noah bowed and introduced themselves, I followed suit.

"Ian Clark of the Clark Barony..."

"You."

Hypnos jabbed a finger at me. Being singled out by a family head was intense pressure. Especially from a seasoned middle-aged powerhouse.

"Everyone out except him. You too, Stella."

Everyone but me filed out. Silence ruled the room long after.

The silence broke after about ten minutes.

"I heard Stella owes you a debt."

"Ah, yes."

I answered belatedly. Hypnos pulled a letter from his desk—Stella's.

He waved it at me.

"Know what this is?"

"Not... really."

"Letter from Stella. Nothing in it but talk of you."

He read an excerpt aloud—a scene that would've made her blush and freak if she were here.

"'To my beloved Father'—how many years since she last said something like that to me?"

Beloved Father. Adorable daughter. Blah blah blah. All to unlock the secret vault. Permission please. Layers of flowery language no one would believe Stella wrote—elegant, feminine words overflowing.

Hypnos stopped reading, neatly refolded the letter, sealed it back in its envelope, and locked the drawer.

"Guess what I thought when I read this?"

"...Stella's got more aegyo than I figured?"

"That she's fallen hard for you."

He clenched his fist. His massive forearm rippled like it could smash a monster barehanded. I flinched a bit, and he chuckled as if amused.

"What do you think? Same?"

"...Stella liking me? Probably not."

Of course, I knew she had some affection—exactly as much as the system had boosted. Beyond that? No reason for her to fall for me. First meeting was a disaster, follow-ups barely better, and now I was squeezing her for favors.

"When did I say she likes you?"

"...Pardon? You said she's head over heels—"

"I meant she's hooked on your talent. Not romantically."

His faint smile vanished. His face darkened like a comic panel shift—already fierce features turning outright mafioso.

"Don't get delusions. Got it? Don't cross that line."

"...Yeah, sure. Understood."

Not that I'd dreamed or aimed for it. I nodded quietly. Arguing with this stubborn type was pointless.

Satisfied I'd gotten the message, he nodded and moved on.

"So, you bet with Stella."

"—Yes. And I won."

"Mind telling me the details?"

"Stella started it..."

A bit of embellishment, 99% truth. No one could call bullshit—mostly facts, so even probing questions held up.

Hypnos grilled me like an interrogation, but realized Stella's loss was legit. No cheats, no tricks—just pure luck. Astonishing.

How the hell...?

Stella wasn't some emotional idiot. Ducal heirs weren't raised that way. She only acted when victory was certain, trained to avoid losses. Yet she'd jumped into a reckless bet on impulse—and lost?

This guy's got something.

Something even Stella's ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠eyes couldn't gauge, leading to her crushing defeat. An unknowable specialness. Hypnos sensed it in me.

And if so...

"Follow me."

One person's uniqueness becomes humanity's. The strong protect mankind. For humanity, the Empire—for the family, a heirloom or two was a small price.

Besides...

Marry her off to him, and it'll come back to the duchy eventually.

Calculations done, the duke rose from his desk.

"I'll show you the ducal treasure vault."

He led the way to the secret vault only the patriarch knew.

Step step.

The secret vault: forbidden to all but the patriarch, its very location taboo. Two men walked its corridor.

Hypnos asked me, trailing behind.

"How much do you know about heirlooms?"

"About as much as anyone..."

"Good. No need for explanations, then."

Clink. At the vault sealed with chains and locks, he pulled a key from his pocket and unlocked it. Seemed flimsy, but the corridor's magic prevented any keyless approach.

Inside, he lit the lanterns. Soon, tiny flames illuminated the vault.

"House Iritz guards the entire south."

In other words, the whole south was his.

"Every heirloom from fallen summons in the south comes to us."

Hundreds of years' accumulation. Unrecorded treasures, identities unknown.

"Pick one from these."

My eyes lit up at his words. I knew every item's info in here.