The Yandere villainess loves the useless engineer

Four months had passed since the creation of the first bloomery.

And in those four months—

Everything had changed.

The once abandoned clearing in the middle of the forest no longer resembled a forgotten ruin.

Smoke constantly drifted upward from two fully functioning bloomeries while the rhythmic sounds of automated bellows echoed through the trees day and night.

HSSSHH.

HSSSHH.

HSSSHH.

Beside the river, two waterwheels now turned steadily beneath the flowing current, powering the furnaces without rest.

The old shack itself had transformed completely.

What was once a collapsing wooden wreck barely fit for animals could now genuinely pass as a proper workshop.

The walls had been reinforced.

The roof no longer leaked.

Glass windows—expensive ones—had even been installed recently after Finn somehow talked a merchant into selling damaged panes cheaply.

Stacks of refined steel lined the interior walls while tools, sketches, and strange half-finished mechanisms covered nearly every table.

It looked less like a shack now and more like the birthplace of a small industry.

And somehow...

It actually was.

I stood outside the workshop watching snow slowly drift from the gray sky above.

Winter was approaching quickly.

The cold air bit against my face while frost coated parts of the clearing.

Nearby, a horse lazily chewed at some feed beside the wooden cart Finn and I had purchased several weeks earlier using profits from steel sales.

The horse itself was brown with a crooked white streak running across its face.

Finn had immediately named it "Potato."

Because apparently that was the peak of his creativity.

"I still think the name’s good," Finn defended while carrying another bucket of charcoal.

"The horse deserves better."

"The horse eats wood if you leave him alone for too long. He does not deserve better."

Honestly...

Fair enough.

Over the past months, steel production had become our daily life.

Experiment.

Refine.

Sell.

Repeat.

And the results spoke for themselves.

Our steel was becoming increasingly popular throughout nearby towns, especially among blacksmiths and weapon craftsmen.

Several merchants had even begun specifically requesting our material by name.

Of course—

Nobody actually knew who produced it.

As far as the public knew, the steel simply came from a mysterious supplier somewhere near the Aldric territory.

And I intended to keep it that way for now.

Because while steel was valuable—

The next step would be revolutionary.

I slowly looked toward the far corner of the clearing where Finn currently stood inside a massive hole dug into the earth.

Covered entirely in dirt and snow, he looked moments away from death.

"I hate you," he said flatly.

"You say that every day."

"Because every day you invent new ways to torture me."

The hole itself was large and wide, deep enough that Finn had needed nearly an entire day to finish digging it.

Perfect.

Finn climbed out while breathing heavily before collapsing onto the ground dramatically.

"There," he groaned. "Your weird giant hole is finished."

I stepped closer and looked down at it approvingly.

"Perfect."

Finn narrowed his eyes suspiciously. 𝕗𝕣𝐞𝐞𝘄𝐞𝚋𝚗𝗼𝘃𝗲𝗹.𝚌𝕠𝚖

"...What exactly is this for?"

"Progress."

"That is not an answer."

"You’ll have to wait here while I bring some stuff."

A couple hours later the sound of wheels crunching against snow echoed faintly through the trees.

A few moments later, I returned riding atop the cart behind Potato.

Several large sacks were piled onto the back.

The moment I climbed down, I was utterly exhausted.

"Getting this stuff was humiliating," I muttered.

"I had to explain to multiple farmers why two teenagers needed this much manure."

But that didn’t matter.

Inside the sacks were exactly what I needed.

Manure.

Straw.

Ash.

Finn stared at the materials before looking back toward me like I had finally lost my mind completely.

"...Leon."

"Yes?"

"...Why are we collecting literal shit?"

I ignored the question and crouched beside the sacks.

"Because," I said calmly, "this is how we make gunpowder."

Silence.

Finn blinked slowly.

"...what powder?"

"A black powder explosive mixture."

"That somehow explained nothing."

I stood up and began speaking excitedly.

"With the right ratios, it combusts rapidly and creates explosive force. Enough force to launch projectiles faster than arrows."

Finn stared blankly.

I continued enthusiastically.

"With enough refinement, entire walls could be destroyed. Armies could be wiped out from a distance. Knights, fortresses, even mages eventually wouldn’t matter."

Finn’s expression slowly shifted from confusion...

To concern.

Then finally—

To the exact look someone gives a person they suspect has gone completely insane.

"...Leon."

"Yes?"

"I genuinely think you’ve become insane."

I grinned.

"No."

Snow drifted softly around the clearing while the bloomeries continued roaring behind us.

"This," I said while looking toward the sacks, "is merely the next step."

————

The following week became one of the most miserable experiences of Finn’s life.

And honestly?

Probably mine too.

Snow drifted softly across the clearing while the cold winter wind howled through the forest trees surrounding the workshop.

Yet despite the freezing weather—

The two of us were outside shoveling manure into a massive pit.

Finn stood inside the hole wearing an expression completely devoid of hope.

"...I used to think working with molten metal was bad."

"You’re adapting."

"I’m becoming a villain."

I ignored him and dumped another bucket into the pit.

The nitrate bed slowly began taking shape beneath us.

Layers of manure.

Layers of straw.

Wood ash.

Then water.

Repeated again and again.

The smell alone was catastrophic.

Finn nearly threw up twice.

"This better create the strongest weapon in history," he muttered while covering his nose with part of his sleeve.

"It eventually will."

"Eventually?"

"It takes time."

Finn froze.

Slowly, he lowered his sleeve.

"...How much time?"

I looked toward the massive compost-like pit thoughtfully.

"...Several months probably."

Silence.

Then—

"You’re telling me we’re bathing in animal shit for MONTHS?!"

"Technically, you’re the one standing inside it."

Finn looked moments away from violence.

Unfortunately for him—

I was right.

Gunpowder required potassium nitrate.

And without access to advanced chemical production, the simplest method available was nitrate beds.

Which meant waiting for bacteria and decomposition to slowly produce nitrate-rich soil over time.

Primitive.

Disgusting.

But effective.

Eventually.

I poured another bucket of ash across the top layer while explaining.

"The manure provides nitrogen. The straw helps airflow and decomposition. The ash contributes potassium."

Finn stared blankly.

"...I regret asking."

"Then after decomposition, we extract the nitrate using water filtration and evaporation."

Finn blinked slowly.

"You somehow made this sound worse."

By midday, both of us smelled horrific.

The horse had even started avoiding us.

Potato physically backed away whenever Finn approached.

"Even the horse fears us now," Finn said sadly.

"That’s because you smell like death."

"You also smell like death."

"Fair point."

Still—

Despite the suffering, excitement steadily built inside me.

Because while steel changed industry—

Gunpowder changed warfare itself.

Cannons.

Firearms.

Explosives.

Everything began with black powder.

And once again—

This world had absolutely no idea what was coming.

By evening, the nitrate bed was finally complete.

A massive layered pit sat near the far edge of the clearing partially covered by wood planks and straw to protect it from snow and excessive rain.

Finn collapsed beside it dramatically.

"I sacrificed my dignity for this."

"You didn’t have much dignity to begin with."

"That somehow hurt more than the manure."

I crouched beside the pit while looking over it carefully.

Now—

We waited.

Nature would handle the rest.

Over the coming months, decomposition and bacterial reactions would slowly produce nitrate-rich material within the bed.

Primitive chemistry.

But chemistry nonetheless.

Finn looked toward me suspiciously.

"So what do we do while we wait for... whatever this is?"

A grin slowly spread across my face.

"We continue progressing."

Finn narrowed his eyes.

"That sentence scares me now."

I stood back up before gesturing toward the workshop behind us.

Steel production continued.

And now that we had reliable high-quality steel—

It was finally time to begin experimenting with mechanisms.

Springs.

Pressure systems.

Moving parts.

The foundations for machines far beyond this era.

Snow drifted gently around the clearing while smoke rose from the active bloomeries in the distance.

The workshop windows glowed warmly against the cold winter forest.

And within this simple forest.

The future of warfare quietly began rotting into existence.