The Yandere villainess loves the useless engineer

Finn remained collapsed in the snow for several more moments before finally managing to sit upright while coughing violently.

Meanwhile, Lilith stood beside me with her arms crossed still staring at him suspiciously.

"...So this is your friend," she muttered.

"Yes."

Finn slowly looked between the two of us before awkwardly raising a hand.

"...Hi."

Lilith ignored him completely.

That probably hurt his feelings a little.

I sighed before stepping between them.

"Finn helps me run this place," I explained. "So don’t threaten him anymore."

"I wasn’t threatening him."

Finn wheezed loudly from the ground.

Lilith glanced at him briefly.

"...He’s dramatic."

"YOU CRUSHED ME INTO THE FLOOR."

She ignored him again.

Eventually, after a few more tense minutes, the atmosphere calmed enough for us to continue the day normally.

Well—

As normal as possible.

Lilith still watched Finn like she expected him to suddenly attack me at any second.

Meanwhile Finn looked at her like she was an ancient evil sealed inside human flesh.

Both assessments were understandable.

————

A couple hours later, the three of us headed toward town with Potato pulling the cart behind us.

Snow continued falling lightly while the cold wind swept across the roads.

Surprisingly—

Lilith had become weirdly attached to Potato almost immediately.

At some point during the trip, she had started gently petting the horse while walking beside him.

"...He’s fluffy."

"That thing bites people," Finn warned.

Potato immediately nudged Lilith affectionately with his head.

Finn looked betrayed.

"...Traitor."

Lilith lightly scratched beneath the horse’s chin while Potato practically melted.

I’d never seen him like someone that quickly before.

The town itself bustled with activity despite the cold weather.

Workers carried firewood through the streets while blacksmith forges burned brightly against the winter air.

Meanwhile, we moved from shop to shop gathering supplies.

Stone blocks.

Clay.

Large quantities of charcoal.

Iron bands.

Metal piping.

Heat-resistant brick.

Sand.

Every purchase made Finn look progressively more concerned.

"...Leon," he muttered quietly while we loaded another shipment into the cart, "are we building a furnace or a fortress?"

"Both."

"That wasn’t reassuring."

By the time we returned to the workshop clearing, the cart was nearly overflowing with supplies.

And finally—

Construction began.

————

The first step was the foundation.

The blast furnace would be significantly taller and heavier than the bloomeries, meaning it needed a strong stone base capable of handling immense weight and heat.

Leon and Finn spent nearly an entire day digging deep into the frozen ground before filling the area with compact stone and clay.

Meanwhile—

Lilith sat nearby beside Potato wrapped in a blanket while watching us work.

"This looks miserable," she commented casually.

"It is," Finn replied immediately.

Next came the outer structure.

Large stone blocks were stacked upward in a cylindrical tower shape while reinforced iron bands wrapped around the exterior to prevent structural cracking from the heat.

Unlike a bloomery, the blast furnace needed to maintain continuous operation at far higher temperatures.

That meant stronger walls.

Better insulation.

And more efficient airflow.

Leon carefully lined the inner chamber with heat-resistant clay and brick to trap as much heat as possible.

"This section is important," Leon explained while applying another layer of clay internally. "If the heat escapes too quickly, we won’t reach temperatures high enough to melt iron."

Lilith tilted her head slightly.

"...So the entire point of this giant tower is making hotter fire?"

"...Essentially."

Finn pointed at her dramatically.

"See? I told you his explanations sound insane."

Once the furnace body was completed, they moved onto the airflow system.

Large pipes connected the blast furnace to upgraded bellows powered by the waterwheel beside the river.

Unlike before, the airflow now needed to remain constant and extremely powerful.

The hotter the internal temperature—

The better the iron quality.

Leon also added angled vents near the lower section of the furnace.

These allowed molten slag and pig iron to eventually drain separately once production succeeded.

Finn stared at the design nervously.

"...That molten metal is definitely going to explode one day."

"Probably."

"...Why do you say dangerous things so casually?"

For several more days, the clearing became nonstop chaos.

Hammering.

Stone cutting.

Clay mixing.

Smoke.

Sparks.

Constant yelling.

Meanwhile, Lilith continued sitting nearby most of the time watching everything with mild fascination while occasionally feeding Potato pieces of fruit she’d secretly taken from the manor.

At one point she looked toward the half-finished blast furnace and quietly asked—

"...So this machine makes liquid metal?"

"Eventually."

"...That’s kind of cool."

That alone nearly made Finn collapse from shock.

"You like one of his weird inventions?"

Lilith crossed her arms proudly.

"It’s better than manure mountain."

"That’s fair," Finn admitted.

Finally—

After nearly a week of exhausting labor—

The blast furnace stood complete.

Towering above the clearing beneath the falling snow.

And as Leon stared up at the massive structure illuminated by firelight—

He couldn’t help smiling slightly.

Because this—

This was the first real step toward true industry.

The blast furnace roared like a monster beneath the night sky.

Orange flames burst from the vents while thick heat radiated across the clearing. The waterwheel beside the river spun continuously, powering the massive bellows that forced air into the furnace without pause.

It was beautiful.

Finn stood beside me covered in soot while nervously gripping a metal rod.

"...Leon," he muttered, "if this explodes I blame you."

" Stop thinking that everything is going to explode."

The furnace suddenly rumbled loudly.

Finn slowly looked toward me.

"...You sound unsure."

I ignored him and focused on the lower vent of the furnace.

This was the critical moment.

Hours earlier we had filled the furnace layer by layer with charcoal and refined iron ore while maintaining continuous airflow to push temperatures beyond anything our bloomeries could achieve.

And now—

If everything worked correctly—

We’d finally have molten iron.

Actual liquid metal.

The foundation for proper casting and industrial machinery.

I tightened my gloves.

"Open it slowly."

Finn swallowed nervously before using the rod to pry open the lower slag vent.

At first—

Nothing happened.

Then suddenly—

Bright orange liquid burst outward.

Molten slag poured from the furnace like glowing lava, illuminating the snowy clearing around us.

Finn immediately stumbled backward.

"BY THE GODS—"

I stared in amazement.

It worked.

It actually worked.

Moments later, a second flow emerged from the lower tap hole.

Thicker.

Brighter.

Liquid iron.

My eyes widened.

There it was.

Molten metal.

Finn stared at it with complete disbelief.

"...We did it."

Hearing those words hit harder than I expected.

We had finally done it.

I immediately grabbed Finn by the shoulders.

"WE MADE MOLTEN IRON!"

Finn grabbed me right back.

"WE MADE LIQUID METAL!"

The two of us nearly started screaming in excitement while jumping around like complete lunatics beside the furnace.

Meanwhile—

Lilith sat calmly beside Potato watching us with complete judgment.

"...You two are celebrating hotter rocks."

"We created the future!" I shouted dramatically.

Finn pointed toward the furnace proudly.

"LOOK AT IT!"

Lilith stared at the molten iron silently for a few moments.

Then—

"...I could do that easily."

The celebration immediately stopped.

Finn blinked.

"...What?"

Lilith stood up calmly while dusting snow from her clothes.

"That furnace is weak."

My eye twitched slightly.

"...Excuse me?"

She casually pointed toward the massive structure we’d spent over a week building.

"That thing."

"That ’thing’ took incredible engineering."

Lilith shrugged.

"I can melt iron faster."

I crossed my arms.

"Oh really?"

"Yes."

"...Prove it."

Finn immediately backed away.

"Oh no."

Lilith stepped calmly toward a nearby pile of raw iron chunks resting beside the workshop.

The atmosphere shifted instantly.

Dark purple mana slowly began gathering around her body.

Then—

She snapped her fingers.

A massive magic circle erupted beneath the iron.

Deep purple symbols rotated violently across the snow while furious flames burst upward.

But these weren’t normal flames.

The fire burned dark violet mixed with black.

And the heat—

The heat was monstrous.

It felt completely unnatural.

The snow around the clearing instantly evaporated while the air itself distorted violently from the temperature.

Even standing several meters away felt unbearable.

My eyes widened in shock.

The iron pile began glowing red almost immediately.

Then orange.

Then—

It melted.

Instantly.

Liquid metal collapsed into the center of the magic circle within seconds.

Finn looked absolutely horrified.

Meanwhile, I simply stared silently.

That temperature...

It far surpassed anything our blast furnace could currently achieve.

Lilith turned back toward me smugly while the dark flames vanished completely.

"...See?"

I stared at the molten iron pile.

Then at the blast furnace.

Then back at her.

"...That’s cheating."

"It’s magic."

"Same thing."

Lilith smiled proudly before walking closer.

"You should just let me work for you instead."

I narrowed my eyes slightly.

"...And what exactly would you want in return?"

Her smile widened instantly.

"Your hand in marriage."

Silence.

Finn immediately looked between us like he was watching a duel.

Meanwhile, I responded instantly.

"I’d rather build another blast furnace."

Lilith’s smile twitched.

Finn burst out laughing immediately.

Then Lilith slowly looked toward him.

The laughter stopped instantly.

"...I suddenly support the marriage idea," Finn said nervously.