The Yandere villainess loves the useless engineer

The next week became one of the most exhausting periods of my life.

Again.

At this point I was starting to suspect industrialization itself was personally trying to kill me.

The shack had completely transformed from a simple workshop into something closer to a battlefield of sketches, metal scraps, charcoal dust, and half-finished mechanisms. Every flat surface had become buried beneath diagrams while tools littered nearly every corner of the room.

And somehow—

Despite all of this—

Finn still kept losing the hammer.

"I swear it was here five minutes ago."

"You said that yesterday."

"That was a different hammer."

I stared at him blankly.

"How do you lose equipment so much?"

Finn pointed accusingly at the workshop.

"Because this place looks like a metal demon exploded."

"That’s called progress."

"That’s called tetanus."

Meanwhile Lillith sat nearby watching me instead of the project itself.

Naturally.

She occupied a chair near the wall with her chin resting against her hand while silently observing me work with the same level of attention most people reserved for life-threatening situations.

Occasionally she would glance toward the engine sketches spread across the table.

Then immediately lose interest.

"...It still sounds inferior to magic."

"It’s not competing with magic."

"It’s making loud noises and leaking hot water."

"That’s temporary."

"It exploded twice yesterday."

"That was also temporary."

Finn raised a hand from across the room.

"One of those explosions almost killed me."

"You’re exaggerating."

"The metal pipe embedded itself in the wall!"

I ignored him and returned my attention toward the diagrams.

The basic principle itself wasn’t difficult.

Compared to rifles, steam power was actually much simpler conceptually.

The problem was precision.

Again.

Everything always came back to precision.

A steam engine only worked properly if the pressure stayed controlled, the piston moved smoothly, the boiler remained sealed, and the valve timing functioned consistently.

Unfortunately—

We were trying to achieve all of that with hand-forged and sand casted components inside a medieval workshop.

Which was deeply miserable.

The first several days were spent almost entirely manufacturing parts.

Iron cylinders.

Pressure pipes.

Valve housings.

Piston rods.

Most of them failed.

Some warped while cooling.

Others leaked steam immediately.

One piston jammed so badly that Finn spent twenty minutes trying remove it before accidentally launching himself backward into a shelf.

Lillith clapped politely after watching it happen.

"You moved very far."

"Thank you Lady Nightbane," Finn answered weakly from the floor.

The scaled bloomeries outside at least made things easier now.

For the first time, we had enough consistent steel production to repeatedly refine components instead of treating every failed part like a national tragedy.

Still—

Even with improved materials, the work remained painfully difficult.

By the fourth day, my shoulders ached constantly from shaping metal manually.

The prosthetic leg made things worse.

Balancing while working heavy equipment still felt unnatural, and more than once I nearly lost balance trying adjust larger components.

Naturally—

Every single time that happened, Lillith reacted like I’d just been fatally wounded.

"Leo."

"I’m fine."

"You stumbled."

"I corrected myself."

"You almost died."

"That is not how stumbling works."

Lillith ignored me completely before physically moving closer to stand beside me while I worked.

Not helping.

Just existing close enough to catch me if necessary.

Which somehow made concentrating harder.

At night the situation became even worse.

Mostly because Lillith did not sleep.

Meanwhile I absolutely did.

Or attempted to.

The problem was that every time I woke up during the night—

She was still staring at me.

Same position.

Same expression.

Same terrifying level of focus.

At one point I woke up at what felt like the middle of the night and groggily looked toward her.

"...Have you seriously not moved?"

"You rolled over twenty-seven times."

I stared at her silently.

"That did not answer my question."

"You also muttered about pistons twice."

"...Why are you collecting information on my sleep habits like military intelligence?"

Lillith smiled softly.

"Because you’re so cute."

Then somehow she’d gently force me back down before stroking my hair until I fell asleep again.

The genuinely terrifying part was that it worked every time.

By the sixth day, the workshop had finally begun resembling an actual engine assembly site instead of a metal graveyard.

A large cylindrical boiler now rested near the rear of the shack connected to a pressure chamber through reinforced piping. Beside it sat the piston assembly attached to a basic rotational beam system that would theoretically convert the piston’s vertical movement into rotational motion.

Theoretically.

Finn stared at the machine cautiously from several meters away.

"...I don’t trust it."

"You don’t trust anything."

"This one hisses."

"That’s steam pressure."

"It sounds angry."

I tightened another valve carefully before stepping back slightly.

Truthfully—

I was nervous too.

Primitive steam engines were dangerous even with modern machining.

This thing had been built with manually forged components beside a forest river by one crippled inventor, one emotionally unstable assistant, and Finn.

The odds were not encouraging.

Lillith quietly approached from behind while resting her chin lightly against my shoulder.

"You’re excited."

"I’m worried."

"Your eyes do the shiny thing when you’re excited."

"That is not a real symptom."

"It is for you."

Finn cautiously poked part of the pressure pipe with a stick.

"Can it explode?"

"Yes."

Finn immediately backed away further.

"WHY WOULD YOU SAY THAT SO CASUALLY?"

"Because if pressure exceeds tolerance levels, the boiler ruptures."

"...You speak like a villain."

I ignored him and moved toward the furnace beneath the boiler.

Then finally—

I lit the fire.

The room slowly grew warmer as flames spread beneath the boiler chamber.

For several long moments—

Nothing happened.

Then gradually—

The water inside began heating.

A faint hissing sound emerged from the pipes.

Steam.

Pressure slowly started building throughout the system while the metal structure groaned faintly from the heat.

Finn looked deeply uncomfortable.

"...I hate this."

The pressure gauge equivalent I improvised slowly began rising.

Not accurate.

But enough.

Steam escaped faintly from one of the side seals.

I immediately moved toward it and tightened the fitting further.

The hissing weakened.

Good.

Then suddenly—

CLANK.

The piston twitched slightly.

All three of us froze.

Another sharp metallic sound echoed through the workshop.

Then—

The piston moved again.

Slowly.

Violently.

But unmistakably.

Steam pressure forced the piston upward before gravity and the return mechanism pulled it back down.

Again.

Again.

Again.

The attached beam system started jerking awkwardly.

Then gradually—

The rotational arm began turning.

Slow.

Uneven.

Barely stable.

But moving.

Actually moving.

Finn stared blankly at the machine.

"...No way."

The rotational wheel continued turning with rhythmic metallic clanks while steam hissed through the valve systems.

It was ugly.

Inefficient.

Dangerous.

But it worked.

A laugh escaped me before I could stop it.

"It works."

Finn slowly looked toward me in disbelief.

"It actually works."

The machine continued chugging beside us while steam escaped from multiple weak seals.

The entire structure shook violently enough that I genuinely worried it might disassemble itself at any moment.

But none of that mattered.

Because the principle worked.

Steam pressure had become mechanical movement.

The implications hit me almost instantly.

Transportation.

Mining.

Factories.

Pumps.

Industry.

Everything changed now.

Finn slowly walked around the machine like he was observing some mythical creature.

"...Leon."

"What?"

"...You made a metal worker."

I grinned slightly.

"That’s only the beginning."

Lillith meanwhile stared at the engine silently for several moments.

Then finally—

"...It’s very loud."

"That’s your conclusion?"

"It also smells strange."

"That’s coal smoke."

Lillith lightly poked part of the rotating mechanism before looking back toward me.

"...You’re happier around machines than most humans."

"That’s because machines make sense."

Finn pointed aggressively.

"THAT IS THE MOST CONCERNING THING YOU’VE SAID THIS WEEK."

I ignored him again while stepping closer toward the engine.

The rotational system still moved unevenly, and pressure output fluctuated badly.

It needed refinement.

Better sealing.

More consistent pressure release.

Improved metallurgy.

But despite all its flaws—

I could already see the future sitting in front of me.

And for the first time since arriving in this world—

The future no longer felt impossible.