The Yandere villainess loves the useless engineer

The sun slowly erupted from the horizon signalling the start of a new day.

For several quiet moments, I simply laid there half-awake staring blankly ahead while trying to gather my thoughts.

Then I turned slightly onto my side—

And immediately locked eyes with Lillith.

She was already staring directly at me.

Of course she was.

Lillith laid beside me with her head resting against her arm while quietly admiring me with the same gentle expression she always had whenever she thought I wasn’t paying attention.

At this point I wasn’t even surprised anymore.

I stared at her silently for several seconds.

"...How long have you been awake?"

Lillith blinked softly.

"I never slept."

Right.

I forgot again.

Or more accurately—

I kept trying to forget because the idea still felt deeply unsettling.

I rubbed my face tiredly.

"You really plan to spend six nights a week just staring at me?"

Lillith smiled faintly.

"I wish it could be seven."

"...That was not comforting."

"It was romantic."

"No it wasn’t."

Lillith ignored me completely before gently reaching over and brushing some hair away from my face.

"You move a lot in your sleep."

"...That sounds like information I shouldn’t know you have."

"You also mutter when stressed."

I immediately frowned.

"I do not."

"You said Finn’s name twice."

"...Why would I say Finn’s name?"

Lillith looked mildly displeased now.

"I’ve been wondering the same thing."

I sighed heavily before slowly sitting upward.

The moment I moved, Lillith instantly grabbed onto my shirt lightly like she expected me to disappear.

"...I’m going to the construction site, not another kingdom."

"Mhm." 𝒇𝙧𝙚𝓮𝙬𝙚𝓫𝒏𝓸𝓿𝓮𝒍.𝓬𝙤𝓶

"You say that but you’re still holding onto me."

Lillith looked down at her hand like she genuinely hadn’t noticed.

Then instead of letting go—

She tightened her grip slightly.

Eventually after another ten minutes of Lillith refusing to let me leave the bed properly, the two of us finally headed toward the construction site.

The morning air felt cool while sunlight poured down across the territory.

As we walked, servants and guards throughout the manor visibly relaxed after seeing me outside again.

Apparently my kidnapping had caused enough panic that people still looked relieved every time they saw I was alive.

That felt strange.

Eventually the large construction site finally came into view through the trees.

And the second I properly saw it—

I stopped walking entirely.

"...Holy shit."

Seven massive scaled bloomeries stood near the river now, all connected to multiple rotating waterwheels that continuously turned beside the rushing current.

Smoke slowly rose into the morning sky while workers moved throughout the site carrying ore, charcoal, and materials between stations.

The entire place looked completely different from when I last saw it.

Larger.

Alive.

Industrial.

For several moments I simply stared.

Then suddenly—

A familiar voice called out proudly.

"Pretty impressive right?"

I looked over.

Finn stood near one of the larger waterwheel systems with his hands on his hips looking unbelievably smug.

Honestly—

He looked like he personally invented civilization.

"You actually finished them..."

Finn immediately puffed his chest out slightly.

"Well obviously."

"You barely understood the sketches."

"I understood enough."

"That is horrifying."

Finn ignored me before gesturing dramatically toward the site around us.

"The workers finally adapted."

That honestly surprised me more than the furnaces themselves.

The first day had been a complete disaster.

Workers installed support beams backwards, built ventilation channels incorrectly, and somehow nearly flooded part of the foundation trying to redirect water toward the wheels.

At one point, two knights had even managed to accidentally reverse an entire wheel mechanism which caused water to spray directly into a furnace instead of powering it.

The resulting explosion of steam nearly killed everyone’s confidence instantly.

But now—

Everything actually worked.

Workers moved between systems confidently while managing the airflow and heat almost entirely on their own.

Finn grinned proudly.

"They know how to run everything properly now."

My excitement immediately grew further.

That changed everything.

Actual scaled production.

Consistent steel.

Machines.

Infrastructure.

For the first time since arriving in this world, industrialization no longer felt like some distant dream.

It finally felt possible.

Then suddenly—

Lillith quietly spoke beside me.

"...You seem more excited about these than whenever you’re with me."

I blinked.

Then slowly looked toward her.

Lillith stared at the furnaces with mild betrayal in her eyes.

"...Lillith."

"You looked happier seeing those giant fire pits than when you saw me this morning."

"That is not true."

"You smiled at the waterwheel."

"...It’s a very good waterwheel."

Lillith stared at me blankly.

Honestly—

I thought she might actually destroy the river out of jealousy.

Luckily Finn interrupted before she could spiral further.

"So what’s next?"

That immediately pulled my attention back toward the site.

I slowly looked across the furnaces again while thoughts raced through my head.

A grin spread across my face.

"We’re heading back to the shack."

Finn blinked.

"...That smile concerns me."

"It should."

Lillith lightly sighed beside me.

"Whatever he’s planning probably explodes."

"That is a unfair assumption."

Finn immediately nodded.

"No it isn’t."

A while later, the three of us finally arrived back at the shack hidden deeper within the forest.

The familiar sight immediately brought back memories of endless nights working beside furnaces, failed rifle prototypes, ammunition experiments, and nearly blowing ourselves up repeatedly.

The place felt nostalgic now.

I headed inside quickly before moving toward one of the larger stacks of sketches resting beside the worktable.

After several moments of searching, I finally pulled out a large rolled parchment bundle.

Finn immediately narrowed his eyes.

"Oh no."

"What?"

"That is the exact face you made before inventing guns."

"That’s ridiculous."

"You literally smiled like a villain."

I ignored him completely before spreading the sketches out across the table.

Complex diagrams filled the parchment.

Pressure systems.

Rotational mechanisms.

Pistons.

Boilers.

Valves.

Finn stared down at the drawings silently for several seconds.

Then eventually—

"...I understand less than usual somehow."

"That’s because this one is important."

Lillith meanwhile walked over briefly, glanced at the sketches once—

Then immediately lost interest.

"Whatever it does, I can probably do better."

"That is not the point."

"It usually isn’t."

I pointed toward one of the larger sections of the blueprint.

"This..."

My grin widened slightly.

"...Is a steam engine."

Finn blinked.

"...A what?"

"A machine that converts heat into movement."

Silence.

Finn continued staring blankly.

Then slowly—

"...Those were definitely words."

I rubbed my forehead.

"Alright. Imagine boiling water."

"Okay."

"The steam creates pressure."

"Still following."

"That pressure moves mechanical components."

Finn stared at me for several more seconds.

"...You lost me again."

I sighed heavily before grabbing another sketch.

"Look."

I pointed toward the piston system.

"Steam enters here."

"Pressure builds."

"The piston gets forced upward."

"And that movement can rotate wheels continuously."

Finn looked increasingly horrified the longer I explained.

"...You’re trying trap explosions inside metal again aren’t you?"

"It’s controlled pressure."

"That is exactly what you said before the rifles."

Lillith casually leaned against me while completely ignoring the sketches.

I wasn’t even sure she’d listened to a single word.

Instead she rested her chin lightly against my shoulder while quietly watching my face instead.

"...Leo."

"What?"

"You’re doing the excited inventor thing again."

"That is because this is important."

"You started glowing when talking about the weird metal tube."

"It’s not a tube."

Finn looked down at the sketches again cautiously.

"...Will this explode?"

"...Probably not."

"That hesitation was terrifying."

I ignored him again before pointing toward another section of the design.

"If this works properly, we won’t need rivers forever anymore."

That immediately made Finn pause.

"...Wait."

For the first time since the explanation began—

He actually looked interested.

"You mean these machines could work anywhere?"

Now he understood.

I nodded slowly.

"Exactly."

Silence filled the shack afterward.

Even Lillith glanced slightly back toward the sketches now.

Finn slowly looked back down at the blueprints.

Then toward me.

"...Leon."

"What?"

"...That sounds insane."

A grin slowly spread across my face again.

"Now you’re starting to understand."