After collecting the black soil, Sienna didn’t waste time standing around.
She brought Wood and Stone back toward the mine, where Mirella and Tiara were directing the slaves.
If Harold’s plan was to build a rabbit ranch, then this mine was the heart of everything.
Sienna needed to see with her own eyes whether it was truly usable.
The iron mountain was full of dwarf tunnels, but calling them “tunnels” was an insult.
This wasn’t some small mine dug for ore.
It was a whole underground world.
The dwarves had hollowed out huge sections of the mountain, leaving behind wide passages and open spaces that looked more like streets and plazas than a simple workplace.
Yet despite being abandoned for years, the structure still felt solid.
The walls were reinforced with stone arches, and the ceiling was supported in a way that made it hard to believe it had been carved out by hand.
Mirella and Tiara were already busy.
They weren’t just standing around shouting orders.
Mirella moved through the workers like a commander, calm but strict, and Tiara stayed close by, quietly checking that the slaves weren’t cutting corners.
Sienna could tell they had done this kind of work before.
They didn’t look like noble servants anymore.
They looked like people who had survived real hardship.
The slaves didn’t need much pushing either.
Sienna’s promise of freedom had lit a fire inside them.
They carried stones, cleared debris, and swept the tunnels with a kind of desperate energy, like their lives depended on it.
In truth, they did.
When Sienna arrived, she noticed something important.
The mine wasn’t equally useful everywhere.
The first part of the mine, near the entrance, had several wide chambers and rows of stone caves, almost like dormitories.
It was clean, dry, and open enough to hold cages and pens.
But deeper inside, the tunnel slanted downward, and water began to collect.
Past a certain point, the floor was wet, the air was colder, and the darkness felt heavier.
Still, the usable area near the entrance was already massive.
Even if they only used the outer chambers, raising tens of thousands of blue-eyed rabbits would not be a problem.
Sienna lifted her gaze toward the mountain itself.
Only now did she truly understand the place she had been exiled to.
The iron mountain wasn’t tall compared to the great peaks in legends, only about a kilometer high, but it stretched far, forming a half-ring around the black soil wasteland like a giant iron arm.
The castle was built into the slope, with the mountain behind it and the dead black land spreading endlessly in front.
Beyond the mountain lay the carrion swamp, one of the forbidden zones of the continent, a place that even nobles avoided.
Even the mountain’s surface looked sick.
The soil was dark brown, weeds grew in patches but looked weak, and the few twisted trees that survived seemed half-dead, their branches bare and their trunks thin like starving bones.
Sienna couldn’t help but sigh.
“I finally understood why the empire had sent us here.
This wasn’t exile.
It was a slow execution.
A place where a noble family could rot quietly until nobody remembered their name.”
But Sienna didn’t intend to rot.
She walked closer to the mine entrance.
The opening was huge, tall enough for a wagon to pass through easily.
Inside, the open space expanded like a hidden city, with small and large caves carved neatly into the stone walls.
If someone told her ten thousand people had once lived and worked here, she would believe it.
This wasn’t a mine anymore.
It was a fortress.
It was a base.
And Sienna felt her blood heat up at the thought.
Mirella finally noticed her and hurried over, wiping dust from her hands.
“Young Miss, why did you come here?
It’s dirty and messy.
You should stay in the castle.”
Sienna smiled.
“I came to see it myself.
We’re going to live here for years, maybe for life.
If I don’t understand this place, how can I lead anyone?”
Mirella’s face softened slightly, but she still looked worried.
“Then please don’t stay long.”
Sienna nodded and asked, “How many mines like this are there on the mountain?”
Mirella replied quickly.
“Two large ones.
This one, and another on the other side of the castle.
Their size is similar.
The rest are smaller passages, dozens of them, but nothing as useful as these two.”
Sienna narrowed her eyes.
“Are these mines connected underground?”
Mirella considered for a moment.
“Dwarves often built connections, but they rarely dug long horizontal tunnels at this height.
It weakens the mountain.
Most connecting tunnels go deeper underground.
Also, this mine goes down and becomes flooded.
It seems to have turned into a dead end.”
Sienna nodded.
That was good news.
If the flooded section blocked access, it meant fewer ways for outsiders or beasts to sneak in.
She pointed at the mine entrance.
“Then make this place our main ranch.
Reinforce the path from the castle to here.
Build barriers.
I don’t want rabbits escaping into the water.
A rabbit that falls in and drowns is the same as throwing money away.”
Mirella nodded firmly.
“Understood.”
Then she tried again to send her away.
“Young Miss, this isn’t a place for you.”
Sienna waved her hand.
“I’m already here.
I want to see the water inside.
If it’s usable, it can help us.
If it’s dangerous, we need to know early.”
Mirella hesitated, then sighed.
“I’ll go with you.
I understand water better than you do.”
Sienna didn’t argue.
“Fine.
Let’s go.”
Tiara remained behind to supervise the slaves, while Sienna entered the mine with Mirella.
Wood and Stone followed closely like silent guards.
The deeper they walked, the colder the air became.
The tunnel slanted downward, not steep, but enough to make Sienna feel as if they were entering another world.
She noticed old tracks carved into the stone floor, likely where carts once rolled.
The rails themselves were gone, but the path remained.
After several hundred meters, the sound of water became clearer.
Then Sienna saw it.
A vast underground lake stretched before them, so wide that even with the torchlight from the entrance behind them, she couldn’t see the far end.
The surface was dark, reflecting faint glimmers from the stone above, and the air carried the clean scent of moisture.
It wasn’t a puddle.
It wasn’t a pool.
It was like a hidden sea inside the mountain.
Mirella raised her hand, and a bright ball of light formed above her palm, illuminating the space around them.
The glow was soft, steady, and strangely beautiful, like a moon trapped in her hand.
Sienna stared for a moment.
Even after all the memories she had inherited, seeing magic used so casually still felt unreal.
Under the light, she noticed several stone pillars rising from the water.
They were thick and strong, and at the top of each pillar was a flat platform, like a small island.
The pillars connected the lake to the ceiling, giving the entire cavern a strange, ancient feeling, as if the dwarves had built a temple instead of a mine.
Sienna pointed.
“Mirella… what are those?”
Mirella smiled faintly.
“Support pillars.
The dwarves left them to hold the mountain.
Those platforms were used as command stands.
Supervisors could stand there and direct workers.”
Sienna’s eyes brightened.
“So, this entire area has been hollowed out…”
“Yes,” Mirella said.
“This is not natural.
It was carved.”
Sienna laughed, unable to stop herself.
“Good.
This is too good.
If we solve the water flow problem, we can raise fish here.
Not a few fish.
A whole lake of fish.”
Mirella’s expression became thoughtful.
She extended her senses, her face serious as she felt the water element around them.
“The idea is good, Young Miss.
But we must confirm whether the water is living water or stagnant water.
Stagnant water will rot.
Fish won’t survive.”
Sienna grabbed her chin in thought.
“So, does it feel stagnant?”
Mirella shook her head.
“No.
The water element here is active.
That usually means flow.
But if there is flow, there must be an entrance and an exit.
If there is an exit, then fish can escape.
We might raise them for months only to have them swim away.”
Sienna’s smile faded slightly.
“Same problem as the moat.”
Mirella nodded.
“Exactly.”
Sienna stared at the lake, thinking hard.
A lake like this was a treasure, but it was useless if it couldn’t be controlled.
She finally spoke.
“Mirella, take some water out.
I want to study it.”
Mirella didn’t ask why.
She simply raised her hand and moved her fingers.
The lake surface rippled, and then a massive ball of water rose from the lake, floating into the air.
It was almost as big as a person, perfectly round, hovering quietly like a trapped piece of the lake.
Wood and Stone stared at it, their eyes wide.
Sienna stepped forward and, with a thought, stored the entire water ball into her space warehouse.
The water vanished instantly.