The next day, I went to the vast grounds located on the outskirts of the Royal Capital.
Set within a grassland, the area was bare reddish-brown earth.
There were sinkholes everywhere, and scorched-looking marks were prominent.
Some distance away, wooden structures towered.
This was the training ground exclusively for the Demon Lord's Army.
As personnel increased, the training grounds within the Royal Capital became cramped, and this new facility was established in response to Henry's request.
Here, training under conditions close to actual combat was possible, and magic could recreate various terrains.
Because it was surrounded by a barrier, there was no need to worry about damage to the outside.
Soundproofing was also perfect, showing thorough consideration for the surrounding environment.
"Oh ho, this is quite something. It explains the soldiers' high proficiency."
The one exclaiming in admiration beside me was the former Demon Lord, Diera.
She was exceptionally energetic.
Having spent the night battling repeatedly with Grom, she seemed mentally and physically satisfied.
Diera was a combat maniac on par with, if not exceeding, Henry.
She was observing her surroundings with keen interest.
A question suddenly occurred to me, and I asked Diera.
"In your era, did you never consider building a facility like this?"
"Training subordinates wasn't something we could afford. If you had been a little lazier back then, perhaps I might have had the leeway for it."
The Demon Lord glanced at me sideways.
A slight note of reproach was contained within.
"...I'm not going to apologize."
"Naturally. You had your own mission. I have no intention of bringing that up now."
Diera shrugged and smiled.
It seemed that was just light banter.
She didn't seem bothered by the past.
She appeared to be enjoying her new life.
She occasionally dug up topics like this, but it wasn't serious.
In fact, she seemed to take some pleasure in my reactions.
Back then, I had no way of knowing, but apparently, this was Diera's personality.
"Still, if you have this much architectural skill, you could at least build me a house, couldn't you?"
"Figure it out yourself. I've already provided the building materials."
I answered immediately.
Currently, Diera lived in the old demon territory.
That land, once polluted by miasma, had been cleansed by the destruction of my forbidden magic.
Now, its environment was not much different from any other land.
She lived there, making a modest living.
She had no intention of joining the Demon Lord's army, maintaining her position as strictly a neighbor.
That was probably her own way of being particular about things.
That said, it seemed she often felt the inconvenience of living there.
The fact that she frequently visited the Demon Lord's territory was proof enough.
Ugh, how heartless... If some sage hadn't blown up my castle, I could have kept living there just like that, you know..."
Diera once again looked at me sideways.
She was referring to the incident where I had blasted her castle away with grand magic.
That was the result of choosing the optimal strategy.
I never imagined that ten years later, the Demon King herself would be complaining about it.
While we were exchanging such words, the Demon King's army began to form ranks in the distance.
They swiftly organized into formation and launched their attacks toward the target.
The sound of countless shots echoed through the air.
Seeing this, Diera squinted and observed carefully.
"That looks like a staff, but what is that weapon?"
"It's a firearm. It launches lead bullets to attack the enemy. It's more of an advanced evolution of the bow."
The firearms captured in the Technomagic Nation had undergone further improvements, evolving into a unique weapon.
Their rate of fire and accuracy had been enhanced to a level suitable for practical battlefield use.
Mass production had already begun.
They were even forming specialized units within the Demon King's army.
Diera observed the training drills with the firearms.
She stroked her chin while offering her opinion.
"From the look of it, those are for anti-personnel use. Mages would probably hate them."
Her observation was correct.
Firearms would likely become the mage-killing weapons in the wars to come.
From afar they deliver precise strikes without needing incantations, yet unlike bows they require no immense training. Once one masters the basic operation, anyone can wield them to full effect. Such versatile weapons are rare indeed.
Behind the musketeer unit, another new weapon emerged. Diera furrowed her brows and tilted her head.
"Is that... an iron carriage?"
"A weapon called a tank. It destroys targets from long range with a beam of magic power. Ordinary magic cannot defend against nor evade it."
I explained. This too was among the weapons captured from the Arcane Kingdom. Its defining feature was the powerful beam fired from its cannon. Though numbers were still insufficient, I intended to form units with them eventually.
"To think they'd develop such a vicious weapon. The Wisdom of the Sage remains sharp, I see."
"I didn't conceive it. They merely repurposed something modern technicians had devised."
All traced back to John Doe's inspiration. His genius would undoubtedly have propelled human civilization by leaps and bounds. Though there were unavoidable reasons, I had snuffed out that potential at its root. I have no regrets, yet I intend not to forget this fact.
After observing for some time, Diera suddenly turned toward me. Then she posed a question to me.
"Why have you shown these to me now?"
"Consider it part of the tour. It just turned out well, and I wanted to show it off."
Diera and I have something in common—we’re both Demon Lords.
Once mortal enemies, we now share a relationship more like senior and junior.
Her perspective is invaluable.
While "tourism" is the official pretext, my real desire is to learn about areas for improvement from the viewpoint of the previous Demon Lord.
The Demon Lord’s army is still very much a work in progress.
By implementing her feedback, I aim to further strengthen it.
Aware of this, Diera lets out an exasperated laugh.
"You're a diligent one, aren't you... By the way, can I operate that as well?"
She pointed toward the tank.
I'd noticed her staring at it intently for a while now, and it seemed to have caught her interest.
She was unusually fidgety, lacking her usual composure.
"It is operable. Would you like to give it a try?"
"Oh! I would very much like to!"
Diera raised both hands in delight.
Her reaction was almost childlike.
Utterly innocent.
There was no way to imagine she was a former Demon Lord from that demeanor.
We moved over to where the Demon Lord’s army was conducting training.
My subordinates looked at us in surprise but did not stop their drills.
Suppressing their unease, they continued their assault on the imaginary enemy.
It was amidst this that Henry approached us.
"Hey, Chief. What's up today?"
"Diera wants to try out the weapons. I'd like you to explain them to her."
"Ah, sure. Leave it to me."
Henry agreed readily.
Meanwhile, Diera declared with a hint of unease, "I can only wield a spear, but will that be alright?"
"Basic operation is something anyone can do."
Henry replied in a cheerful tone.
He beckoned Diera and headed toward the nearest tank.
As I watched them, Diera turned back and shouted, "Dwight! Why are you standing there? You're doing this with us too!"
"...I'm good."
"What kind of Demon Lord is so passive? The archers wouldn't think the same, would they?"
Diera cried out as if in disbelief.
To my astonishment, she even sought an opinion from Henry beside me.
Henry placed a hand on his hip, pondered, then showed a fierce grin.
"True enough. Sorry to do this after your all-nighter, Chief, but let's have a little fun? I've been wanting to have a shooting match with these guns."
"...Fine."
Receiving their expectant gazes, I nod my head, albeit reluctantly.
I had intended to take things slow and simply observe from the sidelines, but it can't be helped.
I was the one who chose to be their guide.
A little company shouldn't be too much to ask.