Desperate reports flooded in to Caligulio from all fronts.
The situation was already hopeless — the failure of the invasion was obvious.
No, it was worse than that.
Things had progressed to the point where whether they could even retreat alive was in question.
*(How did it come to this? No — when did it even begin to go wrong?)* Caligulio tried desperately to pull his spiraling thoughts back to something rational and failed. He stared once more at the catastrophic situation and began reviewing whatever options remained.
There was almost nothing he could do in this worst-case scenario, but he was still the army's commander. He bore responsibility for the lives of every soldier under his command.
Giving up was the one thing he absolutely could not do.
The first report had informed him that the capital assault force had engaged the enemy.
It had been a stalemate — the situation was deadlocked.
Their side held an overwhelming advantage in numbers, but the enemy had formed an ironclad defensive formation that brute force alone could not break through, and they were putting up a valiant fight.
Magic cannons, large-scale sorcery from the mages — everything was intercepted by defensive barriers and rendered completely ineffective.
It was, for all that they were the enemy, a magnificent defensive formation.
On top of that, communication with the Labyrinth assault force had been severed, and the capital offensive was not progressing as planned.
This was no time to be praising the enemy's formations.
Caligulio understood that. He was only just beginning to realize that he had no way out.
But it was already far too late.
The situation began to change rapidly.
A new enemy force appeared. They were the embodiment of terror itself.
Moving with overwhelming momentum, they began to trample through the Imperial forces.
Despite numbering barely a tenth of the Imperial army, they were annihilating them unilaterally.
The energy measurement teams' reports confirmed several individuals with extremely high Magicule counts.
However, the majority of that force had roughly equivalent energy levels even compared to their own troops.
The number of powerful magical beings at A-rank or above seemed to be quite small.
And yet, the reality unfolding before their eyes told a different story — they were being cornered relentlessly.
Then the situation shifted again.
From within the enemy's ironclad formation, a powerful and devastating large-scale spell was unleashed.
The precision-targeted magic and sorcery began inflicting massive casualties on the Imperial Army.
It took Caligulio a long while to realize the purpose behind that purple-armored unit spreading terror throughout the battlefield: it was to throw their forces into chaos and thin out the defensive barriers.
It was brilliant coordination.
But if that were all there was to it, regrouping was still possible.
The capital assault force had been divided into vanguard and rearguard, each consisting of 100,000 troops.
Even if the vanguard took some damage, the rearguard could immediately move in to support, swap positions, and reorganize.
It was a foolproof strategy made possible only by their overwhelming numerical superiority.
*(Even just holding the advantage temporarily would have preserved the Demon Lord's reputation, wouldn't it?)* Even as he recognized that his own options were dwindling, Caligulio still had a margin of composure.
That margin vanished in the next instant.
Several kilometers away, Caligulio and the Imperial staff officers had been observing the battlefield through long-range scrying magic.
Every single one of them lost the ability to speak in an instant.
All remaining composure evaporated in that moment.
The energy measurement team began screaming like madmen with terror.
"We need to issue a full retreat order RIGHT NOW!!"
But everything was already too late.
Before they could even grasp the meaning of those words, the situation before their eyes told them everything.
A tragedy had struck the rearguard that had been moving to support the crumbling vanguard.
It was caused by a type of strategic destruction magic known as **Gravity Collapse**.
An abominable spell that released absolute levels of energy, spreading devastation in its wake.
It warped a planet's gravitational field, generating a localized supergravity field.
Anything caught within the effect range of that ultra-compressed space would be crushed.
If the compression had continued, eventually all energy would converge at a single point and a small-scale supernova would erupt on the surface.
This time, however, that did not appear to be the enemy's goal.
The spell's effect was dispelled once most of the soldiers had been crushed.
But of those hundred thousand soldiers — how many had survived?
"Th-they're monsters. A single... just a single one unleashed that apocalyptic magic...
It's only supposed to exist in theory!
It requires energy on a scale never before used on this land..."
Yes. Even Caligulio knew.
It was a large-scale magic that, in theory, was considered theoretically possible but remained unverified and still under active research. It was not a spell that had ever been confirmed in the past — it was a new-type large-scale magic being developed from the ground up, drawing on the Empire's finest technology and even mobilizing scientific knowledge from other worlds.
And that creature had executed it perfectly.
By a single magical being, no less.
Demon Lord.
That word reached Caligulio's brain accompanied by a visceral, realistic terror.
Had they laid hands on someone they should never have touched?
Moreover, casting a spell of that magnitude normally required at least ten mages working in concert — and even then, it would be risky.
The energy required was incomparable to ordinary strategic magic, and without sufficient concentration to control it, the spell would detonate uncontrollably.
To not only cast it but also stop it midway with perfect precision — that was the work of something beyond human.
"But... we still have the **Magicule Disruption Radiation** and the scientific weapons..."
"No. We must withdraw immediately, Caligulio."
A man suddenly entered the tent and spoke those words.
The guards — what were they doing — turned to look at the man and gasped.
"C-Could that be... Lord
The man who always ranked at the top during the Empire's rank-competition tournaments.
Caligulio had fought him on several occasions himself. He was a swordsman whose strength could never be underestimated.
But now, Krishna looked like a tattered rag. Even the Empire's finest equipment — **Legendary-class** armor — had deep cracks across the upper body, with a hole torn through the chest.
He bore the unmistakable scars of a deathly battle.
"Listen. Basan and Reinha are dead. Colonel Kansas, Brigadier General
And on top of that, two otherworlders. Yet even with all that, we couldn't defeat the monsters in the Labyrinth.
I detected a great magic there just now, but the one who used it is almost certainly not the Demon Lord.
Multiple Ark Demon-class monsters were confirmed inside the Labyrinth.
And beyond that — Demon Lord-class ones as well.
That spell just now was probably the work of one of those.
We need to pull back. There is no shame in this. Please make the decision!"
"Not the Demon Lord? And there are multiple monsters of that caliber? Demon Lord-class, you say?!
Is that what they truly amount to...
And if the Evil Dragon Veldora were to appear as well on top of all this... we'd have no chance of winning.
And Rimuru the Demon Lord still hasn't even moved yet?!
Rally the troops! We're pulling back for now!!"
Of the three resurrection bracelets they possessed, Caligulio had secretly kept the one taken from Shinji's group for himself.
Two had been analyzed at the Technical Bureau, and Krishna had apparently been loaned one of those.
The Emperor's orders were absolute, and the Technical Bureau had handed it over without protest.
One had been completely dismantled, so the last remaining one was the only one that could be carried out — and it was thanks to that bracelet that Krishna had been resurrected.
This confirmed the bracelet's resurrection effect. However, it also confirmed that the replicas had no such effect.
The soldiers inside the Labyrinth had been truly annihilated — that was now the reality.
350,000 soldiers — annihilated.
Caligulio's face went pale, but now was not the time for that.
Saving the living mattered more than mourning the dead.
He needed to merge with the tank division's 400 airships, regroup with this detached force, assess the situation, and reorganize the army.
At worst, they would have to retreat all the way back to the Empire, but that was still better than being wiped out completely.
Caligulio made his decision and issued his orders.
But it was already too late.
"Fufufufu. That is quite the problem. You'll need to entertain me for a little while at least."
The demon had already crept close, and he never let his wretched prey escape.
Tension rippled through the command post.
The intruder was a single magical being.
But the **aura** radiating from that being carried an overwhelming presence unlike anything they had ever encountered.
A creature of their own stature emanated a demonic presence denser and more oppressive than even the greatest of dragons.
Moreover, that creature had infiltrated all the way here without giving off any detection trace whatsoever.
The sheer magnitude of **aura** it possessed — and it had breached their defenses without emitting so much as a whisper.
The guards drew their swords against the intruder.
But their bodies felt heavy, as if their arms refused to obey their commands.
"Fufufufu. You inferior beings — did you truly believe you could fight me as equals?"
The red-haired demon,
Caligulio turned to Krishna, but Krishna had already collapsed to his knees.
He must have sensed the overwhelming gap in power and fallen into despair.
Caligulio clung to one last thread of hope and attempted negotiation.
"Forgive me — my name is Caligulio.
I am the commander of this army and the supreme officer in charge of this operation.
Might I have the honor of knowing your name?"
"Oh my? How polite of you.
My **name** is Diablo. I am the loyal **servant** of Lord Rimuru the Demon Lord."
Just as Caligulio had assessed — the creature was **named**.
Though at this level, it would be harder to believe if it didn't have a name.
Having confirmed that the being possessed reason and intellect, Caligulio placed his hopes on negotiation.
"Lord Diablo, I wish to offer our surrender.
Rather than fighting to the death and costing both sides more casualties, wouldn't it be in your interest as well?
What do you say?
Naturally, we will pay reparations, and we vow to cease all future incursions.
Better yet — perhaps we could even discuss an alliance between the Empire and the **Monster Country**!
We do not forget favors. Would you consider it?
Would you be willing to convey this to Lord Rimuru the Demon Lord?"
Given the current situation, the 350,000-strong Labyrinth assault force was entirely dead.
Of the troops sent toward the capital, more than half were either killed or no longer combat-capable.
As for the detached force — since no communication could be established with them, their remaining strength amounted to roughly 200,000 once survivors from the existing 150,000-strong force were added.
That was still a terrifying number of soldiers who could fight to the death in a frenzy. Since the Empire had no chance of achieving complete victory, this proposal was worth serious consideration.
Caligulio reached that judgment in an instant and requested that Diablo serve as intermediary to Lord Rimuru, hoping to negotiate their release.
This military operation had been a total failure.
They had drastically underestimated the enemy's fighting strength.
This was a force that the Empire had been confident could triumph even against three former Demon Lords simultaneously.
Even combining the entire military might of the western nations, they amounted to barely a third of this force.
They had been so certain of absolute victory, and yet the result was this.
Multiple Demon Lord-class monsters among Rimuru the Demon Lord's subordinates...
They should have cut their losses and retreated once, gambling on rebuilding for the future.
Nearly 500,000 soldiers had already perished. Caligulio's downfall was inevitable, but any further sacrifice could bring the Empire itself to its knees.
Caligulio was greedy, but he was not incompetent.
That was precisely why he had made this proposal.
If the enemy demanded the general's life as the price, he was prepared to sacrifice himself.
But it was all already far, far too late.
"Fufufufu. Those words come a little too late.
By now, you are the only ones left alive."
Caligulio could not comprehend what he had just heard.
The staff officers were the same — none of them could make sense of Diablo's words.
But Diablo did not seem the least bit bothered.
*Snap.* He snapped his fingers.
In an instant, the command tent was blown away, and the scene outside flooded into Caligulio and his officers' field of vision.
Before them lay a mountain of corpses stretching as far as the eye could see.
The soldiers had died in the middle of their duties, as though they had simply fallen asleep.
As though their very souls had been ripped from their bodies — No — their souls had literally been ripped from their bodies. The soldiers had been unable to put up even the slightest resistance as the red-haired demon Diablo harvested their souls.
Diablo had no reason to bother letting enemy soldiers live in order to slip past them.
Killing everyone in sight would have been equally tedious.
So instead, the moment he descended upon the camp, he used **World Collapse** to reap the souls of the enemy soldiers only.
In truth, merely unleashing his **Demon Lord Aura** could have driven them all to death by madness, but that would have caused too much of a commotion.
Diablo had never intended to let a single enemy soldier live from the very beginning.
That was precisely why he had not hesitated for a single moment in annihilating them all in the most efficient manner possible.
Above all, Diablo preferred to work alone.
That was the reason he kept no subordinates of his own.
Useless tools were not worth wielding.
In Diablo's view, a tool demonstrated its worth only by proving its usefulness to its master.
That was why incompetent subordinates were unnecessary, and he himself had to remain a useful **tool** to his **master**.
"Ugh... ugh... UOOOOOOOOOOOH!!"
Caligulio screamed, vomiting blood in his fury as he glared at Diablo.
The rage of having his comrades slaughtered had, for one brief moment, overwhelmed his terror.
In that instant, a radiant and divine armor enveloped Caligulio, restoring his calm rationality.
The greatest equipment passed down since the Age of Gods.
Lent to him by the Emperor — **Mythical-class** armaments.
The proof of being one of only four army commanders in the entire Empire permitted to wear them — the pinnacle of the Empire's military power.
"I won't forgive you, demon! I'll destroy you!"
"Fufufufu. Now *that* is what makes things interesting."
The two locked eyes, and the final battle began.
But it could hardly be called a battle.
Because for Diablo, Caligulio was nothing more than an insect. Before his overwhelming power, the **Mythical-class** armaments meant absolutely nothing.
A tool only held meaning when it could be wielded to its full potential.
There was nothing more sorrowful than a tool whose user could not draw out its true capability.
Caligulio was not worth Diablo's full effort. This was nothing more than a simple harvest of souls — not even a contest.
Of the 150,000 soldiers and officers remaining at the Imperial Army's main camp near the Labyrinth, all but a handful of senior commanders were annihilated without ever understanding what had been done to them.
And so, every single unit that had invaded the **Monster Country** was wiped out without achieving any meaningful result.
The immediate crisis had been averted.
—Whether it had truly been a crisis at all was a matter of perspective and would be judged differently depending on who you asked.
The Empire's invasion of the **Monster Country** had ended in utter failure.