Mechanized Corps Commander Caligurio advanced his army with absolute confidence.
The invasion route had been deliberated with his staff officers numerous times, and he had deliberately made the Magical Tank Division the vanguard, advancing head-on to draw attention.
Even if the Evil Dragon Veldora appeared, they were fully prepared with 100 aerial warships from the Air Combat Squadron providing cover support.
He believed this fighting force alone was more than enough to subdue the entire western region.
After all, those 100 aircraft were loaded to maximum capacity with the finest mages in full operational formation.
As a result, the remaining 300 aircraft transporting the Beast Corps via sea routes had hardly any mages capable of offense, but Caligurio judged this acceptable since their role was primarily logistical support.
In this two-pronged simultaneous operation, his Mechanized Corps would achieve tremendous results.
The thought of how this would elevate his political power within the Empire made Caligurio unable to stop smiling.
Now, once the enemy had taken the bait and engaged the conspicuous vanguard force, his own main army would make its grand appearance and begin the advance.
Even along the border, it was inconceivable that Armed Nation Dwargon would fail to notice Caligurio's movements.
They would certainly respond and contact their allied nation— The Monster Country.
But by then, it would already be too late.
By the time they tried to recall their forces to deal with the vanguard, the distance would be too great and there would be no time.
Even if they regretted falling into his trap, it would be far too late.
Moreover, even if they had deployed forces along every route, they would simply be spread too thin to pose any real obstacle.
Everything was going exactly as he had planned, and victory was assured.
Furthermore, if Dwargon showed any signs of cooperating with the Monster Country, their neutrality would be shattered.
If that happened, so much the better—he had already been contemplating destroying and subduing them simultaneously.
And then, the long-awaited report arrived.
A report came from the vanguard stating that the Monster Country's Tempest forces had been spotted.
There were only slightly over ten thousand of them.
The report confirmed this was unmistakably one of the enemy's main fighting forces.
Victory! Caligurio grinned with satisfaction.
The enemy had taken the bait on his decoy beautifully.
The enemy seemed less intelligent than anticipated—they had apparently split their forces because they couldn't predict the invasion route.
His staff had estimated the Monster Country had somewhere between 120,000 and 150,000 troops prepared.
Of those, the ones capable of actual military operations would number fewer than 50,000 in practice.
Judging from those projections, the enemy having only ten thousand or so meant they had adopted a strategy of dispersing forces to each route to slow the advance.
Such a small force couldn't serve as a meaningful delay and would only be fodder for the vanguard's rampage.
He thought them foolish, but for monsters who couldn't even grasp the importance of intelligence, this was probably the best strategy they could muster.
If Veldora didn't show up, they would simply overrun everything.
Before the frontal forces crushed through and advanced, they would swiftly seize the enemy's stronghold.
Caligurio ordered the entire army to drop their stealth and commanded an immediate advance toward the Monster Country's capital.
The dwarves would learn of their military movements, but he judged this no longer mattered.
On the contrary, he was almost delighted imagining the enemy panicking upon discovering their presence.
Yet in the end, no military action came from Dwargon, and Caligurio's forces reached the area around the
He assumed they had been frightened by the Empire's military display and had given up any resistance.
And why wouldn't they?
After all, the Imperial Army was a massive force of 700,000.
Moreover, despite being in full armor, their marching speed was unprecedented.
It was a new-era corps, enhanced beyond anything the dwarves—who could only produce outdated, antiquated weapons—could ever imagine.
Magic and science.
The ultimate corps built upon a revolutionary new style of warfare born from their fusion.
That was precisely the Mechanized Corps under Caligurio's command.
In the Monster Country's outskirts, at the location where the Dungeon's border cities were supposed to exist, there was nothing but open, empty land—with a single exception.
That exception was an opening in the ground leading to a subterranean staircase, sitting right in the center of the barren expanse—presumably the dungeon's entrance.
This contradicted the reports, raising some doubts, but Caligurio reasoned that merchants and adventurers from the west had fled in a panic upon learning of the Imperial Army's approach.
If that was the case, it made perfect sense why they would have erased everything before the Empire could exploit it.
They had feared pillaging under the guise of "local procurement."
And frankly, denying food supplies was undoubtedly a blow to an army of this size—a tactically valid strategy.
(Such petty cleverness!)
Caligurio spat contemptuously.
His soldiers, enhanced through otherworldly science and magic, were capable of operating at full capacity for an entire week without food or water.
Their rations, designed with careful energy balance, could supply a full day's worth of energy from a single packet.
Each soldier carried ten ration packets in a small portable pack.
Since he could simply distribute replacements from supplies already consumed on the march here, there was no need to rely on this city's food stores, and their combat capability would remain uncompromised.
The successfully miniaturized and lightweight rations had reduced logistics to an absolute minimum.
Even the greatest concern—drinking water—could be magically procured, posing no problem whatsoever.
The enemy had likely placed their hopes on severing supply lines, the greatest vulnerability of large-scale military operations, but Caligurio had to admit their thinking was naïve.
(Hmph! Ranting on about Demon Lords or whatnot—in the end, it's nothing more than shallow thinking!)
Caligurio mocked the opponent's shallow intellect and was now fully convinced of this expedition's success.
First, they would seize the Monster Country's capital and establish a foothold.
They would build a military base and, riding that momentum, ravage the entire western region.
If they didn't hurry, the Beast Corps would ravage the north before they did, and their share of the credit would diminish.
If Veldora appeared and they managed to take him down, the glory would certainly be substantial, but he couldn't count on the Evil Dragon who had yet to show his face.
Come to think of it...
While resting inside the command tent at the provisional headquarters, Caligurio frowned, wondering why there had been no further reports from the vanguard.
Since the first report, there had been complete communications blackout.
According to his personal communications mage, the dense Magicules in the Great Forest of Jura were likely obstructing communication waves.
Thinking about it, the Magicule density did seem high, but this was the Demon Lord's domain after all. He could accept that explanation.
Perhaps the vanguard had encountered other delaying forces and was locked in continuous battle.
(Even so, judging from the strength they encountered initially, they'd only be getting picked off one by one.)
Caligurio saw no reason to worry about the vanguard and stopped thinking about it further.
Just to be safe, he ordered the intelligence officers to dispatch a scouting party, then shifted his focus.
The question was: which to attack first—the dungeon or the capital?
The logical approach was to take the capital first.
It was close by—subdue the Demon Lord first, then tackle the dungeon.
Even if Veldora appeared, they could simply call in the Air Combat Squadron.
Communications might be down, but if they fired a magical signal flare, they would arrive immediately.
Unlike ground travel, their aerial speed meant there would be virtually no wait, and there was no need to fear an Evil Dragon rumored to have weakened.
According to the mage's report, the Monster Country's capital was protected by a defensive barrier.
Even if they used Magicule Disruption Radiation to crack it open, it would regenerate immediately, rendering it pointless.
It was apparently quite powerful—destroying it from within was easier than brute-forcing through.
Magicule Disruption Radiation was enormously effective for disrupting offensive magic, but its weakness lay in its unsuitability for breaking defensive barriers.
However, if magic wasn't effective, that was precisely when the Mechanized Assault Division would shine.
Caligurio saw no problem and convened a meeting to draw up the assault strategy.
From the reconnaissance reports, they had confirmed monster forces deployed in front of the capital.
The numbers: roughly 20,000, with the Beastmen as the main force.
He considered this no threat at all.
Just like Caligurio, his staff officers showed no doubt about victory.
After all, they had 700,000 troops. With a three-to-one advantage, victory was virtually guaranteed—and they had more than thirty times the enemy's strength, so of course it was.
"Might we not attack both simultaneously without issue?"
So spoke a staff officer with connections to the noble council.
No objections were raised.
The situation wasn't dire enough for anyone to risk falling out of favor by opposing the idea.
Above all, they were eager for the riches that might be obtained within the dungeon.
Their greed had won out.
In the end, they reached a consensus: 200,000 for the capital assault, 350,000 for the dungeon.
A simple, straightforward strategy: flood the dungeon with sheer numbers and strip it clean.
The fact that no one objected to this plan over the capital assault spoke volumes about how blinded they were by short-term profit...
Completely certain of victory, Caligurio and his officers approved the plan without ever recognizing their own avarice.
And so, 200,000 soldiers were dispatched to assault the Monster Country's capital, while 350,000 marched to conquer the dungeon.
And...
These blissfully ignorant souls descended the staircase—never to return—brimming with cheerful anticipation.
Convinced without a shred of doubt that the treasures obtained in the dungeon would fill their coffers.
The dungeon did not reject those who entered.
But beyond its deactivated safety mechanisms, a hell like nothing anyone had ever experienced awaited them.
————— One of the innermost chambers of the dungeon.
There, even Rimuru didn't know of a secret meeting room.
For the first time ever, the powerful figures within the dungeon had been assembled by emergency summons from the Master of the Dungeon.
The stated reason was to hold a conference on annihilating the fools invading the dungeon.
However, in truth, the nature of this meeting was somewhat different from the norm.
Those gathered were known as the Dungeon's Ten Great Floor Guardians.
Aware that they were out of place among such powerful beings, the latter two shrank in on themselves.
They had always believed they could defeat anyone, but now, face-to-face with the real thing, they recognized the difference in caliber.
As for Beretta, he himself claimed to only handle menial tasks—and indeed, it was later said that the Demon King
Reflecting Ramiris's capricious nature, the names and composition of the group changed constantly.
Normally, everyone would never gather here all at once, but this time it was an emergency, and Ramiris had exercised her authority to compel everyone's attendance for the first time.
Well, Veldora sitting in the central chair was undoubtedly one of the reasons everyone had shown up.
In truth, this group—excluding Beretta and the Dragon Kings—had always been at each other's throats over who was strongest.
That rivalry had intensified ever since Adalman had been directly praised by Demon Lord Rimuru and promoted in floor rank.
Everyone wanted to prove they were the most useful.
The rulers of the lower floors, in particular, had fewer opportunities to fight, making their desire all the stronger.
And so the friction between them was significant.
Apito and Kumara, especially—both women—were on exceptionally poor terms.
Zegion maintained a stance of indifference, while Adalman burned with ambition.
Yet while their relationships were antagonistic, if anyone asked whether they truly harbored deep hatred for one another, the honest answer would be no.
In the end, they simply wanted to prove they were the best—it was different from trying to tear each other down.
Despite all this, their gathering was surprisingly quiet.
The impending Imperial invasion of the dungeon had shifted their focus from rivalry to a shared sense of enmity toward the enemy.
"Everyone! Good of you all to gather here!
Today, we face an unprecedented crisis—the greatest threat this dungeon has ever known!
I wish to hear your thoughts!"
Ramiris's words served as the signal to begin the meeting.
"Oh my? That's already decided, isn't it?"
"We're killing 'em all, right?"
Stealing Kumara's words, Apito continued: "This time, the battle should come all the way up to my floor, right? Apito's been plenty satisfied playing with the Holy Knight lately, hasn't she?"
"What are you saying! The opponents have been so weak it's actually been boring!"
The glare-down that began added an entirely different kind of tension to the room.
"Kuahahahaha! Stop fighting. And rest easy.
This time, I've prepared opportunities for everyone to fight.
Most of you seem to think the dungeon's deepest point is around the 60th floor, and at first I thought about playing along with that...
But it got troublesome, so I dropped the idea."
"That's right, exactly!
Like Master just said, waiting for them to break through the 50th floor would be tedious, wouldn't it?
Normally it'd be fine, but with this many enemies, it'd take forever.
So instead, I'm sending 10,000 enemies directly to each floor from the start.
If your luck's good, you might even get to fight someone strong!"
At Veldora and Ramiris's words, the gathered guardians' eyes lit up.
"So... everyone gets a chance?" Adalman asked.
"Exactly!" Ramiris nodded enthusiastically.
Ramiris's explanation continued.
Each Dragon King would take 10,000.
100,000 each would be sent in sequence to floors 61–70, 71–80, and 81–90.
The remainder would be dumped into floors 51–60.
It seemed approximately 350,000 troops were heading for the dungeon, so the forces would be distributed accordingly.
"And then, Gozurl and Mezurl will be stationed at floor 30, handling anyone who manages to flee that far! You might accidentally get killed, but you can just revive, so do your best!"
With that, Ramiris concluded.
The dungeon guardians were suddenly filled with enthusiasm.
"Does Lord Rimuru know about this?" Zegion broke his silence to ask.
The others were surprised by this.
The Insect Emperor Zegion was a man of few words who rarely spoke.
He had apparently been training in combat with Veldora recently, and it was said he could now fight on equal or better terms in close quarters.
He was recognized as a powerhouse by Veldora himself, and beyond his loyalty to Demon Lord Rimuru, he had no interest in anything other than strength.
"Hehehe, it's a secret! So let's surprise everyone together!"
Ramiris said this with an innocent-looking smile.
In reality, she and Veldora were likely hatching a mischievous scheme—primarily to surprise Rimuru.
It was the same as always, but for those on the receiving end, it was almost unbearable.
"Hey, this isn't going to get us in trouble with Lord Rimuru later, is it?" Albert asked worriedly.
『No problem!』
Veldora and Ramiris shot back in unison.
The moment Beretta averted his gaze, Albert realized it was pointless to press the matter and fell silent.
But on second thought, perhaps it wasn't an issue.
The key was simply to annihilate the enemy forces.
Striking a weakened enemy was the textbook approach, but they could revive after death.
There was no need to wait while the lower-floor monsters were slaughtered to the last.
"Very well. As long as we win, that's all that matters."
Zegion nodded, and that settled the matter.
Ramiris and Veldora exchanged glances, trading wicked grins, but everyone pretended not to notice.
This would be, for all practical purposes, the first time they could engage in full-scale combat that mirrored a real battle.
No matter how they felt about it, none of them intended to let this opportunity slip away.
The Ten Great Floor Guardians returned to their respective floors, ready to show the enemy the true terror of the dungeon.
And the theater of hell quietly awaited its guests.