This was a semi-transparent, jelly-like blue sphere.
Its surface was smooth, reflecting iridescent light.
A pair of harmless-looking little black eyes stared blankly at Gauss.
The moment he saw the slime appear, Gauss raised a brow.
Aside from its completely different appearance from ordinary slimes, it also gave him a very unusual feeling.
More accurately, in Gauss's perception, it seemed perfectly fused with the surrounding air. If he hadn't seen it with his own eyes, it would have felt more like a patch of empty atmosphere than a real creature.
That discovery immediately put him on guard.
He rarely encountered beings that felt this devoid of "threat."
Even lowly creatures like goblins and ordinary slimes, though now utterly incapable of harming him, still carried a kind of malice he could sense.
That malice had nothing to do with whether they were strong or weak. It was just the instinctive rejection one lifeform felt toward an outsider.
But this thing had none of that. It was just… blank.
That meant, at the very least, its concealment ability was exceptionally strong.
And Gauss could vaguely sense that this slime's intelligence was far beyond that of its kin.
It wasn't just looking at him. Its gaze swept over every adventurer present, and there was a distinctly human-like curiosity in its eyes.
Yet when it looked over the corpses of the monsters strewn across the ground, it showed no extra emotion at all. It seemed utterly indifferent to the deaths of its own kind.
That directly contradicted Gauss's earlier guess.
He had assumed that since the thing had shown up so quickly, it had to be a combative leader that protected its own.
But now, it felt more like it had come out of pure curiosity.
As though, in the middle of a long and monotonous life, it had suddenly discovered a group of strange creatures trespassing into its territory. Not hostile, not friendly—just interested.
The way it looked at the human adventurers was almost like someone watching a few cats and dogs.
Several high-grade myconids beside the blue slime began exchanging information. Invisible streams of thought flowed toward it, like children running to complain to a parent who had just arrived, hoping it would stand up for them.
Once it had taken in the information, the blue slime's interest in Gauss intensified even further.
The next moment, under Gauss's unwaveringly cautious gaze, the small, adorable slime vanished without warning.
And the instant it disappeared, Gauss fully understood how terrifying that "merging into the environment" talent really was.
He pushed his mental perception to its limit. Not the slightest anomaly in the surroundings could escape him now.
Where did it go?
At the same time, the pupils of his eyes turned a faint golden hue as he locked onto every direction around him.
His mental network, vision, hearing, smell, and even the tactile sense of air moving across his skin all surged to their maximum.
All around him, monsters and Red Dragon Company members alike instinctively pulled away from the area he occupied.
Then suddenly, the corner of Gauss's eye caught something beside him.
"Found you."
He directed the silver Bigby's Hand to seize the faintly unnatural distortion in the air.
Boom!
The Grasping Hand snapped shut with a massive sonic burst.
In the next instant, dozens of rainbow-colored spikes burst outward from the center of the palm like branching limbs, punching straight through the hand and piercing it clean through.
Fortunately, Bigby's Hand was only condensed mana. Even though Gauss controlled it as naturally as his own limb, it wasn't a real body, so he felt no pain through it.
Gauss's eyes narrowed.
This was the first time מאז mastering Bigby's Hand that something had actually broken through its defense.
Granted, compared to its offensive power, Bigby's Hand was more attack-focused than defense-focused—but it was still a fifth-circle spell. Its basic durability wasn't something ordinary attacks should have been able to punch through so easily.
The piercing attack just now had been terrifyingly destructive.
More importantly, Gauss realized that the Grasping Hand hadn't actually caught anything.
It was as though it had clenched around a blob of mana, and that mana had immediately burst outward into that spike attack.
Where did the slime go?
When he opened the hand again, the punctured "wounds" on it were already healing rapidly—but there was no sign of the special slime inside.
Honestly, it had been a long time since Gauss had faced an opponent this slippery.
Past enemies, even the stronger ones, at least left trails he could track. This slime, though, was slick as a ghost.
Was it using some kind of spatial magic?
That was Gauss's first instinct, but he hadn't felt the slightest trace of spatial fluctuation.
Clearly, although it was also a floor lord, the fifth-floor slime lord was far more formidable than the fourth-floor frog lord. Just this one vanishing act made it stronger than that mountain-sized magic frog by an absurd margin.
"Whoosh!"
Gauss heard another rush of air.
In the next instant, a figure materialized above him.
Out of the corner of his eye, he caught a flash of blue.
"Vampiric Touch!"
He instantly unleashed close-range magic, sending the black-and-red tendrils coiling around his arm lashing upward like striking tentacles.
Maybe because the distance was shorter this time, he hit the timing better.
He distinctly felt the strike connect with something soft and springy.
The target used its own elasticity to absorb part of the force, like a rubbery jelly taking the blow and then being flung away by the impact.
A streak of blue shot through the air.
Then it slammed into a rock wall in the distance.
The blue slime finally revealed itself, landing against the wall after being blasted back. It was still in that same soft, spherical shape, with no visible deformation at all. The sight was bizarre—something about it completely violated ordinary physical intuition.
And yet behind it, the rock wall had split open into a spiderweb of cracks stretching more than ten meters.
Clearly, during that brief collision, the slime lord had perfectly redirected all the force of impact into the surrounding environment.
A spark of interest flashed through Gauss's eyes.
To be honest, it had been a long time since he'd run into an opponent like this.
And not "strong" in the simple sense of higher level or overwhelming destructive power, but strong in a mechanical sense—its very way of existing was superior.
In fact, he even felt something familiar from that unremarkable-looking slime, almost as though he were seeing a reflection of himself.
In other words, that slime might also be a "mechanics monster" like him.
Of course, their mechanisms and talents were clearly very different.
Thinking that, Gauss felt a faint heat rise in his chest.
Though it was partly deliberate, the truth was he really hadn't faced a proper opponent in a long while.
That half-dragon centaur in Blackwater Town didn't count. At the time, it had been overwhelmingly stronger than him; if they had fought head-on, it would have been one-sided from the start.
But this slime lord, by contrast, sat in that rare sweet spot—just dangerous enough.
His thoughts flashed by like lightning.
The golden dragon eyes reflected the slime's body, and he suddenly realized he might have figured out the principle behind its bizarre, impossible movement.
To anyone unfamiliar with spatial magic, its movement might easily be mistaken for something like his Any Door. And to be fair, the outward effect did resemble that.
But to Gauss, the underlying mechanism felt completely different.
He knew one basic truth well: any spatial effect caused ripples in space.
His own Any Door did. The inter-floor passages of the labyrinth did too. Even the transfer done by that special iron plate to reach the insectoid statue's hidden floor had produced the same kind of sensation.
Someone as sensitive to such things as he was would never fail to detect true spatial magic.
Combining that with the blue slime's initial state—its eerie way of seeming to simply not exist—Gauss had figured out at least part of the truth behind its abilities.
Strictly speaking, the slime lord wasn't merging into the environment.
It was merging into the ambient natural mana filling the air.
Its body was too pure—almost entirely formed from mana itself—so under the cover of natural magic, it could enter a kind of mana-body or elementalized state.
In that state, Gauss couldn't sense it at all. He could only track its external form visually when it chose to reveal it.
As for movement, the slime lord was simply dissolving itself into natural mana, then reforming a solid body the instant it wanted to attack. It could switch between those two states at will.
In that sense, it was even nastier than Shadow's talent.
Shadow still needed a medium—her shadow itself. There was a trace. And if you hit the shadow with energy, she'd still be forced to reveal herself.
But this thing could truly dissolve into ambient mana, becoming formless.
Could it still be attacked in that state?
If not, then didn't that make it naturally unbeatable?
Of course, that thought only lasted a moment.
At least with his current understanding, an ability that absolute was unlikely—or if it did exist, it shouldn't be something he was meeting at this stage.
It had to have some weakness of its own.
Time limit? Usage count? Energy burden? Transformation delay?
Whatever it was, something that strong had to have a flaw somewhere.
For example, just now, when it got too close and was hit by Vampiric Touch, Gauss suspected it had been unable to switch quickly enough—or that the minimum time required for conversion hadn't been met.
Still, the slime's combat instincts were excellent.
In a split second, it had adjusted and used the flexibility of its body to throw all the impact away, reducing the actual damage it took to almost nothing.
Far away, the Red Dragon Company members who had already pulled back were visibly stunned.
None of them had expected that seemingly harmless little slime to possess such frightening combat power.
Over time, they had all come to understand more about their commander's strength. The fact that this blue slime could survive several exchanges with him without immediately collapsing was enough on its own to show how dangerous it was.
At the thought of that, they all felt an immense sense of relief.
Thank goodness none of them had to fight something like that personally. Otherwise, they probably would've just been crushed as meaningless cannon fodder.
"Prepare to engage!"
Albena's booming voice rang out at just the right moment.
Around them, the other monsters were closing in.
It wasn't just Gauss who had a fight on his hands—everyone did.
As for Gauss himself, all of that thinking had taken only an instant.
Now that he had some understanding of the slime's abilities, his confidence only grew.
Sometimes, an enemy whose capabilities were unknown was more dangerous than one who was simply stronger.
With an openly overwhelming enemy, most people at least knew to run.
But with a mysterious one, uncertainty itself became the problem.
Fight—how?
Run—how?
Without enough information, adventurers couldn't make good decisions.
That was the true importance of intelligence in battle.
"Magic Missile."
Gauss swung the white staff in front of him, unleashing a downpour of blue missiles.
Like a torrential rain, they poured toward the cracked rock wall where the slime lord had landed.
The next second, under the fixed gaze of Gauss's golden eyes, the small blue body vanished again.
Boom. Boom. Boom.
The rain of missiles swallowed the rock wall whole.
The already fractured stone couldn't bear the punishment, and immediately began collapsing in a chain reaction.
Hundreds upon hundreds of rocks crashed down, raising dust thick enough to blind.
But neither Gauss nor the slime were the kind of beings who could be concealed by ordinary dust.
And though the attack had technically missed, Gauss showed no frustration at all. If anything, the corner of his mouth curled slightly upward.
"As I thought…"
He had felt it.
When the mass of Magic Missiles detonated and the area was flooded with unstable magical force, the natural mana in the surroundings had also been violently disturbed.
And the slime, dissolved into that natural mana, naturally couldn't remain untouched by the turbulence.
So Gauss had finally managed to catch its trace.
Unfortunately, the moment it realized it had been exposed, it fled at top speed, leaving the disturbed mana zone in an instant.
After the transformation-delay issue, Gauss had now identified a second weakness.
That was how battles worked.
No matter how mysterious an enemy might seem, once actual combat started, you could always gather useful information from its behavior—peeling it layer by layer like an onion.
"Human."
"You are interesting."
A young, cool voice—or rather, a transmitted thought—sounded clearly in Gauss's mind.
He knew exactly where it had come from.
He answered in kind, sending out his own message through his all-pervasive mental force.
"Hello, slime."
"My name is Eden Graham Lydiaporo Sutton Aqua Je…"
The crisp, meticulous voice seemed completely unconcerned by the fact that it had only just exchanged a few blows with Gauss. Instead, it abruptly began reciting an absurdly long full name—dozens upon dozens of syllables long.