To go after the hidden boss, or not.
It didn't take long to make that decision.
"Let's go."
My simple one-liner.
That was all it took.
"Yippee! Sounds good!"
"…If Jeron agrees too, then fine."
That seemed to give them conviction, as even Artel, who had hesitated for a moment, nodded.
Artel had seen plenty from me so far and already viewed me as a considerable powerhouse.
Karen also seemed to mistakenly think I was around her level after witnessing my [Keen Sight] earlier.
We followed the secret passage Karen had found, descending stone stairs downward.
"It's dark."
"I'll light up the view."
The deeper we went, the less light filtered in, and the path grew dim.
At that, Artel conjured a small orb of light above her palm, illuminating the way ahead like a flashlight.
Her main affinity was ice, but she could handle basic light magic without issue.
'…Jealous.'
From behind, I eyed it with quiet envy.
I could wield legendary skills like [Lesser Reflex] or [Mana Blade Slash], yet I was in the absurd position of not being able to use even basic magic like that.
Of course it was natural—I'd never learned any magic.
Thanks to my Sloth trait, I couldn't learn it in the future either.
The Sloth Shop didn't even carry basic skills like that.
So in situations like this, I was little more than dead weight.
Fortunately, my lazy image meant no one batted an eye at me just standing there blankly, doing nothing.
A short while later.
We reached the end of the stairs—a vast cavern.
In the center stood what looked like an altar, and atop it sat a massive throne adorned with all sorts of gems.
"…What's that?"
And on that throne was a crowned skull, sitting there.
Its head bowed as if lost in deep slumber.
Judging by its attire and the throne's grandeur, it had been someone of high status in life.
"Is that the hidden boss of this dungeon? It's a type of beast I've never seen before…"
Artel muttered softly.
"No sense of hostility or anything."
Karen voiced her doubts too.
Skeletons, being undead, usually emanated a distinct murderous aura unlike ordinary skulls.
But this skull gave off no presence at all.
Yet there it sat, smack in the middle of the hidden boss room, so it couldn't be anything ordinary.
That's why Karen and Artel held back, keeping their distance and watching it warily.
Right then.
"…Intruders have set foot here."
The skull spoke.
Its voice was cracked and hoarse, like someone who hadn't spoken in ages.
"…!"
"A beast that talks?!"
Startled, Artel and Karen instinctively aimed their mana and sword at it.
Talking beasts were rare.
Most beasts lacked intelligence and only roared like wild animals.
Like the giant skeleton we'd fought earlier.
Only higher-grade beasts were known to speak properly, and among those, ones using human language were exceedingly rare.
Why would such a beast be in a mere green-grade dungeon?
Tension rippled through the entire party.
"Who are you?"
Artel demanded sharply.
"I was once a king who ruled a nation. This place was my tomb."
It answered with its head still bowed.
"Only after death did I attain true enlightenment, reviving in this body. For eons since, I have cultivated demonic arts here alone."
Then it pointed at us with its withered, twisted finger.
"Intruders. Leave quietly now, and I shall spare your lives."
"Nonsense."
Artel dismissed it outright, of course.
There was no reason to trust a beast's words.
"…Is that so."
The skull fell silent for a moment, then spoke again.
"How regrettable. Just a few more years, and my cultivation would have been complete, my ritual fully prepared…"
Genuine regret colored the skull's voice.
Slowly, it raised its head to gaze at us.
Within the empty sockets where eyes should have been, ominous darkness swirled.
"No need for more talk. Let's fight."
Artel said.
I nodded in agreement.
It was better than Morel, but this one was still pretty chatty. With some weird chuunibyou backstory to boot.
Truth be told, I'd wanted to unleash a slash the moment we met, but there was a reason I held back.
'Not like it'd do anything anyway…'
As I thought that.
"Then I'll go first!"
Flash!
Karen moved first.
Her figure vanished in an instant.
The next moment.
Swoosh!
Her sword sharply targeted the throat of the skull still sitting idly on the throne.
The skull just sat there silently.
However.
Karen's blade bounced back as if it had hit an invisible wall, unable to advance further.
"?!"
She spun in midair and landed safely on the ground, but her face was etched with shock.
"Whatever it is, it's way tougher than that giant skeleton's bone shield from earlier!"
Around the skull on the throne, a dark purple translucent barrier had formed.
"A bit earlier than planned, but no choice. Now, the [Ritual] begins."
And then.
From within, a colossal, sinister power began to emanate—something incomparable to before.
"Whoa."
Even I, who couldn't sense mana or hostility well, could clearly feel the overwhelming pressure.
It was a sticky, repulsive aura.
"…This might be a bit dangerous."
If I felt it that strongly, how must Karen with her keen senses or Artel with her magical talent feel?
Especially Artel, who spoke in a despairing voice.
"That's… demonization…!"
Demons.
The nobility among beasts.
Beings of immense power incomparable to regular beasts.
Demons were usually born as such, but exceedingly rarely, an ordinary beast could evolve into one through some trigger.
People called that process 'demonization.'
And the [Ritual] the skull had mentioned was precisely that.
"Why… would the boss of a green-grade dungeon be attempting demonization…!"
Even for a hidden boss, this defied all common sense.
'Talk about bad luck.'
I clicked my tongue inwardly too.
The hidden boss of the underground tomb dungeon: Skull King.
Its gimmick was none other than demonization.
Demons were foes even the protagonist of [Stella Academia] wouldn't find easy at 1st or 2nd-year level.
Who could've imagined one attempting to become a demon in a mere green-grade dungeon?
"We have to stop it somehow!"
Just as Artel said, we needed to halt the demonization before it completed.
"Hah!"
Karen unleashed her signature [Blade Storm] this time,
and Artel simultaneously fired a powerful freezing spell.
But…
"…!"
It was all for naught.
Every attack was blocked by the Skull King's barrier, vanishing without a sound.
'[Curtain of Darkness].'
That was the true nature of the skill it had deployed.
A barrier that perfectly blocked all physical and magical attacks.
During demonization rituals, the subject temporarily became defenseless, like a pupa metamorphosing into a butterfly.
Hence the barrier to protect itself.
And with our current means, we had no way to pierce it. Even my ultimate [Dismember] couldn't scratch it.
"It's no use, totally useless…!"
As repeated attacks yielded nothing, Karen's expression darkened.
"W-What do we do? Should we run now…?"
Artel looked at me with utter confusion.
But I remained perfectly calm.
'Time to start the second plan.'
Now it was my turn.
[Curtain of Darkness] blocked all physical and magical attacks.
But what if it wasn't an attack?
What if it was instead a buff that 'strengthened' the target?
In fact, buffs could pass through the [Curtain of Darkness].
Of course, a normal buff would just be trolling—benefiting the enemy.
But my skill, [Unstable Amplification], was different.
Rather than simply enhancing magic, it imposed a deadly penalty alongside—a double-edged sword.
Here came the second application of [Unstable Amplification].
This skill wasn't limited to my own magic.
It could forcibly overlay its effect onto an opponent's ongoing spell.
And per [Stella Academia]'s system, 'demonization' was strictly classified as a 'magic' skill.
'Demonization amplified by [Unstable Amplification]…'
Would gain a fatal penalty.
A very fatal one at that.
"…Demonization, huh. Interesting."
Standing in place, I slowly raised only my right hand.
"Since waiting's a hassle, I'll give it a little help."
Then I cast [Unstable Amplification] on the Skull King.