「ミ゛―――――ア゛――――！」

　それは突然現れた。

　いや、もともといたのかもしれない。奥のほうに隠れていたのか。

　ドーム状になった巣全体に残響音を伴い響き渡る、臓腑のど真ん中を貫くような、その名状しがたき叫び声は、ラミアとは全く別の異質なナニカがそこに現れたのだと否応なしに認識させられた。

　

　ザザザザと、地面に何かを擦り合わせるような音が響く。

　ラミア達も動きを止めて、その音の方向へと注意を払っているようだ。

（このタイミングで出てくるのか……）

　暗視を持っている俺にはそ(・)れ(・)の姿が見えていた。

　ラミアとは一線を画す３メートルを超す巨体。

Her upper body is that of a woman, like a lamia, but with pale blue skin and unnaturally long arms, and her abdomen is split wide open, revealing a mouth full of sharp fangs like that of a ferocious beast.

Her lower body is even more grotesque, writhing with multiple soft, tentacle-like limbs resembling those of an octopus.

A creature of the same category as the Demon King.

Truly a beast of chaos—utterly fused and entangled.

Cold sweat trickles down her back.

Is this bad luck—or perhaps good?

The strongest monster of the fourth layer.

This is Scylla's appearance.

"W-what is this?! What is this thing?!"

Refreia nervously scans her surroundings, on high alert.

Since she lacks night vision, she still cannot see it.

"Scylla. I've heard she sometimes appears at the Lamiar nest... What should we do? Shall we break the barrier stone?"

"No, I was planning to take her down anyway. It wouldn't hurt to try hitting her first. Besides, using the barrier stone here would be a mistake. We should at least retreat to the entrance before we leave Flora behind."

"Retreating bit by bit...?"

Jeanne remained calm, but her voice trembled noticeably.

We had been advancing slowly through the Lamiar nest, fighting our way in, and had already reached near the center. Retreating all the way back to the entrance while turning our backs would be too risky.

Above all, Scylla's pressure was unbearable—there was no way I could look away from her right now.

"Mee-mee-mee-mee-mee-mee—!"

Screaming strangely, it contorts its tentacles wildly.

At first, it resembled a squid's limbs, but now it has transformed into the massive head of a wolf.

"Gaaarrrluaaaaa!"

The wolf's head emits a growl as if it possesses a will entirely separate from Scylla, its bloodshot eyes fixed upon us.

The overwhelming presence of this colossal monster, shaking even the very air, sends shivers down my spine—something I've only felt before when facing a demon king.

Even the usually bold Jeanne is visibly flinching, her stance faltering slightly.

　

If battle breaks out now, there will be no chance to flee.

It's possible to temporarily take refuge using a barrier stone, but this is the heart of the Lamia's nest. While we're holed up behind the barrier, the Lamias will only grow in number, making escape increasingly difficult—clearly, we're deep in enemy territory.

We're right in the middle of their stronghold.

"……There's nothing left to do but fight. Or rather, wasn't that always the plan? You two, right?"

"No, I wanted to take them all down first, at least. That's what I had in mind."

"Don't be greedy. Some monsters simply won't show up no matter how hard you search."

"I know that."

We don't even have time for such exchanges.

I've been preparing to fight Scylla all along, and I've studied her thoroughly.

No matter how strong the monster is, if there's known information about it, it shouldn't be that overwhelming... right?

I know for certain I won't be using spirit magic.

We know it won’t jump.

We know its attack range.

We know its element.

Most importantly, we have battle data on how it was defeated from hundreds of previous encounters.

If its level is appropriate, there may be a gap between information and actual combat, but it would be difficult to lose.

"Still, the Lamia are a problem."

The issue remains that there are still many Lamia. Fighting them all at once means facing too many opponents.

Fortunately, Scylla and Lamia don’t seem to coordinate with each other, but regardless, both will target us for attack.

"Hikaru! What should we do!?"

"Kuro! What’s the plan!?"

It’s my job to assess the overall situation and issue orders.

For now, we must avoid getting pushed back as a whole.

"Refray, take out the lamias! Jeanne, hold off the Scylla! I'll cover both of them!"

"Yes!"

"Got it!"

Scylla spread her wings wide, flaring out her tentacles and shrieking.

It was a wild animal's display of aggression, treating us as enemies.

"A giant boss battle? I'm fired up!"

With eyes blazing, Jeanne faced the massive monster, whose mass was several times her own.

She raised her shield and blocked Scylla's tentacle strike, like a whip.

"Miiii—!!"

A guttural, inhuman scream from Scylla.

She dodged the wolf-headed bite with a backstep, and evaded the sweeping tentacles that sent lamias flying, hiding behind her shield.

It would be difficult to launch an offensive, but in terms of defense, Jeanne was holding her own against this vicious monster, even at equal or superior levels.

"Dark Fog!"

I unleashed the shadowy mist on only Scylla's upper body while dispatching the troublesome Lamia, moving around it. Unlike the Lamia, Scylla wasn't a serpent woman—meaning there was a chance the darkness might affect her.

I'd also noticed, during Jeanne's battle, that she was clearly tracking her opponent with her eyes.

Scylla let out a frustrated cry as she wildly flailed her tentacles in the dark.

It would be dangerous to get caught by accident, but as long as I kept a good distance, it was harmless.

Several Lamias were caught in the crossfire, their upper and lower bodies torn apart in tears.

It's an incredible power. If I were hit by it, I'd be gone before I could even recover.

"Refray! Scylla is vulnerable to darkness! For now, stay back and take down Lamia! Jeanne, keep your distance and focus on Lamia first! I'll handle Scylla! Just be careful not to get too close to Scylla! Her tentacles have a wide range!"

If darkness affects her, then I should be the one to fight her.

Once I saw Jeanne keep her distance from Scylla, I expanded the range of my Dark Fog.

I pulled out a spirit potion and drank it.

"Seal shut, Dark Coffin!"

Scylla isn't very mobile, and she's massive.

Dark Coffin is a powerful spell, but it takes time to activate—perfect for this creature.

"A... A... A...………………"

The dark coffin, a solid dodecahedron of mass, sealed the enormous octopus-woman into darkness.

(……Did it work? But… it won't hold for long.)

The opponent was a powerful demon.

If it were just raw strength, it would surpass even the demon king I fought before.

Merely maintaining the spell was draining my spiritual energy at an alarming rate.

"Floo! Summon Dark Knight here! You'll have to focus on your side, so if the demon comes, don't hesitate—shatter the barrier stone!"

The cave echoed well with sound.

Hearing Floo reply, "Got it, nyaa," while glancing over from the entrance, I immediately began refining my spiritual energy.

The barrier stone is a one-point item, fairly valuable, but now is the perfect time to use it.

"Summon Dark Knight!"

"Create Undead!"

Maintaining the Dark Coffin while casting these spells is extremely taxing, but I need to conserve some strength here while keeping Scylla sealed.

I strained every bit of my spirit energy to summon two allies.

The Dark Knight I summoned to guard Flue had already vanished by now—my instincts told me that much.

The Create Undead spell summoned a trusted Lizardman Zombie. Since I’ve been saving the chaotic spirit stones produced by the Lizardmen instead of selling them, I can still call upon more.

Incidentally, the one I summoned the second time also vanished—consumed by the Lamia.

The number of Lamia is definitely dwindling.

The peak has been passed, it seems we're nearing the limit.

I'm collecting the spirit stones rolling on the ground as efficiently as possible using Shadow Storage, so they don't get in the way.

"Dark Knight, get inside the coffin and attack Scylla! You can end her breath, or if that's too hard, just reduce the number of tentacles. Lizardman, help with eliminating the Lamia!"

I'm giving these orders while fighting the Lamia myself.

Honestly, even just the Lamia alone are numerous enough to be a challenge. This isn't a battle where we have any room to spare. Refirea is specialized in offense, but that comes with a vulnerability—she takes more damage.

Against a single Lamia, Refirea can usually win without injury, but when multiple Lamia swarm in, luck plays a bigger role.

Conversely, Jeanne remains stable in any situation, but her destruction power is inferior to Refirea's.

In a situation where two enemies arrive for every one we knock down, it's clearly at a disadvantage.

Jeanne can probably handle about three at once.

As she deals with them, lamias are gathering around her.

"Guh... are these things spawning endlessly?"

Jeanne parries the lamias' attacks with her shield and sword, then slices off both an arm and torso in one swift counterstroke.

With her strength and the prison fire steel blade, the lamias' tough hide is no more effective than paper—essentially impenetrable by defense.

Still, being outnumbered means she'll eventually be overwhelmed.

The relentless persistence of the lamias is beginning to visibly frustrate Jeanne. After all, she wants to fight Scylla—the boss monster.

But the Lamias are just as desperate. Around a hundred of them have already fallen. They must see us as mortal enemies.

While I'm occupied with the Lamia wielding twin blades, more Lamias swarm Jeanne.

"Damn it!"

"Jeanne! Shadow Bind! Shade Shift!"

I immediately lend aid, bringing down one of them.

Even as we fight, Scylla maintains her Dark Coffin, and the strain of depleting spiritual energy makes my body grow hot.

Yet there's no choice but to keep using magic.

Refia is also fighting hard, but she's sustaining minor wounds and bleeding.

The Lamias give her no time to recover.

Though we still have to face Scylla, I can feel our resources gradually dwindling without a decisive breakthrough.

"Mi!... Mi!... Mi! Mi! Mi!"

"N-no way..."

With a *pang*, the Dark Coffin shattered.

From within, Dark Knight and Scylla emerged, writhing.

Dark Knight had clearly put up a strong fight—understandable, given he was battling a creature that couldn't move—but he'd managed to sever four of its tentacles.

The severed tentacles twitched and snapped on the ground, like octopus limbs.

Scylla bore deep blade wounds across her upper body, her crimson eyes blazing with hatred as she writhed her remaining tentacles, vowing revenge on Dark Knight.

"Darkness Fog! Dark Knight, fall back—leave Scylla to me!"

In the current situation, Dark Knight was a valuable asset. There was no strength left to summon him again. He couldn't be allowed to be easily defeated by Scylla.

The Scylla trapped in darkness flails its tentacles wildly through the shadows.

But we're out of range.

One unfortunate Lamia got caught, but fratricide is welcome.

The Scylla is hindered by the darkness, offering at least a temporary delay, but we can't afford to relax.

Just being ambushed by sound alone could easily result in casualties.

Its very mass makes it dangerous—simply being run over by it could be fatal, even without any clear attack.

"The Dark Coffin... impossible. With the remaining spirit power, it won't last a minute. Binding won't mean much either, and me closing in to fight... that's probably reckless."

Honestly, I find close combat against a Scylla extremely difficult.

Though I had my gear on, I didn't think I could withstand that attack. If Reflair uses her sword, she might barely block it, but trying to force it would be too dangerous.

The basic plan should be for Jeanne to handle defense and break through, then launch an attack.

"Jeanne, switch! I'm counting on you, Scylla!"

"About time!"

Thanks to Dark Knight's performance, we gained a little breathing room before switching over.

Now it's my turn to fully commit to eliminating the Lamia.

Scylla's tentacles are half severed. If Jeanne focuses solely on defense, we can definitely gain a few minutes.

According to the guild's strategy guide, the standard approach is to cut off the tentacles before targeting the main body.

"Let's go! Shadow Bind! Shade Shift!"

The very instant he cast a close-combat-oriented spell requiring minimal spirit energy,

＜Congratulations! You are the first transmigrated being to fully develop your Contract Spirit Arts up to the intermediate level. As a reward, you have been granted 3 points＞

"Huh? What?! Intermediate?"

Stunned by the sudden news, unable to comprehend, the spirit's voice continued.

＜Congratulations! You are the first transmigrated being to gain the ability to use magic independently. As a reward, you have been granted 5 points＞

"Huh?! What?!"

Dazed but still focused, he defeated the trapped Lamia using his bind.

Magic.

It definitely sounded like magic.

Taking a quick glance, he opened his status board.

【Dark Spirit Arts】

Third Rank Technique

・Dark Sight 【Dark Sense】 Mastery Level 86

・Shadow Form [Shade Shift] Mastery Level 0

・Shadow Transformation [Phantom Warrior] Mastery Level 76

・Shadow Storage [Shadow Storage] Mastery Level 98

・Shadow Coffin [Dark Coffin] Mastery Level 21

・Shadow Summoning [Summon Dark Knight] Mastery Level 25

Fifth Rank Spell

・Shadow Manifestation [Darkness Fog] Mastery Level 2

Special Spell

・Shadow Return [Create Undead] Mastery Level 16

"……Shadow Form? Shade Shift has advanced to the next level!"

Among the Shadow Spirit Arts, Shadow Form—the only one previously at the Second Rank—had evolved into the Third Rank and progressed to the next stage.

Meanwhile, Darkness Fog quietly leveled up to the Fifth Rank as well.

And beneath it, displayed clearly—

【Magic】

・Fright of the Demon 【Fear】 Level 0

・Break of the Demon 【Dispel】 Level 0

—it was unmistakably the same spell used by the Demon King.