Chapter 41: Advancement – Boss Monster

I had already gathered 200 Dark Bat Souls several days ago.

But since their quality wasn’t exactly ideal, I had held off on using them for an upgrade.

With Roseheart’s support, the collection had gone relatively fast.

What I hadn’t expected, however, was that revamping the Forest Ruins would drain so much of my energy stockpile.

Luckily, fate was on my side.

That long-forgotten quest had completed itself just in time—

Otherwise, I wouldn’t even have had enough energy to cover the 50 points needed to promote a Dark Bat into a boss.

I teleported to the Dark Cathedral.

Under the multicolored light shining down from its arched dome, a lifelike statue stood tall at the center.

Compared to ordinary Dark Bats, this one radiated far more malevolence.

Its black hue was deeper, its presence oppressive—enough to invoke real intimidation.

This… was a Boss-level Dark Bat that had already been successfully promoted.

Over the past few days, with materials accumulated from before, I’d gained enough Dark Crystals to promote four boss-level bats.

As a test, I used lower-quality souls for the first two.

The results? Completely average boss monsters.

But the fourth—

The one before me now—was created using a high-quality soul, and its stats blew the other three out of the water.

Sure, some of that might have been RNG luck, but it definitely reaffirmed my earlier goal:

Collect only high-grade monster souls going forward.

Now came the moment of truth.

With a soft rumble, the promotion ritual began.

The dark bat statue slid to the center of the cathedral, resting atop a massive arcane circle.

Intricate patterns ignited with ominous light.

The bat souls were the first to be absorbed, wailing like banshees as they swirled into the circle.

Then came the Dark Crystals, hundreds of them, born from condensed dark energy.

Finally, shimmering fragments of Stardust merged into the mix.

The moment everything fused into the array, a blinding light erupted.

“…This feels just like a ten-pull in a gacha game,” I muttered.

Except in this case, all the “cards” were predetermined.

The light faded.

A massive new statue stood at the center.

It resembled a Dark Bat, but far more imposing.

Its once-rounded body had been carved into sharp, blade-like edges— like a true predator born of shadow.

I reached out to touch it, and in that instant, the statue shattered.

With a piercing shriek, a pair of glowing crimson eyes opened— like some abominable beast crawling out of the abyss.

The new boss’s stat screen appeared before me:

***

[Dark Bat King]

[Boss] – Lv.15

HP: 6000/6000

ATK: 196

DEF: 167

Traits:

Lesser Vampire Lineage

→ Gains minor flight ability.

→ Recovers HP from damage dealt.

→ Takes increased damage from Holy attacks.

Twilight Instinct

→ Increases overall power based on number of nearby enemies.

Skills:

Bat’s Shadow

→ Summons shadow bats to attack all enemies nearby.

→ Number of shadows scales with nearby players.

→ Cooldown: 1 minute

Dark Dash

→ Dashes through up to 10 targets at lightning speed, dealing damage.

→ Takes 50% reduced damage during dash.

→ Can be used 3 times in succession.

→ Cooldown: 10 minutes

Twilight Domain

→ Creates a dark field.

→ Weakens nearby enemies.

→ Reduces visibility for those further away.

→ Increases user’s attack speed and defense inside the field.

→ Duration: 10 minutes

→ Cooldown: 20 minutes

Dark Rebirth

→ Splits into hundreds of Dark Bats, each attacking all enemies.

→ These bats take 50% reduced damage, +30% ATK.

→ Form ends when all bats die.

→ Triggers at 20% HP. One-time use.

Blood Sacrifice

→ Deals devastating AoE damage.

→ User enters permanent weakened state afterward.

→ -1000% to all stats.

→ Triggers at 5% HP. One-time use.

***

Its balanced offense and defense, paired with built-in lifesteal, meant it could last long on the field.

The passive boost from surrounding enemies only made it scarier.

And its skill set? Brutal.

AoE

Backline assassination

Buffing field

Death-activated swarm

And a suicidal nuke…

This boss was absolutely stacked.

In a great mood, I patted its head.

“There, there~ good boy~”

The Bat King folded its wings and nuzzled into my palm like a big… fuzzy cat.

A far cry from the terrifying beast it was just seconds ago.

Hard to believe this same monster had been snarling like a demon just moments earlier.

I summoned the other three boss-level bats.

And the difference was… obvious.

Not just in size—

Even the aura it gave off had them trembling, like low-level minions around a final boss.

They huddled around it like loyal underlings.

***

“Now then… what to do next?”

I leaned on one arm and muttered.

“Should I just toss it straight into the Forest Ruins?”

Somehow, that felt way too low-effort.

As powerful as the Bat King was, it was still just a Boss-rank monster.

Even with two Dark Bat bosses backing it up, it’d get swarmed by players.

One Dark Bat Boss might stall 70–80 players.

The Bat King? Maybe 8 times that—so ~600 players.

Add all four together? At best, they could fight off around 800 players.

Sounds like a lot, right?

But energy income scales with damage dealt and player deaths.

Unless all 800 players died, I wouldn’t profit much.

And let’s face it—

As long as 10% of that group are healers, the rest will survive.

They’ll just whittle the boss down over time.

And even if my promoted boss dies, it can only revive after 7 days, and only if I have a Cemetery Building, which unlocks at Heart of Herentis Level 2.

“…My head hurts.”

I rubbed my temples.

Thinking back, I may have put too much faith in the Boss Promotion feature.

All that prep… and while the result is strong, it’s not game-breaking.

I’d hoped to earn enough energy to finally level up the Heart of Herentis to Tier 2.

“If only I could manually control you during battle…”

I muttered as I rubbed the Bat King’s head again.

And then I froze.

“Wait… manual control…?”

I shot open my Status Menu, flipping through the pages as fast as I could— searching for one particular line I had almost forgotten about.

And sure enough, there it was:

***

[Demon King Authority]

[Descend]

→ Possess any allied Dark Faction monster.

→ Increases level.

→ Alters appearance based on user stats.

***

I’m saved.

The Bat King is no longer just an AI-controlled boss.

It’s my new ride.