Chapter 5: The Heart of Herentis

“Where are we?” 

I asked, curiosity bubbling as I trailed Syl through the winding corridors of the castle, descending to the third basement level.

“The core chamber of the Demon King’s castle,” Syl replied succinctly, activating the intricate mechanism of the fortified door before us.

As the door slid open, a majestic hall unfurled before me. 

Dozens of white jade pillars, etched with delicate patterns, soared to support a grand domed ceiling. 

The walls glowed with an ethereal blue, illuminating the subterranean space as brightly as daylight. 

Polished obsidian tiles lined the floor, their surface adorned with intricate silver-liquid runes forming a mesmerizing magic array that demanded attention.

But my gaze was swiftly stolen by a colossal mechanical structure at the hall’s center—a towering edifice bridging floor and ceiling. 

Its black-and-white metal surface bore finely etched patterns, each component crafted with meticulous precision. 

At its heart, a dark golden crystal hovered in a recessed groove, pulsing with faint glimmers of light.

For reasons I couldn’t name, it felt alive, like a beating heart. 

The magic arrays, the machinery, the very hall itself seemed to serve as its veins, pumping lifeblood not just to the castle but to the entire dark world.

“This is the Heart of Herentis, the supreme artifact of the dark faction,” Syl said, her voice steady at my side. 

“Your Majesty, you may attempt to control it.”

Control it?

I glanced at my small, pale hands, then up at the floating crystal. 

Hesitant, I reached out—only to confront a glaring issue.

“Uh, Syl… could you give me a lift?”

The height disparity was painfully real. I covered my face in embarrassment.

Shaking off the moment, I refocused on the crystal. 

With Syl’s help, I could now easily touch its surface. 

The instant my fingers made contact, a blinding golden light erupted, surging through the machinery, the magic array, and the walls, igniting the entire chamber like a flipped switch.

Before I could process what was happening, a silver interface materialized before me.

—

Heart of Herentis [Level 1]

Bound to: 19th Demon King

Energy: 200

Existing Structures: Obsidian Castle, Warehouse, Eternal Tree

—

The panel was starkly minimal, offering little beyond the basics. 

“Syl, that’s all it shows,” I said, puzzled.

“Your Majesty, there should be initial building blueprints in your inventory.”

A Demon King with a player inventory? 

I stifled a chuckle at the absurdity but followed her advice, retrieving three blueprints from my inventory and feeding them into the machine.

As the blueprints dissolved into streams of light, a new line appeared on the panel.

Available Structures: Dark Bat Nest, Slime Nest, Goblin Nest

Curious, I tapped one. 

Detailed information sprang up.

—

Dark Bat Nest

Type: Monster Nest

Capacity: 2000

Construction Cost: 30 Energy

Spawnable Units: Dark Bat (99%), Dark Bat Elite (1%)

Spawn Requirements: Energy, Dark Element

—

The other two nests were similar.

“These are starter monster nests for spawning dark faction creatures,” Syl explained. 

“The percentages indicate spawn rates. Your Majesty can spend extra energy to produce elites. Beyond energy, spawning requires specific materials, obtainable through resource points, defeating wild monster groups, or challenging bosses.”

“Oh? You can see this too, Syl?”

“Yes, but only Your Majesty can control the Heart of Herentis.”

She continued, “Monsters can be assigned to your army or teleported to bright faction monster zones, provided Your Majesty uses the Demon King Authority’s Dark Erosion ability to establish a domain in their world.”

“What’s the point of these monster zones?” 

I asked, vaguely recalling the term—likely Epoch’s equivalent of leveling areas. 

The idea of a Demon King manipulating such zones sounded… intriguing.

“Monsters defeated by players in these zones revert to energy and return to the nest without loss. In fact, they yield a slight surplus. For example, a Dark Bat costs 0.05 energy to spawn but returns about 0.052 when defeated.”

A grinding idle game? My enthusiasm waned at the thought.

But Syl’s next words reignited my interest. 

“If adventurers are defeated or take significant damage, their level determines the energy returned—far more than other methods. 

Equipment they fail to retrieve within a time limit is converted to energy or stored in the castle’s warehouse.”

“So, maximize their pain or outright defeat them, right?”

“That is Your Majesty’s prerogative.”

The safe route—grinding energy slowly—was tempting, but energy was clearly a vital resource. 

At that pace, the dark faction would be outpaced by players. 

The aggressive approach, though, promised faster gains.

And, frankly, crushing players as the Demon King sounded fun. 

No moral qualms here.

But how to best sabotage them? That required strategy.

“Let’s try spawning a monster first.”

I selected the Dark Bat Nest for construction and, per Syl’s guidance, used the Eternal Tree to spawn a sprite. 

While Dark Bats cost just 0.05 energy, a sprite required a steep 1 energy. 

With no other production options, I grudgingly spent 20 energy, puffing my cheeks in protest.

On the Heart’s projected screen, a towering tree bathed in soft light appeared. 

From its base emerged black orbs, oddly reminiscent of plump dumplings.

Why did the dark faction have such a cute aesthetic? Was it my minor protection mode?

Grumbling, I directed the sprites to a resource point. 

Dark elements were abundant in the World’s Backside, and with Syl’s guidance, I located a collection site. 

Sprites harvested 0.5 units of dark element per minute, and each Dark Bat required 1 unit. 

Excluding energy, the nest could spawn ten bats per minute.

In game terms, that meant ten Dark Bats refreshing every minute in the monster zone.

The nest’s low level meant construction was swift.

—

System: New Task Unlocked [Dark Bat Feast (Part 1)]

Task: Dark Bat Feast

Description: Create a chaotic feast with the Dark Bat Nest—a lesson for the bright faction.

Objective: Spawn Dark Bats (0/5000)

Rewards: 20 Energy, 1000 EXP, 500 Dark Element Units

—

“A task? I can get quests as Demon King?”

I blinked, but given I had an inventory, it wasn’t too shocking. 

Spurred by the task, I poured the harvested dark elements into the nest.

About thirty Dark Bats materialized outside the nest. 

Using the Heart’s power, I teleported one to my side. 

It resembled a real bat but cartoonish, almost cute.

—

Dark Bat [Editable]

Level: 3

Health: 150

Attack: 30

Defense: 18

Drops: Bat Claw, Bat Venom, Random Equipment, Skill Book

—

A standard low-tier monster, its traits favoring high attack and low defense.

“Hey, Syl, what’s this ‘Editable’ tag?” I asked, noticing the button.

“Your Majesty can upgrade monster levels or tweak abilities within limits,” Syl replied, sparking inspiration.

If defeated monsters returned extra energy, and defeated players yielded even more, could I optimize their stats to maximize both? 

High attack to down players, low health and defense to ensure quick defeats.

But balance was key, and my past life’s experience would guide me.

“Level 3 stats… top-tier shield warriors max out at 50 defense with Defensive Stance and Iron Wall, and maybe 200 health. If I bump the attack to 40…”

I adjusted the Dark Bat to 40 attack, 10 defense, and 120 health—an extreme build. 

I left the level untouched since players were mostly level 2 or 3, perfectly matching the zone. 

Raising levels cost energy, and I wanted to conserve my reserves.

This setup would already give players headaches—even I’d struggle against it—but I wasn’t satisfied.

“Syl, can I fine-tune them further?”

“You can access the editing space.” 

With the Heart bound to me, I removed it from the machine, sparing Syl the effort of lifting me.

Following her instructions, I explored the editing space. 

It allowed creating templates to define monster traits, applicable to some or all units.

First, I set Dark Bats to move in groups of three or four. 

Even a high-defense tank would fall in three rounds. 

With their attack speed, it’d be as swift as a shut-in gamer croaking after spamming “awsl” at their 2D waifu.

Then, a new idea struck. 

“Make one bat in each group smaller, with 20 attack, 30 defense, and 150 health.”

Defense wasn’t just about stats—visual cues mattered. 

Smaller bats would seem weaker, luring players into a trap. 

A smirk curled my lips at the thought of their miscalculation.

“Not enough. Next…”

“The largest AOE spell, Flame Burst, has a three-yard range. Set the bats’ spacing to 3.1 yards—no, 2.6 yards. Close enough.”

After countless tweaks, I clapped my hands. “Perfect~”

A strange gaze prickled my back. 

Turning, I found Syl watching me.

“What’s up?”

“Would Your Majesty like tea?”

“Absolutely!”

A break after all that work was divine, and Syl’s tea was surprisingly delectable—no wonder Alice raved about it.

“What’s this tea called? It’s amazing.”

“Dried and crushed Kopa petals from the Catscar Forest, hence ‘Windcat Kopa’ tea.”

“…Syl, are you implying something?”

“I would never, Your Majesty.”