"Stress," Isla said simply. "Dungeons aren’t only about fighting enemies. They test your patience and teamwork.
"Think about it, haven’t we been thinking like this...
"How long do we need to walk? How many more monsters before we reach the boss? What if we’re in the wrong corridor?
"What if monsters attack from behind while we’re lost? All those questions wear you down. That’s how they test you."
She paused, then glanced toward Isaac.
"We were lucky. Lord Isaac handled every monster without trouble. Because of that, we never really felt that stress."
Isaac didn’t respond immediately, but he nodded once.
He understood what she meant.
The dungeon was meant to grind down both strength and mind, yet for them, the fights had been more like a walk.
They rested briefly before moving closer to the door.
The surface shimmered faintly when they approached, like ripples on water.
Isaac turned to the group. "You all stay outside the room and watch from there."
Warn frowned. "Are you sure? We can at least support you from behind."
Isaac shook his head. "The barrier will block everything once the fight starts. It’s safer that way."
He was right.
Once the mid-boss room was activated, a transparent wall would replace the door.
The monster couldn’t leave, and those outside couldn’t interfere. Even sound wouldn’t pass through.
They nodded reluctantly.
Isaac gripped his sword and pushed the door open.
The air inside was heavier, charged with mana that hummed through his bones.
He took a single step in, then another.
Behind him, the others stayed by the threshold, their figures reflected countless times on the mirrored walls.
The light from the corridor dimmed as the opened door was replaced by invisible walls.
Isaac stopped just inside the chamber and looked around. The silence was unnaturally still, like the dungeon itself was holding its breath.
A faint vibration passed through the floor.
Something was waking up.
He raised his sword, the blade gleaming with Dark Lightning Aura.
The light it gave off reflected against the mirrored walls, scattering shadows in every direction.
A tall, humanoid being emerged in the center of the chamber.
Its face was smooth glass with smoky tendrils swirling inside.
The lower half of its body faded into dark mist, floating just above the ground.
Surrounding it were several armored knights with reflective armor, each one holding a longsword made of fractured crystal.
The knights moved first.
They rushed toward Isaac, metal feet clanging against the mirrored floor.
Isaac stepped forward, calm and steady.
He swung his sword once, cutting down the first two with minimal effort.
The attack was clean. Too clean.
The moment their bodies shattered, each knight split into two smaller versions of itself.
Their armor looked thinner, but their speed increased.
He exhaled quietly and shifted his stance.
The smaller ones charged again, slashing at him from different directions.
Isaac barely moved.
He tilted his head slightly to the side, dodging a blade by a hair’s breadth, then stepped left to avoid another.
His sword flashed again.
The same thing happened.
The cut knights split again into even smaller versions.
"So they divide every time they’re cut," Isaac muttered.
The chamber began filling with more of them.
Each time he destroyed one, two more appeared, though weaker than before.
The mirrored floor rippled slightly as the monsters summoned faint, translucent barriers around him.
He could tell they were trying to trap him.
He touched one of the invisible walls and felt resistance, then simply walked through it.
His physical stats were high enough to ignore such restrictions entirely.
Finally, after the tenth split, the smaller knights stopped dividing.
Isaac narrowed his eyes.
"Looks like now I can kill them."
This time, when he swung his sword, the shards scattered and vanished.
Mirror Sentinel (Elite Rank) Defeated
Drop: 2 Silver Coins, EXP
As soon as the last one fell, the tall, floating figure—the boss monster—moved.
Its glass face turned toward Isaac.
The air in the room changed, growing thick and heavy.
Its gaze locked on him, and for a moment, his body froze.
He couldn’t move.
’It paralyzed me,’ Isaac realized, watching as the creature’s smoky lower half flared with energy.
The boss dashed forward.
Its arm, long and distorted like liquid glass, swung down with enough force to crush stone.
The impact filled the chamber with dust and shockwaves, shaking the mirrored walls.
When the dust settled, Isaac stood unmoved. Not a scratch on him.
He looked at the monster calmly.
"I guess this really is a tutorial dungeon," he said, brushing his shoulder as if wiping away dust. "A direct hit from the mid-boss feels like a tickle."
The boss twitched, almost as if insulted.
It jumped back and raised its arm again.
Flames gathered around its palm, forming into a glowing spear that pulsed with heat.
’That’s the Flame of Judgment skill I copied from Alice. So it can copy my skills too.’
While the boss charged its attack, Isaac was already cutting down the remaining Mirror Sentinels that had reappeared.
When the boss finally threw the spear, he dodged sideways.
The spear struck the floor, exploding into waves of flame.
Isaac glanced at it briefly. ’I could block it, but there’s no point in being stupid and taking it head-on.’
The fight continued.
For the next thirty minutes, Isaac kept dodging and observing.
The boss mixed physical attacks with copied skills.
Its movements grew sharper with every exchange.
The mirrored walls around them pulsed whenever it absorbed light from its surroundings, suggesting some kind of field control.
By the end of that time, Isaac had cleared every Mirror Sentinel and fully understood how the boss fought.
’It can copy one of my attack-type skills every thirty seconds.’
’It can use a Paralyzing Gaze every minute.’
’And it can detonate the mirrors in the room for area damage.’
Once he was confident, he made his move.
The boss lunged again, its smoky body twisting like a whirlpool.
Isaac dodged its arm, stepped forward, and leaped.
His body moved in a smooth arc until he was at the creature’s head level.
Instead of swinging his sword, he simply slapped the back of his hand against its head, as if swatting a mosquito.
The impact was quiet, but the result wasn’t.
The boss’s upper body exploded into shards and smoke.
Mirror Wraith (Mid-Boss, Elite Rank) Defeated
Drop: 50 Silver Coins, Aether Glass ×10, Binding Crystals ×10, EXP
"Oh? The drops are nice," Isaac said, lowering his hand.
He looked at the small pile of glowing items floating in front of him.
The Aether Glass and Binding Crystals were valuable.
He needed both for building Sky Dome later.
With the boss gone, the invisible barrier that had been sealing the door vanished.
The mirrored air shimmered faintly, and then the door opened.
Celia was the first to rush in.
"Isaac! That was a nice fight!" she said, practically beaming as she jogged up to him.
Beatrice, Isla, and Warn followed behind more slowly.
Their expressions carried a mix of awe and fear.
"That... was the mid-boss, right?" Warn asked, his voice uncertain.
"It was," Isaac replied.
He began explaining what he had learned about the Mirror Sentinels and the Mirror Wraith, their division mechanic, the boss’s skill-copying, and the paralysis timing.