Isekai Dungeon Architect

Cass was on edge, though not from fear. The air in the hunting ground was thick with the scent of damp earth and wild energy, a stark contrast to the sterile halls of his noble house or the familiar, boisterous inn.

He had chosen to be here, to join the others on this mad, exciting quest for a suitable mount.

He had been hesitant when Aria suggested the lake. His initial instruction was to stay in Haimdel, lay low, and be the party's inconspicuous anchor.

But after the conversation with the family's right-hand man, after trading a piece of his inherited freedom for the right to follow Aria, he felt an urgent need to prove his worth. He was tired of being the 'young Lord' who needed protection.

He followed the edge of the forest path, moving with a quiet caution that belied his age. Unlike Aria, who had walked around unseen, Cass made no attempt to conceal his presence fully; instead, he managed his sound.

He wore simple leather armor, purchased just this morning, but his most potent weapon needed no scabbard or sheath.

He lifted his right arm, and with a familiar, searing heat, the silver-runed longsword, Silas, grew out of his very skin, a seamless, shimmering extension of his arm and will. Its blade, cool to the touch despite the warmth of its creation, hummed with contained, deadly power.

In the dungeon, Silas had been the sword of a fallen knight, gifted to him by Aria after they defeated the Shade.

Now, after his leveling and the strange integration process that occurred when he left the core chamber, Silas was no longer merely a weapon; it was an innate skill, a part of his body. It felt right, an answer to the helplessness he'd felt during the Naga raid.

"Alright, Silas," Cass whispered to the wind, his voice firming up. "Let's find a decent fight. We need something with speed."

He had broken off from Aria and Qwy near the first bend in the road, choosing a path that led through a rocky, less-frequented stretch of the forest, the hunting ground Vice had dismissed as containing only 'low-end, aggressive fodder beasts.' Cass wanted fodder. He wanted practice.

The first opponent came quickly: a Granite Boar, a low-level monster whose thick, gray hide granted it powerful resistance to physical blows.

It charged from the brush, its eyes red with hunger, aiming its rock-solid tusks at the boy.

Cass stood his ground, letting the beast close the distance. He had trained tirelessly with Borin and Kaela after every dungeon excursion, refining his stance and footwork. He was faster now, his reactions sharpened by months of combat.

[ Skill Activation: Silas's Cleave ]

Silas flashed forward, not in a brute-force slash, but a precise, arcing movement that bypassed the boar's armor. Instead of targeting the tough hide, Cass aimed for the soft, vulnerable joint behind the foreleg, a technique Kaela had repeatedly drilled into him.

The sword was liquid silver in his grasp, moving with an impossible speed that left a shimmering trail in the air. The beast grunted, a noise of surprise rather than pain, before its entire body staggered.

Silas didn't just cut; it momentarily disrupted the internal flow of Mana, causing localized paralysis.

THUD!

The Boar collapsed, twitching. Cass stepped back, his chest rising and falling rhythmically, his breath perfectly controlled. He looked down at the defeated beast, a faint layer of gray dust already forming on its hide as it died.

"Too slow," he critiqued himself, retracting Silas until only his bare, unblemished forearm remained. "And I used too much energy on the Mana disruption. Next one, no skills."

He continued deeper. He encountered three Shadow-Blink Dogs next, creatures that relied on chaotic, brief teleportation. This was a challenge of anticipation and timing, things he struggled with when fighting alongside Aria. But alone, his focus was absolute.

He allowed them to surround him, the darkness of their fur blending with the forest shadows. When the first one vanished, Cass didn't look where it was or where it should appear. He listened to the subtle shift in the Mana flow around him—a hint Rose had given him long ago.

WOOSH!

The dog appeared right at his flank, teeth bared. Cass didn't even activate Silas fully. A dagger-like protrusion of the silver metal extended just three inches from his elbow, intercepting the attack. A sickening CRUNCH sound echoed as the beast collided with the impossibly hard material.

The other two hesitated, startled by the failure of the sneak attack. That hesitation was all Cass needed.

He moved, a blur of motion, Silas flashing out and retracting, each movement a strike and a block combined.

THWACK! THWACK!

Two more Shadow-Blink Dogs fell without a single visible scratch on their bodies. Cass hadn't cut them. He had used the flat of Silas to deliver a focused Mana shockwave, effectively knocking them unconscious or, at best, killing them with blunt force.

He checked his status—his proficiency with Silas had jumped again. His control over the Mana flowing into the blade was stabilizing. He was growing stronger, faster than he ever had in the confines of Westford.

This is what I needed, he thought, a sense of grim satisfaction settling in. He wasn't relying on anyone else's Mana or skills. This was his power.

He moved toward the lake, the sound of water growing louder, the forest thinning slightly.

He had fought half a dozen more beasts—a pair of venomous Adder Vipers that he incapacitated with a low-power sonic blast from his palm, and a slow, heavily armored Iron Beetle that he simply bypassed, knowing it lacked the speed he sought in a mount.

He emerged from the trees onto a small, sandy clearing. The lake was vast, stretching out into the afternoon sun, its surface placid and sparkling. It was a beautiful, serene scene, utterly unlike the violent chaos of the forest floor.

Cass immediately stopped, hiding himself behind a thicket of weeping willows. The air here was different. It wasn't just the scent of fresh water; it was the presence of an incredibly pure, ancient form of energy—not World Energy, but close enough to make his skin tingle.

Then he saw it.

In the middle of the lake, where the water was deepest and darkest, a figure moved. It was a deer-like creature, but unlike any animal he had ever seen, even in the magical texts of his house.

Its body was slender, built for grace and speed, yet it was composed entirely of what appeared to be carved, pale blue rock—the color of glacial ice under a winter sky. Its antlers spiraled upward, glowing with a soft, ethereal light that cast a gentle blue shimmer on the water.

A Crystal Hart, his inherited noble knowledge whispered in the back of his mind. An A-Rank elemental creature. Extremely rare, shy, and virtually untouchable. It is said to walk on water and is an embodiment of pure Earth and Water Mana.

The Crystal Hart was not submerged. It was walking slowly across the surface of the lake, each delicate, four-toed hoof touching the water without breaking the tension, as if walking on solid glass.

It moved with a quiet dignity, periodically lowering its head to graze on the thick, unseen energy floating just above the water line.

It's magnificent, Cass realized, forgetting why he was even here. He wasn't thinking of defeating it or taming it. He was simply captivated.

He watched for what felt like an eternity, careful not to move a muscle, the handle of Silas remaining a quiet part of his arm. He didn't want to break the moment, didn't want to see the beast flee from his brute presence.

The Hart eventually reached the far shore and paused, lifting its head as if listening to something only it could perceive. Then, its head slowly turned, its attention shifting away from the unseen sounds of the forest and directly toward Cass's hiding spot.

The Crystal Hart's eyes were large, dark, and utterly pure, reflecting the blue sky and the deep water. There was no fear, no aggression, and no predatory instinct in its gaze. It simply saw him.

Cass froze. He waited for the inevitable—the flash of light, the quick retreat, the vanishing act. Any wild beast would flee an exposed hunter.

But the Hart did not flee.

Instead, it took a single, deliberate step back onto the water. Then another. Its movement was slow, measured, and serene, the blue light of its body approaching the edge of the lake where Cass stood.

It didn't increase its speed. It approached him as if he were a gentle, known part of the landscape. It walked right up to the bank, its hooves finally touching the damp sand near the water's edge, barely ten feet from the willow thicket.

The blue, crystalline antlers glowed, bathing Cass in a cool, calming light. He felt the wild, volatile Mana in the air around them become still, held in check by the creature's serene power.

Cass knew what he had to do. He stepped out from the willows, Silas dissolving instantly back into his arm, leaving him standing before the majestic beast unarmed and exposed.

The Crystal Hart watched him with those pure, deep eyes. It lowered its head slightly, not in challenge, but in a silent acknowledgment.

Boy and beast, the young hunter and the elemental monarch, stood face to face in the quiet afternoon sun, a contract unspoken, yet already forged between them.