Arthur reached the heart of the underground market with a serious expression on his face. Behind a rotting wooden table, an old man sat, his face hidden in shadows. He spoke in a low voice, as if he had been expecting him:
"You… want to go in alone, don't you?"
Arthur looked straight at him without lowering his head.
"Yes. Alone."
A faint smile appeared on the old man's face.
"Brave… or foolish. We shall see."
He placed a heavy stone seal on the table. The seal glowed red, strange runes vibrating across its surface. When Arthur reached out, the energy emanating from it was enough to make the people nearby recoil.
"This seal will take you to the entrance of a B-rank dungeon," the man said. "But no one can know what awaits inside. Those who enter alone… rarely return."
Arthur paused for a moment. The conversations he had with the gods, the mission given to him, and the sealed power within him echoed in his mind. He closed his eyes, took a deep breath, and replied with determination:
"I'm not going in to return. I'm going in to win."
The moment he grasped the seal, he was enveloped in intense light. Everyone in the underground market squinted, and Arthur's silhouette disappeared within the radiance.
In an instant, he found himself in front of massive stone doors. The doors were adorned with blood-red symbols, each one seeming to herald death. The heavy metallic scent in the air warned of the danger that awaited inside.
Arthur stepped in without hesitation.
"So this is what a B-rank dungeon looks like."
As he entered, darkness and dampness surrounded him. Chunks of stone fell from the high ceilings, each drop echoing like a drum in his ears. Reddish moss glowed on the walls, illuminating the depths of the dungeon eerily.
Arthur moved carefully, his blue eyes scanning, trying to catch every subtle sound. The spear in his hand seemed to track his every breath, ready for action.
Suddenly, a strange creaking arose from the stone floor. The corridor in front of him began to tremble. From the shadows, a massive humanoid creature with long legs crawled forward. Its body was covered in a black, armor-like shell, and its eight legs dug into the stone floor like sharp blades. Its red eyes locked onto Arthur.
"So… you're my first trial," Arthur muttered under his breath.
The creature let out an ear-piercing scream and lunged. The ground shattered as its legs rushed toward him.
Arthur did not step back. He gripped his spear with both hands; sparks of lightning danced around his wrists. He lunged forward, the spear piercing the creature's first leg. It shrieked in pain and retreated, but did not stop—it became even more ferocious.
Taking a deep breath, Arthur whispered to himself:
"Raikiri-no-Metsujin… First Form."
Blue-white lightning crackled along the tip of his spear. In a flash, Arthur surged forward like a bolt of lightning, piercing the creature's body. Sparks flew, leaving scorch marks on the stone walls.
The creature let out one final scream before collapsing lifelessly. Its shell shattered, and a pitch-black liquid oozed from within.
Arthur held his breath for a moment, then gripped his spear again.
"This is just the beginning…"
Deeper in the corridor, stronger rumblings began. Hundreds of footsteps echoed. Arthur's blue eyes glowed in the dark. From his lips came a single sentence:
"Come, then."
The dungeon's darkness became his battlefield. Arthur struck the approaching creatures one by one. Lightning from his spear illuminated the narrow corridors, shaking the rune-carved stone walls with each strike. The air grew heavy, mingled with the smell of blood and burnt stone.
But there was determination, not fatigue, on Arthur's face.
"If this is only the first floor… what else awaits me inside?" he thought.
After what felt like hours, he reached a vast hall—the heart of the dungeon. Massive stone crystals hung from the ceiling, pulsating with red light, while ancient symbols glimmered on the floor.
Suddenly, the ground trembled. The floor cracked, and from the darkness, a gigantic creature emerged. Its body resembled an armored gorilla, its arms bound in thick chains. Its eyes glowed blood-red, and even its breath shook the stone floor.
Arthur gripped his spear.
"So… you're the boss."
The creature roared, a sound powerful enough to crack walls. It swung its chains, massive whips tearing through the air toward Arthur.
Arthur dodged at the last moment; the chains smashed into the stone floor, creating a huge crater. His blue eyes blazed.
"I need to finish this quickly."
He raised his spear, lightning surging along it.
"Raikiri-no-Metsujin… Second Form!"
Suddenly, he moved at incredible speed, his steps sounding like thunder. He sliced one of the chains with his spear and struck toward the creature's chest. But it unexpectedly grabbed him mid-air.
Arthur's ribs cracked, his breath hitched—but the resolve in his eyes did not fade.
"You cannot chain me…"
Lightning blazed through his spear, piercing the creature's arm. He freed himself and landed. The creature roared in rage.
Arthur took a deep breath.
"Now it's time to get serious."
He raised his spear to the sky. Even the crystals seemed to tremble in response. Lightning filled the room.
"Raikiri-no-Metsujin… Third Form: Celestial Collapse!"
Lightning struck from the sky along with his spear. The colossal creature was hit, shaking the stone hall itself. Its armor shattered, chains broke, and it collapsed with a scream.
Arthur approached slowly. Before the red glow in its eyes vanished, the creature spoke its last words:
"You… are not human…"
Among the last sparks, the creature became a lifeless heap.
Arthur planted his spear in the ground, sweat dripping from his forehead. Yet the glow in his eyes had not dimmed.
"This is just the beginning. Greater battles await me."
The dungeon doors trembled open, revealing a new path leading deeper inside.
As Arthur stepped forward, the door behind him sealed shut like a stone bound by a seal. The room was engulfed in deep darkness. The air itself was heavy and oppressive; even breathing felt difficult. In the center, a massive being chained to the ceiling, floor, and walls by thick chains loomed.
When its eyelids opened, two crimson fireball-like eyes locked on Arthur.
"So… finally, a mortal has stepped in," said the demon, its voice echoing off the stone walls.
"Ever since they chained me here, I've only spoken with darkness. But you… you remind me of something I haven't felt in a long time: the scent of life."
The chains creaked, sparking as the demon lifted its head; its muscles rippled even beneath the chains.
"You don't know me, do you? I am the Shadow of Destruction—Asmodar. I burned kings' armies alone. I made continents bleed. And now…" A venomous gleam appeared in its eyes.
"I face a mortal child chained before me. How tragically ironic."
Arthur replied coolly:
"You are merely an obstacle. If you stand in my way, I will destroy you."
The demon chuckled lowly.
"Brave… but foolish. The chains may limit my power… but I can still obliterate you with my S-level strength. Even if you were SS+, here, you are in my domain!"
Asmodar pushed his arms forward. The chains strained with an ear-splitting noise, then suddenly slackened as if released. Its massive paw smashed into the floor, pulverizing the stone. The shockwave threw Arthur backward.
Arthur recovered at lightning speed, his spear crackling with electricity. A blue glow shone in his eyes.
"Raikiri-no-Metsujin: Stage One – Lightning Strike!"
In an instant, he vanished, leaving only the flash of lightning behind. His spear was about to pierce Asmodar's chest when the demon met it with his claw. The clash echoed like thunder.
"You're fast…" Asmodar hissed, swinging his claws violently. He created a gust strong enough to lift Arthur into the air.
Arthur changed direction mid-air with a lightning step, planting his spear into the ground upon landing. The stone floor cracked, lightning illuminating the room.
Arthur narrowed his eyes.
"These chains are holding you back. If you were at SS-level, you might have challenged me. But right now… your only advantage is your stubbornness."
Asmodar's laughter filled the room.
"You're mistaken, mortal! My power may be limited by chains… but each chain also fuels my rage! Can you feel it?"
Suddenly, the walls began to crack. The demon's body was engulfed in black flames, the chains seemingly drawing power from them.
Arthur did not retreat. He gripped his spear with both hands.
"Raikiri-no-Metsujin: Stage Two – Sharp Lightning!"
The spear glowed, slicing through the air. Arthur lunged like lightning. This time, his attack pierced Asmodar's chest. The chains shimmered, restraining the demon once more.
Asmodar dropped to his knees, letting out a mix of laughter and pain.
"You pushed me back into my chains, mortal… But this victory will not last. My name is Asmodar. When my chains break… I will show true apocalypse to you and your kind."
The demon's silhouette vanished into darkness. The chains resealed, and the room fell silent.
A black Crystal Scroll lay on the ground. Arthur picked it up. Its surface felt cold and sharp. The demonic energy vibrating within made his wrists tingle.
Ancient writings covered the scroll. Though Arthur could not read them, a system voice echoed in his mind:
[Item Acquired: Sealed Scroll – Fragment of Asmodar]
• Type: Mysterious Relic
• Grade: ??? (Restricted)
• Effect: Grants the user temporary power to summon Asmodar's Black Flames. (Uses: 3)
• Side Effect: Each use imprints a small dark mark on the user's soul. As the mark grows, Asmodar's chains break faster.
Arthur gripped the scroll tightly. His vision darkened for a moment, but he quickly regained focus.
"This power… is dangerous. In the wrong hands, it could be catastrophic."
He slung his spear on his back and took a deep breath. This dungeon held far more than he had imagined. Perhaps this was just the first whisper of the approaching darkness.