The dungeon chamber was empty now, except for the faint glow of residual magic and the black mist still hovering over Min Jae-hyun's hand. His heart pounded as he stared at it. The energy was alive, writhing as if it had its own will.
[Echo System Activated]
[Host: Min Jae-hyun]
[Echo Inventory: 1/∞]
[Echo: Stone Troll]
He hesitated. "What do I even do with this?"
The black mist twisted and solidified into a creature unlike anything he'd seen. It wasn't just a shadow—it was fragmented, flickering like broken glass, glowing faintly where the troll's body had once been. Its eyes glimmered with faint white light, and for a moment, it tilted its head, studying him.
Then it spoke—not in words, but in a feeling. A weight pressed into his chest: curiosity, caution, and awareness.
He realized immediately: this Echo was sentient.
Back in the city, life moved on. Hunters patrolled the streets, gates shimmered in the distance, and ordinary citizens avoided the danger zones. No one noticed Min Jae-hyun slipping through the rain-slicked streets, his new companion hidden in the folds of his coat.
At his small apartment, he examined the Echo more closely. Hye-jin, his younger sister, watched him curiously.
"You look tired," she said. "Did something happen in the dungeon?"
He forced a smile. "Just… a long day."
The wolf-shaped Echo shifted beside him, translucent yet solid enough to leave faint shadows on the floor. Jae-hyun's heart beat faster. He could control it, but not perfectly. Every movement required focus, and it seemed to respond to his emotions.
When he concentrated on calmness, the Echo mirrored him, moving smoothly. When fear surged, it trembled and flickered.
"This… isn't just a summon," he muttered. "It's alive."
The next morning, he returned to the Hunter Association. Rumors of a solo dungeon clear had already spread, but no one had seen exactly what happened. He kept the Echo hidden, letting the whispers work in his favor.
"You cleared the dungeon alone?" a hunter asked, eyes wide.
Jae-hyun shrugged. "I… managed."
The leader approached. "You're lucky. That troll was C-rank. Most F-rank hunters would've died instantly."
"I survived," Jae-hyun said quietly, focusing on the flicker of the black mist inside his coat.
The leader studied him, eyes sharp. "Potential, maybe… but still weak. Learn to fight. You'll need it."
Later, in a quiet alley, Jae-hyun finally experimented with the Echo system. He tried to make it attack.
"Strike," he thought.
The creature hesitated. Its fragmented form flickered between solid and mist. Then it lunged at a nearby pile of crates, smashing them with a bone-like hand.
"Good… good," he whispered.
He learned quickly: the Echo responded to his intent, not just commands. Mental clarity and calm focus made it obey faster. Emotion could disrupt control. Fear, anger, or impatience made the creature unpredictable.
He experimented for hours, summoning the Echo, making it move, testing attacks, and retreating. Each trial taught him more.
By nightfall, he could summon it reliably. It crouched beside him, alert, its fragmented shadow body twitching like a living storm.
A few days later, reports came in of a new Gate forming in the east district. Min Jae-hyun sensed it immediately through the faint hum of magical energy in the city air. Hunters gathered around the shimmering portal, their faces pale as they assessed the danger.
Jae-hyun clenched his fists. This was his chance to test the Echo in a real battle.
He slipped through the crowd, keeping the Echo hidden. It followed silently, its white eyes glowing faintly in the shadows.
The Gate pulsed. Shadows crawled from within, twisting and merging into shapes. But these monsters were different—not ordinary dungeon creatures. Their limbs were thin and jagged, almost skeletal. Their eyes glowed red like coals, and they moved with eerie precision, coordinating with each other as if thinking collectively.
Even seasoned hunters froze.
Jae-hyun took a deep breath. "Alright…" he whispered. The Echo responded, growing larger, its black mist solidifying into a wolf-like warrior.
The first skeletal monster lunged. Jae-hyun focused. The Echo mirrored his intent perfectly this time, striking the monster with claw and shadow-enhanced strength. The creature fell, but more advanced monsters poured out of the Gate.
He realized quickly: this Gate was different from the D-class dungeon. These creatures were coordinated, smart, and fast. They weren't just mindless monsters—they adapted.
Hunters around him faltered. One F-rank tripped, another low-level hunter screamed as a creature grabbed him. Jae-hyun's Echo moved with deadly precision, striking down one monster after another. But the more he used it, the more he noticed something worrying: the Echo drained his energy slightly every time it struck, linking his vitality to its attacks.
The battle became a test not just of strength, but of endurance. He had to keep calm, focus, and balance his energy with the Echo's power.
Finally, after what felt like an hour, the last skeletal monster fell. Hunters looked at him in shock. None could believe an F-rank had held the line.
The Echo dissipated into shadow, leaving Jae-hyun trembling, drained but alive.
That night, he returned home, exhausted. Hye-jin greeted him at the door.
"You fought again, didn't you?" she asked.
Jae-hyun nodded. "Yes. But I… can't explain." He stared at the empty space where the Echo had vanished. "It's alive, and it's not just a weapon."
Hye-jin frowned. "Are you sure you're okay?"
He forced a smile. "Yeah… I'm fine."
But deep inside, he knew this was only the beginning. The Echo system was more than just a power-up. It was a link to something bigger—a world behind the Gates, full of dangers, secrets, and ancient beings waiting to awaken.
And he had no idea how far he would need to go to survive it.