The hum of the Abyssal Vanguard submarine was steady, like the heartbeat of some sleeping leviathan. Kairen sat pressed against the cold metal wall, the borrowed coat heavy on his shoulders, as the vessel descended deeper beneath the ocean.
Every vibration of the engines echoed in his bones. Each flicker of light across the ceiling reminded him of the hospital ward—except now there were no flickering bulbs, no drone cameras watching. Only silence, broken by the occasional clatter of tools from the engineers or the faint murmur of voices he couldn't fully hear.
It was both safer and infinitely more dangerous.
Kairen pressed his hand to his chest. The codex shimmered faintly, a translucent glyph hovering just above his skin. It pulsed slowly, like a second heart.
Nulla.The word Nolan had spoken with deliberate weight, as if testing how it tasted in the air.
Nobody explained what it meant. Not really.
The system's voice was cold and mocking in his mind:
Codex: Nulla – Extremely RareLevel: 1 (Tier 1)XP: 0.7 / 100Available Skills: Echo Shield (Unlocked)
Nothing else. No strength stat, no speed. Just a single shield he barely understood how to summon.
He clenched his jaw. If I really am this "rare," why do I feel so weak?
"Still brooding?"
The voice cut into his thoughts. He looked up. Lira was crouched across from him, emerald eyes bright in the dim cabin light. Her hair—fiery, untamed—seemed almost out of place against the subdued blues and silvers of the submarine.
Kairen shifted uncomfortably. "I'm not—brooding."
Her smirk said otherwise. "Nolan told me you nearly collapsed after pulling an Echo Shield. That's normal. Codex activation is like stretching a muscle you didn't know you had. But if you keep doubting yourself, you'll never strengthen it."
Kairen frowned. "And you're supposed to fix that?"
"I'm your mentor, remember?" She leaned back, crossing her arms. "Which means my job is to get you moving before Obsidian Tide does. They won't care if you're tired, or scared, or confused. They'll just take what you are and rip it out of you."
The words sent a chill through him. He wanted to ask more—who exactly were the Obsidian Tide? Why did they want him? What was a Nulla lineage?—but before he could, Nolan's voice carried through the cabin.
"Maric, status."
The pilot's answer was crisp, professional. "Approaching Abyssal Sector Nine. Mana currents are stable. No hostile signatures detected."
"Good." Nolan adjusted the holo-display hovering at his wrist. His blue eyes flicked to Kairen. "We'll begin his first drill in the outer trench. Nothing too dangerous. Just a taste."
Lira stood, offering Kairen a gauntleted hand. "On your feet, rookie. Time to learn how not to drown."
The airlock chamber hissed as the outer hatch sealed. Cobalt lights flared along the edges of the walls, illuminating runes etched into the plating.
Kairen's breath hitched. He stood inside a pressurized exosuit, the gauntlet Lira had given him linked to the codex glyph pulsing on his chest. The suit felt alien—too tight around his limbs, too heavy at the shoulders. He shifted his stance, but every movement felt delayed, like wading through syrup.
Lira, already suited, moved with ease. Her armor gleamed faintly, runes etched into the plating glowing with steady rhythm. "Relax," she said through the comm. "You're thinking too hard. Let the codex do the adjusting. Feel the mana currents."
"How am I supposed to 'feel' water?" Kairen muttered.
She laughed. "Not the water. The energy inside it. The ocean here is alive with mana. Let it guide you."
The outer hatch opened.
Blackness swallowed the chamber, broken only by streams of bioluminescent light drifting like constellations across the abyss. Kairen's stomach lurched as the water rushed in, but the exosuit held firm. His visor adjusted instantly, overlaying faint glyph-lines across the environment.
The abyss. Endless, cold, alien.
For a moment, he forgot his fear.
They drifted into the trench, Lira leading with confident strokes, her gauntlet leaving faint trails of aqua light in the water. Kairen followed clumsily, kicking too hard, arms jerking awkwardly.
"Slow down," Lira's voice chimed in his ear. "The codex currents are like music. Don't thrash—listen. Let them carry you."
Kairen gritted his teeth. He tried again, reaching out with his senses. At first, nothing. Just cold pressure and the muted rush of water.
Then… something shifted.
He felt it. Threads of energy weaving through the trench, pulsing faintly like strings of a harp. When he matched his movement to that rhythm, his suit glided smoother.
His heart quickened. "I… I can feel it."
"Good," Lira said. "That's step one. Step two—defense."
Her form blurred. One moment she was ahead, the next she darted to his side, gauntlet glowing. A sphere of compressed mana shot toward him, fast and sharp.
Kairen panicked. His breath caught. Instinctively, he raised his arm.
The codex glyph on his chest flared. A translucent violet barrier snapped into existence—imperfect, shaky—but enough. The mana sphere struck it and dissolved into harmless sparks.
Kairen's legs trembled inside the suit. "I… I did it?"
"Barely." Lira smirked, circling him. "Your Echo Shield is reactive. It only triggers when you're in real danger. That's both good and bad."
"Bad… how?"
"Because hesitation will kill you."
She struck again, faster. This time, Kairen hesitated. The shield flickered too late, the mana sphere grazing his shoulder. His suit groaned, sparks flaring across his visor.
"Dammit—!"
"Focus!" Lira snapped. "You can't survive if you wait until the last second. Anticipate. Control it before the codex chooses for you."
Her voice was sharp, but beneath it Kairen sensed something else—urgency. Fear, maybe, buried deep. She wasn't just training him. She was preparing him.
But for what?
They drilled for what felt like hours. Attack, defend, reposition. Lira never slowed, never relented. Each failure burned Kairen's pride, each success gave him fleeting relief before the next challenge hit harder.
By the time Nolan's voice cut through the comms, his arms ached, lungs burned, and the codex glyph on his chest pulsed weakly.
"That's enough for today."
Lira exhaled. "He's rough, but not hopeless."
Kairen wanted to retort, but exhaustion swallowed the words.
As they turned back toward the submarine, a faint tremor rippled through the trench.
Kairen froze. The mana threads he'd sensed earlier twisted, vibrating out of tune. His visor flickered, glitching with static.
"Did you feel that?" he asked, voice tight.
Lira stilled. "Yeah."
From the shadows of the trench, shapes began to move.
Glowing eyes. Too many. Too close.
Nolan's voice sharpened. "Get back inside. Now."
But before they could retreat, the abyss shuddered again. A deep, resonant pulse echoed through the water—like the heartbeat of something vast.
Kairen's codex flared violently, searing his chest with violet light.
The system whispered in his mind:
[Warning: Reality Distortion Detected]Codex Resonance – UnstableNulla Sequence – Phase Fragment Approaching
Kairen's vision blurred. In that instant, he saw not the trench, not the abyss, but a vast island of obsidian stone rising from beneath black waters. Its surface writhed with runes, alive, awake.
His voice cracked through the comm, almost involuntary:
"The island… it's awake."