The submarine stopped spinning.
Not because the water calmed—far from it—but because something else asserted dominance over the space around them.
Karl dragged himself upright, boots magnetizing to the deck as emergency stabilization kicked in. The control room lights were dimmer now, most of the soft ambient glow replaced by harsh red and amber strips that painted everything in warning tones.
Outside the viewport, the ocean was no longer empty.
It was occupied.
Agnes's hologram flickered beside the sonar display, her usual warmth gone, replaced by a focused stillness that only surfaced when she was genuinely unsettled.
"…Karl," she said quietly. "I am reclassifying the contact."
He wiped blood from the corner of his mouth with the back of his hand and looked at the screen.
The sonar return had stopped being abstract.
It had shape now.
A massive silhouette drifted just beyond visual range, its form unmistakable even through distortion and particulate interference. A body built like a living torpedo. A head too wide, too blunt, jaws that extended far past what any modern shark should possess.
And then there was the fin.
A dorsal fin tall as a building, scarred and asymmetrical, split in places where something unnatural pulsed beneath the flesh. Embedded at its base, half-fused into cartilage and bone, was a glowing sphere of condensed energy.
Not technology.
Not metal.
Something older. Denser.
Agnes swallowed. Not a sound effect. An actual pause in her projection, as if she needed the gesture to steady herself.
"…That's a Megalodon."
Karl exhaled slowly. "You're joking."
"I wish I were," she replied. "Size estimate exceeds historical maximums by thirty-eight percent. Musculature density is impossible by biological standards. That fin-mounted object is emitting a stabilized ichor-core signature."
The creature shifted.
The water outside the viewport moved with it, not flowing so much as being displaced by sheer presence. The submarine's hull creaked again, a deep, stressed groan that vibrated through Karl's chest.
"Agnes," Karl said carefully, "tell me I'm wrong."
She didn't look away from the display.
"It is not a normal demon," she said. "And it is not merely a beast."
The Megalodon turned.
Not toward the smaller figure that had been fighting it moments ago.
Toward them.
Its eye slid into view through the darkness, enormous and glassy, reflecting the submarine's lights as a dull, predatory sheen. There was no rage in it.
No hunger.
Just recognition.
"It's locked onto us," Agnes said softly. "New prey. New stimulus."
Karl's jaw tightened. "That thing shouldn't exist anymore."
"That," Agnes replied, voice dropping, "is exactly why it does."
The core embedded in the fin pulsed once.
The water around it warped.
Agnes brought up a new overlay without being asked. Data streams snapped into place, her tone shifting into something colder, more clinical.
"Karl. You are looking at a Core Demon."
He didn't respond immediately.
He didn't need the explanation for the danger. He could feel it. The way the ocean itself seemed to bend subtly around the creature, as if reality deferred to it.
The Megalodon's tail moved once.
The resulting current slammed into the submarine's flank, sending ripples across the hull plating despite the nanite reinforcement.
The Megalodon opened its mouth.
Rows upon rows of teeth unfolded, each one the size of a blade, layered so deep they seemed to recede forever into darkness. The water around its jaws vibrated with low-frequency resonance as pressure condensed between them.
"This one is worse," Agnes added quietly. "It's most likely a Mythic Core Bearer."
Karl felt a chill that had nothing to do with the cold.
"…Mythic."
The sonar flickered as the creature's outline sharpened further, as if the system itself was being forced to acknowledge the truth of what it was seeing.
"Megalodon," Agnes continued. "A name humans whispered with fear. A monster magnified by absence. The apex predator of an ocean humans barely understood."
The creature drifted closer.
Every movement was unhurried.
Confident.
"People remembered it as unstoppable," she said. "As something that ruled the sea absolutely. So that is what it became."
Karl's hands curled into fists. "So the legend made it stronger."
"Yes."
The Megalodon's eye rolled slightly, fixing fully on the submarine now.
Silence filled the control room.
Outside, the Megalodon began to circle.
Each pass was wider than the last, its bulk eclipsing the distant glow of the submarine's lights. The water churned in its wake, forming slow, spiraling currents that tugged at the vessel like invisible hands.
The smaller figure from earlier was gone now.
Either fled.
Or crushed.
The Megalodon's fin tilted, the core pulsing brighter as if in anticipation.
The ocean growled again, louder now, closer. A sound so deep it bypassed hearing and went straight to the bones.
Outside the viewport, the Megalodon turned fully toward them, jaws parting as the water compressed violently around its head.
The core in its fin flared.
The submarine's alarms began to rise again.
And somewhere in the deep black of the Pacific, a legend decided to hunt something new.
The Megalodon did not lunge.
It simply closed the distance.
One moment it was circling at the edge of the lights, a vast suggestion in the dark. The next, the water in front of the viewport compressed so violently it looked like the ocean itself was folding inward.
"Karl—!"
The impact came before Agnes could finish the warning.
Jaws slammed shut around the forward quarter of the submarine with a sound that should not have existed underwater. Not a crunch. Not a snap.
A detonation of pressure.
The entire vessel shuddered as something colossal bit down and tore.
Metal screamed. Not metaphorically. The hull let out a shrill, shrieking protest as layers of reinforced plating, nanite lattice, and pressure shielding were ripped away in one savage motion. The submarine lurched violently, alarms erupting in a full cacophony as internal pressure spiked and systems screamed their objections.
Karl was thrown forward, slamming shoulder-first into the console. Pain flared white-hot down his arm, but he barely registered it.
On the viewport, the Megalodon's teeth slid past the glass.
Close enough to see the grooves in them. The scars. The old fractures that had healed crooked.
And then it pulled away.
A chunk of the submarine went with it.
Red lights flashed everywhere.
HULL BREACH — FORWARD SECTION
PRESSURE INTEGRITY FAILING
WATER INTRUSION DETECTED
Cold flooded the compartment as seawater forced its way through ruptured seams, spraying in a violent mist that instantly crystallized against emergency seals.
Karl didn't think.
He reacted.
"Agnes—seal it—now—!"
"I'm trying—!" she snapped, already rerouting power, her projection flickering violently as systems overloaded. "The breach is too wide—Karl, it tore through multiple layers—!"
"I know!"
He slammed his hand against the bulkhead, eyes burning as he reached inward, deeper than he ever liked to go in base form.
Nanites answered immediately.
Not armor. Not weapons.
Structure.
They poured out of the Drive Regulator in a blinding surge, flooding through conduits, crawling across torn metal, weaving themselves into the shredded edges of the hull. Karl felt it instantly—the pull, the drain—as his own Vythra was ripped into motion, converted directly into matter and force.
VYTHRA ENERGY: 24% → 18%
His knees buckled.
He caught himself on the console, teeth clenched hard enough to ache as he forced the nanites to keep moving, keep building, keep holding back the ocean that was desperately trying to crush them flat.
Outside, the Megalodon circled again.
Slower now.
Satisfied.
It knew what it had done.
Agnes's voice cut through the alarms, sharp with barely contained fear. "Karl, you cannot transform. Every nanite you have is reinforcing the hull. If you divert even a fraction—"
"I know," he growled. "I'm not letting go."
Another surge of pressure slammed into the submarine as the Megalodon's tail passed close, its movement alone enough to send destabilizing currents rippling across the half-repaired hull.
The nanites strained.
Karl felt it like a muscle tearing.
VYTHRA ENERGY: 18% → 14%
Blood dripped from his nose onto the deck.
"Pressure's climbing," Agnes said, hands flying over holographic controls. "Hull integrity at seventy-one percent and falling. Karl, it's testing us."
As if to prove her right, the Megalodon turned sharply and charged again.
This time it didn't bite.
It rammed.
The side of the submarine caved inward under the impact, reinforced plating bowing dangerously before the nanites barely managed to lock it in place. Karl screamed as feedback tore through his nervous system, his vision blurring at the edges.
VYTHRA ENERGY: 14% → 10%
"I can't—" he gasped, forcing more nanites into the breach. "I can't keep this up—!"
"You have to," Agnes said, voice low and fierce. "If the hull fails, we die instantly. There is no second chance at this depth."
The Megalodon drifted past the viewport again, its eye sliding into view.
It watched.
Not attacking.
Waiting.
Letting the pressure and exhaustion do the work for it.
Its fin-mounted core pulsed slowly, rhythmically, as if synced to Karl's faltering heartbeat.
Another alarm blared.
STRUCTURAL STRAIN CRITICAL
REINFORCEMENT OVERRIDE REQUIRED
Karl laughed weakly, breath hitching. "Override… with what?"
Agnes didn't answer.
Because something changed.
The sonar pinged.
A second contact appeared.
Small.
Fast.
Moving hard against the surrounding currents, cutting sharp arcs through the Megalodon's pressure wake.
Karl blinked through the haze. "Agnes… is that—"
"Yes," she said, relief and tension colliding in her voice. "It's back."
Outside, the water shifted violently as the smaller figure darted into view at the edge of the lights. It moved nothing like the Megalodon—no mass, no dominance. Just speed. Precision. Purpose.
The Megalodon reacted instantly.
Its head snapped toward the disturbance, jaws opening in a silent bellow as it surged forward, abandoning the submarine without hesitation.
The pressure on the hull eased slightly.
Karl sagged, nearly collapsing as the nanites finally stabilized the last of the breach, locking the reinforced plating into place with a dull, final thrum.
VYTHRA ENERGY: 10% → 6%
He slid down against the console, chest heaving, vision swimming.
Outside, far ahead in the darkness, two shapes collided again.
The ocean trembled.
The legend had turned away from them.
For now.
And whatever had come back to challenge it was not done yet.