The sea did not sleep.
It breathed—slow, vast, ancient—rolling against the hull of the Kuroshio Maru like a living thing that knew their names. Moonlight fractured across the water, silver veins stretching into blackness. Somewhere beneath that surface, the Umibōzu moved.
Riku stood at the bow, fingers white around the rail. The salt wind cut his face, sharp and cold, but it steadied him. Since the Black Tide receded, the ocean had felt… watchful. As if it were waiting for something to be finished.
Behind him, Aiko adjusted the lanterns, their blue flames warded with old sutras. "The charts don't agree," she said quietly. "The currents say we should be drifting east. But we're being pulled south."
"Toward the Trench," Kenji replied from the helm. He didn't look up. He didn't need to. Everyone aboard knew where the water wanted them to go.
Riku closed his eyes. The memory returned unbidden—the towering silhouette rising from the sea, featureless and endless, blotting out the stars. The voice without sound that had spoken inside his bones.
You carry what was taken.
He opened his eyes again. "It remembers," he said. "The sea remembers us."
A low tremor ran through the deck. Not a wave—something deeper. The lantern flames leaned as if bowing to an unseen presence.
Aiko swallowed. "We sealed the Tide Gate. We did what the elders asked."
Kenji's jaw tightened. "The elders never said that would be the end."
The water ahead began to darken, swallowing the moonlight entirely. A circle formed—perfect, vast—its edge marked by a faint, churning foam. The sea fell unnaturally still.
Riku felt it then: the pull in his chest, like a tide answering a tide. The mark on his palm burned, the same place where the ocean had once cut him and taken something more than blood.
"It wants a reckoning," he said.
From the heart of the dark circle, the sea rose.
Not crashing. Not violent.
Rising—slow, deliberate—until a colossal form emerged, blacker than night, smooth as obsidian, its shape barely definable against the sky. No eyes. No mouth. Yet its presence pressed down on them, heavy with centuries.
The Umibōzu.
Aiko dropped to her knees, whispering prayers that trembled apart in the wind. Kenji held the wheel, frozen, knuckles bleeding where wood bit into skin.
Riku stepped forward.
"I'm here," he said, his voice small but steady. "You called me."
The sea answered—not with words, but with memory.
He saw ships swallowed whole, villages drowned in storms with no names, offerings cast into waves by desperate hands. He felt the weight of promises broken and bargains forgotten. The Umibōzu was not a monster born of hunger.
It was a guardian abandoned.
What was taken must be returned, the presence pressed into him. Or the tide will rise again.
Riku understood then. The Tide Gate had been sealed with something impure—power stolen, not given. A fragment of the sea's own will, bound and caged to save the shore.
Saved… at a cost.
He looked back at his companions. "If I do this," he said softly, "the ocean takes back what it's owed."
Kenji finally turned. "And you?"
Riku smiled, a thin, brave thing. "I don't know what's left when a debt like that is paid."
The Umibōzu loomed closer, the water lifting Riku's feet until he stood ankle-deep in the sea that climbed the deck without soaking it.
Aiko reached for him, tears streaking her face. "There has to be another way."
Riku shook his head. "The sea remembers. It doesn't forgive what's stolen."
He stepped forward—into the black.
The mark on his palm flared like a dying star. The water surged upward, wrapping him in cold and silence. For a heartbeat, the world held its breath.
Then the sea roared.
Not in anger—but in release.
The dark circle collapsed inward. Waves crashed, real and wild again. The lanterns guttered, then steadied. The night sky returned, stars trembling but whole.
Where the Umibōzu had stood, there was only water.
And where Riku had been—
Nothing.
Aiko screamed his name into the wind. Kenji slumped against the wheel, eyes shut, salt and blood on his face.
Far below, in the deep where light never reached, something ancient settled back into its slumber, whole once more.
And on the surface, the sea rolled on—quiet, vast, and remembering.