Renju left the fishing shack at the cusp of dawn, the sky a bruised violet that matched the fading bruises on his ribs. He didn't leave a note for Kaito, nor did he wake Renza. Between him and his partner, there was a silent understanding: Renza was the Gale, a force that belonged to the open sky and the high-speed thrill of the hunt. But Renju was the Abyss. He was drawn to the quiet, the heavy, and the deep.
He followed a sensation that was less of a sound and more of a localized change in gravity. As he hiked inland, away from the salt-spray of the coast and toward the jagged, basalt-crowned mountains of the interior, the air began to feel "thick." It was the kind of atmospheric weight he usually only felt when he pushed his Water Breathing to its absolute limit.
After three hours of navigating through treacherous, mist-slicked ravines, he reached the lip of a hidden valley. In the center of the crater sat a lake.
It was vast, its surface as flat and dark as a sheet of obsidian. No ripples disturbed the water, and no birds flew over its expanse. To a normal shinobi, it would have looked like a dead body of water. To Renju, it looked like a pressurized reservoir of ancient, dormant chakra. The lake wasn't just water; it was a living lung, pulsing with a frequency that vibrated in the marrow of his bones.
"Something is calling," Renju thought, his dark blue eyes reflecting the sunless surface. "Something that has been waiting for someone who knows how to breathe in the dark."
He didn't hesitate. He stripped off his tattered black flak jacket and the heavy bandages Kaito had wrapped around his chest. Standing at the water's edge, he took a long, measured breath—not the explosive intake of the Gates, but the Rhythmic Expansion Kaito had taught him.
He plunged into the center of the lake.
The Descent into the Deep
As a master of Water Breathing, Renju's lung capacity was already superhuman, but this lake was different. The water here was dense, laced with a natural chakra that sought to reject his intrusion. It felt like swimming through cold, liquid mercury.
He dove deeper. Ten meters. Thirty. Fifty.
The light of the morning vanished, replaced by a suffocating, pitch-black void. The pressure began to mount, pressing against his eardrums and his chest, but Renju leaned into it. He utilized his Abyss Sensing, sending out microscopic pulses of chakra that rippled through the water like sonar.
At first, the pulses hit nothing but the infinite dark. Then, at the eighty-meter mark, he felt a massive, solid geometry resting on the lakebed.
A fallen temple.
He swam toward the outline. It was a structure of white stone that had turned a ghostly grey over centuries of immersion. Massive pillars, carved to look like coiled, multi-eyed serpents, rose toward the surface like the ribs of a leviathan. As he approached the main archway, his sensory pulses suddenly hit a wall.
A barrier. It was invisible, but it tasted of ancient salt and blood-seals. It was a "Void Gate," designed to keep the unworthy from even perceiving the heart of the sanctum.
Go back, his rational mind whispered, his lungs finally beginning to burn. You are miles from home, broken and alone. If you die here, Renza will never find you.
But the magnetic pull in his chest—the "Abyss" within him—screamed for him to continue. He pressed his hand against the barrier, pouring his remaining chakra into his palm. He didn't try to break it; he tried to match it. He adjusted his internal vibration until he was one with the seal.
The barrier shivered and melted away.
Renju stumbled forward, expecting the crushing weight of the lake to follow him through the gate. Instead, he fell onto dry, freezing stone.
He gasped, his lungs filling with air that was stale, ancient, and heavy with the scent of ozone and iron. He was inside a massive, magically maintained air pocket that encompassed the central sanctum of the temple. The space was lit by a faint, bioluminescent moss that grew in the cracks of the floor, casting a ghostly green glow over murals that would have rewriten the history of the Shinobi world.
The carvings depicted the era before the Hidden Villages—a time of "Spirit Kings." The central figure in every mural was a Sea Dragon, a creature of terrifying grace with scales of sapphire and eyes that held the spark of lightning. It wasn't depicted as a beast, but as a judge, a guardian of the world's deepest secrets.
Renju moved toward the center of the sanctum, his wet boots echoing like drumbeats on the marble floor. In the exact center of the room, driven deep into a jagged ocean rock that seemed to have grown naturally out of the temple floor, was a weapon.
It was a katana hilt, the blade buried halfway into the stone. Renju approached it with the reverence of a monk entering a holy site. Even from five paces away, the aura of the weapon made the hair on his arms stand up.
He reached out and gripped the hilt.
"Water Breathing, Second Form: Water Wheel... EXTRACTION!"
He didn't pull with his muscles; he knew better. He vibrated the moisture still clinging to his skin to create a microscopic layer of pressurized lubrication between the steel and the rock. With a high-pitched, crystalline shing, the blade slid free.
Renju held it up to the phosphorescent light, his breath catching in his throat.
The Blade's Design: The katana was a masterpiece of elemental smithing. The hilt (tsuka) was wrapped in the hide of a deep-sea ray, dyed a midnight blue that seemed to shift under the light. The guard (tsuba) was made of blackened silver, shaped into a swirling whirlpool that appeared to be spinning if viewed from the corner of the eye.
The blade itself was the true marvel. It was forged from a rare "Ocean Steel" that possessed a natural, undulating ripple pattern—a hamon that looked like moving waves frozen in time. The steel was translucent, having a faint blue tint, and when Renju channeled a drop of chakra into it, the blade emitted a low, predatory hum like a shark cutting through the surf.
The pommel (kashira) featured a miniature, exquisitely detailed head of the Sea Dragon, its eyes set with tiny glowing gems that pulsed in time with Renju's own heartbeat.
As the blade left the stone, the ocean rock didn't crack—it uncurled.
The "rock" was actually a specialized, fossilized shell of an extinct deep-sea mollusk, acting as a biological safe. As the shell opened, it revealed two more items hidden for eons: a lacquered black scabbard adorned with silver sea-serpents that seemed to swim along the wood, and a massive, heavy Summoning Scroll.
The scroll was bound in thick, waterproof leather and sealed with a wax emblem of the Sea Dragon.
"This isn't just a sword," Renju whispered, his voice trembling in the hollow silence. "This is a contract. A legacy of the Abyss."
He looked at the scroll, then back at the dark water above. He had come here looking for a way to recover his strength. Instead, he had found a power that could either save Konoha or drown the entire world in its wake.
He took the scabbard, sheathed the beautiful blade, and slung the heavy scroll over his shoulder. The Abyss had spoken, and Renju had answered.