The Great Black Sea
黒海
Arthaex
Chapter 1: The Shadow of the Black Tide
12/12/1523
19 Years earlier:
"200 Years ago lived a demon who had the Staff of the Sea-" "OH OH I know!" exclaimed Ryūkai "His name was Jigoku no Umi!" "NO IT WASN'T! HIS NAME WAS UMI NO OMI!" screamed Kurohane "Hey kids, can you guys stop screaming and let me finish my sentence please..?" said Ryuyaiba "FATHER! CAN YOU TELL US ABOUT YOUR CHILDHOOD AGAIN??" said Ryukai excitedly "Ok ok kids!" replied Ryuyaiba.
"You want to know who I am? Sit close, because this isn't a story for the faint of heart. I was born in a small coastal village, the kind of place where the wind smells of salt and freedom… or at least, it should. My father taught me how to wield a sword before I could even walk properly. Not for honor, not for glory… just to survive. And survive I did… until the day they came. A corrupt governor, greedy and blind, burned my village to the ground. Took what they wanted and left nothing but ashes and screams. I was lucky… maybe unlucky, I don't know. I lived. And when I swore vengeance, I didn't just swear it with words I forged it with blood and steel. I became a pirate not for treasure… though it has its charms but for freedom. For the sea, the wind, the fight, and the thrill of striking where no one dares. They call me Ryuyaiba now. Dragon Blade. My twin katanas… Ryū and Ha… they've tasted more than a few lives. And if you've got enemies, consider them warned. I've sailed through storms, evaded navies, and faced killers who thought themselves legends. But the sea… the sea is mine. And those who dare cross me? Well… the dragon doesn't forgive easily. So, that's me. Ryuyaiba. Don't forget the name. You'll hear it whisper in the wind… and maybe, if you're unlucky, feel it in the flash of steel." Explained Ryuyaiba
"Oh wow… I wanna become like you father!" exclaimed Kurohane "What about Umi No Omi?" asked Ryukai
Ryuyaiba: "Umi No Omi… my own brother. Once, we sailed together, laughed together, shared the same wind in our hair. But he… he changed. Power… it consumed him. He wanted more than the freedom of the sea, more than treasure… he wanted control. Absolute control. He found it in the Staff of the Sea, a weapon older than any man alive, forged by the tides themselves. With it, he can bend the oceans to his will, turn the waves black as night. But the staff is not simple… to reach its full power, to truly make the sea black, he must defeat every Umi No Omi that stands against him. Each victory makes him stronger, each battle twists him further from the brother I once knew. I spent three years chasing him across the oceans, honing my skill, sharpening my twin katanas, Ryū and Ha, for the inevitable confrontation. But even I… even I am no match for him now. The first time I faced him, the sea itself obeyed him. Waves crashed like walls, storms obeyed his will, and I felt the full weight of what he has become. The sea… my brother… unstoppable. And yet… I will not give up. No matter how many battles it takes, no matter how black the sea becomes… I will confront him. Umi No Omi may have power, but I have something stronger. I have the will to protect, to fight for what he lost when he let ambition consume him. One day… one day, I will bring my brother back from the darkness… or fall trying."
Ryukai : "Wow, Soo where is Umi No Omi? And who is Umi No Oni??"
Ryuyaiba : "Umi No Omi… your uncle… my brother… he's not the man he used to be. He sought power, and he found it in the Staff of the Sea. With it, he can control the oceans, twist the waves into storms, and turn the waters black as night. But that power isn't complete yet. To become the most powerful, he must defeat every Umi No Oni warriors like him, who guard pieces of the sea's true strength. Each Umi No Oni he defeats makes him stronger… darker. That's why I've been chasing him for three years, Ryukai. Because if he finishes this ritual, the Black Sea will rise… and no one, not even me, could stand against him. That's why you must learn, train, and grow. One day, you may have to face the darkness he's creating… to protect the sea, our family, and the world."
Ryukai: "Wow… so, where is Umi No Omi? And… who are the Umi No Onis?"
Kurohane: "Yeah… Can you tell us all their names, father?"
Ryuyaiba: "Listen closely, both of you… the Umi No Oni are not ordinary warriors. They are guardians of the sea, each one stronger than most men could ever dream. And yes… your uncle, Umi No Omi, is one of them now the Black Tide. He seeks ultimate power, and with the Staff of the Sea, he can bend the oceans to his will and turn the waters black. But to reach that power, he must defeat every Umi No Oni… including me. And I won't let him succeed."
"There are five of them, the strongest of all the ocean's warriors: your uncle… Umi No Omi, the Black Tide, who can command storms and twist the seas. Me… Ryuyaiba, Dragon Blade of the Sea, who wields twin katanas, Ryū and Ha, and moves as one with the currents. Then there's Shikonami, the Wave's Fang, guardian of the northern seas, who strikes like a razor-sharp fang from the waves. Kurogiri, the Shadow Current, guardian of the stormy depths, who can hide in the darkness and drag enemies under. And Aokami, the Azure Tempest, guardian of the southern waters, who controls lightning and typhoons, striking like a living storm."
"Each one must be defeated before your uncle can complete the ritual to turn the sea black. That's why the oceans tremble when his name is spoken… and why we must prepare, train, and stay strong. One day, you may have to face these warriors too… to protect the sea, our family, and everything that matters. Do you understand?"
Ryukai: "Yes… father. I want to learn."
Kurohane: "We'll train hard… we won't let uncle win."
Ryuyaiba: "Good… because the sea does not forgive the weak."
Years passed, and the winds of the sea carried change to those who had once been children at their father's side. Kurohane, the eldest, had grown into a disciplined and sharp-minded warrior, his every movement precise, his mind always calculating the tides and the currents of battle. Ryukai, the youngest, had inherited his father's fiery spirit, his speed and agility now rivaling the fiercest storms of the open sea. Together, they trained relentlessly, mastering the techniques their father had taught them and discovering powers of the ocean that ran in their blood.
At twenty-five, both siblings were no longer the wide-eyed children who had first heard of the Black Tide. Their eyes now held the weight of years of training, the scars of countless trials, and the determination of those who would not let their family's legacy fall into darkness. On the horizon, the sea churned with unseen currents, whispering tales of their uncle, Umi No Omi, whose power had grown stronger with each fallen Umi No Oni.
The time for learning, for preparation, for surviving, had ended. The Black Sea was approaching, and with it came the trials, the battles, and the choice between shadow and legacy. Kurohane and Ryukai stood at the edge of the deck, the wind in their hair and the salt of the ocean on their skin, ready to face what their father had warned them about. The age of the children was over… Now, the age of warriors has begun.
6/2/1542
Kurohane was 25 while Ryukai was 23
Something wasn't right… Ryuyaiba was scared, he wasn't ever scared like this. Ryuyaiba had locked himself in his room for three days. He did not eat nor drink. The sea outside his cabin raged as if it felt his torment, waves crashing endlessly against the hull. Inside, the air was heavy and still. His twin katanas, Ryū and Ha, rested against the wall, untouched, an unusual sight for a man who treated them as extensions of his own soul.
Memories haunted him without mercy. His brother's face. The moment the Staff of the Sea answered Umi No Omi's call. The blackened waves. The crushing truth that, for the first time in his life, Ryuyaiba had been powerless. Not defeated by skill, not by strategy, but by something far greater than steel.
Each hour passed like a wound reopening. Guilt gnawed at him, guilt for surviving, guilt for failing, guilt for knowing the darkness would one day reach his children. When the third night came, Ryuyaiba finally rose. His eyes were hollow, but within them burned something fierce, resolve.
He opened the door.
The sea had taken much from him, but it would not take his will.
Ryuyaiba grabbed his 2 Katanas, Ryu and Ha and stormed out of his ship, Ryukai and Kurohane were confused looking at each other.
Ryuyaiba had a vision… A vision that had Umi No Omi ruling over Kuroshima, Ryuyaiba's territory… If Umi No Omi got his hands over Kuroshima, Umi No Omi would be able to kill Ryuyaiba and Umi would be a step closer to turning the sea BLACK, Ryuyaiba had to somehow stop this from occurring…! "PIRATES!" screamed Ryuyaiba, a roar of "YES SIR!" erupted from the pirates. As the pirates lined up came a storm.
So powerful that you cannot even see anything, the sky was covered with black fog, they couldn't see anything, only screams…
"Well, well, well… look who we have here," he sneered, his grip tightening around Ryuyaiba's neck as he lifted him off the ground.
"You… you cannot do this," Ryuyaiba gasped, struggling against the unrelenting strength. "I'm your… your own brother…"
"Oh My, Look at him begging for his life" laughter emerged from the pirates of Umi No Omi,
"SILENCE."
The word alone crushed the air.
From within the fog, a massive silhouette advanced, each step slow, deliberate. The waves beneath his feet stilled, as if the sea itself feared him. Broad shoulders, unmoving posture, and a presence so heavy it made breathing feel difficult.
Umi No Omi released Ryuyaiba, his eyes narrowing. "And who is this?"
The figure stopped.
"Your nightmare."
In a blur, Kurohane exploded forward. His fist tore through the mist, aimed straight for Umi No Omi's face without a shred of hesitation.
But Umi No Omi reacted instantly. As an Umi No Oni, he caught the punch with one hand, the impact cracking the air between them.
For the first time… the sea trembled.
With a swift, merciless sweep, Umi No Omi struck both of Kurohane's legs, the force tearing his footing away. Umi No Omi's hand closed around Kurohane's neck with a force that felt inhuman, crushing the air from his lungs.
"Woah, woah, woah… now you're crossing the limit."
Flames erupted from Ryukai's palms as he hurled fireballs forward, the blast slamming into Umi No Omi and tearing him away from Kurohane.
"W–wait… I can do that?" Ryukai stared at his hands in disbelief.
Kurohane exhaled sharply, a quiet smirk forming. "Nice, kid."
"IM NOT A KID" Shouted Ryukai angrily
He stepped forward, eyes locked on their enemy; Umi No Omi.
"Now… it's time to finish him off."
The deck was silent.
No waves.
No wind.
No fire.
Kurohane's hand hovered where the Staff of the Sea had been.
Nothing.
A sound came from behind them.
Clap
Clap Clap
Slow. Deliberate.
They turned.
Umi No Omi stood untouched, the sea kneeling at his feet like a living shadow. His eyes were no longer human—black oceans swirling endlessly within them.
"Well done," he said calmly. "You killed me perfectly."
Ryukai's breath caught.
"…What?"
The corpse behind them melted, collapsing into black water that slithered across the deck and vanished into the sea.
"That body," Umi No Omi continued, lifting the Staff of the Sea from thin air, "was only the sea wearing my shape."
Kurohane stepped in front of Ryukai.
Umi No Omi smiled wider.
"You see," he said, voice dropping, "the ritual is complete."
The ocean screamed.
The horizon darkened as far as the eye could see. Waves turned pitch-black, swallowing the moon's reflection until the sea became a single endless void.
Umi No Omi raised the staff.
"And now," he whispered, "the Black Sea recognizes its king."
The water beneath the ship began to pull downward.
Not crashing.
Not flooding.
Dragging
The deck cracked as the ship started sinking—slowly—into the living darkness.
Ryukai fell to his knees, blood dripping from his nose.
"Kurohane… I can't feel the fire anymore."
Umi No Omi stepped closer.
"You were never meant to kill me," he said softly. "You were meant to prove yourselves… so I could take what you awakened."
He reached out.
The sea answered.
Black tendrils wrapped around the brothers' arms, their legs, their shadows.
"Run," Kurohane growled, teeth clenched.
Umi No Omi leaned close, his voice a whisper meant only for them.
"There is nowhere to run."
The sea swallowed the ship.
Darkness closed in.
And far beneath the Black Sea, something ancient opened its eyes.
— End of Episode 1 ⚫🌊