Kai arrived at Onigashima beneath the cover of night, the massive skull-shaped island looming like a demon frozen in stone. Even in ant-size, he could feel the oppressive weight of powerful presences layered across the fortress.
He moved carefully through corridors and chambers, slipping past guards and drifting above torchlight. Whenever he sensed a strong aura—sharp, disciplined, and deadly—he changed direction immediately.
"I'm not here to get caught by King," he muttered under his breath. "And I definitely don't feel like meeting Kaido tonight."
He avoided the higher levels entirely, sticking to servant paths and storage tunnels. Voices carried easily through the stone halls, and Kai slowed whenever groups of subordinates gathered.
"Did you hear?" one guard whispered. "Young Master Yamato got locked up again."
"Again?" another replied. "What did she do this time?"
"She fought Lord Kaido. Shouted something about being Kozuki Oden."
Kai froze midair.
Imprisoned? His eyes narrowed. Did she fight Kaido again?
A cold edge entered his thoughts, but he pushed it aside. He followed the direction of the guards' chatter until the air grew damp and heavy.
The prison.
Kai slipped through a crack in the stone and entered the dim chamber. Torches flickered weakly, casting long shadows against iron bars.
Inside one of the cells, Yamato sat cross-legged, talking animatedly to three battered samurai.
All three of them stiffened at once.
They sensed him.
Kai returned to his original child size for a moment, then immediately expanded into his Oni Samurai form—appearing around twenty-five years old. A dark Oni mask covered his face, concealing his identity.
He stepped forward casually and lifted a hand. "Yooo—"
He never finished the greeting.
"KAIIIIIIIIIIIIIIII!"
Yamato launched herself at him like a cannonball, tackling him to the ground. Even in his enlarged form, the force surprised him.
She clung to him tightly, her voice echoing through the chamber. "You finally came! That bastard father of mine locked me up here! And he didn't even give me food!"
Kai blinked behind his mask, then gently wrapped one arm around her back.
"I can see that," he said calmly. "You look like a starving wolf."
"I am starving!" she shot back, still hugging him. "He said I need to 'learn my lesson.' What lesson?!"
Kai listened without interrupting, stroking her hair gently as she vented her frustration. He let her pour out every complaint, every ounce of anger she had bottled up.
After a few moments, she suddenly froze and stepped back.
"Ahhh… sorry about that," she muttered, scratching the back of her head in embarrassment.
Kai flicked her forehead lightly through the mask. "You're loud."
"That hurt!" she protested, rubbing the spot.
He chuckled softly before turning toward the three samurai.
One of them stood out immediately. His sharp eyes and stern expression reminded Kai of someone from another era.
"You must be from the Roronoa family, right?" Kai asked.
The man narrowed his gaze. "I am Shimotsuki Ushimaru. And who might you be?"
Kai placed a hand over his chest. "Kai. Tempest. D. Kai. I was the one Oden was talking about."
The three samurai stiffened in shock.
"You…" Ushimaru stepped forward despite his chains. "You are the young man Lord Oden mentioned?"
"I suppose that depends," Kai replied lightly. "Did he say I was handsome?"
One of the other samurai snorted despite himself.
Ushimaru bowed his head slightly. "It was you who opened Lord Oden's eyes. For that, we are grateful."
Kai shook his head slowly. "Sigh… if only he had opened them earlier."
Ushimaru's expression softened. "It is not your fault. Even if you had tried harder, you would have failed."
Kai raised an eyebrow. "That confident?"
"Oden has been like that since childhood," Ushimaru replied. "Unless he fails with his own eyes, he never listens to anyone."
Kai was silent for a moment.
Then he crossed his arms. "So. Want me to save you?"
The three samurai exchanged confused glances.
Kai continued, his tone steady. "Lady Toki is alive. Hiyori is alive as well—she's with Kawamatsu. As for the others, Toki used her power to send them twenty years into the future."
The cell went utterly still.
"That… is impossible," one of them whispered.
"I saw her fall," another said hoarsely.
"You saw what I wanted you to see," Kai replied calmly. "She's resting now."
Ushimaru dropped to one knee despite the chains. "Thank you… for saving Lady Toki."
Kai waved dismissively. "Don't thank me yet. I didn't do it out of charity."
All three looked up.
"If you stay here," Kai continued, "you'll be useless. Come with me. Help me prepare to reclaim Wano."
Silence lingered heavily.
"You want to reclaim Wano?" one samurai asked sharply. "Do you know how strong Kaido is?"
Kai's masked eyes sharpened. "I'm the only person here who knows exactly how strong Kaido is."
"Then why?" Ushimaru pressed.
"Because," Kai answered without hesitation, "I know I can surpass him. And it won't take long."
For a moment, the only sound was the crackling of torches.
Then Ushimaru laughed quietly. "You speak like Oden."
"I'll take that as a compliment," Kai replied.
The three samurai straightened. "Very well," Ushimaru said. "We will follow you."
Kai grinned beneath his mask. "Good choice."
He shrank to ant-size and slipped out unnoticed, returning shortly after with stolen food.
Yamato devoured her portion immediately. "This is the best thing I've ever eaten!"
"It's rice," Kai said flatly.
"It's freedom rice!" she declared dramatically.
Kai shook his head.
After ensuring the samurai had regained some strength, Kai turned to Yamato. "Come on."
"You're taking me out?" she asked excitedly.
"For a while," he replied.
He shrank again, slipped through the bars, unlocked her chains silently, and guided her out through hidden paths. Once they were far enough and alone in a secluded cavern near the waterfall, Kai removed his Oni mask.
Yamato beamed instantly. "There you are."
He summoned his wings and carried her into the open night sky. They flew toward the waterfall where fish leapt upward in glittering arcs.
Yamato gasped. "They're flying!"
"Climbing the waterfall," Kai corrected.
He dove down suddenly, emerging moments later with a struggling Sea King in his grasp. With controlled flames from his wings, he roasted it carefully on a rocky outcrop.
Yamato tore into the cooked meat happily. "You're amazing!"
"Obviously," he replied smugly.
After they ate, Kai led her to a quiet corner. His expression shifted to something more serious.
He placed his hand gently over her heart.
The Seraph Contract activated.
A glowing golden, flaming wing mark appeared over her chest before fading beneath her skin. Warmth spread through her body instantly.
"The Sea King… it's dissolving!" she gasped.
"Turning into energy," Kai explained. "You'll recover faster now."
She hugged him tightly in excitement. "Kai!"
He hugged her back and spun her once before setting her down.
"Listen to me," he said, holding her cheeks gently. "Stay here. Learn. Grow stronger."
She nodded immediately.
"I want to take you with me," he admitted quietly. "But I'm not strong enough yet to fight Kaido head-on if he comes for you."
Her jaw tightened. "I'll become super strong. Strong enough to smash him!"
He smiled softly. "That's my vice-captain."
She blinked. "Vice-captain?"
"Of course," he replied confidently. "Who else?"
Her grin widened.
"After I leave," he continued, "go to Kaido and tell him this."
She leaned closer.
"Someone calling himself 'Oni Samurai' came and took the three samurai away."
She nodded seriously. "I'll say it exactly like that."
Kai hugged her one last time before stepping back and putting the Oni mask back on.
"Don't miss me too much," he teased.
She crossed her arms. "I won't!"
"Liar."
He returned to the prison entrance, drew his sword, and cut through the rock sealing the cave with a single controlled slash. The stone split cleanly.
The three samurai followed him silently as they escaped toward the docks. They stole a small boat and pushed off into the dark sea.
Once they were out of sight of Onigashima, Kai expanded to his full adult size again and leapt into the air.
The samurai stared as he lifted all three effortlessly.
"You can fly?" one breathed.
"I can do many things," Kai replied.
Golden wings flared wide as he carried them across the night sky toward Wano.
Behind them, Onigashima remained silent.
But the name "Oni Samurai" had just begun to echo within its walls.