Hiyori woke slowly, her lashes fluttering as pale morning light filtered through paper walls. The ceiling above her was unfamiliar, the scent of the room different from the damp forests and abandoned huts she had grown used to. For several quiet seconds, she did not move.
Then memory struck like cold water.
The clash of steel. Kawamatsu's roar. The strange boy. Darkness swallowing her senses.
She sat up immediately and scanned the room with sharp caution. Her small hands tightened into fists as she measured distance to the window, the door, anything she could use as a weapon if necessary. Hunger had weakened her body, but it had sharpened her instincts.
"Yoo, so awake already?"
Her head snapped toward the voice with startling speed.
A boy stood near the doorway, no older than nine. He looked relaxed, almost casual, yet there was a quiet steadiness in his posture that did not belong to a child.
She blinked but did not lower her guard.
Kai smiled faintly and stepped forward. In a movement far too fast for someone his age, he reached out and took her wrist gently. It was not rough, not painful—but precise and controlled.
Hiyori tried to resist.
But she was only seven.
Though stronger than most children, months of running and barely eating had drained her strength. Her arm felt heavy, her legs weak.
"Relax," Kai said calmly. "You're not in danger."
She didn't respond, only watched him carefully.
He led her down the hallway and slid open another door. The moment she saw the woman resting inside, everything else vanished.
"Aunty!"
Hiyori tore free and rushed forward, nearly stumbling as she threw herself beside Toki. Her hands clutched at the woman's sleeve, eyes glistening with relief.
Kai froze.
Aunty?
His mind went blank for a moment. Confusion flooded him in waves. What did she just call her? Who was who? Something wasn't aligning.
He stepped forward quickly and grabbed Hiyori by the shoulders.
"Hay, what are you talking about? Isn't she your mother?????"
There was urgency in his voice now. A horrifying realization was forming, and he needed confirmation.
Hiyori turned toward him with equal confusion. "Who said that? She is the little sister of my mother. My mother passed away long ago. When I was little."
Kai barked instinctively, "You are little."
Her cheeks puffed up instantly, and she lunged at him with small fists thudding against his chest.
"Who are you calling little?!"
To Kai, her punches felt softer than a massage. He barely felt the impact.
But his thoughts were racing.
AU.
Whatever had sent him here had said it was an alternate world. He had assumed that meant divergence because Luffy lost to Imu. But this… this was deeper. Bloodlines shifted. Family roles altered.
"Damn…" he muttered, rubbing his forehead. "So I'm blind in this world now."
Hiyori stopped punching. "Blind?"
"Nothing," he replied quickly. "Just thinking out loud."
If Imu here was multiple times stronger than the Main Timeline version, then relying on manga knowledge would be reckless. The message had been clear—wait until Luffy is ready and decide whether to join him or fight after he is defeated.
"Looks like plans have to change," he murmured.
He turned back to her, eyes thoughtful.
"So the one with the Devil Fruit is…?"
Hiyori crossed her arms, still slightly angry. "My mother was the Time-Time Fruit user before dying. She used some ancient technique to store her ability to send some people one time in twenty years into the future."
Kai let out a low whistle.
"Troublesome," he muttered, shaking his head. "This really is troublesome."
Yet there was opportunity here.
If he could secure a powerful Devil Fruit for Hiyori in the future, both aunt and niece could grow strong together. A stable Wano with capable fighters would shift the balance of power significantly.
Then a stray thought slipped through his mind.
If Toki was only her aunt… that meant she was single.
His eyes lit up briefly before he forced his expression back to neutral.
Focus.
He crouched down to Hiyori's level.
"You want to be stronger, right?"
She hesitated only a moment before nodding firmly.
"Here, you won't have to keep running," he said. "You can ask Kawamatsu to train you in swordsmanship and Haki."
She nodded again, determination flickering in her gaze.
Then she narrowed her eyes suspiciously.
"But wait… who the hell are you?"
Kai blinked once.
"Oh," he replied calmly, "well, my name is Tempest D. Kai. I'm the one who brought you here."
She gave him a look that clearly said do you think I'm easy to fool?
His mouth twitched slightly.
Without replying, his body expanded. Bones lengthened, muscles broadened, and in an instant he stood in full adult form.
Hiyori's mouth hung open, eyes nearly popping out of her head.
"You… that's… that's cheating!"
He shrank back down casually.
"Mythical Zoan," he said. "One of many things you don't know about this world yet."
He sat cross-legged and began explaining.
"Haki is the power of will. There are three types. Observation lets you sense others. Armament lets you harden your body. Conqueror's… that's rare. Only those born with the spirit of kings have it."
Hiyori listened carefully.
"And Devil Fruits?" she asked.
"They grant abilities," he replied. "But take away your ability to swim. In this world, power always comes with a price."
"I see," she said slowly. "Since you saved aunty, I will trust you."
Her stomach growled loudly at that exact moment.
Her face turned bright red.
Kai didn't laugh.
Instead, he took her small hand and guided her toward the kitchen.
"Food first," he said. "War later."
He prepared a simple meal—rice, fish, and warm soup. The aroma filled the room, and Hiyori's hands trembled as she ate.
Tears streamed down her cheeks.
"Slow down," Kai said gently, handing her water. "Or you might choke."
She nodded, swallowing carefully.
"You cook better than Kawamatsu," she muttered.
Kai smirked. "Don't tell him that. His pride can't handle it."
Just then, his senses sharpened.
"Kawamatsu's awake," he said calmly. "Well, looks like Kawami is up. I'll go and explain everything."
Outside, Kawamatsu stood tense but composed.
"You," the kappa said. "Explain yourself."
Kai met his gaze steadily.
"I brought her here. Toki is safe. And I want you to train Hiyori."
Kawamatsu's eyes narrowed. "Why should I trust you?"
"Because if I meant harm," Kai replied evenly, "you would not have woken up."
Silence lingered.
Finally, Kawamatsu sighed. "I did not train her before because we had no safe place. Now… perhaps we do."
Training began that very afternoon.
Hiyori gripped a wooden sword tightly.
"Lower your center," Kawamatsu instructed. "Balance is everything."
She swung at him.
He blocked effortlessly.
"Too wide," he said. "Again."
She attacked again, faster.
"Better," he acknowledged, stepping aside. "But you telegraph your intent."
"I'm not weak!" she shouted.
"Then prove it!" Kawamatsu answered, tapping her shoulder with the wooden blade.
Kai observed from the side.
"Control your breathing," Kai added. "Feel his presence before he moves."
Kawamatsu lunged.
"Left!" Kai called.
Hiyori reacted barely in time, deflecting the strike.
Kawamatsu smiled slightly. "Good. You learn quickly."
Hours passed.
Bruised and sweating, Hiyori stood again.
"That's enough for today," Kawamatsu said.
Kai stepped forward.
"Take care of Toki," he said. "I have somewhere to be. A few months."
Hiyori stiffened. "You're leaving?"
"Yes."
She looked reluctant but nodded. "Then… don't die."
He smirked faintly. "That's my line."
Soon after, he departed for Onigashima.
Storm clouds loomed above the skull-shaped island. Yamato met him near the cliffs, kanabo resting against her shoulder.
"You're late," she said.
"Had business," he replied.
He explained everything briefly.
"So you're heading to the Grand Line," she said.
"Yes."
Without warning, she swung her kanabo.
He hardened his arm and blocked.
"Still slow," she teased.
"You're holding back," he shot back.
They exchanged several rapid blows, shockwaves cracking the stone beneath them.
"Don't underestimate the sea!" she warned mid-swing.
"I never do!" he answered.
Finally, she stepped forward and hugged him tightly.
"Come back," she said quietly.
He hesitated… then returned the hug.
"Train harder," he replied.
Reluctantly, he pulled away.
With one final wave, Tempest D. Kai launched into the sky and flew toward the Grand Line.
This alternate world was unpredictable.
And that made it dangerous.