"Alright, here's the basic principle!" Kai said, standing before the crew. "We'll start with mastering Armament Haki. I'll teach you the quickest and easiest way to grasp it."
As he spoke, a large staff appeared in Kai's hand. When it comes to teaching, who's the best in the entire Grand Line?
In Kai's opinion, there was only one worthy of that title—Kaido of the Beasts, one of the Four Emperors, currently ruling over a territory in the New World.
Kaido's method was simple yet effective: one strike for basic mastery, two strikes for advanced skills, and three strikes to awaken Devil Fruit abilities. He trained Luffy from barely scraping by to emperor-level strength in an unbelievably short time.
Normally, it would take others years to get there, but Kaido was different. That's why he's the best teacher in the world.
Kai wasn't aiming to teach the crew like Rayleigh did. His own Haki was only at a decent level, and he didn't have that deep understanding to guide them through subtle lessons. His method? Brutal force.
"I'll beat the strength into you," Kai thought. "Alright, all of you—attack me!" he commanded.
Without hesitation, Luffy, Zoro, and Sanji launched themselves at Kai . Nami and Usopp, on the other hand, stood frozen, clearly hesitant.
Kai didn't flinch. As the attacks from the three neared him, he moved with blinding speed, dodging their strikes effortlessly. Then...
Bam!
Bang!
Boom!
In an instant, Kai knocked all three of them down.
Turning his calm gaze to Nami and Usopp, he said, "Are you two going to join in? I won't go easy on you."
Suddenly, Kai disappeared from sight, reappearing next to them before they could even react. Both were sent flying with a light hit.
The intensity of Kai's attacks varied depending on who he hit. For Nami and Usopp, it was a softer blow, but for Luffy, Zoro, and Sanji, he didn't hold back. Especially with Luffy—he hit him even harder.
This wasn't because he favored some of them over others. Nami and Usopp simply couldn't handle the same power. If he used full strength on them, they'd be out cold for days.
Still, even with his gentle approach, Nami and Usopp lay on the ground, groaning in pain.
Sighing, Kai muttered, "Their strength really needs work." He turned to Vivi and Mr. 9, who had been standing on the sidelines watching. "Hey, you two—you're their opponents now!"
"Huh?" Vivi and Mr. 9 were stunned, but quickly responded, "Y-Yes!"
They had just witnessed Luffy and Zoro—two people who had easily overpowered Mr. 5—get toyed with by Kai. The sheer power difference left them speechless. They now understood why Kai had a bounty of 300 million berries.
With a serious tone, Kai spoke to Nami, "Nami, I know you're the navigator, and your strength isn't your priority. But the enemies we'll face from here on will only get stronger. We can't protect you all the time, so you need to get stronger for yourself. The harder you work now, the easier your life will be later on."
In this world, danger lurks everywhere. Because of Kai's presence, the usual course of events had already shifted slightly. He couldn't guarantee what challenges lay ahead, but one thing was clear—Nami needed the strength to protect herself.
He turned to Usopp next, eyes narrowing. "And you, Usopp. Your combat ability is far too weak!" he said without holding back.
Though Kai knew that Usopp had the potential to grow stronger, he was still the weakest in terms of raw power. Kai couldn't afford to let him lag behind.
"Usopp, remember what I told you last time about your dad, Yasopp, being part of Shanks' crew?" Kai said, leaning in. "Your dad is strong. Do you really want to meet him one day, only for him to be disappointed in your weakness?"
Usopp's eyes widened as that painful image flashed through his mind. Without a second thought, he shouted, "No way! I don't want that!"
A smile crept onto Kai's lips. "Good," he thought. "A little tough love never hurts."
Now that Nami and Usopp were motivated, Kai turned his attention back to Luffy, Zoro, and Sanji, who had already stood up, brimming with fighting spirit. Luffy rolled up his sleeves, Zoro tightened his bandana, and Sanji lit a cigarette.
The three locked eyes with Kai, ready for round two.
Kai cracked his knuckles. "Alright, bring it on. Let's see how many hits it takes to get through to you."
And so, the cycle continued.
Three days passed. The crew was finally ready to leave the island and head toward Little Garden. In reality, their Log Pose had already locked onto the next island's magnetism, but the extra days spent training had been worth the delay.
During those three days, Luffy, Zoro, and Sanji spent nearly every moment being knocked down, only to get back up again. Surprisingly, the method worked. Their strength had noticeably improved. While they hadn't yet mastered Armament Haki, it was clear they were well on their way.
Nami and Usopp had also grown stronger, each gaining a better understanding of their roles in battle.
Even Kai himself had improved slightly from all the combat, though he preferred his usual method of growing stronger by simpler means—relying on the effortless rewards of his system.
Relaxing on a chair, basking in the sun, and sipping coffee as the sea breeze swept over him, Kai let out a content sigh.
"This... this is the life," he muttered. "No loans, no insurance... pure bliss!"
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Power Stones would be appreciated if you liked the story