The Z Fighters on Earth each began their own training, while Son Goku returned to Kami's Lookout.
" Kami, I feel like I've hit a bottleneck. My power won't increase much in a short time. Is there a way to break through my limits?"
Kami fell silent for a moment, then slowly replied, "Goku, with your current strength, it's already difficult to find anyone on Earth who can challenge you. But... if you truly want to break through your limits, I do have someone in mind."
"Who?"
"North Kai." Kami's voice held a hint of reverence. "He's the deity who governs the North Galaxy and lives on the King of Worlds Planet. If you can become his student, perhaps..."
Here it comes! North Kai, Kaio-ken, Spirit Bomb!
Son Goku's eyes lit up at once, like stars suddenly blazing in the night sky. "Then what are we waiting for? Kami, take me there!"
Kami shook his head with a wry smile. "The road to the King of Worlds Planet isn't that simple. First, you need King Yemma's permission. Then... you have to make it across Snake Way."
"Snake Way?" Son Goku scratched his head. "Is it long?"
"Long enough to drive most people crazy. But with your current strength, you should be fine!"
The Other World, at King Yemma's Palace.
The enormous King Yemma sat on his throne, looking down at the tiny human before him.
After hearing Kami's explanation, he pondered for a moment before finally waving his huge hand. "All right. Since Kami recommended you, I'll grant permission. Little guy, take him to the entrance to Snake Way!"
Son Goku grinned and waved at King Yemma. "Thanks!"
King Yemma froze for a moment, then chuckled. "That kid... He's quite something."
At the entrance to Snake Way, Son Goku gazed at the road winding into the endless void and took a deep breath.
He pushed off the ground, shooting forward like an arrow loosed from a bow.
At Son Goku's current level of power, the illusions and exhaustion along Snake Way couldn't slow him down at all. He became a streak of golden light racing down the road. Wind roared past his ears as the clouds on either side flew by.
After an unknown stretch of time, a small planet finally appeared ahead.
The King of Worlds Planet.
The moment Son Goku set foot on the ground, a heavy pressure pressed in from all sides—ten times Earth's gravity.
He adjusted his Gravity Suit, set the combined gravity to 15, then strode toward the seated figure.
At that moment, North Kai was sitting on the grass, playing with his monkey Bubbles and his grasshopper Gregory while muttering a corny joke he'd just made up.
Seeing Son Goku approaching at a brisk pace, he first looked startled. Then his eyes shifted behind his glasses, and he decided to tease the newcomer.
"Hey, you little whippersnapper! What are you doing on my turf?" North Kai deliberately put on a stern face, pretending to look imposing.
Son Goku scratched his head and smiled honestly. "I'm Son Goku, from Earth. I want to learn martial arts from you."
North Kai raised an eyebrow and waggled his antennae. "You can learn martial arts, but first you have to pass my test."
"A test?" Son Goku's eyes lit up. "What is it? Bring it on!"
North Kai held up three fingers. "First, tell me a joke that'll make me laugh. Second, catch my pet Bubbles. Third, hit my other pet, Gregory, with a hammer. So, do you have the guts to try?"
Son Goku grinned confidently. "No problem!"
The first test: a joke.
Son Goku scratched the back of his head. Then an idea suddenly came to him, and he turned to North Kai.
"Um... Lord Kai, one day Tien Shinhan went to a restaurant. The waiter asked how many bowls of rice he wanted. Tien Shinhan said, 'Three.' The waiter asked, 'Can you eat that much by yourself?' And Tien Shinhan said, 'I have three eyes, so each one needs a bowl to look at!'"
North Kai froze, then burst out laughing. His round belly bounced up and down. "Hahaha! What kind of joke is that? Three eyes looking at three bowls of rice... Hahaha!"
Seeing North Kai laugh, Son Goku joined in with a goofy chuckle.
The second test: catching Bubbles.
Bubbles was a nimble monkey, still incredibly agile under ten times Earth's gravity. He hopped all over the King of Worlds Planet, moving so fast he was little more than a blur.
Son Goku stood still and closed his eyes, spreading his ki sense around him.
He snapped his eyes open and flashed forward, appearing beside Bubbles like a ghost. Before the monkey could react, Son Goku grabbed him by the scruff of the neck.
"Got you," Son Goku said with a smile.
Bubbles squeaked twice, looking aggrieved.
North Kai's eyes widened. "Th-that was fast!"
The third test: hitting Gregory.
Gregory was a winged insect-like creature who flew at incredible speeds, following an erratic, unpredictable path.
Son Goku picked up a small hammer from the ground and weighed it in his hand.
He took a deep breath and focused his ki in his eyes. Gregory's flight path instantly became clear to him.
"Now!"
Son Goku swung his arm, sending the hammer flying in a perfect arc—
"Thwack!"
It hit the mark.
Gregory spun dizzily twice before tumbling to the ground.
North Kai's mouth hung open. For a long moment, he couldn't say a word. He looked Son Goku up and down. The disdain in his eyes had vanished, replaced by a faint admiration.
"You... What kind of guy are you?"
Son Goku scratched his head sheepishly. "I'm just an ordinary martial artist from Earth. Lord Kai, I've passed all your tests. Can you teach me how to train now?"
North Kai took a deep breath, his expression turning solemn. "Good! Since you've passed the tests, I'll teach you one of the most powerful techniques I've ever created! Listen carefully. This technique is called... Kaio-ken!"
"Kaio-ken?"
"That's right!" North Kai clasped his hands behind his back and paced in front of Son Goku, his expression serious. "Kaio-ken is a technique that can temporarily boost your power, speed, strength, and defense. But it has one fatal flaw—it puts an enormous strain on your body. If your body isn't strong enough, using it will put your life at risk!"
Son Goku listened intently, his eyes shining with curiosity.
"The higher the multiplier, the greater the increase in power, but the strain on your body also multiplies. One times, two times, three times... In theory, there's no limit. In practice, the number you can use depends entirely on your physical condition and willpower. If you exceed the limits of your body or will, your body or soul will collapse, and even the gods won't be able to save you! So remember: never use a multiplier beyond your limits!"
As he spoke, North Kai held out one hand, palm up. "Come, first feel how your ki flows. The essence of Kaio-ken is to make the ki inside your body circulate along a special frequency and path, unlocking the potential in your cells. But this circulation is extremely violent. The slightest mistake, and it'll turn against you."
Son Goku closed his eyes and, following North Kai's instructions, began to sense the flow of ki within his body.
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