Naruto: Kakashi, the Ultimate Shinobi

Seeing Guy radiating unrelenting enthusiasm, Kakashi hesitated to interrupt. Yet if he didn't speak up now, he feared Guy would dive straight into his intense training regimen and vanish before they got to the point.

He didn't come just to watch another youthful explosion.

With the frequency of Anbu missions, Kakashi never knew when he'd next have free time—this was a rare opportunity he couldn't waste.

"Guy, wait a minute," Kakashi called, his voice firm.

The shout successfully broke through the wall of Guy's spirited momentum.

"Huh? Kakashi? You need something?"

Guy blinked, genuinely surprised. It was hard to tell whether he hadn't expected the interruption—or just hadn't noticed Kakashi standing there.

Kakashi rubbed the back of his head, helpless. This brain really is all muscle.

"I won this bout," Kakashi said, his tone turning serious. "So I want you to teach me the Eight Gates."

"The... Eight Gates?"

Guy's eyes widened. It was clear this wasn't what he had expected to hear.

"Kakashi, you realize that's not a simple request."

Guy's expression grew solemn, a rare moment of gravity from the ever-spirited taijutsu master. "I've trained nearly my whole life, and even now, I can only open up to the Sixth Gate."

Kakashi nodded with quiet determination. "I know. But this isn't a whim—I've thought it through."

Bamen Dunjia—the Eight Inner Gates—is not only the pinnacle of taijutsu but also a method to strengthen the body to its limit. And to Kakashi, that meant strengthening his chakra as well.

Chakra stems from both physical and spiritual energy. With his spiritual side already enhanced by the fusion of two souls—a gift from his experience with Obito—Kakashi now needed to develop his body to match. The stronger the foundation, the more chakra he could wield.

Furthermore, Eight Gates didn't necessarily need to be taken to the fatal extreme. If used strategically—without ever opening the Eighth Gate—it could become a crucial trump card. Against future threats like the Rinnegan's Deva Path or chakra-absorbing enemies like Kisame Hoshigaki, raw taijutsu would be a powerful countermeasure.

And on a more practical note, mastering the technique would drastically improve his swordsmanship. Taijutsu complemented kenjutsu, and the fusion could bring the Flag-style blade to new heights.

Given all this, the choice was obvious.

And in all of Konoha, only one man mastered the Eight Gates: Might Guy.

Guy stared into Kakashi's steady gaze and realized how sincere he was. A wide grin split his face. He raised a clenched fist, teeth gleaming in the sun.

"You truly are my eternal rival, Kakashi! That same burning resolve! Very well—from today onward, we train together in the Eight Gates!"

Kakashi nodded with rare gratitude. "Thanks, Guy."

"No need to thank me! In exchange, you must teach me the secrets of that Konoha Body Art—your Thousand-Year Kill technique! The force behind it was... incredible!"

Kakashi stiffened, caught off guard. Of all things Guy could want, it was that?

For a moment, Kakashi just stared at him, trying to decide if Guy was joking. He wasn't.

"...Sure. No problem," Kakashi replied dryly, knowing resistance was futile.

"YO SHAAA! I knew it! My youth burns brighter already!"

Kakashi sighed. Did I just make a mistake?

"Alright, Kakashi. Let me explain the foundation of the Eight Gates," Guy began, suddenly switching into his serious mode.

"Right."

Kakashi focused. This was the real reason he'd come here today.

"The Eight Gates," Guy said, "are eight chakra limiters located within the chakra circulatory system. They exist to protect the body from overexertion. But by forcibly opening them, a ninja can gain tremendous power—for a time."

Kakashi listened carefully. He had read about this in old scrolls, but Guy's words added a personal layer.

"When all eight gates are opened, the user's power can rival or surpass even the Five Kage. But the price… is certain death. That's how my father, Might Duy, perished. He opened the Eighth Gate—The Gate of Death—and took down four of the Seven Ninja Swordsmen of the Mist."

There was a shadow across Guy's face, brief but telling. Though he spoke with pride, Kakashi could hear the ache beneath the words.

He didn't speak—just gave Guy a moment of quiet support.

Guy smiled again, as vibrant as ever. "But that's not where we start! The Eight Gates are: Gate of Opening, Rest, Life, Pain, Limit, View, Wonder, and Death. The higher you go, the more strain you place on your body—but the more strength you unlock."

"The first three gates," Guy continued, "are relatively safe. The real danger begins with the Gate of Pain—the fourth. That's when you begin to damage your body to increase your power."

"Gate of Opening removes mental inhibitors. It lets you use 100% of your physical capacity, breaking past natural limits."

"Gate of Rest allows the body to recover fatigue temporarily—by force. It restores energy by accelerating the metabolic process."

"Gate of Life causes your muscles to swell with blood, turning your body red. It greatly boosts your power and speed—and marks the last 'safe' gate."

"After that comes Gate of Pain. Opening it risks tearing muscle and breaking bone. From here on, every step could cripple or kill you."

Guy paused to make sure Kakashi was absorbing the information.

Kakashi's analytical mind quickly parsed the structure. So the first three gates can be mastered with low risk... that alone is a huge edge. The chakra strain is likely even lower than using Kamui.

With those three under his belt, Kakashi could vastly improve his short-term combat strength. Especially when swordsmanship and speed were involved.

"Kakashi," Guy asked, "did you catch all that?"

"I did. I've got the basics down."

"EHHHH? You already understand?! That quickly?!"

Guy looked as if he'd been struck by a Rasengan. When his father had taught him, it had taken weeks just to grasp the theory.

Kakashi gave a sheepish nod. "Yeah. Roughly."

Guy collapsed to his knees in exaggerated emotion. "As expected of the rival of my life!!"

Kakashi chuckled, eyes crinkling into crescent moons.

"Well then," Guy declared, springing back up, "let's start with basic conditioning! The road to the Eight Gates begins with understanding your own body!"

"Understood," Kakashi replied, expression sharpening.

Finally, he would lift the veil on the ultimate taijutsu—and uncover the true force hidden behind the Eight Gate