Using the Marine Six Powers in the world of shinobi came with a major prerequisite:
It consumed chakra.
While Lee had absolutely zero talent for Ninjutsu or Genjutsu, he wasn't a total failure as a ninja. He possessed a modest amount of chakra—just barely enough to qualify for the rank of Genin.
The real headache was the sheer lack of it. His reserves were too shallow to unleash the true devastating potential of the Six Powers.
He had tested his limits several times. Currently, his chakra only allowed him to use the Six Powers four times before he was completely tapped out.
Before he had started focusing on chakra control, he'd searched for ways to increase his overall reserves, but the results were exactly as he'd expected. In this world, chakra was a blend of spiritual and physical energy; its growth wasn't just about training, but was deeply tied to physical development and, more importantly, lineage.
The most famous example was the protagonist, Naruto Uzumaki.
Naruto had inherited the Uzumaki bloodline from his mother, Kushina. His natural chakra reserves were so massive they could only be described in "tons." Even an Elite Jonin like Kakashi Hatake had admitted his own reserves couldn't compare.
Since Lee's lineage was a dead end and he couldn't exactly "speed up" his physical growth at twelve years old, he had to look elsewhere.
There were other ways to boost chakra in this world, of course.
The Fifth Hokage, Lady Tsunade, had the Strength of a Hundred Seal, which allowed her to store chakra over time and release it when needed. Then there were the Cursed Seals created by Orochimaru, the "Mad Scientist" of the ninja world. A Cursed Seal could grant a massive temporary surge in power, but the price was becoming a grotesque freak while enduring unimaginable side effects.
Lee knew these paths existed, but given his current status, something like the Strength of a Hundred Seal was light-years out of reach. As for Orochimaru's Cursed Seal? He didn't give it a second thought. To become a true powerhouse, one could never rely on such twisted, "crooked" methods.
His inspiration for practicing chakra control came from watching the tutor Ebisu teach Naruto how to walk on water.
Now that the Marine Six Powers had been adapted into the chakra system, they were essentially a "Ninjutsu-style Taijutsu." Since they required chakra just like a standard jutsu, Lee reasoned that chakra control would be just as effective for them.
If he could use chakra control to minimize waste, he could increase his "stamina" with the Six Powers. That was his best path forward.
When two ninjas with equal reserves cast the same jutsu, the actual amount of chakra spent could vary wildly. One might use a lot, while the other used very little. The difference lay entirely in the precision of their chakra control.
Staring up at the tree trunk, Lee took a deep breath and centered himself. "Keep going!"
For the rest of the afternoon, he poured every ounce of his focus into climbing. When his chakra ran dry, he sat down to refine more, then started again. Over and over.
Time flew by. Soon, the golden hues of sunset draped over the land of Konoha, casting long, shifting shadows across the training grounds.
Tenten and Neji, having finished their own training, returned to the assembly point. Their eyes immediately drifted to the tree where Lee was still working.
About ten meters up the trunk, there was a fresh mark carved by a kunai. By the looks of it, Lee was still only halfway to the top.
"Why is Lee suddenly so obsessed with chakra control?" Tenten asked, leaning back. "I remember he used to say he didn't care about it. He even put it off so he could focus entirely on his physical conditioning."
Neji rubbed his chin, falling into brief contemplation. "In the Hyuga clan, activating the Byakugan constantly drains chakra. If I had to guess, his goal is to minimize unnecessary waste when he uses that 'Bloodline Limit' of his."
"Is Lee's chakra reserve really that small?" Tenten asked, curious. To her, the concept of individual chakra volume had always been a bit vague.
"Chakra volume is tied to one's innate constitution," Neji said with a shake of his head. "Some are born with oceans of it, while others have nothing but a shallow pond. Look at him. Even with a Bloodline Limit, someone with such pitiful reserves is destined to go nowhere as a shinobi."
Tenten was used to Neji's fatalistic outlook by now. She pivoted to a more personal concern: "How does my chakra compare to Lee's?"
Neji paused for a moment. "In our team, Guy-sensei has the most, reaching the threshold of a Jonin. I'm next, at a Chunin level. Our 'dead last' over there? He doesn't even have two-thirds of what you have. He barely meets the standard for a Genin."
"Hahaha! I didn't realize Lee was that low," Tenten chirped, her mood lifting instantly. "As long as I'm not the one at the bottom. Anyway, I'm heading home for a bath. Bye, Neji!"
She skipped away, leaving Neji alone.
"Fate occasionally offers a surprise," Neji muttered, glancing one last time at the boy struggling against the tree, "but behind every surprise is an inescapable destiny. Dead last... no matter how hard you struggle, the future written for you will never change."
With a cold turn, he walked away.
"Finally... the top."
Standing on the highest branch, looking out over the darkening forest, Lee wiped the sweat from his brow. Droplets flew from his hand as he exhaled sharply.
"Excellent work, Lee! To master the first stage of chakra control in a single day... your teacher has seen every bit of your hard work!"
Below the tree, a figure emerged from the shadows. Sporting an identical bowl cut and thick, bushy eyebrows, the man flashed a dazzling grin and a "Nice Guy" pose, thrusting a thumb into the air.
Lee leaped down from the tree, landing gracefully. He approached his mentor with a humble bow. "I couldn't have done it in a day without the techniques you taught me, Sensei."
Might Guy nodded vigorously, clearly touched by Lee's attitude.
"Lee, I've been trying to figure out how to restructure your training now that you've awakened your Bloodline Limit. I'll admit, beyond our usual Taijutsu, I was at a bit of a loss. But seeing you dive into chakra control like this tells me you've found your own path. I only have one thing to say to you: Lee! You will succeed!"
Guy struck a dramatic pose against the twilight sky. "Your Sensei believes that a man's Youth can make the impossible possible!"
Looking at the hyper-enthusiastic man, Lee felt a mix of genuine warmth and suppressed laughter. Might Guy—a man so simple and pure that it was almost absurd. Yet, it was exactly that purity that would eventually allow him to shock the entire world during the Fourth Great Ninja War.
The Hyuga Estate, Training Dojo.
"Why is she so weak, yet she gets to be the heir to the Main House?!"
"Why am I the one branded with the Caged Bird?!"
Neji's mind was a storm of resentment. The perceived injustice of the Hyuga clan burned in his chest. As he effortlessly swatted aside Hinata Hyuga's strike, his anger boiled over. Losing his typical composure, he leaped forward, his palm aimed at Hinata with lethal intent.
Observing from the side, Hiashi Hyuga's eyes narrowed. "Presumptuous!"
He formed a hand seal.
"AAAAAAGH! MY HEAD...!"