After dinner, Kairi returned to his room and pulled out the book on chakra extraction techniques. Honestly, he hadn't studied this diligently even in his previous life.
He already had a general understanding of what chakra was, though he didn't yet know how to extract it. He'd once asked Sina to teach him, but she admitted she hadn't used those techniques in years and had forgotten much of what she learned in school. Besides, she didn't recommend that he try extracting chakra before the age of six it could have negative effects on a growing body.
Kairi had thought deeply about chakra. It was a combination of physical and spiritual energy, so the process of extracting it was bound to impact the body.
Spiritual energy determined how much chakra one could extract at a time. Physical energy, on the other hand, dictated how much chakra one had in total. Only once the two were fused could chakra be used.
To Kairi, physical energy was influenced by both bodily fitness and bloodline. The former could be improved through training, but the latter was mostly fixed at birth.
Ordinary people had a low bloodline coefficient, meaning they needed to work significantly harder to build up a decent chakra reserve. But certain lineages like the Uzumaki clan had a naturally high coefficient. Even without exceptional physical training, they could hold monstrous amounts of chakra.
And bloodlines didn't just affect chakra capacity. They influenced how quickly one could recover. Not that it mattered much in most fights, since battles were usually decided in just a few exchanges.
Kairi had once wondered if there were any special treasures in this world that could improve one's bloodline coefficient. But the more he thought about it, the less hopeful he felt. The only example he could recall was the Dragon Vein, and even that was vague. He didn't remember when it appeared in the timeline, and it might not even align with his goals.
He let out a quiet sigh. If only this were a xianxia world. There'd be all sorts of rare herbs and artifacts to enhance one's foundation. Sure, they'd be hard to come by but at least there'd be hope. Unlike here, where the only solution seemed to be winning the genetic lottery.
Still, if someone handed him such a treasure now, he wouldn't hesitate to use it. As much as he idealized the idea of pure human progress, logic still came first at least while he was weak. He could afford to be idealistic once he had real power.
After reading for a while and giving his food time to digest, Kairi closed the book and stood up.
"Mom, I'm heading out!"
"Be home early, alright? Stay safe!" Sina called back. She was already used to his habit of going out every day. She'd thought that school might finally keep him in for once, but no it was back to the routine.
But playing around wasn't on his agenda. Since chakra was fueled by the body, and the body was his foundation, Kairi was determined not to slack off. If he didn't build up a strong enough physique, a few jutsu would be all it took to drain him dry in battle.
He figured that despite consistent training, his current physical level probably matched that of an average second-year student.
That said, he'd noticed something lately. Though his training intensity hadn't changed much, his body had definitely improved. Likely due to natural growth with age. Which meant he could start increasing the training load a little.
He needed to test that increase first. It was fine to push himself occasionally, but he had to be careful not to damage his still-growing body. One wrong move could cost him long-term development.
Still, a single trial wouldn't hurt. If anything, it might help him gauge his limits. Maybe even break through them.
He arrived at a quiet training ground tucked away from the main roads and just as expected, someone was already there.
Kairi wasn't surprised. He was more than familiar with this person by now. Most days, by the time he arrived, the other boy was already mid-workout. And even when Kairi left, the boy would still be going strong.
Yep. It was Rock Lee.
The hardworking prodigy.
But honestly, Kairi sometimes wondered if Lee's body could even handle his own insane routine. In theory, Kairi believed his own potential ceiling might be a bit higher.
The problem was time. Human growth had a deadline. If he couldn't reach that theoretical ceiling before his body stopped developing, then it didn't matter how high it was.
That was the difference between theory and reality. For now, he couldn't see himself surpassing Lee in physical ability and he wasn't even trying to. After all, he respected Lee's relentless drive.
"Oh! Kairi, you're thirty minutes late today! That means extra training sets as punishment!" Lee's eyes lit up the moment he saw him. He was used to training alone, but having a partner made it more fun.
"Sure," Kairi agreed without hesitation. He'd been planning to push his limits today anyway.
Lee was momentarily stunned. Usually, Kairi would dodge extra sets. His surprise quickly turned to excitement. Fire practically blazed in his eyes.
"Ohhh! You actually agreed? You're burning with youth! I can feel it! This is youth! Today, I'll reward myself with extra sets too!"
Kairi felt a bit awkward. Even though he'd seen it many times before, Lee's passion still caught him off guard.
They began training.
Although they shared the same space, their methods were quite different.
Kairi never pushed himself to extreme intensity. He believed his body was still growing, so he preferred low-intensity workouts stretched over longer periods. Build consistency, not exhaustion.
Minute by minute, time passed. Despite the lighter load, Kairi was panting heavily. He hadn't reached his target yet, but his body was already nearing its current limit. Mentally, though, he felt like he could still power through.
From the side, Lee watched in awe, tears welling in his eyes.
It was happening. The fire of youth was truly burning!
Kairi's movements suddenly smoothed out, as if his body had entered a flow state. Lee knew this feeling well. He experienced it all the time. It was the flame of youth!
Lee was now crying openly, deeply moved.
"Phew. Made it," Kairi whispered. He realized his current limit was higher than he'd thought. Though it wasn't a true "limit," it was the edge of what his body could safely handle.
After a bit more training, Kairi said goodbye and trudged away, his steps heavy with fatigue. His body was exhausted, but his spirit felt fine. He planned to read more when he got home he was determined to master chakra extraction as soon as possible.
The next day, something odd happened.
He felt... okay.
Could his body have improved that much?
He tested himself with another push.
And then, on the third day he crashed.
Exhaustion hit like a freight train. His body screamed with fatigue, leaving him no choice but to stick to basic exercises.
So, no back-to-back breakthroughs.
He'd have to find the right spacing between these intense sessions.
Kairi sighed. Building his body and accumulating chakra would be a long road but he was ready to walk it.