Natural Energy

On the ocean surrounding the Land of Waves, three ninjas and five figures stood upon the surface of the sea.

"Sage Art: Wind Style: Ultra-Big Ball Rasenshuriken!"

Naruto and two Shadow Clones used their six hands together to support a massive shuriken, over a meter in diameter and composed entirely of chakra.

"What astonishing chakra; it can already be observed directly with the naked eye!"

Sakura struggled to steady her body: "If we're talking purely about destructive power, hasn't this jutsu already surpassed S-rank?!"

"But since there is no rank higher than S, this jutsu remains S-rank."

Naruto said: "The Rasengan itself is only an A-rank jutsu, but theoretically, as long as you continue to pour chakra into it, the power of the Rasengan can continue to increase. However, the more chakra you use, the harder it is to maintain the Rasengan."

"Why didn't you use this jutsu when we fought Orochimaru before?"

Sasuke asked: "With this jutsu, you should have been able to kill him before he could 'shed his skin'."

"Theoretically possible, but in that situation, Orochimaru wouldn't have given me the chance to cast it."

Naruto reminded them: "Look at how long I've been standing here. In actual combat, which opponent would be foolish enough to watch me finish this jutsu? Besides, this jutsu doesn't just consume a massive amount of chakra; it also requires the additional refinement of Sage Chakra. If I were to use it at full power, even I would have to expend thirty percent of my chakra."

"Indeed, the chakra consumption of this jutsu is terrifying."

Sasuke had kept his Sharingan active the entire time watching Naruto craft the sphere. Now, he understood the theory, but given his own chakra levels, let alone creating a sphere this large, he wasn't even sure he could fully form one a tenth of this size: "Is this size your current limit?"

"I could make it even larger, but for a demonstration, there's no need to push to that extreme."

As he spoke, Naruto threw the Ultra-Big Ball Rasenshuriken into the distance.

The Ultra-Big Ball Rasenshuriken maintained high-speed rotation as it surged forward, moving with such velocity that it flew over a hundred meters in the blink of an eye.

About fifteen seconds later, whether it struck something or simply hit the surface of the sea, the Ultra-Big Ball Rasenshuriken detonated.

The highly condensed chakra expanded into a spherical shape, though the lower half was obscured by the seawater, leaving only the hemisphere above the surface visible.

A few seconds later, the chakra sphere gradually elongated and rotated, whipping up a storm that drew in the seawater before venting its energy toward the sky, transforming into a brilliant, flashing pillar of water that shot into the heavens.

The energy release process lasted for about a minute, during which the seawater swept into the sky continued to fall, as if a torrential rainstorm had broken out in a small area.

Gazing at the "sea crater" blasted out by the ninjutsu in the distance, Sakura and Sasuke felt a small sense of "power" shock.

Afterward, the three returned to Naruto's secret base.

"Naruto,"

Sasuke asked: "Is that 'Sage Art' you used earlier something Master taught you? Can Sakura and I learn it too?"

"Naturally, it was taught by Master."

Naruto said: "As for you two, Master says you need to wait until your 'Qi Refining' progresses a bit further."

Sakura: "Does Sage Art require the consumption of Qi?"

"Not Qi, but 'Natural Energy'."

Naruto explained: "Natural Energy is a type of energy that exists in the environment around us. But under normal circumstances, it is very difficult for us to perceive it. Qi can help us sense it and assist us in controlling that energy better. When refining chakra, if you add Natural Energy in a specific ratio, you can obtain Sage Chakra."

"What is the specific ratio? What happens if there's too much or too little?"

Sakura asked: "If you don't control the Natural Energy well, is there some kind of danger?"

"Natural Energy, physical energy, and spiritual energy—only by precisely mixing these three in equal parts can you refine Sage Chakra. If the proportion of Natural Energy is too low, you won't be able to refine Sage Chakra. But if the proportion of Natural Energy is too high, our bodies will turn to stone."

Naruto said solemnly: "Also, be aware that if you absorb too much Natural Energy into your body at once and fail to control it, even if you don't use it to refine chakra, your body will still turn to stone."

"Turn to stone?!"

Sakura was shocked: "That risk is too high!"

Sasuke didn't speak, but judging by his expression, he was likely thinking the same thing.

"That is why you need to become more familiar with Qi Refining. Qi can suppress the petrification effect of Natural Energy. As long as you have enough Qi in your body, even if you accumulate a lot of Natural Energy, you won't turn to stone."

Naruto explained: "Furthermore, don't think that absorbing Natural Energy is a simple matter. Right now, our surroundings are filled with a vast amount of Natural Energy, and you have both mastered Qi Refining, but have you felt the Natural Energy?"

They hadn't.

Before, they didn't know Natural Energy existed, so it was normal not to feel it.

Now, both of them knew of its existence, but even when they consciously focused their minds to perceive it, they still felt nothing.

"It's normal that you can't feel it now; how long have you even been practicing Qi Refining?"

Naruto said: "From the time I started Qi Refining to sensing Natural Energy, and finally successfully refining Sage Chakra, it took me five years in total. Even if you are both smarter than me and have better talent for Qi Refining, it should still take a year or two, right?"

"Indeed, I was too impatient."

Sasuke took a deep breath and exhaled slowly: "Lately, realizing how large the gap is between you and me has made me a bit anxious."

"This... wait."

Naruto suddenly closed his eyes. After a long moment, he opened them and asked: "Master says he has a special training method that can make you both grow stronger in a short time, but the process will be quite difficult. He told me to ask if you want to try it."

Sasuke instinctively wanted to answer immediately, but he suddenly felt a chill. He paused and added one more question: "Have you tried it?"

"No."

Naruto was very honest: "I wanted to try it back then, but my parents felt I was still too young and there was no need to rush, so they had Master switch me to the more time-consuming, standard training method."

"Um, specifically speaking, what kind of price are we talking about?"

Sakura asked with some hesitation, "Like overdrawing our life force or something?"

"No, Master said it's a tempering of the spirit. It won't cause physical harm, nor will it drain your body's potential."

Naruto relayed, "But it is a bit brutal. You have to be mentally prepared beforehand. If you fail to make it to the end, you could suffer a mental breakdown—that is the greatest price."

"A tempering of the spirit, huh..."

Sasuke was inclined to accept, but he was still bothered by the chill he had felt earlier. "Can you explain the specific content of the training in more detail?"

Naruto closed his eyes to communicate with Master for a moment, then opened them and said, "Simply put, it uses Sealing Space techniques to seal the spirit, then takes advantage of the fact that time flows differently inside the Sealing Space than it does in the outside world to temper your spirit to your own limit within a short period."

"That doesn't sound all that brutal."

Sasuke relaxed slightly. "How exactly does it temper the spirit inside the Sealing Space?"

"The specific method of tempering changes based on each person's thoughts and perceptions. You'll only know once you've experienced it yourself."

Naruto looked at Sasuke. "Well, do you want to try?"

After struggling for two seconds, Sasuke said resolutely, "I do. Let me try!"