Natural energy could not be absorbed in excessive amounts, as too much would cause severe corrosive damage to the practitioner's body.
But it couldn't be too little either, otherwise it would be completely crushed and devoured by the overwhelming spiritual energy.
Shihouin Naraku sat cross-legged on the smooth stone platform, carefully sensing the natural energy flowing around him while seeking the perfect balance between all three energy types.
As the training time slowly passed by, a light drizzle began to fall from the sky above. The droplets poured down onto the flowers, trees, and other vegetation, as well as Naraku's exposed upper body, causing small puffs of green smoke to rise into the air.
Although the scene might have looked almost peaceful from a distance, these seemingly innocent raindrops were extremely corrosive.
Not only were the surrounding plants being steadily corroded by the acid rain, but Shihouin Naraku's entire body was also suffering severe chemical burns from the acidic precipitation.
Naraku's upper body became covered with painful, bloody scars from the corrosive effects of the acid rain. He looked absolutely miserable, but his powerful natural recovery abilities were constantly working to repair the damage being inflicted on his body.
The terrible sensations of burning pain and intense itching spread throughout his entire body, making him want to reach out and scratch uncontrollably at the affected areas.
The unbearable discomfort penetrated deep into his bones, severely disturbing Naraku's concentration and making it nearly impossible for him to maintain the calm focus necessary for his training. He almost failed completely to condense the natural energy properly.
"This represents the first major hurdle!"
"I wonder how long Lord Naraku will be able to endure this trial!"
Katsuyu watched carefully from her position nearby, not daring to relax her vigilance for even a moment.
The arrival of acid rain would bring abundant natural energy that was perfect for training, but at the same time it would also cause significant harm to any shinobi attempting to practice sage arts.
If someone possessed too little chakra reserves and inadequate recovery abilities, the average ninja would not be able to survive for very long in the corrosive acid rain.
And this was merely the beginning of the challenges. Whether it was the continuous damage caused by the acid rain or the ninja's own healing processes, both factors would significantly affect the absorption and balance of natural energy, making it extremely difficult to successfully condense sage chakra.
As the acid rain containing abundant natural energy continued to fall, Naraku clearly felt that it became much easier to sense and condense the natural energy around him, but he first had to learn to ignore the severe impact that the external environment was having on his physical and mental state.
"THUD!"
Katsuyu jolted Naraku awake once again.
"This is troublesome!"
Naraku opened his eyes and looked down at the miserable condition of his upper body, but he didn't take the damage seriously at all.
"When natural energy becomes too abundant or too active, problems arise. If it becomes too concentrated, the delicate balance will be broken in an instant."
Katsuyu offered her gentle reminder: "Whether the natural energy is abundant or insufficient, we must ensure that the natural energy being absorbed remains perfectly balanced—not too much and not too little."
"As long as you can accomplish this consistently, you will have basically entered the foundational stage of Sage Mode practice."
"Alright, I understand completely!"
Naraku snapped his fingers with determination, forcing himself to completely ignore the intense itchiness and burning pain throughout his body, and entered into a deep meditative state once again.
As more time passed, Naraku became increasingly familiar with natural energy and began to develop a better mastery of the balance between the three different energy types.
"It should work properly this time!"
Bathed in an environment completely saturated with natural energy, Naraku began the careful process of absorbing natural energy into his body.
"Oh no!"
At that precise moment, the acid rain suddenly stopped falling and the natural energy concentration in the outside environment dropped significantly. Naraku was negatively affected by these external changes, resulting in yet another absorption failure.
"THUD!"
Naraku opened his eyes yet again!
As the acid rain disappeared entirely, the wounds covering his body quickly returned to their original healthy state. If it weren't for the faint bloodstained patterns remaining on his skin, no one would have known that he had just endured what appeared to be torture-like corrosion.
Naraku said with obvious frustration: "If there's even the slightest movement or change in the external environment, the entire process fails. The natural energy is far too sensitive to outside influences."
Katsuyu comforted Naraku with her characteristically gentle voice: "Lord Naraku is already performing exceptionally well. Most people spend their entire first day simply getting familiar with and learning to sense natural energy, and they don't even dare to expose themselves to the acid rain."
"Ha, well that's genuinely reassuring."
Naraku smiled with determination and continued his intensive training.
Before coming to Shikkotsu Forest, he had known that successfully mastering Sage Mode would not be easy, but his current rate of progress was already quite impressive.
At least Naraku could still see genuine hope for eventual success instead of facing outright failure.
In this manner, Naraku practiced continuously day and night, never stopping except for brief periods of rest and meals.
There was no shortage of suitable places to rest within Shikkotsu Forest. As for food, Naraku had wisely brought his own supplies. He remembered very clearly the unpleasant lesson of being forced to eat insects when Naruto had gone to Mount Myoboku to learn Sage Mode.
Even though Naraku had come to Shikkotsu Forest, where the Great Slug Sage probably didn't consume insects, he had still brought food with him just to be safe.
Shikkotsu Forest remained perpetually quiet and peaceful, as if it were completely isolated from the chaotic ninja world. Naraku, who was training intensively in this environment, became completely unaware of the passage of time and remained focused solely on mastering Sage Mode.
All endeavors are difficult at the beginning. Naraku found himself stuck on the very first step of Sage Mode training for two full days. It wasn't until the third day that he finally succeeded in achieving a new balance of energies within his body and successfully created Senjutsu Chakra.
"Excellent!"
At this crucial stage, Naraku could be said to have successfully entered through the door of Sage Mode training.
"Lord Naraku is truly remarkable! In just three days, you were able to create Senjutsu Chakra successfully."
Katsuyu felt genuinely surprised and impressed, exclaiming that Naraku's training speed was really extraordinary.
"No, while it's true that I succeeded, I can only maintain the state for less than ten minutes at the moment. This duration won't be sufficient."
"And at my current skill level, it takes me twenty-three minutes to enter Sage Mode. This speed is far too slow and would be completely impractical in actual combat situations."
Naraku shook his head, feeling somewhat dissatisfied with his current progress and limitations.
Katsuyu offered encouragement: "Being able to maintain Sage Mode for approximately ten minutes on your first successful attempt is already a sign of extraordinary talent. The First Hokage could only sustain it for less than five minutes when he first successfully entered Sage Mode."
"Really?"
"Yes, absolutely."
Naraku nodded thoughtfully. He hadn't expected his initial results to be superior to Senju Hashirama's early performance. Perhaps it was because his soul and spiritual talents were exceptionally outstanding, which positively affected his learning process.
That was definitely a positive development!
"Also, if Lord Naraku practices consistently for an extended period, you can definitely accelerate the process of refining Senjutsu Chakra, and you might even be able to enter Sage Mode instantaneously. However, reaching that level is extremely difficult to achieve."
Katsuyu spoke with obvious hesitation: "To enter Sage Mode instantly, a practitioner not only needs to have complete mastery over natural energy and perfect bodily adaptation to sage chakra, but must also possess truly amazing natural talent."
Enter Sage Mode instantly?
It seemed that from beginning to end, only Senju Hashirama and Namikaze Minato had ever accomplished such a feat.
Both of them could enter Sage Mode instantaneously, which stood in stark contrast to the lengthy preparation times required by Jiraiya and Uzumaki Naruto.
"Next, Lord Naraku must quickly familiarize yourself with maintaining the Sage Mode state," Katsuyu reminded him. "Before entering the Sage Arts Cave for advanced training, you must shorten the time required for refining Senjutsu Chakra to less than fifteen minutes."
Enter Sage Mode in fifteen minutes?
This requirement should be easily achievable. Naraku felt confident that as he became more familiar with Sage Mode techniques, even if he couldn't activate Sage Mode instantaneously, the preparation time could definitely be reduced dramatically.
In the following period, Naraku focused all his attention on accelerating the condensation of Senjutsu Chakra and maintaining the Sage Mode state for as long as possible.
----------------
You can read advanced chapters here: patreon.com/GregariousLion