The smaller Katsuyu glided gracefully through the humid air of Shikkotsu Forest, leading Sasuke deeper into the verdant expanse.
They finally arrived at a clearing, where an immense slug, radiating an aura of serene power, rested upon a moss-covered boulder.
Sasuke's eyes widened slightly at the sheer scale of the being before him. He immediately offered a respectful bow.
"Lady Katsuyu," Sasuke began, his voice carrying a note of polite inquiry, "are you… the real one, I mean.."
A soft, bubbling chuckle emanated from the large slug.
"Sasuke," Katsuyu's voice echoed gently, yet with a profound resonance, "we are all Katsuyu. Think of these smaller forms as extensions of myself, real in their own right."
Sasuke's brow furrowed in momentary confusion. He opened his mouth to seek further clarification.
"There is no need to dwell on such matters now," Katsuyu interjected with gentle firmness. "Our focus should be on the path of Senjutsu."
Sasuke offered a curt nod, his curiosity momentarily suppressed.
"When can we begin the training, Lady Katsuyu?" he inquired, his tone now focused.
"There are fundamental principles you must first understand," Katsuyu replied calmly, "both about Senjutsu itself and the unique nature of your chakra."
"Your chakra," Katsuyu continued, her gaze seemingly piercing, "has already begun to merge with the residual natural energy within your curse mark. This has made your chakra more potent than it otherwise would be."
"This unique characteristic," she elaborated, "will prove advantageous in the initial stages of your Senjutsu training, allowing for a smoother transition in sensing natural energy."
"However," Katsuyu's tone shifted slightly, gaining a note of caution, "Senjutsu is not a permanent state. Even with complete mastery, the Sage Mode will eventually dissipate. Similarly, the effect of the natural energy within your curse mark on your chakra will also diminish over time."
Sasuke absorbed this information, his expression thoughtful. He refrained from interrupting, allowing Katsuyu to continue.
"There are three crucial steps in mastering Senjutsu," Katsuyu explained, her voice measured. "First, you must learn to sense the natural energy that permeates all living things."
"Second," she continued, "is the ability to draw this natural energy into yourself."
"Finally," Katsuyu concluded, her gaze unwavering, "and most importantly, you must achieve a perfect balance between your physical energy, your spiritual energy, and the natural energy you have absorbed. It is this balance that allows you to enter Sage Mode."
Sasuke nodded, the information aligning with his knowledge from his previous life.
'The curse mark…' he mused internally. 'In the original anime, it never had this kind of interaction with natural energy. This 'System' of mine… it seems to have unforeseen influences, even beyond displaying mere stats.'
Katsuyu's voice broke his internal contemplation.
"Because your chakra has already absorbed a small amount of natural energy," she stated, "the first two steps – sensing and absorbing – will likely come more easily to you than to others."
"However," she emphasized, "achieving that crucial balance will still require significant time and focus. It is the most delicate and potentially dangerous stage."
"Failure to maintain this balance," Katsuyu warned, her voice now carrying a distinct weight, "will result in your body turning to stone."
A flicker of apprehension ran through Sasuke, despite his prior knowledge.
"I understand," Sasuke replied, his voice firm despite the underlying tension. "I will not rush. I will take the time necessary to learn Senjutsu properly."
Katsuyu offered a slow nod, her immense form shifting slightly.
"Tell me, Sasuke," she inquired, her tone now probing, "do you wish to undertake this training independently, relying solely on your own senses once you grasp the initial steps?"
"Or," she continued, alluding to the method Tsunade had likely discussed, "would you prefer to utilize the… secretions that can aid in the initial sensing of natural energy, even though your unique condition already provides an advantage in that regard?"