A handful of weeks passed, the forest a silent witness to Sasuke's unwavering focus. Then, one serene morning, the faint discoloration of the curse mark vanished entirely, his skin returning to its natural hue. A subtle shift occurred in his perception, the intrusive pull on the natural energy gone.
With renewed determination, Sasuke resumed his attempts to draw in the ambient energy, this time without the chaotic interference. He carefully guided the potent force, meticulously blending it with his internal spiritual and physical energies, striving for the elusive equilibrium.
Days bled into nights, marked by focused meditation and the subtle hum of natural energy resonating around him. Finally, a breakthrough. A tangible shift occurred within his chakra, a harmonious fusion of his own energy with the power of the forest. Sage Mode had been achieved.
The transformation was gradual, a subtle intensification of his senses and a faint golden hue around his eyes. It took a noticeable span of time, some few hours, before the shift was complete. And the heightened state, while potent, only lingered for a handful of fleeting minutes before beginning to wane.
Katsuyu observed the transformation with a knowing gaze. "Congratulations, Sasuke-san. You have successfully entered Sage Mode. The initial activation time and duration are typical for this early stage. With consistent practice, you will gradually reduce the former and extend the latter."
Sasuke absorbed the information, a thoughtful expression on his face.
'Hashirama Senju… he could maintain Sage Mode for the entirety of his legendary battle against Madara at the Valley of the End… for three days straight. Naruto, even with Kurama's assistance, never truly reached that level of sustained power in the original timelines.'
He turned his gaze towards the colossal slug. "Lady Katsuyu, how long would it realistically take me to achieve the level of mastery where Sage Mode can be activated with a mere clap, like Hashirama-sama, and sustained for days?"
Katsuyu's voice held a note of ancient wisdom. "The First Hokage, Tsunade-sama's grandfather, possessed an unparalleled affinity for natural energy and dedicated many years to attaining complete mastery over Sennin Mode. It is a feat that requires exceptional talent and relentless dedication of years, Sasuke-san."
"However," she continued, "with diligent and consistent practice, you can certainly reduce your activation time to mere seconds. But extending the duration to the level of the First Hokage will indeed require years of dedicated training."
Understanding dawned in Sasuke's eyes. "Activating it in a few seconds… even if it only lasts for a few hours initially, that would still be a significant milestone." A spark of excitement ignited within him.
He glanced at his internal status once more.
(Senjutsu : Advanced)
Sasuke's brow furrowed slightly.
'Advanced? Is that the final stage? Or is there a level beyond?'
He pushed the thought aside, his focus returning to the task at hand.
He continued his rigorous training, diligently working to shorten the activation time and extend the duration of his Sage Mode.
_______
Months passed in this focused endeavor. The leaves of the forest turned through their seasonal hues, and with each cycle, Sasuke's control grew. Now, he could enter Sage Mode in approximately five to seven minutes, and the enhanced state lasted for over an hour. It was progress, significant progress, though the instantaneous activation he envisioned remained a distant goal.
One crisp morning, after a prolonged session, Sasuke opened his eyes, a new intensity in their depths. "Now," he stated, his voice carrying a note of finality.
Katsuyu tilted her massive head, her multifaceted eyes regarding him with genuine curiosity. "Now? What do you mean, Sasuke-san?"
A determined glint shone in Sasuke's eyes. "Now… it is time to begin creating that ninjutsu. The one that merges the Rasengan with my Fire Release."
He settled into a meditative pose once more, focusing his chakra, drawing in the now familiar natural energy. Slowly, deliberately, the golden hue returned to his eyes. After the customary few minutes, Sage Mode was active.
With focused concentration, Sasuke formed a single hand seal, and a swirling vortex of chakra materialized in his palm – the Rasengan. Then, channeling his Fire Release, he began the intricate and perilous process of attempting to fuse the volatile flames with the chaotic energy of the Rasengan.
Ten shadow clones flickered into existence around him, each mirroring his movements, ready to assist in this unprecedented endeavor. The fusion of Sage Mode, Fire Release, and the Rasengan had begun.