Two years had passed. Beneath the flowing waters of a secluded waterfall on Konoha's outskirts, a lone figure sat cross-legged on a compact earthen platform sculpted with Earth Style. Clad in a black uniform similar to the Shinigami's robes, Aizen presented a stark contrast to the vibrant dawn breaking over Konoha. His youthful features matured, framing his face with a familiar three-to-seven haircut. Black-rimmed glasses perched on his nose, concealing the glint that now resided in his eyes.
Gone was the oversized blade from his early days. In its place, Kyōka Suigetsu, its true form still beyond his physical limitations, rested at his hip. Undeterred, Aizen focused his immense spiritual power. A complex network of channels guided natural energy into his being, imbuing his very breath with an air of serenity and transcendence. As the natural energy saturated his spirit, Aizen meticulously drew in his Chakra, merging the two into a unique power source within his soul. Upon achieving this delicate balance, a potent aura erupted from him – a blend of raw power, natural essence, and a fierce determination that mirrored a released Hollow's.
A low growl escaped Aizen's lips as he vanished from the platform in a blur of speed, reappearing above the cascading waterfall. With a swift movement, he unleashed Kyōka Suigetsu, cleaving the rushing water with a single, powerful slash. A flash of silver ripped through the air, cleaving the waterfall in two with a resounding crash. Seconds later, the severed torrent resumed its flow. Aizen landed back on the platform, a satisfied smirk playing on his lips as he reviewed the attack.That blade wasn't child's play.
Two years of relentless effort had finally yielded results. He'd mastered the absorption of natural energy and completed his experiment with synthetic spiritual power. Drawing inspiration from the Shinigami arts, Aizen named this new force as Reiryoku (Spiritual Pressure).
It's important to note that while he named it Reiryoku, this essentially functioned as the chakra system of the Ninja world. Interestingly, the natural energy Aizen absorbed mirrored energy in a one-to-one ratio – a stark contrast to the three-way fusion of spiritual, physical, and natural energy utilized by the Ninja world's energy. However, Aizen theorized this was simply a consequence of the differing arts he practiced. Unlike Uzumaki Naruto and other descendants, who absorbed natural energy to merge with their Chakra upon entering Sage Mode, Aizen's method achieved a true, continual absorption and cultivation process.
He suspected there were hidden layers within the so-called inheritance of the arts passed down in places like Mount Myoboku. Perhaps it was more about training expendable tools. The most significant change he noticed was the evolution of his soul after absorbing and cultivating natural energy. It could now automatically generate natural energy after its reserves were depleted. Additionally, he felt a slight enhancement of his vitality, hinting at shackles being unlocked within his body. While the improvement wasn't drastic, Aizen estimated he'd need to absorb natural energy for a century to achieve complete transformation. This timeframe didn't surprise him. After all, if cultivating natural energy offered no benefit to vitality, how else did the 'Frogs' in the sacred lands live for millennia?
Aizen's power, Reiryoku as he'd names it, granted him a permanent Sage Mode-like state. While limited by his current capacity to absorb and refine natural energy, it offered a significant advantage. This newfound ability was a game-changer. With Reiryoku alone, Aizen could hold his own against Jōnin-level opponents without relying on swordsmanship (Kendo), Shunpo (high-speed movement), or Kyōka Suigetsu's illusions.
It's worth noting that Aizen's Chakra reserves had grown to the peak of an Elite Chūnin, nearing the threshold of a Jōnin specialist. He was on track to become a specialist himself within a month. By then, Aizen could potentially face off against average Elite Jōnin using only Reiryoku. Adding swordsmanship and Shunpo to the mix would elevate him to a level where he could challenge Jōnin who possess powerful secret techniques or even those with advanced bloodline limits.
Speaking of Swordsmanship, Aizen's swordsmanship had noticeably improved, reaching the stage of "sword power" – a significant milestone. His Shunpo (high-speed movement) had also made strides, a far cry from his abilities two years ago. The slash he unleashed at the waterfall, despite only channeling B-rank ninjutsu power, represented a mere 1% of his true potential. This didn't even factor in the additional edge Kyōka Suigetsu's illusions would provide. For any ninja below Jōnin rank, lacking unique abilities or powerful techniques, a single encounter with Aizen could be fatal – especially if they remained unaware of Kyōka Suigetsu's deceptive nature. This was the result of Aizen's two-year training regimen!
A satisfied smile graced Aizen's lips as he drew a deep breath. The tangible improvements in his strength brought him immense joy. "Time for work," he muttered, gathering his belongings and heading towards the medical department. He donned the standard white coat and entered the medical department on schedule."Good morning, Brother Aizen!" chirped a chorus of female voices. "Come here, Aizen! Let me check if you've grown any taller!" giggled one of the medical-nin sisters.
"Maybe I should examine you myself," another teased with a mischievous glint in her eyes.As soon as he stepped through the door, Aizen was bombarded with the playful affection of the women. His charming looks and gentle demeanor, coupled with his teenage years, had made him a favorite among the female ninjas. Initially resistant to their teasing, Aizen eventually learned to roll with it. After all, the past two years had been peaceful and fulfilling. No threats of war loomed, allowing him to focus on his training in tranquil seclusion.
This idyllic existence filled him with a sense of smug satisfaction about his "masterplan." He projected that by the time he reached Jōnin rank, the Second Shinobi World War would be over. His next move: discreetly subdue Hiroku and implement his long-awaited "power-up project." Once his strength reached a critical point, he'd make a grand entrance, surpassing both Uchiha Madara and even the legendary Ōtsutsuki Kaguya. Unfortunately, life rarely follows to pre-written scripts. Just as Aizen reveled in his carefully crafted destiny, a single person threatened to throw a wrench in his meticulously planned "scheme." That person? None other than his closest friend and companion – Namikaze Minato.