Naruto: Aizen's Shadow in Konoha

Watching Aizen's hurried retreat, Hideki Kitagawa couldn't shake the feeling that his friend seemed different today. But pinpointing the change was impossible.

"Did my cowardice disappoint Aizen? How could someone like me be worthy of his friendship?" Doubt gnawed at Hideki.

During the recent encounter with the Sarutobi clan, he could only cower silently while Aizen stood up to them. By the time the Sarutobi retreated, Hideki was too afraid to approach Aizen until much later, offering empty words of comfort.

"No, I have to change," Hideki clenched his fists, staring at Aizen's vanishing form. "Aizen is such a kind and exceptional person. I need to become a friend he can truly rely on."

Oblivious to the impact of his actions, Aizen continued his walk.

Muye East District - A Quiet Corner of Konohagakure

Aizen's residence was a traditional single-family home. Despite its slightly secluded location within the Eastern District, it remained relatively close to Konohagakure's center.

The original owner's father was a standard Chuunin, while his mother, was a true Jonin! A classic case of a strong kunoichi and a less-prominent husband.

While Jonin's appearances in the series might seem inconsequential, especially regarding Konoha's Anbu – who often meet untimely ends – Jonin level fighters are the backbone of any Great Ninja Village. Even a powerhouse like Konoha only boasts a few hundred Jonin in total.

Therefore, the original owner's family held a modest upper-middle-class status within Konohagakure. However, after the tragic passing of both parents, a decline in their social standing was inevitable.

Aizen bolted the door shut behind him, retreating into the confines of his mind. Within his inner world, a katana with an emerald-green hilt floated serenely.

This was Kyoka Suigetsu, the Zanpakuto – a Shinigami's materialized soul weapon – and arguably the strongest genjutsu (illusionary technique) in existence. Its ability: complete hypnosis.

Upon activation, it could completely control the target's senses: sight, hearing, smell, taste, and touch. It could alter the perceived appearance, shape, and even the physical sensation of objects. As Aizen Sousuke, the infamous Shinigami captain, once said, it could turn flies into dragons and swamps into flower fields.

An undeniably powerful tool.

"But using Kyoka Suigetsu requires Reiryoku," Aizen frowned, a thorny question presenting itself. "And that's something I currently lack."

This was a major concern he'd intended to discuss with the system before accepting Shinigami Aizen's memories. Integrating Shinigami lore into the Naruto world presented challenges.

Previously, this lack of Reiryoku (spiritual power) would have been a significant obstacle. However, after absorbing Shinigami Aizen's memories, his understanding of the soul arguably surpassed anyone in the ninja world.

One could even say that the lifetime experiences of Shinigami Aizen Sousuke held far greater value than Kyoka Suigetsu itself.

These memories encompassed not only centuries of life experience and combat honed through countless battles, but also mastery over advanced techniques like Kido (demonic arts), Shunpo (high-speed movement), Hakuda (hand-to-hand combat), and various esoteric soul-based arts and experiments from the Shinigami realm.

While these elements might not offer the immediate power boost of Kyoka Suigetsu, their value to Aizen's future growth as a powerful ninja would be immeasurable.

For him, they were a treasure trove of knowledge.

If Kyoka Suigetsu represented Aizen's current power, the memories of Shinigami Aizen Sousuke embodied his potential. Their true worth far exceeded that of the Zanpakuto itself.

"The chakra of the ninja world," Aizen mused, "is a fusion of physical and spiritual energy. In essence, it shares properties with Reiryoku. Perhaps I can use chakra to wield Zanpakuto."

He lowered his head, contemplating for a moment before giving a decisive nod.

In theory, chakra functioned similarly to spiritual power, potentially substituting for Reiryoku.

Taking action, Aizen channeled chakra through the few points he'd unlocked within his body. He began experimenting, mimicking the methods Shinigami used to activate their Zanpakuto.

A faint hum resonated...

Simultaneously, Kyoka Suigetsu within his soul responded. The blade vibrated and pulsed with a soft hum.

Then, with a flourish, Kyoka Suigetsu materialized from his inner world, solidifying in his grasp.

"Is this truly Kyoka Suigetsu?" Aizen held the katana across his chest, a hint of elation flickering in his eyes as he traced the gleaming blade. With Kyoka Suigetsu, he possessed a measure of self-preservation in this cutthroat world of ninja.

"Though I can't utilize its Shikai abilities yet," Aizen acknowledged with a sigh, a sudden realization dawning on him.

The moment he'd summoned Kyoka Suigetsu, he'd attempted to activate its Shikai ability – the release form that unleashed its true power. However, the attempt failed.

Shikai activation required a specific amount of energy. In Soul Society, many ordinary Shinigami never achieved Shikai in their entire lives.

Even with the memories of Shinigami Aizen, who likely possessed methods to significantly reduce Kyoka Suigetsu's minimum energy requirements, Aizen's current reserves fell short.

Undeterred, Aizen maintained his composure. No matter how potent Kyoka Suigetsu's power, it remained a supplementary ability. While Complete Hypnosis offered undeniable advantages, it ultimately deceived the target's senses.

Unlike Uchiha Itachi's Tsukuyomi, which could inflict lethal damage through illusions, or basic genjutsu that merely stuns opponents, Kyoka Suigetsu's hypnosis operates differently. While the initial activation requires minimal chakra, maintaining the illusion over time demands significant reserves. Furthermore, the stronger the opponent, the greater the chakra expenditure necessary.

Shinigami Aizen Sousuke's power was truly versatile! Aizen, possessing all those memories, understood this intimately. In a way, it wasn't Kyoka Suigetsu that made Aizen Sousuke powerful, but rather Aizen Sousuke who elevated Kyoka Suigetsu's potential.

This realization solidified Aizen's resolve. A glint of determination flashed in his eyes.

The path to strength held no shortcuts.

Starting today, diligent cultivation begins!