Naruto: Aizen's Shadow in Konoha

Aizen smiled warmly, his voice calm yet firm. "That's right, Shuji. That's exactly what I'm thinking."

Kitagawa Shuji pointed at himself, his expression a mixture of disbelief and astonishment. "Me? Are you serious?"

Aizen nodded solemnly. "Yes, Shuji. You're the first member I've chosen."

For a moment, Shuji stood frozen, overwhelmed by the unexpected honor. "This... I don't know what to say..."

"Shuji," Aizen continued, his tone imbued with sincerity, "I've had this idea for quite some time, but I've never found the right person to help me. Will you assist me in forming this unit?"

Aizen's words were carefully chosen. By phrasing it as a request for help rather than a gift, he framed the opportunity in a way that made it nearly impossible for Shuji to refuse. He wasn't giving Shuji something; he was entrusting him with something significant.

Shuji's face flushed with excitement, his eyes glistening. "Of course, Aizen! I'll do everything I can to help you!" he declared, thumping his chest with determination.

"Thank you, Shuji." Aizen replied with a look of heartfelt gratitude, though inwardly, he admired how easily he had steered the conversation.

"But," Aizen added, his tone shifting slightly, "I'd also like to recruit some of your friends for this unit. Could you provide me with their details?"

Shuji's face turned emotional as he processed Aizen's words. His thoughts raced, and he blinked back tears. To Shuji, it was clear that Aizen wasn't just looking out for him but also extending this opportunity to their entire group—a gesture of unparalleled kindness. He vowed to repay Aizen's faith in him.

"I'll do it, Aizen," Shuji said, wiping his tears. "I'll make a list of my friends and give it to you."

With that, Shuji turned and ran off, leaving Aizen standing alone, bemused by his friend's theatrics. After a moment of silence, Aizen sighed, his expression contemplative.

Aizen had been planning to form his own combat unit for a while. As someone with grand ambitions, he knew that having elite allies like Hyuga Gin, the Sasori, and Hiruko wasn't enough. A truly formidable leader needed a cadre of loyal, well-trained soldiers to carry out their will.

His existing allies already had specialized roles. The Red Sand Scorpion was tasked with establishing an intelligence network, a field perfectly suited to his expertise in espionage and subterfuge. Hiruko and Hyuga Gin, meanwhile, were focused on their own unique objectives, leaving Aizen to shoulder the responsibility of creating this new combat force.

Aizen's ambition to form a loyal combat force began with a single, crucial principle: selecting the right people. Talent was secondary; loyalty and a shared vision were paramount. For this reason, Aizen's secret medicine had been meticulously prepared—not just to enhance strength but to ensure unwavering allegiance. Even with its soul-binding poison to prevent betrayal, Aizen remained wary of individuals indoctrinated by Konoha's "Will of Fire." Such individuals, fiercely loyal to the village's ideals, posed a risk to his plans.

The physical techniques of the "Six Forms," created by Aizen himself, were powerful secrets he would not allow to fall into the hands of Konoha's establishment. This made his selection criteria even stricter. When Aizen encountered Kitagawa Shuji, a civilian ninja with no ties to the powerful clans and ostracized by Konoha's elite, he knew he had found the type of person he needed.

Kitagawa Shuji returned with a list of more than one hundred names. "This guy is more popular than I expected," Aizen murmured, skimming the list. After dismissing Shuji, Aizen carefully reviewed the names, prioritizing orphans and those without familial connections. These individuals, he reasoned, were more likely to pledge their loyalty to him than to Konoha.

When he met the recruits, Aizen used a mixture of promises, the allure of his secret medicine and Six Forms, and a clear warning about the poison within the medicine to secure their allegiance. The offer was irresistible: the chance to rise above their status as overlooked civilians and achieve power akin to that of a Jōnin. For most, it was an easy decision. Aizen's approach struck a chord with those who had long suffered under the rigid hierarchy of Konoha.

Of course, not everyone accepted. For the few who refused, their fates were... dealt with swiftly.

After days of recruiting, Aizen gathered thirty reliable members. But his plans required more. Thus, he submitted a formal request to Sarutobi Hiruzen: "Report on the Formation of the Fifth Division of the Medical Department."

The proposal landed on Hiruzen's desk. The Third Hokage hesitated, conflicted. Aizen's justification for forming a combat unit within the Medical Department was logical, but the implications were troubling. The Medical Department already wielded considerable influence, and adding a combat force could shift the balance of power. Still, Aizen's recent victory on the Western Front had bolstered his reputation. Rejecting the request outright could damage the trust between them.

Furthermore, Aizen assured that the combat unit would consist solely of civilian ninjas, deliberately excluding members of prominent clans. He emphasized that the unit would be small, capped at under one hundred members. With these assurances in mind, Hiruzen reluctantly approved the proposal.

Thus, the Fifth Division was born.

Over the next several weeks, Aizen quietly expanded his search within Konoha's Western Army, recruiting an additional fifty members. When his pool of candidates dwindled, Hyuga Gin contributed by enlisting a dozen members from the Hyuga clan's branch house. This finalized the formation of the Fifth Division.

Aizen wasted no time. Training began in secret, blending rigorous physical regimens with the unique techniques of the Six Forms. Iron Body, Tempest Kick, and Finger Pistol became the cornerstones of their physical prowess, while Shave and Moonwalk granted them unprecedented mobility. The integration of elemental chakra further elevated their capabilities, turning them into a formidable force.

All the while, Aizen balanced his responsibilities as commander of the Western Front alongside Namikaze Minato. The collaboration between the two strategic minds ensured continued success in Konoha's campaigns. 

Two years passed.