Onepiece: I'm Aizen Sosuke

**Time Flies**

Two months had passed quickly.

Since the last clash between the Whitebeard Pirates and the Golden Lion Pirates, Aizen had been stationed at the Marine Base with Garp. Life in the base was quiet and uneventful.

At first, some of the nautical basics caught Aizen's interest, but he quickly mastered them all. Within a week, he had learned what most navigators would never achieve in their careers.

But soon, the mundane routine bored him. His days consisted of eating, training his Reiatsu, perfecting his Kidō, and honing his swordsmanship.

After his previous duel with Rayleigh, Aizen felt closer to reaching the realm of a great swordsman. Though his skill in swordsmanship had improved, the speed at which his power was growing was becoming undeniable.

Sitting in the training grounds, Aizen sighed. "It's so quiet..." The world around him felt different, quieter, almost as if he had stepped into another realm where everything had fallen silent.

But then, Aizen sensed something. It wasn't the breath of a person or any animal—it was the breath of the wooden stake in front of him.

The sound of its breathing grew louder, more pronounced, and soon it filled the air. Aizen stood up, walked toward it, and without drawing his Zanpakutō, grabbed a simple wooden knife.

*Shh-ssshhh—*

The sound of air being split was sharp and sudden, slicing through the silence. Aizen's strike was precise, a brilliant flash of blue light as the wooden knife sliced the stake cleanly in two.

A voice echoed in his mind:

[Congratulations to Host for advancing to the realm of Great Swordsman! Reward: Template unlocked to 10%]

Aizen stood still, processing what had just happened. The Great Swordsman realm—he had stepped into it.

However, what truly intrigued him was the unlocking of the template system. This was a development that he had not expected.

"10% combat power, huh?" he muttered, considering the implications. His current strength felt significantly more potent. He was already capable of protecting himself in this world. But the fact that this was only 10% of Aizen's full power was staggering.

Despite the immense power, Aizen couldn't help but feel a nagging thought. "Though the Great Swordsman isn't at Admiral-level, it's certainly close. And this is only 10% of my full strength?"

As he pondered, the system suddenly chimed in to clarify:

[The unlocking to 100% of the template will not be achieved until the fusion with the Hōgyoku. However, the strength of Aizen during the Millennium Blood War is reflected in the current 10%.]

Aizen's thoughts shifted as the system provided its answer. During his time imprisoned, even while sealed, Aizen's Reiatsu continued to grow. By the time of the Millennium Blood War, his strength had surpassed even the evolved form he had with the Hōgyoku. It seemed that even in confinement, his heart continued to push him toward greater power.

"Hmm, it's truly fitting. This is Aizen at his finest." Aizen smiled softly, feeling the power coursing through his veins. Even at only 10%, he could already wield all forms of Kidō—a skill far beyond the reach of most Shinigami.

With that in mind, he whispered, "Hadō no Ninety: Black Coffin."

The air around him seemed to warp as thick black lines spiraled from the ground, enveloping an iron pillar in front of him. Within moments, the Black Coffin had taken form, its massive, ominous shape casting a shadow over the training grounds.

The Marines nearby stopped what they were doing, staring in wide-eyed confusion as the towering coffin appeared before them. Panic spread as they wondered what was happening.

Seconds later, an eerie sound came from within the Black Coffin—a relentless, spine-chilling hiss as if countless blades were whirring inside, scraping and cutting at the air.

"Has the kid thought about developing some strange new abilities?" Garp muttered, sensing the Reiatsu emanating from the coffin. He could immediately tell it was Aizen's doing.

The massive coffin trembled and then shattered into fragments, vanishing into the air. The iron pillar had completely disappeared, leaving no trace behind.

Garp raised an eyebrow. "That's some serious power." He had long known Aizen's potential, but seeing it in action was a different experience entirely.