Fate in Bleach: Unlimited Blade Works!

"Lady Haruko Kuchiki is your leash," Yoruichi continued. "As long as she's there, you won't lose yourself. But if something were to happen to her, you would become the Seireitei's greatest threat."

Ailin smiled and did not refute. While Urahara's assessment wasn't entirely inaccurate, he had underestimated Ailin's ambition.

Aizen and Yhwach both aspired to become the Soul King.

But Ailin's ambition was to surpass the Soul King.

Only by surpassing the Soul King could he reach the level of the being who had created the Soul Society. He yearned to see what lay beyond their world.

Ailin had never forgotten that the Soul Society's current state was primarily due to its creator's abandonment.

Amidst primordial chaos, the world's nascent consciousness had awakened, giving birth to the "Soul King," a "god" wielding the power of the "Almighty."

If the creator hadn't abandoned his creation, if he had continued to nurture it, what would the Soul Society have become?

As Ailin's power grew, coupled with the memories of his previous life, his understanding of the Soul Society deepened. He realized that their world was incomplete, a mere fragment of what it could have been.

A complete world would possess the ability to transform the chaotic energy from beyond its boundaries into its own energy. This would grant it the potential for growth.

Otherwise, once the creator's power waned, the world would stagnate, then eventually be destroyed.

A world needed inhabitants. While the creator had departed, his creation had begun to evolve, slowly taking shape.

The world's energy transformed into souls. This was the source of power within the Soul Society.

Whether it was Hollows, Quincy, Bounts, Shinigami, or Fullbringers, all their extraordinary abilities originated from "souls."

The more one understood the essence of souls, the greater their power. However, because the Soul Society was incomplete, the number of souls, born from the world's source energy, was finite.

Moreover, the world's operation constantly consumed souls.

From the ancient Hollow devouring countless souls, only to be vanquished by the Soul King, to Yhwach, responding to humanity's desires, sharing his power and creating the Quincy, and the countless wicked souls, upon death, being captured by Hell, bypassing the Soul Society's reincarnation cycle, the Soul Society's source energy had been steadily dwindling.

Those within the Soul Society who possessed a certain level of power, or who had a deep understanding of souls, knew this truth.

Therefore, even before Genryūsai Shigekuni Yamamoto established the Gotei 13, the Soul Society had a research institute dedicated to studying souls.

Countless researchers, driven by a desire to create a new source of souls, sought to save their world.

Whether it was Ōetsu Nimaiya's creation of Zanpakutō, Senjumaru Shutara's creation of the shihakushō, or Kirio Hikifune's creation of artificial souls, these were merely byproducts of that research.

Perhaps only Ōko Yushima, building upon Hikifune's "Temporary Souls," had made significant progress with his "Mod Souls."

Sadly, "Mod Souls," being artificial, couldn't join the Soul Society's reincarnation cycle. Therefore, they couldn't replenish the world's source energy.

While the Quincy had been almost completely eradicated, wicked individuals, upon death, their souls tainted by their actions, were still being captured by Hell, becoming its fuel.

Ailin suspected that the creator, when forging their world, had intended to create a "Heaven," an "Earth," and a "Hell," but for unknown reasons, he had only created a rudimentary "Hell" before abandoning his creation.

Based on a typical world's structure, souls should reincarnate within the three realms.

The "Soul King," born from the incomplete world's consciousness, had created the current "three worlds" based on this template.

The Soul Society, representing "Heaven," was tasked with maintaining balance between the three worlds.

Hueco Mundo, representing "Hell," housed the fallen, wicked Hollows.

The World of the Living, representing "Earth," was where humans lived and procreated, also serving as the primary location for soul reincarnation.

However, because the Soul King's power was limited, his creation was on an entirely different level compared to the creator's original "three worlds."

Even in its rudimentary form, "Hell" was far more powerful than Hueco Mundo. When wicked souls died, Hueco Mundo couldn't compete with Hell's grasp.

Moreover, the Soul Society was incapable of facilitating reincarnation for the sinners within Hell.

They could only watch as Hell expanded, destined to consume their world and become the only remaining realm.

But because all souls would be trapped within Hell, unable to reincarnate, it would eventually resemble the primordial chaos, eternally unchanging, waiting for the day when a "god" would emerge, capable of devouring all souls and becoming the only being within Hell, then shattering it and creating a new world.

Of course, whether that "god" could actually shatter Hell was uncertain. After all, even the Soul King, at the peak of the world's source energy, lacked the power to destroy Hell. Could a "god" born from a world whose source energy had been significantly depleted surpass the Soul King?

These thoughts swirled within Ailin's mind, but his expression remained calm. While Urahara and Aizen might be the most intelligent individuals in the Soul Society, their limited experience had confined their thinking.

Their focus never strayed beyond the Soul Society.

Ailin was different. While he might not be as intelligent as Urahara or Aizen, often, what limited a person's perspective wasn't intelligence, but experience.

In his youth, the memories of his previous life hadn't provided much benefit. Back then, Ailin's goal had simply been to survive until the story's conclusion. But with his Zanpakutō's awakening, those memories had transformed into a wellspring of knowledge, propelling his growth to unimaginable heights.

The reason he used the word "unimaginable" was because Ichigo Kurosaki, the protagonist of the Bleach world, had progressed even faster. It had taken Ailin over two hundred years to reach his current level.

Ichigo had done so in two years.

A hundredfold difference.

However, Ichigo's potential was limited. Unless Urahara created another complete Hōgyoku for him to fuse with, Ichigo would never reach the Soul King's level.

Therefore, Ailin simply chuckled at Yoruichi's revelation of Urahara's assessment.

In a sense, Urahara was right. Ailin's current inaction, his decision to simply wait for Aizen and Ichigo to mature, was largely due to Haruko Kuchiki's presence.

After over two hundred years together, Haruko had become an indispensable part of Ailin's life. He shared almost all his secrets with her, except for the fact that he was a transmigrator.

He had even told her about his strength. He didn't want her to feel insecure, believing he was weaker than others, then being forced to make irrational decisions under duress.

To further solidify her trust, he had brought her into Unlimited Blade Works, allowing her to witness his vast army of Zanpakutō.

If Ailin were to claim he could create a new world, Haruko would believe him without question.

Before Yoruichi departed, Ailin offered her two promises.

"Lady Yoruichi, rest assured. As long as Shino Madarame's life isn't in danger, I won't interfere with your and Aizen's little game.

Furthermore, if this Ōko Yushima fellow attacks the Seireitei, I can't speak for the others, but I will personally eliminate my Mod Soul. I won't allow him to harm the Shinigami."

Ailin's clone within Unlimited Blade Works shared his thoughts and intentions. He naturally knew about his Mod Soul. What he didn't know was that the Mod Soul of Aizen, slain by his clone in the World of the Living, had also been infused with his memories.

Yoruichi, having received Ailin's promises, was satisfied. As long as Ailin didn't interfere, she was confident that Urahara would emerge victorious in his battle against Aizen.

To defeat Aizen, Urahara had meticulously analyzed their situation, simulating countless scenarios. He had arrived at five potential outcomes. For each outcome, Urahara had devised a corresponding plan.

As Urahara's childhood friend and most trusted confidant, Yoruichi was privy to those plans.

Just as Ailin was with Haruko, Urahara didn't want Yoruichi to lose faith in him.

Hiyori Sarugaki's injury a century ago had been Urahara's last moment of weakness.

It was then that Yoruichi had reprimanded him, teaching him a valuable lesson: When entrusting a task to someone, one must have absolute faith in their abilities.

Even the slightest hesitation was an insult, not just to oneself, but also to the individual being entrusted.