Ailin Enters Hueco Mundo  

"If either Byakuya or Rukia disagrees with the marriage, we can always adopt Rukia as our daughter later," said Ailin.

"Rukia will bear the Kuchiki name for the rest of her life, one way or another. How about that?" Ailin was serious.

Would Rukia still be Rukia Kuchiki without the Kuchiki name?

The only difference was whether it would be Byakuya Kuchiki's "Kuchiki" or Haruko Kuchiki's "Kuchiki."

"Sigh..." Haruko sighed, conflicted.

Arranging Byakuya's future marriage while Hisana was still alive felt inappropriate. However, considering Byakuya's personality, if she adopted Rukia, then Rukia would become Byakuya's younger sister.

That would likely lead to the outcomes Ailin had mentioned.

Either Byakuya would remain alone for the rest of his life, forever mourning Hisana and bearing the guilt of ending the Kuchiki bloodline, unable to face his ancestors.

Or, he would compromise for the sake of the family, betraying his love for Hisana and marrying a woman he didn't love just to continue the Kuchiki lineage.

But would that Byakuya still be the Byakuya they knew?

"Don't worry, Haruko," Ailin reassured her.

"We cannot predict the future. But I will do my best to clear the path for Byakuya, ensuring his future isn't filled with darkness and despair."

"Yes, I know," Haruko leaned against Ailin's chest, her gaze distant. "Ailin-kun, meeting you was the greatest blessing of my life."

"As it was for me."

...

Hisana Kuchiki didn't survive the night.

However, she passed away peacefully in Byakuya's arms and with a smile on her face.

Upon her death, Hisana's body dissolved into reishi, leaving behind only her white clothing.

Byakuya carefully folded the clothes and placed them in a small box, storing it within the Kuchiki family's ancestral grounds.

Hisana's early life had been filled with hardship.

She had taken her dying sister away from their home but was forced to abandon her due to her own weakness.

However, her later years were filled with happiness. She had found a man who truly loved her, and she loved him in return. And in her final moments, she was reunited with her sister, Rukia.

Rukia's hardened features suggested that she had endured many hardships over the years. But with Uncle Ailin's care, Hisana no longer needed to worry about her sister's future.

She had even entrusted Rukia with the task of caring for Byakuya in her place, not as a replacement but as someone who could share Hisana's love for him.

Unlike Hisana, Rukia possessed reiatsu. Perhaps she could accompany Byakuya for the rest of his life.

The passing of the Kuchiki clan's mistress was a significant event within the Seireitei. However, according to Hisana's wishes, the Kuchiki family held a small and private funeral.

Hisana had considered her sister's feelings. In her eyes, Rukia, who could potentially stay by Byakuya's side for a long time, was the ideal candidate for the position of Kuchiki clan mistress.

After Hisana's death, Byakuya fell into a period of deep mourning.

During this time, Ailin refrained from arranging a meeting between Rukia and Byakuya, instead focusing on teaching Rukia the ways of Kidō.

Rukia's talent for Kidō was truly remarkable.

Although her reiatsu limited her ability to cast high-level Kidō spells, after a period of training, she could even perform Hadō #31: Shakkahō without incantations.

Of course, to avoid disrupting the future storyline, Ailin, like Byakuya, focused solely on Rukia's Kidō training, neglecting combat practice.

...

One day, Ailin encountered Byakuya. It was evident that he had become the stoic and expressionless "Byakuya" from her memories.

"By the way, Byakuya, do you have any free time lately?" Ailin asked.

"The nobles of the Seireitei have been relatively peaceful. There haven't been any matters requiring my attention," Byakuya replied.

In other words, he had time.

"Oh? That's convenient," Ailin said, patting Byakuya's shoulder. "Your uncle recently took on a new disciple. She has been studying Kidō with me for some time now. However, her Kidō skills have reached a bottleneck, and I want her to practice swordsmanship. But..." Ailin swayed his body slightly, drawing Byakuya's attention to his empty sleeve.

"As you can see, Uncle is currently not in a suitable condition to teach swordsmanship. Would you be willing to train her in my stead for a while?"

Byakuya looked at Ailin as if he had lost his mind.

Just a missing arm, and he claimed to be unfit to teach swordsmanship?

Did he have some misunderstanding about his own "swordsmanship"?

However, Byakuya was well aware of his uncles tendency to shirk responsibilities.

So, despite the flimsy excuse, he agreed.

"Alright, as long as it doesn't interfere with my duties as captain."

"Excellent! As expected of my nephew. I have high hopes for you, Byakuya," Ailin said, patting his shoulder again before turning to leave.

"I'll have her wait for you at the cherry blossom tree in the front courtyard every day at six in the evening. Just go there directly. Oh, and since I brought her directly from the Shin'ō Academy, she doesn't have a Zanpakutō yet. Remember to bring her an Asauchi..."

Byakuya watched Ailin depart, a frown creasing his forehead.

He couldn't shake the feeling that there was some mischievous intent behind his uncle's actions. It felt like he was setting him up for a joke.

Could it be that this new disciple possessed some unique qualities that would clash with his own?

That evening, as Byakuya returned from the Sixth Division and headed towards the cherry blossom tree in the front courtyard, his eyes widened in shock upon seeing a familiar face.

"Is that... Hisana?"

"Greetings, Captain Byakuya. I am Rukia, Teacher Ailin's new disciple," the young woman, who looked remarkably like Hisana, bowed respectfully. "I will be under your guidance for swordsmanship training."

A gentle breeze rustled the leaves of the cherry blossom tree, sending a shower of pink petals cascading down.

For a moment, Byakuya could have sworn he saw his wife waving at him.

...

"The Hōgyoku is truly a remarkable artifact..."

Within the Fifth Division barracks, Ailin retrieved the blue, glowing Hōgyoku from his pocket.

As a clone created from Ailin's severed arm, his reiatsu shouldn't have been able to increase.

However, under Ailin's strong desire, this half-formed Hōgyoku had absorbed his wish and manifested it, allowing him to break through the limitations of being a clone.

Now, Ailin's clone's reiatsu had surpassed the level of a hundred-year captain and was steadily approaching the limit of a Shinigami.

This effectively gave Ailin two bodies for cultivation. Once the clone returned to the main body, the immense reiatsu would further enhance Ailin's own power.

"Everything in Soul Society is proceeding according to plan. But it's been a while since I visited Hueco Mundo. This is the perfect opportunity. The Zanpakutō of the Espada will significantly increase my main body's reiatsu."

With that thought, Ailin tucked the Hōgyoku back into her pocket, opened a Garganta with a casual swipe of her hand, and stepped into Hueco Mundo.

"Lord Aizen."

As Ailin's figure materialized within Las Noches, a young man with black hair, green eyes, tear-like marks below his eyes, a half-mask covering the left side of his face, and a white hakama over a black kosode bowed respectfully before him.

This was Ulquiorra Cifer, the 4th Espada.

Unlike the other Espada who had their own palaces within Las Noches, Ulquiorra remained stationed at the main palace, serving as Aizen's personal attendant and messenger.

Among all the Hollows, only Ulquiorra was truly loyal to Aizen and had earned his complete trust.

The other Hollows had joined Aizen's ranks partly due to his overwhelming strength and partly because he could make them stronger.

Furthermore, Aizen had promised to lead them in a war against the Seireitei, ascend to the Soul King Palace, become the new god of the world, and create a new world ruled by Hollows.

This was a far more appealing prospect than their current awkward position within the three realms.

Hueco Mundo served as a buffer zone between the Human World, Soul Society, and Hell.

Souls who committed grave sins in life would descend into Hell upon death.

And as Hell absorbed more of these sinful souls, it would gradually expand, eventually engulfing the entire world and transforming it into a desolate wasteland inhabited only by the dead, with no future.

The Soul King created Hueco Mundo to prevent the souls of evil humans from immediately falling into Hell. Instead, they would enter Hueco Mundo and transform into Hollows.

When these Hollows were slain and purified by Shinigami, their souls would be reincarnated into the world.

However, if these Hollows were severely injured before being purified, their leaking reiatsu would attract the gates of Hell, dragging their souls into its depths before they could be reincarnated.

No one wanted to die.

And they certainly didn't want to end up in Hell.

But after regaining their intelligence as Gillian-class Menos Grande, these Hollows couldn't be sure if they had devoured any sinful souls during their mindless rampage.

The more they learned about the truth of the world, the greater their reverence for the being who had created the three realms.

If Lord Aizen could truly lead Hueco Mundo to victory over the Seireitei, ascend to the Soul King Palace, and become the new "god," they were willing to sacrifice everything for that cause.