Analysis and Creation  

"What is called Shunpo, refers to rapid footwork, as well as the method of attacking and evading. Since time is limited, what I'll teach you today is how to gain 'control' over Shunpo. How much spiritual power you use, and how far you can advance, you must commit to memory.

If you're twenty meters away from an enemy, you can use Shunpo to instantly charge in front of them to attack, or use the first Shunpo to bait out their opening, then precisely seize that opening with a second Shunpo for a decisive strike."

After explaining the main applications of Shunpo to Shūsuke Amagai, Ailin had him directly practice it, pointing out any shortcomings on the spot.

This guidance continued until nightfall.

"For this final night, I'll teach you hakuda. Nearly seventy percent of a Shinigami's strength lies in their Zanpakutō. But in certain special situations where you can't use your Zanpakutō or don't have it on hand, hakuda becomes the last guarantee of a Shinigami's life. So my teaching of hakuda to you will be through actual combat!"

***

Whoosh!

The sky of Hueco Mundo is always a deep black, with only a crescent moon casting its light over the entire realm, bringing illumination.

Having spent an extra three days guiding Shūsuke Amagai, Ailin wasted some time in his search for the Forest of Menos.

However, knowing the location of the Expeditionary Force's base indirectly narrowed Ailin's search area somewhat. Skillfully drawing Kidō patterns in the desert sands, he began chanting the incantation:

"Bakudō #58: Kakushitsuijaku!"

A white light flared, and then Ailin's perception spread out with the expanding range of Kakushitsuijaku, detecting countless Hollow reiatsu signatures.

"Not here."

After scanning the area, Ailin shook his head, instantly vanishing, then reappearing far away before disappearing again into the moonlight.

Then, less than three minutes later, Ailin's reiatsu flared again in Hueco Mundo.

"Bakudō #58: Kakushitsuijaku!"

Suddenly, Ailin's eyes lit up.

"Found it."

This time, in addition to the Hollows on the surface, Ailin finally detected far more powerful reiatsu underground than the Hollows above. Moreover, the concentration was extremely dense.

In all of Hueco Mundo, only the Forest of Menos contained so many Gillian-class Menos Grande.

Drawing his Zanpakutō from his waist, Ailin leapt high into the air, then unleashed his sword strike down towards the desert floor.

Boom!

A strike spanning hundreds of meters descended from the sky, smashing into the desert and carving a massive chasm. Following right behind this strike, Ailin flew down into the breach in the sands.

Boom!

Soon, Ailin's strike over a hundred meters wide had already pierced through the surface, crashing into the very depths of the Forest of Menos below.

This commotion quickly attracted the surrounding Gillian to Ailin's location. But the moment these Gillian laid eyes on Ailin, their mouths gaped open, amassing a huge concentration of reiatsu that formed into red orbs.

This was the Menos' strongest technique – Cero!

However, they failed to successfully unleash these Ceros.

Because in that moment, Ailin suddenly held his Zanpakutō horizontally in front of his chest and uttered the release command:

"Shatter - Kyōka Suigetsu!"

In order to analyze Negación and create "Avalon" in advance, Ailin took out all the Zanpakutō he had obtained from the Soul Society for the first time.

If Yhwach, who possessed "all-knowing and all-powerful" abilities, had witnessed this scene, Ailin might have become a "special war potential" even in their thousand-year-long war.

Upon seeing Ailin release his Zanpakutō, the Ceros forming in the Gillians' mouths instantly dissipated.

Because in their eyes, the Shinigami who had seemed so delicious just moments ago had now become no different from themselves - Gillian Menos Grande.

Ailin then released Kyōka Suigetsu a few more times in the surrounding area, putting hundreds of Gillian under his hypnosis.

Ailin controlled these hundreds of Gillian, keeping their gazes fixed on himself.

Then, one of the Gillian opened a Garganta to the Living World. After passing through this Garganta, it remained open, allowing the Gillian to still see Ailin.

Suddenly, in the Gillians' view, the Gillian that Ailin had transformed into was ambushed by dozens of Shinigami, in grave peril.

Under these circumstances, a few Gillian Menos suddenly extended their massive masks through the Garganta, and the spatial forces within the Garganta manifested as a yellow barrier enveloping Ailin.

"Here it comes, this is it!"

Seeing the yellow barrier around him, Ailin extended his hand and pressed it against the barrier, his palm emanating a blue light.

"Decipher material composition!"

The blue light from Ailin's hand transformed into strands of blue patterns spreading outward from his palm as the center across the transparent barrier.

"Decipher fundamental particles!"

Not just within the barrier around Ailin, but even the outer surface of the barrier began being covered by the patterns from his hand.

"Decipher spatial structure!"

Through the repeated castings of "Negación" by the Gillian, Ailin gradually unraveled and fully analyzed the secrets behind this technique.

***

In the underground base of Kisuke Urahara in the Soul Society, the interdimensional gate suddenly lit up with a blue glow. The next instant, Ailin's figure emerged from the swirling blue spatial vortex.

"Huh? Urahara isn't here?"

After fully analyzing Negación, Ailin killed all the Gillian he had completely hypnotized before returning to the Soul Society from the interdimensional gate in the underground base beneath his family home in Sakura Village.

"Since Urahara isn't here, I might as well create Avalon while I'm at it."

With that thought, Ailin set up a high-level defensive barrier - Kyōmon - around himself, then sat cross-legged on the ground, entering his inner world.

Standing atop the highest Sword Hill, Ailin closed his eyes and extended his right hand towards the empty space before him.

"Identify creative concept..."

Avalon, also known as the 'The Everdistant Utopia', is the fairy kingdom of ideals existing independently from the world, only in imagination.

"Define basic framework..."

A golden main scabbard with blue cross-shaped stripes, giving Avalon an elegant and noble appearance.

"Replicate material composition, mimic manufacturing techniques..."

The ability to anchor the wielder's body, maintaining an ageless, undying state, and possessing tremendous regenerative power over the wielder's injuries. The ability to form a powerful barrier protecting the wielder in other worlds, absorbing enemy attacks and returning them with double the force.

"Imbue growth experience, recreate accumulated time..."

Avalon is the 'Sword of Promised Victory' scabbard wielded by King Arthur Altoria, accompanying her through many years of war. After becoming a Heroic Spirit, it aided Arthur in defeating the oldest king Gilgamesh in the Holy Grail War.

"Transcend, complete manifold processes..."

Within Ailin's innate barrier, a massive amount of "sword" elements converged in his palm, solidifying into a golden scabbard with blue cross-shaped patterns.

Buzz--

The instant Avalon manifested, the Zanpakutōs within Ailin's innate barrier trembled uncontrollably - a sign of reverence before a superior weapon.

Soon after creating Avalon, Ailin received the blessing of Unlimited Blade Works, his reiatsu skyrocketing.

As the light faded, Avalon reverted to the appearance of a normal Zanpakutō scabbard, gripped in Ailin's hand.

"Not bad, from now on, I, Ailin, can be considered 'invincible'!"

Since Ailin had never seen Tenjirō Kirinji's Zanpakutō Kinpika, he did not gain Tenjirō's ability to convert reiatsu into healing hot springs. Therefore, the "Avalon" Ailin created lacked the ability to rapidly heal injuries simply by wearing the scabbard.

However, Ailin already possessed a very powerful Zanpakutō for healing in his arsenal.

Void Bandages ability to restore anything to its original state perfectly complemented Avalon's power to "anchor the wielder's body state, preventing aging and death."

Thus, the moment Avalon was released, Ailin's body would revert to the physical state "anchored" by Avalon. As long as Ailin had even a shred of life remaining, he would instantly heal.

Dispelling the barrier around himself, Ailin left Urahara's underground base and headed towards the Shin'ō Academy.

***

"Hm?"

When Byakuya returned to the Kuchiki Manor, he suddenly heard his aunt Haruko humming a lively tune. This greatly surprised Byakuya.

"Auntie, did something happy happen?"

But then Byakuya realized the likely reason. The only one who could make his aunt so happy was probably that man.

"Oh, Byakuya, you're back." Haruko's eyes crinkled with a smile.

"Yes, it's been a while since I've seen Auntie so happy, so I was a bit curious."

Ever since his aunt and uncle returned to the Seireitei, Byakuya had clearly sensed his aunt's foul mood. She spent each day either training or training, as if only training could bring a semblance of peace to her heart.

As for the reason, Byakuya had some understanding. It was likely related to his Uncle Ailin.

After returning to the Seireitei, his Uncle Ailin and Aunt Haruko acted as if they didn't recognize each other, never appearing together.

The reason for this situation was that Ailin's reiatsu was simply too powerful, and Haruko's soul could not withstand exposure to it.

In the Soul Society, without the protection and gradual recovery of a physical body, prolonged contact with Ailin's reiatsu would cause Haruko's soul to weaken and eventually perish, just like over a decade ago.