BOOM!
A mushroom cloud, hundreds of meters high, erupted from Las Noches, the force of the blast leveled the fortress. The cracks in the artificial sky above shattered, raining sand and debris, revealing the true sky of Hueco Mundo: a grey expanse under a pale crescent moon.
Ulquiorra Cifer, caught in the downpour, plummeted from the shattered canopy, buried under the sand.
Grimmjow Jaegerjaquez, already injured from Ichigo's earlier attack, was similarly overwhelmed, his weakened body was unable to resist the onslaught of falling debris.
As the dust settled, Aizen's eyes widened. A massive crater, a hundred meters deep, marked the spot where Ichigo had stood. The crater, however, stopped abruptly before reaching Ichigo himself, its path diverted, forming a V-shape in the ground. And at the point of the V… stood Ailin.
Ailin had intercepted Aizen's attack.
"When…? I didn't even see him move." Aizen, in his evolved state, possessed near light-speed movement. Yet, he hadn't perceived Ailin's actions. Could it be… even now, he wasn't Ailin's equal?
"Impossible! This can't be happening! I am the strongest! The Hōgyoku chose me!"
"Die!"
Enraged, the six growths on his wings unleashed a barrage of purple Ceros at Ailin.
Golden ripples shimmered behind Ailin. Zanpakutō emitting powerful auras emerged.
Golden lightning flashed, intercepting the Ceros mid-flight and detonating them in the air.
The resulting explosions shook Hueco Mundo.
…
A black fissure opened, and Byakuya Kuchiki stepped into Hueco Mundo. He glanced around while expanding spiritual sense.
Mayuri Kurotsuchi hadn't provided him with a method to open a Garganta from Hueco Mundo to the World of the Living. But that didn't concern him. He simply needed to find an Arrancar with enough sentience to understand his demands.
To his surprise, however, his spiritual sense detected no Hollows nearby. This wasn't entirely unexpected. Even Hollows possessed a basic survival instinct. The repeated battles within Las Noches had driven them away, seeking safety in the vast emptiness of Hueco Mundo.
As Byakuya considered his options, a series of explosions echoed from the distance, accompanied by two immense spiritual pressures.
"Those spiritual pressures… One is Uncle Ailin's… The other… resembles Aizen's… Does that mean the battle isn't over? Is Uncle Ailin fighting Aizen?"
He leaped into the air, heading towards the source of the disturbance. "But… shouldn't the battle be taking place in the replica Karakura Town? Why are they in Hueco Mundo? And where are the other captains? I only sense Ailin and Aizen."
He couldn't shake the unsettling thought that the other captains, including Yamamoto, might be dead. The sheer power radiating from the distant battle was overwhelming. Even he, caught in the crossfire, would likely be killed.
"Wait… another faint spiritual pressure… Is that the Substitute Shinigami?" Sensing a familiar presence further away, he changed course, abandoning the distant battle for now.
"Ichigo Kurosaki?" He arrived beside Ichigo, frowning at his weakened state. He remembered Ichigo, during his intrusion into Soul Society, having already achieved Bankai. Now, however, his spiritual pressure was barely captain-level.
"Captain Kuchiki of the Sixth Division?" Ichigo looked up, surprised. "Substitute Shinigami, what happened here? Shouldn't the battle be taking place in the World of the Living? Where are the other captains? Did Aizen kill them?"
Ichigo blinked, then answered. "No. The other Shinigami were defeated, but Captain Unohana healed them. There were no casualties. They're still in the World of the Living."
"Is that so? That's good." Byakuya was relieved. If all the captains sent to fight Aizen had been killed, the Soul Society would be in crisis. While his uncle was powerful, strength alone wasn't enough to lead. Knowing Ailin's personality, even if he were placed in a position of authority, he wouldn't care about the consequences.
…
BOOM! BOOM! BOOM!
Ailin stood in midair, watching as dozens of Zanpakutō, each radiating captain-level spiritual pressure, emerged from the golden ripples behind him. They were unleashed upon Aizen.
After each attack, the blades dissolved back into Unlimited Blade Works, where their energies replenished, ready to emerge again.
Aizen, having undergone five evolutions, his fusion with the Hōgyoku complete, was a formidable opponent. Even against the combined assault of hundreds of captain-level Zanpakutō, some wielding the power of century-old captains, he held his own. However, he couldn't reach Ailin.
The sky above Hueco Mundo crackled with energy, the constant bombardment of Aizen's attacks against Ailin's Zanpakutō resounded through the desolate landscape.
"Very well. Since you're so persistent… I'll get serious."
A golden ripple appeared beside Ailin, and the hilt of a Zanpakutō materialized. He drew the blade, raising it above his head.
"Bankai – Excalibur Galatine: Sword of Revolving Victory!"
BOOM!
A torrent of flames erupted skyward as Ailin swung his blade, a golden arc of energy shot towards Aizen.
Aizen's eyes narrowed. The flames reminded him of Yamamoto's Ryūjin Jakka.
Excalibur Galatine like Ryūjin Jakka, was an incredibly powerful fire-type Zanpakutō. While Ryūjin Jakka converted its wielder's spiritual pressure into heat comparable to the sun's core, Excalibur Galatine was said to contain the sun itself. Upon release, it unleashed solar flames, incinerating everything in its path.
However, unlike Ryūjin Jakka, which focused its power on its blade, Excalibur Galatine's power was dispersed, its attacks wide-ranging.
"Ryūjin Jakka? No… Ryūjin Jakka converts spiritual pressure into heat. This blade… unleashes the sun's flames directly." Aizen quickly recognized the difference. "I'm not afraid of Ryūjin Jakka. Why would I fear this?"
"If this is your strongest Zanpakutō, Captain Ailin, then I win!"
BOOM!
He unleashed a torrent of purple spiritual pressure, forming a solid barrier to defend against the incoming flames. Aizen's near-limitless spiritual pressure, amplified by the Hōgyoku, held firm against the solar flames of Excalibur Galatine. Even Yamamoto, at his peak, might not be able to overcome such a defense. To harm Aizen now required even greater spiritual pressure.
Having extinguished the flames, Aizen vanished and reappeared before Ailin. The six growths on his wings glowed purple, six Ceros converged into a ring of energy that trapped Ailin.
"Captain Ailin, I win!"
BOOM!
The explosion rivaled a nuclear blast, a mushroom cloud rose hundreds of meters into the air, shockwaves rippled outwards, creating kilometer-wide sonic booms. The delayed roar of the blast echoed through Hueco Mundo, the force of the explosion devastated everything within a radius of tens of kilometers.
As the dust settled, however, Aizen stared in disbelief at the unharmed Ailin.
"Impossible! I hit you!"
"You almost hit me. But why would you assume an attack that couldn't harm Ichigo Kurosaki would be effective against me?"
Aizen then noticed Ailin's Zanpakutō. It was no longer the massive, two-handed blade that had unleashed the solar flames. It was now a slender, elegant sword.
Ailin swung the blade.
Aizen gasped as he was bisected from shoulder to hip.
"You're lucky, Aizen. This blade… is among my strongest. Its name… is the Black Lily Blade." Its sole ability, for now, was to condense Ailin's spiritual pressure into the sharpest edge imaginable, capable of cutting through anything.
The Black Lily Blade originated from the Integrity Knight, Scheta Synthesis Twelve, from the world of Sword Art Online Alicization. It was forged by Administrator from a million-year-old black lily flower, infused with Scheta's latent bloodlust. Its defining characteristic was its ability to cut through anything. Scheta herself had stated her purpose was to find something she couldn't cut. Thus, the blade possessed a unique property: it wouldn't harm those she didn't wish to harm.
In Ailin's hands, it was still incomplete. For now, it simply condensed his immense spiritual pressure into an incredibly sharp edge. To complete it, he needed to either draw the Soul Society's sharpest Zanpakutō, Sayafushi, within Unlimited Blade Works, or witness Sayafushi in person within the Soul King Palace. Alternatively, he could encounter Lille Barro, the leader of Yhwach's Schutzstaffel, and replicate his "X-Axis," the concept of piercing anything. By imbuing the Black Lily Blade with Sayafushi's concept of sharpness, or Lille's X-Axis, he could achieve its true potential, its ability to cut through anything.
Even incomplete, however, the blade, fueled by Ailin's immense spiritual pressure, was incredibly sharp, its edge rivaled even Sayafushi or Lille Barro's X-Axis.
"Your attack… I cut it before it reached me."
Indeed, Ailin had only held the Black Lily Blade upright in front of himself, and the power of Aizen's attack was all split apart.
"Damn you! Die."
Aizen shouted loudly and spiritual pressure surged from his bisected body as he attempted to regenerate.
"It's useless."
Just when Aizen had recovered, Ailin slashed down again with the Black Lily Blade.