Harribel's Transformation  

Booms echoed through the air as cliffs crumbled. The Hollows dwelling within scrambled to escape. The stronger ones managed to flee before the explosions, suffering only minor injuries from the shockwaves. Those who were too slow were either killed outright or buried beneath the rubble.

Two figures, one clad in blue, the other in white, clashed between the cliffs. Each impact unleashed a deafening roar, generating invisible shockwaves that pulverized the surrounding landscape.

Boom!

After another collision, Harribel's feet left white streaks in the air as she used reishi to halt her backward momentum. The friction against the air generated visible trails.

"He's strong!" Harribel frowned. "When did such a powerful being appear in Hueco Mundo? And his reiatsu… it's so strange..."

As a Vasto Lorde, one of the strongest Hollows in existence, the most powerful being Harribel had encountered was Baraggan Louisenbairn, the self-proclaimed King of Hueco Mundo.

While her strength was inferior to Baraggan's, both were Vasto Lordes, the apex of Hollow evolution. If she chose to flee, Baraggan, who wasn't particularly fast, would have a difficult time catching her.

But this peculiar Hollow before her… His reiatsu indicated he was merely an Adjuchas, but his appearance…

What made this Hollow so strange was that, in the hierarchy of Hollows, the higher their level, the more humanoid their form. As a Vasto Lorde, Harribel had only recently attained a near-human shape. Her body was still encased in a white exoskeleton, and her face was hidden behind a Hollow mask.

Yet, this Adjuchas possessed a fully humanoid form and had no mask. If not for his overwhelming reiatsu, Harribel would have mistaken him for a Shinigami.

Moreover, his power far exceeded what his Adjuchas classification suggested.

"Who are you? Why have you trespassed on my territory?" Harribel watched as the Hollow across from her regained his composure.

"Oh? Trespassed on your territory?" The Hollow scoffed. "Woman, are you mistaken about something? I'm here to either kill you or be killed by you!"

"Hahaha, hahahaha..."

With a burst of laughter, Nnoitra Gilga charged towards Harribel with his crescent moon staff held high.

Clang!

Clang! Clang! Clang! Clang!

Blue and white figures blurred as they clashed. Harribel, resembling a mermaid with fins for arms, parried each strike of Nnoitra's staff, sparks were flying with every impact.

Having become an Arrancar, Nnoitra's strength now rivaled that of a Vasto Lorde. However, he was still outmatched by Harribel, who stood at the pinnacle of Vasto Lorde evolution. If not for his incredibly tough Hierro, he would have already been defeated.

As their battle raged on, Harribel gradually gained the upper hand. Nnoitra's body was marred with wounds. Even his "strongest Hierro" was no match for a Vasto Lorde of Harribel's caliber.

"Surrender, intruder," Harribel declared, kicking Nnoitra through a cliff face. She stood above him, blue reiatsu swirling around her right fin. "I cannot guarantee your survival if you continue to resist."

"Hahaha, woman, you don't really think that was my true power, do you?" Nnoitra wiped a trickle of blood from his mouth and smiled cruelly. Then, to Harribel's astonishment, his body erupted with golden reiatsu.

"Pray - Santa Teresa!"

Boom!

Nnoitra's reiatsu increased tenfold in an instant. Not only that, but his form changed as well. Two devilish horns sprouted from his forehead, and his crescent moon staff transformed into a scythe-like blade.

But the most dramatic change was to his arms. He now had two extra limbs, each wielding a scythe.

This was Nnoitra's true form - Santa Teresa!

"What, what is this form?"

Before Harribel could recover from her shock, Nnoitra vanished, reappearing before her in a blur, his four scythes slashing down.

"Cero!" Harribel countered, her right fin glowing with blue reiatsu. The energy coalesced into a sphere, firing towards Nnoitra as a powerful beam of light.

Boom!

However, the attack that had once injured Nnoitra proved ineffective against his Resurrección. He shattered the Cero with a single swipe and closed the distance, then his four scythes descended upon Harribel.

Bang!

With a single blow, Nnoitra sent Harribel crashing through another cliff.

"He's so strong!" Harribel thought as she emerged from the rubble. Nnoitra's Resurrección had increased his power fivefold.

Boom!

Shhh, shhh, shhh...

Having released his Zanpakutō, Nnoitra now surpassed Harribel in strength. Crimson blood splattered across the battlefield as Harribel's exoskeleton cracked under his relentless assault.

Many of the Hollows who had pledged their allegiance to Harribel fled in terror, seeing her losing the battle. If this new adversary decided to go on a rampage…

However, amidst the fleeing Hollows, three remained loyal, charging towards Nnoitra.

"Apacci! Mila Rose! Sung-Sun! Run!" Harribel cried out, desperately urging her subordinates to escape.

But Apacci, Mila Rose, and Sung-Sun refused to abandon their leader. Before Harribel's horrified eyes, they were swiftly struck down by Nnoitra. He severed their left arms at the shoulder.

"Apacci! Mila Rose! Sung-Sun!"

Harribel struggled to rise at the sight of her injured followers.

Bang!

But her determination was no match for Nnoitra's superior power. He slammed her back to the ground, pressing his scythe against her throat.

"Well, well, well, is that all you've got? I haven't even warmed up yet!"

"Indeed, you haven't even warmed up yet. You've merely released your Zanpakutō."

That was when Ailin arrived.

Using Kyōka Suigetsu, he had concealed himself from Nnoitra's senses. He approached Harribel with a gentle smile.

"Tier Harribel, I've heard much about you."

"Who are you?" Harribel asked, gazing at the Shinigami before her.

"Hah? Who am I?" Nnoitra's grin widened even further. "Listen well, I am Nnoitra Gilga, the strongest Espada of Las Noches!"

He didn't notice that Harribel had merely glanced at him before turning her attention elsewhere.

This Hollow named Nnoitra couldn't see the Shinigami?

Was this a hallucination brought on by her impending death?

"My name is Aizen. I am the master of Las Noches," Ailin introduced himself. "Tier Harribel, you seem to be in need of assistance. Are you willing to accept my help and become my subordinate?"

"Las Noches?" Harribel questioned, confused.

Wasn't Las Noches the domain of Baraggan Louisenbairn, the King of Hueco Mundo? Since when had a Shinigami become its master? And that Hollow who had attacked her… he had claimed to be the strongest Espada?

"I don't know what's happened in Las Noches, but…" Harribel glanced at Apacci, Mila Rose, and Sung-Sun, lying wounded nearby. Then, she bowed her head before Ailin.

"I am willing to become your subordinate, Lord Aizen."

"Very good."

…

Boom!

"What, what is this?"

Immense reiatsu erupted from Harribel's body, tangible energy that forced even Nnoitra to stumble backward.

Nnoitra's expression shifted from smugness to horror. He recognized this phenomenon. He had experienced it himself.

The Hollowfication of a Shinigami—the process that created an Arrancar!

But how was this possible? How could this woman have become an Arrancar without Lord Aizen's aid?

Nnoitra's only hope was that Harribel's transformation would fail. Despite his boasts of being the strongest Espada, he knew that his title was only valid among the Adjuchas-class Espada.

The Arrancar born from Vasto Lordes were in a league of their own, far surpassing him in power.

Nelliel Tu Odelschwanck, the former 3rd Espada, had effortlessly defeated him in her base form.

Nnoitra had never fought Ulquiorra Cifer, the 4th Espada, but his instincts screamed that he would die if he ever faced him. However, due to Ulquiorra's stoic nature, Nnoitra didn't believe he would ever strive for the title of "strongest." Therefore, he had never considered seeking death at Ulquiorra's hands.

Harribel was a Vasto Lorde, standing at the pinnacle of Hollow evolution. If her transformation into an Arrancar succeeded, her power would undoubtedly surpass his.