"You like to make holes in my chest, so why are you running?"
Yekawa continuously tapped his toes against the void, maintaining Sonido to keep pace as he arrived directly in front of Ulquiorra.
He gripped his Zanpakuto with both hands and unleashed a relentless storm of slashes, forcing Ulquiorra to dodge without pause.
At this time, Ulquiorra had not yet become an Arrancar.
Although a Vasto Lorde was the highest-ranking Great Hollow and the closest existence to humanity, it was still, at its core, a savage monster.
Yekawa, however, was different.
Though he too was a Hollow, he had first obtained the Asauchi left behind by Ito Kai, then arranged for a clone to enter Soul Society and enroll in the Spiritual Arts Academy, systematically studying Zanjutsu, Hakuda, Kido, and Shunpo.
While techniques such as Kido and Shunpo were unusable for Yekawa in his Great Hollow form, Zanjutsu and Hakuda translated perfectly.
That was why, despite his Reiatsu being slightly inferior to Ulquiorra's, Yekawa showed no fear.
With tools in hand and the knowledge to wield them, there was no reason he could not overwhelm a native beast.
Under the pressure of Yekawa's relentless assault, Ulquiorra was forced to retreat again and again.
Suddenly, the enormous bat wings on Ulquiorra's back snapped fully open, their span exceeding two meters. Like steel blades, they swept forward at terrifying speed.
Yekawa failed to evade in time, and both arms were sliced open by the wings.
Ulquiorra seized the opening and delivered a brutal kick, sending Yekawa flying.
Bang!
Yekawa crashed into a massive tree trunk, collapsing dozens of trees in succession and kicking up a vast cloud of dust.
The assault did not end there.
Ulquiorra raised his right index finger, deep green Reiatsu condensing at the tip before firing forward as a Cero.
At the same moment, Yekawa burst from the dust cloud, Zanpakuto in his right hand. Black-red Reiatsu gathered at the blade's tip, releasing a Cero of his own to meet Ulquiorra's attack head-on.
Boom!
The two Cero collided, producing a catastrophic explosion that resembled the end of the world itself.
A towering mushroom cloud rose between them.
When the dust finally settled, Yekawa's figure emerged.
"Cough, cough. So my Reiatsu really is still slightly inferior to a true Vasto Lorde. No wonder. I'm still just a Gillian, after all."
The result of the Cero clash was clear. Yekawa had been pushed back and injured by Ulquiorra's attack.
From afar, Ulquiorra watched as the wounds on Yekawa's body writhed and regenerated completely within mere seconds.
"You… how is this possible…"
Seeing that this unfamiliar Great Hollow possessed Speed Regeneration no weaker than his own, Ulquiorra's eyes widened in disbelief.
"What's so surprising about that? Who doesn't have Speed Regeneration these days?"
The corner of Yekawa's mouth curled upward beneath his mask. He brushed off the dust, raised his Zanpakuto once more, and charged forward.
"You should have more than this. Let me see what you're truly capable of."
Yekawa let out a low, sinister laugh as threads of dark golden lightning wrapped tightly around his blade.
Ulquiorra responded in kind, grasping the air with both hands. A long spear formed instantly, constructed entirely of dense deep green Reiatsu.
Clang, clang, clang!
The lightning-wreathed Asauchi and the spiritual pressure spear clashed repeatedly, sparks scattering in all directions. With uncanny mutual understanding, both fighters disengaged at the same time.
"Gran Rey Cero!"
Once again, they chose to compete head-on, unleashing not ordinary Cero, but the strongest variant.
Yekawa held his Zanpakuto in both hands as a Cero intertwined with dark gold and black-red energy formed instantly.
Opposite him, Ulquiorra fired a Cero mixed with deep green and pitch-black Reiatsu.
Boom!
An explosion far surpassing the previous clash erupted across the Black Night Jungle, radiating pure destruction.
Most of the jungle was obliterated in an instant.
Outside the jungle, Yuan Puck and Jiwa Barnes trembled violently as shockwaves rolled outward.
"This is… a battle between Vasto Lorde…"
While Ulquiorra remained focused on the Cero struggle, Yekawa activated Flash Lightning, piercing the ground and slipping underground unnoticed.
The next instant, he burst forth from behind Ulquiorra and slashed downward with his Zanpakuto.
Pffft!
Lightning-infused steel tore open Ulquiorra's back, carving a deep wound down to the bone and nearly severing his left bat wing. The flesh immediately began to writhe, attempting to regenerate.
Yekawa did not allow it.
A massive lightning whip crashed down upon the wound.
"Ah!"
Ulquiorra cried out in pain, twisting around and thrusting his hand forward like a blade, aiming straight for Yekawa's heart.
"Damn it. Is he really this obsessed?"
Yekawa knew the original history well. Ulquiorra had always enjoyed tearing hearts from chests.
At this stage, Yekawa's Speed Regeneration could not restore internal organs. Losing his heart would be fatal.
Clang!
Just as Ulquiorra's pale hand was about to strike, the centipede-like armor on Yekawa's back surged outward, rapidly forming a layer of white bone that sealed tightly around his heart.
Ulquiorra's attack failed.
Yekawa seized his arm and delivered a horizontal slash, carving a massive wound from Ulquiorra's cheek all the way down to his waist.
Ulquiorra collapsed to the ground, exhausted and powerless.
Though his wounds continued to regenerate, a corner of his mask had been cleanly cut away, leaving a visible gap.
The moment the crack appeared, his aura did not weaken. Instead, it deepened, as though a qualitative transformation was imminent.
"Is this… Arrancarization?"
Yekawa picked up the broken fragment of Ulquiorra's mask and glanced at the fallen Vasto Lorde.
"Ulquiorra, you have lost."
"Feel the new power I have granted you. Power that transcends the limits of the Hollow world."
"From today onward, I am your King. Your only King."
"This Arrancar power is the gift of the King."
After declaring this, Yekawa turned and left without looking back.
Yes, he had to run.
If he lingered any longer, his secret would be exposed.
Though Ulquiorra was exhausted, Yekawa's own Reiatsu reserves were also nearly depleted.
His goal had been achieved. He had successfully fractured Ulquiorra's mask.
To fight a Vasto Lorde to this extent as a Gillian was already more than enough.
If he stayed, once Ulquiorra fully adapted to his incomplete Arrancar state, escape would be impossible.
Ulquiorra was a Vasto Lorde. Even with a shattered mask, he would not regress like an Adjuchas.
Instead, he would begin evolving into an Arrancar.
In the original timeline, Ulquiorra had first become an incomplete Arrancar on his own, before Aizen used the Hōgyoku to perfect the transformation, creating Espada Number Four.
Yekawa had never expected to become the catalyst for that evolution.
By a twist of fate, he had accelerated Ulquiorra's first Arrancarization.
At this moment, Ulquiorra squatted silently in the jungle, touching the pale skin exposed beneath the fractured mask.
His Reiatsu had already risen a full tier beyond what it had been before.
Outside the jungle, Yuan Puck and Jiwa Barnes looked at Yekawa with trepidation.
"How was the battle, my King?"
"Hmph. Less talking. Move faster."
The three Hollows immediately activated Sonido and vanished into the distance.
Not long after, Ulquiorra emerged from the Black Night Jungle, now largely adapted to his incomplete Arrancar form. He stared blankly in the direction Yekawa had gone.
"…King?"