No one except Aizen possessed the spiritual fortitude necessary to withstand the overwhelming pressure of facing Uehara Shiroha in single combat. This challenge extended far beyond what a being of Harribel's caliber—formidable as she was—could reasonably handle, regardless of her determination or tactical acumen.

The assembled Shinigami watched with growing apprehension as the ominous black void expanded, revealing a diminutive, vacant-eyed Arrancar standing within its shadowy depths.

This peculiar Arrancar possessed curly golden hair framing a childlike face, unusual purple pupils that seemed unfocused, scattered freckles across pale cheeks, and two prominently protruding upper front teeth that gave him a distinctly rodent-like appearance. His expression and gaze projected an unsettling emptiness—devoid of comprehension or emotion—yet paradoxically, he appeared harmless and inconsequential. At the center of his pristine white uniform was an oval opening that revealed a perfectly circular Hollow hole beneath.

The newcomer was immediately recognizable to some as "Wonderweiss Margela"—also known as the "Prince of Fire Extinguishing" or more ominously, the "Convection Blade Jakka Neutralizer."

This unique creation represented the only Arrancar that Aizen had personally transformed using the Hōgyoku's reality-altering power, a formidable Hollow entity that had undergone two separate enhancement procedures, each amplifying his specialized capabilities.

Looming behind Wonderweiss stood an immense Arrancar with an extraordinarily bulky frame, towering approximately eight feet tall with proportions that defied conventional anatomy.

This rotund Arrancar, shaped remarkably like a massive barrel with limbs, possessed a single, slender eye that emanated an eerie golden light resembling a crescent moon against the darkness. This behemoth was Fura, Wonderweiss's inseparable companion and guardian.

Prior to this moment, it had been Fura who had commanded the Menos Grande during the operation that facilitated Aizen and his conspirators' escape from Soul Society to Hueco Mundo, coordinating their movements with surprising precision.

Upon observing Fura's distinctive crescent-shaped eye, Ukitake Jūshirō experienced a moment of profound realization, his thoughts racing: "When Aizen executed his betrayal, a Hollow tore open the fabric between worlds, creating a Garganta and employing Negación to provide extraction support. During that critical moment, I glimpsed a peculiar elongated golden light manifesting behind Aizen's position. This must be the very same anomalous illumination! It was actually the ocular structure of this extraordinary Hollow."

Stark shifted his attention toward Wonderweiss, his analytical mind immediately assessing the strategic implications: "Wonderweiss's emergence indicates that Lord Aizen has exhausted his patience reserves. Has this moment arrived so prematurely? Is Uehara Shiroha truly exerting such insurmountable pressure?"

According to their meticulously constructed strategic framework, Wonderweiss represented a crucial tactical element specifically engineered to neutralize the most formidable Shinigami in existence—Yamamoto Genryūsai Shigekuni. This concealed asset was intended for deployment exclusively under conditions of absolute necessity.

Wonderweiss's mere presence signaled the commencement of the decisive confrontation phase and the sacrifice of their primary opposition. This critical juncture had materialized substantially earlier than anticipated in their timeline, suggesting that circumstances were rapidly escaping Aizen's control, compelling him to prematurely reveal the Wonderweiss countermeasure.

This realization caused Stark's assessment of Uehara Shiroha to grow increasingly respectful yet wary. Reestablishing situational control demanded an immediate reversal of momentum. They needed to overcome this particular obstacle with absolute priority! The inevitability of direct confrontation crystallized in his mind.

The other Arrancar forces similarly registered Wonderweiss's unexpected appearance and recognized the implicit command to abandon restraint and engage with maximum lethality.

The Shinigami's collective attention fixated primarily on the gigantic Arrancar Fura, largely disregarding Wonderweiss, whose diminutive stature resembled that of a young child. Compared to Fura's imposing physical presence, Wonderweiss appeared categorically non-threatening—a dangerous misconception.

Uehara Shiroha recognized that Wonderweiss was substantially more dangerous than his outward appearance suggested—potentially one of the most lethal entities on the battlefield. This Arrancar possessed a cunning intelligence disguised beneath his seemingly simple demeanor, and his childlike proportions and features effectively disarmed opponents' natural defensive instincts.

In practical combat scenarios, Wonderweiss demonstrated exceptional proficiency in ambush tactics, with strikes characterized by ruthless precision targeting exclusively vital anatomical regions. His ability to suppress his spiritual pressure signature approached mastery level, granting his surprise attacks an unusually high probability of success against even experienced combatants.

Previously, this deceptively innocent-looking Arrancar had successfully infiltrated the perimeter defenses established by Urahara Kisuke and very nearly executed a lethal surprise attack. If an individual with Urahara's legendary situational awareness could be momentarily vulnerable to such tactics, what defensive chance remained for someone with Ukitake Jūshirō's inherently compassionate nature?

Indeed, upon registering that the opponent possessed physical characteristics reminiscent of a child, Ukitake Jūshirō had already unconsciously lowered his defensive posture. He failed to perceive Wonderweiss as representing any significant threat—a fundamental battlefield error with potentially catastrophic consequences.

Thus, during the precise moment when Ukitake Jūshirō's attention diverted slightly, Wonderweiss silently maneuvered into optimal striking position, materialized behind his unsuspecting target, and unleashed a devastatingly powerful attack accompanied by a haunting, otherworldly vocalization.

With an agonized scream that echoed across the battlefield, Ukitake Jūshirō, caught entirely unprepared for the assault, suffered a grievous wound to his lower abdominal region, crimson blood flowing freely as he collapsed heavily onto the ground. His combat awareness had indeed proven substantially inferior to Kyōraku Shunsui's finely honed battle instincts. Attacked without forewarning, he had no opportunity to evade the strike, much less establish an effective defensive barrier using his considerable spiritual pressure.

Within the Bleach universe's combat paradigm, being caught unprepared typically created an almost insurmountable disadvantage—the tactical advantage of initiative proved decisive, similar to ancient dueling traditions.

Consequently, despite his status as a Thousand Year Captain with corresponding spiritual power, Ukitake Jūshirō sustained grievous injuries that temporarily neutralized his combat effectiveness. His momentary compassion-driven carelessness extracted a severe toll.

Before the assembled combatants could fully process the implications of Captain Ukitake's sudden incapacitation, Captain Kyōraku Shunsui of the 8th Division launched himself into immediate action.

"Ukitake!" Following a primal roar filled with anguish, Kyōraku Shunsui materialized directly behind Wonderweiss in a masterful display of Shunpo, his dual blades poised to deliver retribution. However, at the precise moment he began his downward strike, Stark executed a perfectly timed countermeasure, discharging a concentrated spiritual projectile with unerring accuracy.

A warrior of Stark's caliber could never overlook such a tactical opening. This unexpected intervention similarly caught Kyōraku Shunsui at a moment of vulnerability.

Kyōraku Shunsui, attacking with uncharacteristic emotional abandon, found himself without sufficient time to implement evasive maneuvers—mirroring Ukitake Jūshirō's previous predicament—and received the full impact of Stark's attack, the force propelling him violently toward the ground below.

Witnessing this rapid succession of devastating events, all Shinigami present experienced a collective moment of dread, their spiritual pressure fluctuating with uncertainty.