The Vasto assumes that the Fullbringer lacks the strength to swipe him away. This is incorrect. Due to his Clad Armor, the second of his Dual-Fullbring, Watchman’s strength, indeed all of his physical attributes, are exponentially boosted. Shizuka had trained against the his former Captain in order to develop his strength, strength which is now boosted by the mask he dons. What if Justin had done the same? What if he had dedicated every moment of his existence towards developing his physical might? What if he had trained for every instance of his life and afterlife, to increase his Spiritual Power? Due to his fullbring, he would not have to. As his Clad Type bestows upon him the pinnacle of his achievement in every timeline, selecting for him the strength and power of his ultimate peak.
Additionally, the Vasto Lorde believes that due to his lightning-like speed, he is capable of moving faster than Watchman can comprehend, while he himself can comprehend the Hero's instantaneous movements. This too, is incorrect. Due to the instant transportation of his Armament Spear, the second of his Fullbring Abilities, Watchman is capable of slowing down his perception of time. This means that when he teleports, he observes the scene around him in nearly halted time. Though he cannot physically move at a speed that keeps up with this frozen time, he is able to perceive all that occurs upon his arrival. The vasto on the other hand, was not expecting the arrival of the hero, nor did he possess any knowledge of the hero's abilities. This means that the creature would not have time to both observe the arrival of his opponent and also react to grab his spear before the transportation. Instead, from the vasto’s perspective, he was moving to kick at a shinigami, and instead appeared in the skies. It is here that his reaction would allow him to try and wrap around the Hero. In turn, the Hero would watch in slow motion as the vasto curled his tail around the spear and arm of his armor, permitting the action to happen.
Having placed his vice grip around the Hero, the Vasto Lorde overestimates his own ability. He believes that the boost in power of his mask was superior to the Fullbring of the Hero, which he assumes is undeveloped and weak. It assumes that what he faces is a meager human, who cannot hope to match the spiritual power of this truly underdeveloped hollow. While Justin’s fullbring is indeed new, and not entirely under his control, it is by no means incomplete. That is the very nature of the armor which he dons. Shizuka trained to harness his spiritual power, but did he dedicate every moment of his life towards this pursuit? What if Justin had? What if he, as a soul, spent a hundred years doing nothing but training to increase his level of power? What if he did so for a thousand years? The hollowfied boost of Shizukas mask was indeed great, but what if Justin, in his death, would one day evolve to wield the same? What if he were to go beyond this fledgling Vasto form that Shizuka possesses, and actually obtain control of his power? That power, that boost, is what Watchman’s armor draws upon now. That is why, if Shizuka had not succumbed to the base instincts of his beastial form, and still maintained his sensory, he would see that the Reiatsu emitting from Justin is not that of a simple human.
Defender
Shizuka Hyouzoku, no matter how much power he had obtained due to his raw and underdeveloped hollowification. At the end of the day he was still just…. A Hollow. His level of power would never hope to reach something as dominant as the pinnacle form of the Hero. Who was in his own right, by every definition of the term, a complete body of work.
All happening in an instant, beyond the lightning reflexes of the beast, Justin Taimu watches from within the safety of his fullbring, as the Creature harmlessly claws and constricts against the unwavering ivory of his Clad Armor. Ignorant to the swift flow of reiryoku escaping the Vasto’s body, one of the flows releasing from near his mouth. A teal colored Cero would appear, its size in its orb shaped form dwarfing the entire torso of the fullbringer. There wouldn’t even be a slight hesitation for mercy, forgiveness, or lamentation. The Vasto only wanted to annihilate everything in its path.
When he releases the orb of teal which colors the sky, the Vasto would be unable to see its upward trajectory. From the ground, those observing, if they could even see from such a distance, would witness a Cero fired harmlessly upwards and away from the city. The vasto however, would have his entire vision rendered teal. The armor he feels gripped between his tail and the helmet he feels his claw squeezing, would be nowhere. Instead, the Vasto Lorde would find himself in the exact same position, only rather than being wrapped around the fullbringer, he is wrapped around his very own Cero.
Caught within the dead center of his blast, he would be forced to take its entirety at point blank range. Literally wrapped around the explosive projectile, he would not be able to release it, or escape, the transition happening instantaneously. This means that one moment he is firing the cero at Justin, the next he is wrapped around the Cero just as it detonates. Even at his Beyond-lightning speed, he had intended this blast to consume an opponent faster than him, meaning that even if he had the inclination to run, he would not out-pace it. Further, he would not be able to observe the threat in the first place to determine that he should run, lacking not only the intelligence, but the visual cue to flee. His entire vision was consumed by teal light, and remained that way. His instant transportation would be discombobulating, unable to predict where he was, he would be forced to try and observe his new surroundings instead. At this moment, the Cero would already be mid-detonation. A cero, which he fired with the intended power to utterly obliterate the Fullbringer, a power which would easily do the same to the premature Vasto Lorde.
How had this occurred? The very same way they had ended up in this situation. The vasto had wrapped himself around Watchman and the Armament Spear, subjecting himself to the power of the Fullbring. Watchman had permitted the Vasto Lorde to wrap around himself for this very reason. While the Vasto was building up the Cero, though the Watchman could not observe the flow of Reiatsu, he does not need to consciously control his spear's ability. The power of the spear is fully developed, it is the control over it that is a handicap to this new fullbringer. Fortunately, the spear will act to place Justin Taimu in exactly the place in space that he needs to be, at exactly the right time. As such, while the Vasto was focused on blasting the Fullbringer, the armament spear simply inverted their positions, causing the Vasto to fire upwards rather than down, without providing any tells towards the new trajectory.
Following this, once the Cero was fired, The spear would teleport the two of them to the center, then teleport Watchman away, leaving the Vasto Lorde in his same position, only pinned around the Cero rather than Watchman. Indeed, the Vasto’s strength was great, but Watchman’s was perfect. Correct, the Vasto’s speed was fast, beyond lightning, but was it beyond time? Watchman’s was.
Three teleportations, happening with literally no time between them. Literally no time to react, literally no time to observe. Even to Watchman, who can slow time to a near-halt, there would be no gaps for which he could note the movements of his own spear. Instead, the Hero was forced to observe the outcome at the same time as the Vasto Lorde. Watching from a new position in the skies as the Hollow is engulfed in his own cero.
The hero does not even squint at the blinding light, which falls upon the lenses of his Clad Armor harmlessly. Instead, he observes clearly as the Hollow is consumed by his own power. Yet, Watchman does not seem to relax, nor remove his eyes from the creature, anticipating that somehow the Hollow would be able to endure for itself a blast that it thought could disintegrate the Hero. Clutching his ebony spear in his ivory hand, the Watchman stands above Naruki City as its defender, protecting it from the invasive force of this Monster, for all to see. A fullbringer, who was meant to be eradicated, facing against a Shinigami that was meant to protect this city. How the tables have turned, that a protector is rendered opposition, while an opposition is rendered the sole protector.