Natsuro walked across the seemingly endless desert. With no landmarks in sight, even he could only confirm that he wasn't retracing his steps.
By now, he had no idea how long it had been since his arrival in Hueco Mundo.
There was no day here; above him, the same solitary moon always hung in the sky.
With a casual slash, he shattered the mask of yet another ordinary Hollow. Watching its body break apart with a scream, hefrowned.
His purpose in coming to Hueco Mundo was to study the power of Hollows, and to test something.
If Shinigami could Hollowfy, then could Hollows become Shinigami?
He also knew of the Arrancar, but he understood that Aizen had only created them through the Hōgyoku.
Still, he didn't need to recreate true Arrancar. What he cared about was the process of transformation that occurred when a Hollow's mask was broken.
Unfortunately, most of the Hollows he encountered were mere small fry. Even medium-class Hollows were rare, let alone the higher ranks.
At least he had run into Gillians, but he hadn't seen a single Adjuchas, much less the highest-ranked Vasto Lorde.
And that was despite his ability to sense and search with incredible speed which was faster than nearly anyone else.
Yet even so, finding powerful Hollows proved difficult.
Hueco Mundo was vast, filled with countless Hollows, but the overwhelming majority were the weak and ordinary kind.
Gillians required extremely harsh conditions to form: hundreds of Hollows engaged in long-term mutual slaughter and cannibalism until they fused into a new being.
Adjuchas, meanwhile, only arose when a Gillian with strong individuality devoured other Gillians to evolve.
And even then, talent was key. Most Gillians, born from mass fusion, lacked self-awareness and acted purely on instinct, and were mere fodder to be eaten.
Only those rare Gillians with a distinct self and power far surpassing others had the chance to evolve into Adjuchas.
As for the Vasto Lorde, the requirements were surely even harsher.
So far, he had only encountered Gillians. He hadn't seen the faintest trace of an Adjuchas or a Vasto Lorde.
"…This is truly a bit of a waste of time." Natsuro sighed, but pressed on.
Since he had chosen this path, there was no question of giving up so soon.
As he continued searching for stronger Hollows, his mind sank into Meikyō Shisui.
In that empty desert, though only one man walked, it seemed as if two figures moved side by side.
A palace-dressed woman strode next to Natsuro, though her feet left no prints in the sand.
"How does it feel?" Natsuro asked.
"There's no real change." Meikyō Shisui answered after some hesitation.
He frowned. Strange. Back in the Human World, Meikyō Shisui had seemed close to touching Hollowfication. Yet here in Hueco Mundo, nothing?
It was the same as in Soul Society.
He had thought some other factor was interfering back then. Coming here should have sped up the process.
And yet Meikyō Shisui now told him that here, the progress was no different than in Soul Society?
"What exactly in the Human World accelerated your transformation?" Natsuro muttered, puzzled.
Could it be that lower spiritual density quickened the process?
But Hollows themselves survived on reishi. That explanation was clearly wrong.
At that moment, hesitation showed more strongly on Meikyō Shisui's face.
"Just say it," Natsuro told her, setting aside his confusion.
She nodded. "…It may just be my imagination, but within the area of Urahara's shop, the change felt easier."
"Urahara's shop?" Natsuro blinked.
She nodded again. "It might have been a false impression."
"No… perhaps not." Natsuro thought, and his eyes lit up.
That detail was crucial. What was different about Urahara's shop compared to anywhere else?
He knew: Kisuke Urahara possessed the Hōgyoku.
Even half-finished, it was powerful enough to be coveted by Aizen, its power surely surpassed captain-class.
So perhaps faint traces of the Hōgyoku's energy still lingered in Urahara's shop, though most of it must have been sealed away.
But with something as strong as the Hōgyoku, complete sealing was unlikely.
Otherwise, Urahara would have destroyed it, not merely sealed the half-finished gem.
And those Visored captains had clearly relied on Urahara's Hōgyoku to remain Shinigami while gaining Hollow powers.
Not to mention, in Natsuro's memories, the Arrancar too had been born when Aizen used the Hōgyoku to Shinigamify Hollows.
So, was the true power of the Hōgyoku to break down the barrier between Shinigami and Hollow?
As this thought crystallized, he felt a strange sense of familiarity, as if he had indeed seen this idea before.
That feeling only made him more certain of his guess.
What Natsuro didn't know was that the Hōgyoku's power went beyond even that. Still, it could certainly help him achieve this goal.
"Meikyō Shisui, tell me next time you feel anything like that." Natsuro said firmly.
"Yes. Back in the Human World, our place was so close to Urahara's shop that it wasn't noticeable. Only after we came to Soul Society did I feel it, and here in Hueco Mundo it became clearer, so I guessed…" she explained.
"It's not your fault. I just forgot too much." Natsuro rubbed his forehead.
He remembered the Naruto world so well only because upon arriving there, he had forced himself to recall the story again and again, reinforcing his memory.
But with Bleach, he hadn't. So he'd forgotten much. Even now, with his memory vastly improved, he couldn't recover what was completely gone.
"Then… should we return to the Human World?" Meikyō Shisui asked.
"No rush. Umbreon still needs to rest. And I want to wander Hueco Mundo a while longer." Natsuro replied.
"I see. Then, will you still have time to train?" she asked suddenly.
"Of course. Training never stops." Natsuro looked at her and smiled.
"Yes!" Meikyō Shisui beamed.
Here in Hueco Mundo, he had no other opponents, so his sparring partner would naturally be her.
That made her think perhaps this trip wasn't so bad after all. She would still often serve as his practice partner, but she was no longer just a second choice.
Unlike back in the Spiritual Arts Academy, when he almost daily entered her inner world to duel her with swords.
And as his zanpakutō, every bit of combat experience Natsuro gained was also hers to share.
So her swordsmanship improved as well.
Unfortunately, her growth never matched his speed.
She could only sigh at how terrifying his talent was, greater even than hers, though she was literally the spirit of the sword.
Natsuro, seeing her retreat back into the blade, gave a helpless smile.
He knew she loved dueling with him, and worked tirelessly to absorb battle experience for that sake.
But there was no helping it, she always fell just a step behind. Sparring with her did bring gains, but not nearly as much as fighting Unohana or Zaraki Kenpachi.
Of course, even so, Natsuro still often sparred with Meikyō Shisui. After all, it was his zanpakutō, and he felt it necessary to cultivate its combat strength as well.
Besides, Zaraki Kenpachi and Unohana weren't available every day to fight him. The only one who could always be by his side was Meikyō Shisui.
Natsuro continued walking forward. Passing by ordinary Hollows, he no longer had the urge to act.
After all, he had already confirmed that even if he forcibly shattered their masks with external power, it was useless. They would die instantly, without the slightest possibility of transformation.
And when these Hollows saw him, they didn't even think of running. Instead, they collapsed to the ground... as if welcoming him to take their lives.
That was the absolute dominance his spiritual pressure exerted over Hollows. Even Gillians would be unable to resist him if he willed it.
As for Adjuchas, he wasn't sure, since he still hadn't encountered one.
So he wandered forward aimlessly.
After some time, the desert before him remained unchanged.
In the days that followed, he came across another couple of Gillians. This time, when their masks were broken, they didn't die immediately.
Instead, it was as though memories from their past lives surfaced, they howled in agony, but in the end, they still couldn't escape death.
That discovery gave him some excitement. If he truly found an Adjuchas, would its broken mask allow it to advance even further than a Gillian?
But unfortunately, in the following days, he still didn't find a single Adjuchas.
He did encounter a few more Gillians, but they were weaker than the earlier ones. When their masks broke, they simply died on the spot, without any of the strange reaction he had seen before.
"At this rate, who knows how long the experiments will take? If I can't find an Adjuchas or stronger, I'll return to the Human World."
Natsuro frowned and made up his mind. Since coming to Hueco Mundo, he had almost been wasting time, with no substantial progress at all.
Yet even after several more days, there was still nothing.
"Umbreon," Natsuro called.
"Gula?" The creature appeared on his shoulder, blinking.
"Let's head back to the Human Wor..." Natsuro stopped mid-sentence, his eyes flashing with surprise as he turned toward a direction.
Because at the very edge of his perception, a massive spiritual pressure had entered his range.
A spiritual pressure greater than that of an ordinary captain!
"Adjuchas? …No, it should be a Vasto Lorde!" Natsuro felt a surge of excitement.
Although he had never seen an Adjuchas, he knew it was just an evolved Gillian, it couldn't be this far above. Which meant this power could only belong to a Vasto Lorde, the legendary highest class of Hollow.
Such beings were so rare that even in Unohana's thousand-year life, she had hardly encountered any.
What's more, given the Gotei 13's stance as "mediators" of the world, they would never allow Hueco Mundo to nurture a powerful force unchecked.
Under such conditions, it was even harder for a Hollow to grow into a Vasto Lorde.
He had only expected to maybe find an Adjuchas. He hadn't even considered seeking out a Vasto Lorde.
"I guess my luck isn't bad after all." Natsuro muttered with a faint smile.
Then he paused. With his speed and sensing ability, even in such a vast Hueco Mundo, he should have been able to find at least a few Adjuchas.
But until now, he hadn't encountered a single one.
Now he understood why.
The reason lay in that Vasto Lorde within his perception. Its existence alone had wiped Adjuchas from this entire region.
But he felt it was a blessing. After all, what was an Adjuchas compared to a Vasto Lorde?
With that thought, he sent Umbreon back into its space and walked toward the immense spiritual pressure.
Soon enough, the other side seemed to notice his presence as well. Yet it paid him no heed, continuing straight toward him.
Finally, Natsuro laid eyes on the Vasto Lorde he had long been seeking, and the creature saw him too.
Both froze in shock.
Because both were astonished...
Why did the other have no Hollow mask?
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Currently on Chapter 494 - Returning to Hueco Mundo