Hueco Mundo.
Under the unchanging moonlight, a deep black rift appeared above the desolate desert, devouring vast amounts of white sand and grinding it into fine spiritual particles dispersed into the atmosphere.
Small animal Hollows that couldn't avoid the immense spiritual pressure were also crushed, their bodies disintegrating into white sand.
As the spiritual pressure drew closer, several figures emerged from the simulated Garganta, landing smoothly on the white sand.
"Why is there a Kōtotsu appearing at this time?" Tokikaze turned to Mayuri Kurotsuchi beside him. "You'd better have a reasonable explanation."
"Well, the Research and Development Institute's study of the Dangai is still limited," Mayuri replied, spreading his hands with a nonchalant grin. His face was painted in black and white, and the corners of his mouth nearly reached his ears.
"The Kōtotsu, which sweeps through the Dangai every seven days, sometimes experiences irregularities. It's within acceptable margins of error."
Earlier, as they passed through the simulated Garganta into the Dangai, they encountered the massive Kōtotsu that inhabited the Dangai.
The Kōtotsu is a unique entity that doesn't rely on spiritual pressure for existence and acts as a cleaner, obliterating anything in its path.
With no current method to harm it, the captains and officers had to sprint through the Dangai at full speed, narrowly escaping into Hueco Mundo.
"Though this isn't my first time here," Mayuri glanced around at the towering quartz-like dead trees in the distance, "the monotonous colors are still rather dull."
"The density of spiritual particles in the atmosphere is high enough to sustain ordinary Hollows," Yamada Kiyosuke spread the fingers of his right hand, where star-like patterns flickered in his palm. "But to evolve into Menos Grande, they must devour large numbers of their own kind."
This was a support Kido had developed to measure spiritual particle density, soul strength, and spiritual pathways.
Tokikaze released his spiritual pressure, expanding his perception to its limits.
A call from Mayuri had prompted him to bring Yamada Kiyosuke and his brother to the Research and Development Institute. From there, they used the simulated Garganta to return to Hueco Mundo.
As a partner, Mayuri and Kiyosuke knew Shijō Sōya's existence.
They tacitly kept this secret for Tokikaze, patiently waiting to enjoy its benefits—like a steady supply of Menos Grande-level experimental materials.
Tokikaze didn't mind.
Mayuri had monitoring devices in the Soul Society and the human world and in Hueco Mundo. Though he couldn't fully observe all of Hueco Mundo, he could easily keep track of specific Hollow activity zones.
From the start, Tokikaze hadn't planned to hide anything from him.
As for Yamada Kiyosuke, he was now a trusted ally.
In terms of loyalty, Kiyosuke's dedication to Tokikaze was second only to his loyalty to Unohana Retsu.
And Hanataro? He was just along for the ride.
As Yamada Kiyosuke had once said, he would walk it to the end without hesitation since he'd chosen this path.
This trip to Hueco Mundo was a perfect opportunity to hone their skills.
And with two captains accompanying them, the level of safety was maxed out.
If they still hesitated to step onto the sands of Hueco Mundo, they might as well remain as support personnel in the Fourth Division.
In the atmosphere was a sudden, violent fluctuation of spiritual particles.
Amid the flickering light, a white figure appeared before them.
But before the figure could fully materialize, a massive fist, the size of a cauldron, roared through the air, heading straight for it.
Boom!
The impact sounded like thunder as Yamada Hanataro's fist slammed into a transparent barrier.
"Bakudō #31: Shakkahō."
A voice of mild surprise came from Shijō Sōya as spiderweb-like cracks spread across the shield in front of him.
"Where did you find this brute?"
"My younger brother, Yamada Hanataro," Kiyosuke replied dryly, clearly not wanting to linger on the topic.
Shijō Sōya fell silent.
If he remembered correctly, Hanataro used to be a skinny, timid little guy—the kind that even foot soldiers would bully.
But now… what on earth had happened to turn him into this massive brute?
Had Mayuri done something bizarre to him?
However, he quickly put aside this thought, as the situation was more critical.
"Three hundred kilometers northwest, beneath the white sand," Shijō Sōya reported calmly, "there's a Menos nest known as the Forest of Menos."
"Countless Gillians and Adjuchas live there, and some of the Adjuchas are strong enough to rival a Shinigami captain."
"My ability faced unprecedented resistance when I tried to merge with that area."
"As a result, I suspect there may be a Vasto Lorde with special abilities there."
Mayuri cracked his fingers rhythmically, a habit he'd developed after leaving the Maggot's Nest, as he entered deep thought.
"If that's all, you wouldn't have called Captain Tokikaze here, would you?"
Shijō Sōya glanced at Mayuri and continued, "Aside from the Hollows, there's also a squad of Shinigami trapped there."
"To be precise, only one remains."
"The others have already perished in continuous battles with the Hollows."
Tokikaze raised an eyebrow, already guessing who the survivor was.
The friend of Kuryashiki Kenpachi, the expedition's leader to Hueco Mundo—Sajin Asido.
"It seems you know who it is," Shijō Sōya noticed the change in Tokikaze's expression.
"Kuryashiki Kenpachi's and Captain Kyōraku's friend," Tokikaze responded. "He led a group of Shinigami into Hueco Mundo after learning of a Hollow King named Barragan. No word has come back from them since."
"Most believe he's dead, though Kyōraku still holds out hope that he's alive."
Hearing Kuryashiki Kenpachi's name, Shijō Sōya fell silent.
He had once killed Kuryashiki using the spiritual particle fusion ability of Rain of Red Lotus.
"My current identity makes it unsuitable for me to interact with him," Shijō Sōya said after a pause, his voice devoid of emotion. "Someone like him shouldn't remain in the Forest of Menos."
"Bringing him back to the Soul Society is your task."
Hearing this, Tokikaze raised an eyebrow in surprise. "Wasn't Sajin's goal to kill Hollows?"
"His thinking is just like yours was in the beginning. You should have plenty in common," Tokikaze remarked.
Shijō Sōya didn't respond, turning and disappearing with a flash of Shunpo toward the northwest.
It was clear he didn't yet know the answer to that question.
…
Thick quartz roots towered above in the dark underground space, piercing straight through the white sand at the top.
"What a magnificent sight!" Mayuri exclaimed in admiration. "Who would have thought there'd be such a space beneath Hueco Mundo? Truly surprising."
Yamada Kiyosuke continued measuring the spiritual particle density in the Forest of Menos with his support, Kido.
"It's even denser than aboveground Hueco Mundo."
"It far exceeds the density found in the various districts of Seireitei. Perhaps only places like the Pure Clean Tower and the homes of the Five Noble Families can compare."
Indeed, the spiritual particle density in Hueco Mundo was much higher than that of the Soul Society. Only a few places in the Soul Society could match it, such as the residence of Central 46 or the shrines of the Kanmyōdai family.
As the group surveyed the underground space, the ground began to tremble as if a large mass was moving beneath it.
"A horde of lower-level Hollows," Shijō Sōya noted. "Not even Gillians."
As the creatures approached their location, the rumbling grew louder, accompanied by dust clouds.
"The exits here are lined with detection webs. As soon as any Hollow or being enters the Forest of Menos, they are immediately detected."
"Now, you've been marked as prey."
For some reason, Tokikaze detected a hint of schadenfreude in Shijō Sōya's voice.
The group finally saw their enemies as the spiritual solid pressure closed in.
Giant spiders, several meters in diameter, stared greedily at Tokikaze and the others with their two rows of eyes, their long legs skittering back and forth.
Unlike the lower-tier Menos Gillians, these Hollows were the lowest of the low—neither solid nor intelligent.
However, what piqued Tokikaze's curiosity was that while ordinary Hollows weren't as intelligent as humans, they became mindless upon evolving into Gillians, driven only by the urge to devour.
Only rare Gillians or those who evolved into Adjuchas regained their intelligence.
While the spider Hollows had low intelligence, they still had the cunning to set traps and catch prey.
The Forest of Menos was vast and full of strange creatures. Anything was possible.
"Hanataro, you're up," Tokikaze said, giving Hanataro a swift kick that sent him flying into the swarm of Hollows.
Yamada Kiyosuke, about to shout a warning, was stunned to see his brother not resisting. Hanataro snarled with glee as he charged into the horde, tearing through the formation like a runaway truck.
The sight left Kiyosuke in deep thought and drew bemused expressions from Shijō Sōya and Mayuri…