Deep within a desolate mountain range west of the Rukongai, the land was barren, uninhabited, and shrouded in a perpetual gray mist. This was a wasteland rarely ever trodden by the Gotei 13.
Aizen had chosen this spot for his Garganta experiments, erecting a cloaking barrier to shield it from detection and keep it completely hidden from the Seireitei's watchful eyes.
Hasumi Ren stood in the center of the open hollow, verifying the recorded data and repeatedly calibrating the Garganta's positioning nodes.
Not far behind him, Tosen Kaname stood ready, still assisting with whatever tasks he could manage.
Ever since their brief encounter in the noble district, Ren could clearly feel a subtle shift in Tosen's attitude. It wasn't overt hostility, nor was he deliberately keeping his distance. Yet, an inexplicably eerie aura seemed to constantly hang around him.
While Ren conducted his experiments, Tosen silently went about his duties—preparing materials, checking the barriers, recording data... His movements were precise and flawless. In terms of pure execution, Tosen was truly an impeccable assistant.
But Ren could feel that faint, ever-present sense of oppression lingering around the man, making him thoroughly uncomfortable.
Ren hadn't paid it much mind at first. Tosen was naturally brooding, and being stone-faced and emotionless was normal for him. Sorting through the Kido formulas, Ren glanced back at Tosen, who was standing in the corner. With his hands hanging at his sides and his face completely still, he looked like a statue.
Ren had originally figured that as long as Tosen didn't drag the experiments down or hinder their progress with the Garganta and spatial spells, his behavior didn't really matter. But having this guy hover around with a sour face every single day, dragging the atmospheric pressure down to sub-zero levels, was incredibly bizarre and deeply annoying.
Ren fell silent for a moment before simply halting his work. He turned to Tosen and spoke in a low voice. "When I ran into you in the noble district the other day, were you there to eat at my shop?"
Tosen's fingers paused slightly. "...Yes."
Ren placed the spell matrix foundation back onto the rack, his tone flat. "Next time you go, just mention my name. You'll get a twenty percent discount."
Tosen fell silent. He remained quiet for so long that Ren thought he wouldn't answer at all. Then, Tosen's voice drifted from the corner, low and carrying a trace of coldness. "That won't be necessary. And I won't be going back."
Ren paused for a fraction of a second. He turned around to look at Tosen. There was absolutely no expression on that dark-skinned face. Pulling his gaze away, Ren gave a casual reply. "Suit yourself."
Silence descended over the testing area once more, broken only by the faint hum of the Reishi lamps and the occasional rattling of the experimental equipment.
Tosen stood in place, continuing his work. After a long while, he suddenly spoke. "Hasumi."
Ren didn't turn around. "Yeah?"
"You clearly hold a grudge against the nobles, and you share Lord Aizen's ideals. Why do you still indulge yourself in mundane, worldly affairs?"
Ren's brow twitched slightly.
Tosen pressed on. "The deeper your connections with others, the easier it is to get entangled. This does nothing but hinder our plans."
In Tosen's eyes, Ren's focus was far too scattered. Plotting with Aizen to overthrow the old world while simultaneously burying himself deep in mundane society would inevitably turn him into a liability for their plans.
Ren turned around to face him. Tosen stood there with his hands at his sides, his expression serene. His blind eyes were closed, but Ren could clearly feel his spiritual awareness locked firmly onto him.
Ren lowered his head, his fingertips returning to calibrating the spatial nodes as he spoke in a tone completely devoid of emotion. "That has nothing to do with you. There's no need to concern yourself with it. I suggest you focus on the experimental formulas instead. That way, you might actually be of some use in the upcoming trials, rather than standing around totally blind to what's happening."
"Why you...!" Tosen gritted his teeth, his breathing turning shallow and sharp. He let out a cold snort and fell silent. He knew he couldn't sway Ren, nor did he have any valid reason to criticize his actions. Furthermore, Aizen's growing appreciation for Ren made any argument Tosen could muster seem hollow and ridiculous.
Ren withdrew his gaze and went back to packing up his things. Neither of them spoke another word.
Standing in the center of the testing area, Ren faced a complex Kido barrier. The Spiritual Pressure nodes were densely packed, resembling a sprawling spiderweb. Tosen stood on the perimeter, responsible for monitoring the Spiritual Pressure and recording data.
Ren took a deep breath, channeling his Hollowfied Spiritual Pressure. A dark red Reiatsu surged from his body, swirling around him before climbing up his face to form a partial mask. He raised his hand, gathering the Hollowfied Reiatsu at his fingertips to begin carving out the spell. The spiritual tracks interlaced and overlapped in midair, solidifying into a complex runic structure.
Space began to shudder, and a visible warp distorted the air. Then, a pitch-black rift slowly tore open.
A Garganta.
It was several meters wide, spacious enough for multiple people to walk through at once—far larger and more stable than their previous attempts. Dark red Reiatsu flickered along the edges of the rift, actively maintaining its torn state.
Ren was in no hurry to close the Garganta. Drawing upon the theories provided by Urahara Kisuke, he steadily expanded the tracking range of the void, probing for the deep-layer coordinates of Hueco Mundo.
Right then, a bizarre and incredibly well-hidden spatial ripple suddenly breached his sensory range. It wasn't from the direction of Hueco Mundo, nor was it from the World of the Living. It was an entirely foreign spatial vibration unlike anything he had ever felt before. The fluctuation was exceptionally faint, as if tucked away between the folds of Soul Society's spatial barriers—hidden, profound, and resembling a wild beast lurking in the dark.
'Where... is that?'
Ren held his breath, focusing every ounce of his mental energy to trace that stealthy ripple down to its source.
What he was doing right now was opening a Garganta within Soul Society to map the exact coordinates of Hueco Mundo. Yet, in the process of calculating those coordinates, he had somehow brushed against a completely separate, concealed dimension. The unique spiritual signature of that space didn't belong to Hueco Mundo or the World of the Living. Instead, it was an entirely unprecedented, icy-clear Reishi fluctuation that carried a strange sense of absolute order—completely distinct from standard spatial wavelengths.
Ren immediately adjusted his technique, cross-referencing the hidden pocket dimension's coordinates against real space to deduce its precise location. But as he repeatedly calibrated and mapped it, his brow furrowed deeper and deeper.
A moment later, his pupils dilated as his heart skipped a beat. He looked up toward the direction of the spatial ripple. It was actually located right inside Soul Society.
And the exact coordinate path of that hidden pocket pointed directly to... the Seireitei.
It wasn't just some random corner of the Seireitei either, but a massive, independent realm quietly superimposed over the very core of Soul Society.
Ren's mind raced at breakneck speed as a term buried deep within his memories instantly surfaced.
The Wandenreich.
The empire built by Yhwach, the Quincy kingdom hidden within the shadows of the Seireitei. Though supposedly wiped out during their ancient invasion of Soul Society, they had actually been lying dormant for a thousand years, recuperating in the shadows of the Seireitei while plotting to overthrow the three worlds.
Ren had never imagined that while researching spatial techniques and calculating Hueco Mundo's coordinates within the Garganta, he would quietly stumble upon the spatial orientation of the Wandenreich. This really was...
"Hasumi," Tosen's voice called out from behind. "Why did you suddenly stop working? Did you discover something?"
Ren's fingers twitched slightly. He turned his head to look at Tosen, who was currently tilting his head, focusing his senses in Ren's direction. Tosen's brow was slightly furrowed, indicating he had clearly noticed something. 'For a blind guy, his senses are incredibly sharp.'
Ren pursed his lips. He didn't know how to break this discovery to anyone just yet. If he told Aizen, how would Aizen react? Would he try to exploit that space? Perhaps it would be better to discuss it with Urahara first; they might be able to figure out a different course of action.
Ren took a deep breath, forcing down his rising emotions. He slowly turned around to face Tosen, adopting a slightly grim expression to smoothly cover his tracks. "There's a minor issue with the experiment. The spiritual pressure connection at the spatial nodes has drifted out of alignment. I need to recalibrate this barrier formula. Let's call it a day for the experiments."
Without waiting for Tosen's reply, Ren packed up his gear and walked out of the testing area.
Standing alone, Tosen listened to Ren's retreating footsteps, his brow knitting tightly together. He couldn't shake the feeling that Ren's reaction just now was off. It didn't seem like a simple technical glitch; it felt more like he had unearthed a secret and was deliberately hiding it.
After Ren left, Tosen silently walked over to where the other man had just been standing. Extending his spiritual pressure into the barrier formula, he repeatedly adjusted the spatial data, trying to replicate Ren's technique to uncover whatever was being concealed. However, his mastery of spatial spells fell far short of Ren's. After fumbling around for quite a while, he detected nothing but a chaotic mess of spatial ripples, coming away completely empty-handed.
After swiftly leaving the desolate mountains of the Rukongai and returning to the Seireitei, Ren bypassed the Fourth Division barracks entirely and headed straight for the Sokyoku Hill. Before long, he arrived at the cavern hidden beneath the hill.
Passing through the layers of barriers surrounding the Sokyoku Hill, Ren opened the secret door using the method stored in his memory and descended the passage into the subterranean training ground. Brilliant light from spiritual ore radiated down, illuminating the vast cavern. But as Ren stepped into the center of the hollow, his feet suddenly froze.
Urahara Kisuke was nowhere to be found inside the massive cave. Instead, a figure both unfamiliar yet recognizable stood right in the center, her back turned to him.
Shihoin Yoruichi stood there clad in form-fitting black stealth gear, her posture upright and her presence piercingly sharp. With her back to Ren, she was silently examining the gashes and burn marks left on the rock walls by sword strikes and Kido spells.
Ren blinked in surprise but quickly put the pieces together. This was originally a private space hollowed out by Urahara Kisuke and Shihoin Yoruichi years ago for their secret training and discussions. It was perfectly natural for Yoruichi to be here. However, he didn't know if Urahara had filled Yoruichi in on Aizen's situation, nor did he know how much she understood about their operations. If Yoruichi started questioning him, he would have to watch his step.
Sensing someone behind her, Yoruichi slowly turned around to face Ren. A flash of scrutiny, surprise, and uncontainable curiosity gleamed within her golden eyes. "Hasumi? What are you doing here?"
Snapping out of his brief daze, Ren immediately composed himself, using Urahara Kisuke as a shield. "Urahara Kisuke asked me to come," he said naturally. "He mentioned he had something to discuss with me."
Yoruichi's brow arched slightly. "Is that so?" She surveyed her surroundings, her eyes scanning the sword gashes and structural damage. "Since when did you two get so close? I can't believe he'd even tell you about a place like this."
"Well... Captain Yoruichi should probably ask Third Seat Urahara about that."
Yoruichi pouted slightly and looked away, scanning the residual marks once more. She had actually come here looking for Urahara Kisuke in the first place. Her hands had been itching for a good fight lately, and she wanted someone to go a few rounds with to stretch her limbs. She had checked the Onmitsukido's Detention Unit earlier but was told Urahara was out. Guessing he would most likely be at their old spot under the Sokyoku, she had headed down. She hadn't expected to run into Ren instead of Urahara.
Yoruichi's gaze settled on Ren before drifting back to the cavern walls. Some of the sword slashes were several inches deep, while even the shallower ones had sliced clean through the dense rock. There were scorched burn marks on the ground, patches of frost, and craters blasted out by Reiatsu explosions. Yoruichi's brow furrowed. With her sharp eyes, she could easily tell that the sheer power behind these sword techniques was extraordinary—certainly not something ordinary fighters could pull off. "Did you two do this?" Her voice carried a hint of suspicion. Setting Ren aside, Urahara Kisuke was hardly someone she associated with high-level swordsmanship.
Ren gave an awkward chuckle. "Actually... Captain Unohana has been here too. She trains with me here quite often."
Hearing this, Yoruichi's eyes snapped wide. "Who? Captain Unohana?" "What is she training you in, Kido?" "...Actually, it's Zanjutsu."
At Ren's answer, Yoruichi's lips parted slightly as she stared straight at him, her utter shock written all over her face. She, of all people, knew Unohana Retsu's true identity—the First Kenpachi, a diabolical killer whose terrifying name echoed from a millennium ago. She also knew that since transferring to the Fourth Division, Unohana hadn't drawn her blade for centuries. Practically no one in the current Seireitei had ever seen her fight. So why on earth would she be with Ren...?
Yoruichi suddenly recalled how Unohana Retsu had personally requested Ren's transfer from the Onmitsukido to the Fourth Division. Back then, her public excuse was that Ren possessed an outstanding talent for Kaido, making him a perfect fit for the medical squad. Looking at it now, could there have been... a hidden motive?
The way Yoruichi looked at Ren changed instantly. A long-lost thrill surged from the depths of her chest. She was a battle fanatic by nature, and it just so happened her hands were itching for a fight today with Urahara nowhere to be found. Looking at Ren now, and hearing that he was learning swordsmanship from Unohana, her urge to fight flared up even hotter.
A bright, confident grin broke across Yoruichi's face. She rolled her wrists and ankles, her spiritual pressure beginning to steadily emanate outward as a thick wave of battle intent filled her voice. "Hasumi," she said, a playful lilt in her voice. "It's been a while. I wonder if your Hakuda skills have gotten rusty since you left the Onmitsukido." Cracking her knuckles, her Reiatsu began to surge. "Come on, let's trade a few blows first."