The darkness of Muken surged once more, attempting to completely swallow Soya Azashiro's figure.
Kaname Tosen did not stop him, nor did he show the slightest hint of disappointment.
He simply stood quietly in place, listening to Azashiro finish speaking. Then, just as the man's presence was about to vanish completely, he slowly pulled an object from his robes.
"What if Lord Aizen had already anticipated your concerns?" Tosen's voice rang out in the darkness.
Soya Azashiro's fading figure suddenly paused.
He turned back, gathering his Reishi into a sensory perception that landed on the object in Tosen's hand.
It was a perfectly square box. No larger than the palm of a hand, it was a dull yellow all over. The material was neither gold nor copper, and its surface was covered in complex, indecipherable patterns.
Even while resting quietly in his hand, the box exuded an... extremely ancient and evil aura.
"What is that?" Azashiro furrowed his brow.
In the years he had spent merged with the majority of the Seireitei, he believed he had seen countless rare treasures and forbidden Kido of the Soul Society through the eyes of various people. Yet, he had never seen anything like this.
The object possessed no Spiritual Pressure and emitted no Reishi fluctuations, but it harbored a power that made him instinctively repulsed.
"This object was brought back by Lord Aizen from a special place." Tosen held the box up as if supporting a supreme, holy relic.
"You may have heard that eighteen years ago, a Spiritual Disaster that shook the three realms occurred in Fuyuki City in the World of the Living. Although that disaster was quelled, many people are unaware..."
"That same night, in the Shibuya District west of Karakura Town, a small-scale spiritual disaster also occurred and was quickly suppressed..."
"Lord Aizen was there that night, and he obtained this." Tosen's fingers gently brushed across the surface of the box.
In the next instant, the surface actually squirmed, slowly opening a single eye.
*Hum!*
A bizarre fluctuation instantly swept through the entirety of Muken.
Even in his state of Reishi fusion, Soya Azashiro felt an intense wave of dizziness from the fluctuation, as if his soul was being forcibly torn from this world.
"Wh-What is this?!" For the first time, a look of utter shock appeared in Azashiro's eyes.
"A seal." Tosen spoke slowly, providing the answer. "This is not the Kido seal of the Soul Reapers that you and I are familiar with. It is more like a... conceptual cage."
"Its name is—[Prison Realm]."
"Prison Realm..." Azashiro repeated the unfamiliar name.
"Lord Aizen told me that this is a special grade item used to seal the strongest."
Tosen offered the Prison Realm forward, allowing that crimson eye to stare directly at Azashiro through the boundless darkness.
"Its activation conditions are extremely harsh, but as long as those conditions are met, it can seal any existence."
"This object cannot be opened from the inside. Only someone on the outside who obtains it and uses a specific item in conjunction with it can release the prisoner within."
"Therefore, no matter how massive the target's Spiritual Pressure is, or how absolute their abilities may be, they cannot escape."
"Even if..." Tosen paused, his tone laced with a confident chill. "Even if it is Genryusai Shigekuni Yamamoto."
"What did you say?!" This time, Azashiro was completely astounded.
Seal Genryusai Yamamoto? That monster hailed as the strongest Soul Reaper, who had never been surpassed in two thousand years? That old man who, if he got serious, could reduce the entire Soul Society to ashes? If this could truly be done...
"That's impossible," Azashiro instinctively retorted. "Head Captain Yamamoto's level of Spiritual Pressure is simply not something this little box can contain."
"You are still trying to understand it with the mindset of a Soul Reaper, Kenpachi Azashiro." Tosen shook his head. "This is a conceptual seal. It does not target the strength of one's Spiritual Pressure, but their very existence."
"As long as Genryusai Yamamoto is sealed within the Prison Realm, even if it is only for a short month, or even just a week."
"Without the Head Captain, the Gotei 13 is nothing but scattered sand, easily dealt with."
"As for those in the heavens..." Tosen sneered. "Lord Aizen naturally has other preparations."
Azashiro stared at the box named Prison Realm, remaining silent for a long time.
'Is this real... Sosuke Aizen... Has this man actually grasped a power that transcends dimensions?'
"...What exactly are you trying to do?" he asked.
"Reshape the order of heaven and earth, and revolutionize the three realms," Tosen replied, tucking the Prison Realm back into his robes. "Rest assured, Lord Aizen knows your thoughts. During this time, he will not force you to do anything you do not wish to do."
"He hopes you understand that for the sake of a grander peace, minor sacrifices are necessary."
"You only need to stand by his side and witness the final outcome..."
"At the very least, do not stand in opposition."
A long, dead silence fell between the two once more.
Soya Azashiro closed his eyes, seemingly engaged in a fierce internal struggle. He pondered the credibility of this matter, and whether he and they could truly be considered fellow travelers on the same path.
But the reason he pondered in silence was because he knew very well that deep within his heart, that flame had never truly been extinguished.
His hatred for the corrupt nobles, his dissatisfaction with the current state of the Soul Society, and the vision of his own ideals. They had always been silently burning in this darkness.
"...It is worth a try."
He slowly took a step forward, truly emerging from the darkness to stand before Tosen.
"Although I do not trust Aizen, this has indeed moved me."
"I also want to see with my own eyes whether that otherworldly object can truly seal Genryusai Yamamoto."
Azashiro reached out, grasping an ordinary-looking Zanpakuto that resembled an Asauchi from the void. Uro Zakuro.
"I accept your invitation, Kaname Tosen."
He gently stroked his Zanpakuto, his cold expression hiding whatever thoughts lingered in his mind.
"But remember, the only part I will help with is destroying this rotting Seireitei."
"As for your other schemes and tricks, I don't care, and don't drag me into them."
"If Aizen fails, or if he tries to betray me... I will use my own methods to make you pay."
Tosen nodded, turning around to head back the way he came.
"A wise choice."
"Welcome to our ranks, Kenpachi Azashiro."
Meanwhile, on the surface of the Seireitei.
Deep within the Fifth Division barracks, there was a secluded courtyard where very few ever set foot. The chaos outside seemed to have absolutely nothing to do with this place.
It was planted full of rare flowers and plants that did not belong to the Soul Society, but rather came from the World of the Living.
Sosuke Aizen was standing in front of a white plum blossom tree.
As soon as he returned to the barracks today, he had been fully engrossed in studying the potted plant before him, carefully pruning its branches.
Ryoka? Interception? Leave that to the others.
Suddenly, the corners of his mouth curled into an unconscious smile.
*Snip.*
A soft sound echoed.
A branch that, despite having a hint of green, ruined the overall aesthetic due to its incorrect growth direction, fell silently into the soil.
"Excessive care often achieves the opposite effect."