Chapter 73

After confirming that Kaelith Yurei had no intention of interfering, Aizen, with a complex mix of emotions, sealed Goken Kenpachi into a containment tank.

As the sealing liquid filled the tank and layers of Kidō were applied, Goken sank into a deep slumber, officially becoming one of Aizen's experimental subjects.

Staring at the floating form of Goken, Aizen's lips curled slightly upward. 

With Goken in his hands, his experiments would progress at an accelerated pace. Many trials that ordinary Shinigami couldn't endure could now be tested on Goken. 

The very thought filled Aizen with satisfaction.

Once the work with Goken was complete, Aizen conjured two chairs and sat down with Kaelith Yurei. 

Facing Kaelith, Aizen began to explain the history and purpose of the lab.

He revealed that, long before enrolling at the Shin'ō Academy, he had conceived an idea. If a Shinigami's power was fundamentally tied to the strength of their soul, then their potential upper limit was determined by the soul's capacity. 

Upon entering the academy, Aizen buried himself in the library, poring over numerous texts. Eventually, he confirmed his hypothesis: stronger souls could contain more power and progress further. 

From this realization emerged a new ambition. 

What if, by collecting enough souls and forcing them into resonance, one could artificially amplify the strength of a single soul? Could a Shinigami's talent and potential be enhanced through scientific means?

Initial experiments yielded promising results, motivating Aizen to establish the lab in Rukongai. 

At first, he used vagrants and thugs from the outer districts of Rukongai as test subjects. However, their inherent weaknesses caused their souls to disintegrate under even minor stress. 

This limitation forced Aizen to turn his attention to Shinigami. 

Kaelith listened intently, already familiar with what came next. Aizen's growing notoriety as the "Shadow Killer" had stemmed from his increasing focus on killing rebel-affiliated Shinigami for his experiments. His assassination of the Seventh Division Vice-Captain had escalated the situation, prompting him to fake his death and escape pursuit.

Aizen omitted any mention of Kyōka Suigetsu, vaguely attributing his escape to "certain methods." He admitted, however, that Goken Kenpachi's unexpected allegiance to the rebels had thrown his plans into disarray.

Kaelith stroked his chin thoughtfully after hearing the story.

"I've got a question."

"Go on," Aizen replied with a nod.

Kaelith's expression turned serious. 

"Sōsuke, why on earth would you cross half the Seireitei in the middle of the night just to kill the Seventh Division Vice-Captain? Did he offend you, or was he playing some critical role in this incident?"

Aizen: "…"

He stared at Kaelith for a few seconds before sighing and pinching the bridge of his nose.

"Interpret it however you like… Fine, let's say he offended me."

Hearing this, Kaelith's face lit up with understanding.

"As expected of the ultimate boss of the Shinigami world. Ruthless and vengeful—a bit cool, honestly."

Quickly shifting the topic, Aizen asked, "Kaelith, has your Spirit Pressure broken into the third-class level?"

Kaelith's lips curled into an enigmatic smile. "It has."

In truth, while rushing to Rukongai earlier, Kaelith had been somewhat uncertain. If Yamamoto had sent a particularly powerful captain, he and Aizen might not have stood a chance. 

But halfway through his journey, the system had notified him that Aizen had broken into the third-class Spirit Pressure level. That alone was enough to erase his doubts.

The third-class Spirit Pressure tier marked the dividing line between captains and vice-captains. Even without their Bankai, both Kaelith and Aizen now possessed the raw Spirit Pressure to rival standard captains. Together, they had little to fear.

Hearing Kaelith confirm this, Aizen's expression grew pensive. 

Just when Aizen thought he had left Kaelith in the dust, Kaelith had once again proven that there was still room for Aizen to grow. 

"I need to push myself even further" Aizen resolved, his ambitions quietly reignited.

After this battle, Aizen and Kaelith Yurei had fully revealed their cards to each other.

From a rational perspective, Aizen didn't enjoy this feeling. 

His approach had always been to hide nine parts of himself and show only one. Even during training sessions and sparring matches with Kaelith, Aizen had held back a portion of his strength, never allowing Kaelith to get a complete picture of his abilities.

But now, with everything laid bare, it felt unsettling. Strange. 

Yet, he had to admit—at this moment, he also felt unexpectedly relieved. 

Having someone who understood his efforts, someone he could talk to without pretense, was oddly refreshing. Especially since Kaelith was such an eccentric, Aizen didn't need to worry about him becoming a threat after learning these things.

Looking at Kaelith, Aizen felt genuinely pleased.

"Look forward to it, Kaelith. When I achieve results here, I'll make sure you get to enjoy the fruits of victory alongside me."

Kaelith furrowed his brows in thought, then replied cautiously, "I think I'll wait and see when the time comes."

Aizen's experiments… if his understanding was correct, they would ultimately lead to the creation of the Hōgyoku. 

And the most immediate result of using the Hōgyoku on a Shinigami was Hollowfication.

If the transformation made him look as cool as Ichigo Kurosaki in his Hollow form, Kaelith thought, maybe it wouldn't be so bad. But if he ended up like some pink-haired chubby guy in a goofy mask, it would ruin his reputation forever.

"Power is temporary; being good-looking is forever." (t/n Preach it) 

In the world of the Shinigami, losing your looks was akin to running out of luck. Kaelith wasn't about to gamble with his face. 

Seeing Kaelith's reaction, Aizen mistook it for skepticism about his experiments. 

A smirk tugged at his lips. "In that case, I'll just have to produce results sooner. Let Kaelith regret doubting me."

After finishing their discussion about the lab, the two shifted focus to handling the aftermath of Goken Kenpachi. 

Sending a captain to the battlefield only for him to never return was, by the standards of Soul Society, a major incident. It would undoubtedly raise questions.

After a moment of thought, both of them looked up simultaneously. 

Aizen raised an eyebrow, gesturing for Kaelith to speak first.

Kaelith grinned mischievously. "Didn't he defect to the rebels? If that's the case, let's solidify that narrative."

"You're skilled with Kidō disguises. Think of a way to impersonate Goken Kenpachi and expose his supposed allegiance. The real guy is already in your hands, so it's not like he can jump out and deny it, right?"

Hearing Kaelith's calm delivery of such a devious plan, Aizen couldn't help but smile.

Until now, he hadn't truly noticed Kaelith's knack for villainy.

He nodded, standing up. "Alright. Leave it to me."

And thus, on that day, Aizen Sōsuke and Kaelith Yurei officially became allies. 

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