"The Shiba Clan..."

Several shadowy figures gathered within a dim room, their voices hushed and devoid of vitality, perhaps due to the enclosed space.

"Are you certain?"

"Not entirely..." one figure replied. "Three hundred years ago, we found the main house of the Shiba clan..."

"Although we killed the head of the family at that time, we didn't obtain any information about that item, and we lost track of the Shiba clan."

"We've confirmed that the Captain of the 10th Division isn't from the main house due to his age, so we haven't taken action against him."

"Our initial plan was to use this branch family member to lure out the main house."

"After three hundred years, a member of the Shiba clan has finally entered the Seireitei..."

"Don't be hasty. We can't confirm whether this Kaien Shiba is from the main or branch family. We'll act once we're certain."

"Otherwise, our aspirations to obtain that item and ascend to the ranks of the 'Great Nobles' will be delayed even further..."

"Indeed, but how do we determine whether he's from the main or branch family?"

"Leave that to me!" one figure volunteered. "Coincidentally, my clan has some children of the right age to enroll in the Shin'ō Academy. I believe they'll bring us good news."

"Very well, we'll leave it to you..."

Kaien Shiba, newly enrolled in the Shin'ō Academy, remained oblivious to the fact that his arrival had stirred unease among certain individuals within the Seireitei.

Since the creation of the three realms, there had only ever been "Five Great Noble Houses" in Soul Society.

The founders of these houses were individuals who had followed the Soul King since the very beginning. After the realms were established, the Five Great Houses became the true rulers of Soul Society, each wielding a unique "authority."

The Kuchiki clan maintained the order of the nobility and upheld the "rules" of the Seireitei.

The Shihōin clan controlled the "Heavenly Bestowed Armaments," possessing numerous powerful weapons with various abilities.

The Tsunayashiro clan wielded the strongest Zanpakuto, "Enrakyōten," making them the most individually powerful family among the Five Great Houses.

The Shiba clan held dominion over the "Fireworks Cannon" and "Reishi Shells," granting them free access to the Soul King Palace and the right to meet with the Soul King.

The identity of the final Great Noble House remained Soul Society's greatest secret. Even Ailin, who nearly became the head of the Kuchiki clan, couldn't glean any information about them from Ginrei Kuchiki.

However, after years of speculation, Ailin had a hunch.

The fifth Great Noble House was likely the Ise family, guardians of the sacred "Eight Mirror Sword."

The "Eight Mirror Sword" was an artifact incapable of harming mortals but possessing the power to "slay gods."

To mortals, Shinigami were "gods."

So, who were the "gods" to Shinigami?

The Soul King!

The "Eight Mirror Sword" was the Five Great Houses' trump card against the Soul King, a safeguard should he ever refuse to remain as the "Linchpin" and attempt to break free from his crystalline prison to seek vengeance.

Although the Soul King wouldn't do such a thing, his will instinctively rejected anything harmful to his existence. This was the reason behind the curse associated with the "Eight Mirror Sword."

Anyone who wielded the "Eight Mirror Sword" would lose their spouse to an unnatural death.

Each occurrence of this curse signified that the Ise family had inflicted harm upon the "god" of the Shinigami.

From this perspective, the Ise family likely aligned with the Tsunayashiro clan.

Perhaps only a divine weapon like the "Eight Mirror Sword" could sever the Soul King's limbs and extract his internal organs...

Nanao Ise's mother might have witnessed the darkest secrets of Soul Society after being ordered by the previous head of the Tsunayashiro clan to attack the "Soul King."

This could explain why she entrusted the Ise clan's heirloom to Shunsui Kyoraku and chose to commit suicide after her husband's murder, seeking atonement through death...

As for Nanao's father's killer, Ailin believed there was only one possibility – Tokinada Tsunayashiro.

The previous head of the Tsunayashiro clan had orchestrated the use of the "Eight Mirror Sword."

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After Tokinada Tsunayashiro eliminated all members of the Tsunayashiro clan and gained the secrets of the "Soul King's Power," he collaborated with Aura Michibane to collect "Soul King fragments" from Fullbringers, combining them with Hollows and Shinigami to create an incomplete "Hikone Ubuginu."

However, due to the absence of "Quincy power," the current Hikone lacked any body parts above the neck, sustained only by the flow of spiritual energy between his "Saketsu" and "Hakusui."

To complete Hikone, Tokinada Tsunayashiro attempted to coerce Nanao's mother into attacking the Soul King again, but she refused.

Even if she hadn't entrusted the artifact to Kyoraku, Nanao's mother would never raise her blade against that "god" again.

A million years ago, the Five Great Noble Houses gained control of these "authorities" due to their status.

Now, the high-ranking nobles who sought to ascend to the ranks of the "Great Nobles" needed to seize the corresponding authorities from the Five Great Houses.

The other three Great Houses were still at their peak.

Even Tokinada Tsunayashiro, alone but wielding the power of "Enrakyōten," remained one of the Five Great Nobles, with numerous high-ranking and low-ranking nobles serving him.

The Shiba clan, however, due to their persistent efforts to expose the crimes of the Five Great Houses, faced ostracization from all nobles. No noble family would dare support them.

If they could obtain the Shiba clan's legacy, the means to transport individuals to the Soul King Palace, they would gain the "authority" of a "Great Noble" and replace the declining Shiba clan as the new "Fifth Great Noble House."

...

"Hadō #31: Shakkahō!"

Within Kisuke Urahara's underground base, Nanao Ise vanished with Shunpo. A moment later, a red fireball struck her previous location, causing a massive explosion.

"Hadō #12: Fushibi!"

Nanao reappeared in midair, chanting a Kidō incantations. With a wave of her hand, seven or eight fist-sized fireballs shot towards Ailin.

"Bakudō #8: Seki!"

Ailin countered the incoming fireballs with a wave of his hand, generating an invisible repulsive force that deflected them.

Boom, boom, boom...

The fireballs exploded upon impact with the surrounding ground, leaving behind craters nearly a meter wide.

"Hadō #1: Shō!"

Ailin pointed his right index finger at Nanao, launching a transparent shockwave towards her.

"Bakudō #8: Seki!"

Nanao thrust her hands forward, creating a barrier of repulsive force before her.

Bang!

With a muffled thud, Nanao was pushed back.

"Bakudō #4: Hainawa!"

Just as Nanao prepared to continue her assault, a golden rope materialized beside her, binding her hands tightly.

"You lose, Nanao."

Ailin held the other end of the rope. He pulled Nanao down from the air. As she neared the ground, Ailin released his grip. Nanao, regaining her freedom, touched the ground with her hand and performed a somersault, landing gracefully before Ailin.

"Not bad, Nanao. Your use of Kidō has become quite proficient."

Although Nanao still couldn't hold her own against Ailin for long, he could see that she had developed her own "style" in utilizing Kidō.

"I still have a long way to go."

Nanao didn't show any pride in response to Ailin's praise. Despite feeling her strength growing rapidly during this period, it seemed to make little difference before Ailin.

Since she began training with him nearly three months ago, every spar ended within fifteen minutes.

"Hahaha, Nanao, don't be discouraged. There are few your age who possess your level of skill," Ailin chuckled, wondering if he had been too obvious.

He had deliberately timed each spar with Nanao to last exactly fifteen minutes.

Kidō battles were essentially battles of "wit."

Choosing the right Kidō for the right situation and environment was crucial.

During this fifteen-minute window, Ailin would sometimes surpass Nanao in speed, sometimes in strength, and sometimes employ various Bakudō techniques for distraction...

After spending the first two months learning new Kidō spells, Nanao had spent the past month sparring with Ailin in simulations of various environments and against opponents with different abilities.

Through this training, Nanao's Shunpo had improved significantly, alongside her Kidō skills.

"Nanao, remember, all battles are about defeating or killing the enemy while ensuring your own survival," Ailin explained.

"Therefore, before engaging in combat, you must remain calm, observe the battlefield, identify your advantages and disadvantages compared to the enemy, and find ways to turn those disadvantages into advantages."

"Yes, I understand, Uncle Ailin."

"There are still a few days left before the three-month mark. During this time, I'll teach you another interesting technique, Nanao," Ailin smirked. "If you can master this technique, you'll secure your place among the top vice-captains of the Gotei 13!

This technique is a pure perception skill, which I call 'Kenbunshoku'. First, let's take a look at Bakudō #58: Kakushitsuijaku, and then observe Bakudō #77: Tenteikūra..."

"These two Kidō spells are tracking techniques capable of sensing and locking onto another's spiritual pressure."

Ailin had previously taught this "Kenbunshoku" technique to his second disciple, Gin Ichimaru.

Combining Kidō with Hakuda was known as "Shunkō," a technique developed by Yoruichi Shihōin that rivaled the power of a Zanpakuto's Bankai.

After obtaining Yoruichi and Soi Fon's Zanpakuto, Ailin gained deeper insights into merging Kidō spiritual pressure with one's own.

Yoruichi, Soi Fon, and Yushiro Shihōin, all used "Shunkō" as an offensive technique that combined their spiritual pressure with the destructive power of Hadō.

"Kenbunshoku," on the other hand, was a support ability developed by Ailin based on the principles of "Shunkō" and inspired by the cultivation system of another world. By merging the perception of Bakudō with his own spiritual pressure, Ailin created a Shinigami version of "Kenbunshoku Haki."

Unlike "Shunkō," which significantly enhanced one's offensive capabilities, "Kenbunshoku" focused on enhancing perception.

Upon activating "Kenbunshoku," the user's awareness within a certain range would be amplified, allowing them to sense the enemy's movements, attacks, and even predict their actions with further mastery.

In Ailin's view, "Shunkō" was similar to the "Busoshoku Haki" of the pirate world. It was impossible to definitively say which was stronger, as it depended on the individual and their style.

For example, even if Ailin taught Nanao "Shunkō," her poor Hakuda skills would likely result in her defeat before she could even land a blow on the enemy.

"Kenbunshoku," however, would significantly improve Nanao's adaptability on the battlefield, allowing her to better utilize various Kidō techniques against her opponents.

As for Gin Ichimaru, "Kenbunshoku" perfectly complemented his Zanpakuto, "Shinsō."

Within the range of "Kenbunshoku," no one could evade Gin's attacks.

Of course, mastering such a powerful ability wouldn't happen overnight. Even after learning it, one needed ample time to familiarize themselves with it before applying it in combat.

To demonstrate the capabilities of "Kenbunshoku," Ailin closed his eyes and stood before Nanao.

"Nanao, you can use any means to attack me. I won't fight back or defend myself," he instructed. If you can force me out of this circle within fifteen minutes, I'll tell you something about your Ise family."

"Really?" Nanao's expression turned serious upon hearing Ailin's words.

Nanao had been a member of the 8th Division for decades. However, despite her extensive investigations, she found almost no records of the Ise family within Soul Society. It was as if the Ise family had never existed.

Such a situation was highly abnormal unless someone had deliberately erased all traces of their existence.