It is also meant to protect the truth.
For countless years, the people of the Soul Society have known only of the Spirit King—never His true form, never the royal family, never the reality of what the Royal Realm is. The entire system is designed so that the masses believe a supreme monarch sits above them, maintaining absolute control.
Every few years, the Central 46 arranges for the ceremonial transfer of the Ōken Seal, an artifact forged from the Spirit King's own power. It is displayed publicly to imply the royal family's continued oversight.
The great noble houses adopt their most humble posture during these displays, bowing deeply as if they are loyal servants.
But the truth is very different.
Their ancestors were the ones who murdered the Spirit King.
Back to the matter at hand.
The power of rules—the fundamental laws that bind the world—is the key to sealing the Spirit King. Accumulating more rule-based power also strengthens the legitimacy of the Shinigami as rulers within the cosmic balance.
At present, the four major rule-bearers of the Zero Division provide more than enough stability.
But now, in the Soul Society below, a new rule-type power has been born, and it happens to align with a fragment of the future Ichibei Hyōsube glimpsed long ago.
And Ichibei Hyōsube has never minded preparing early.
When Kirinji Tenjirō, Nimaiya Ōetsu, and Shutara Senjumaru gathered before him in the Palace of the Spirit King, Ichibei sat cross-legged on the polished floor and spoke:
"In Seireitei, Kirio Hikifune, Captain of the 12th Division, has created something that shifts the foundation of Soul Society. It is enough for her to ascend to the Royal Guard."
He opened his eyes slightly.
"Which of you will go down to retrieve her?"
Naturally, Ichibei cannot leave the Spirit King Palace casually.
Even in the manga, he only descended because the situation with Yhwach threatened the world itself.
Under normal conditions, bringing someone to the Zero Division must be handled by the other members.
"Going to Seireitei, huh?"
Ōetsu stroked his chin. "Can't say I've been down there in ages. Always wanted to take a look again."
Kirinji immediately rejected the idea.
"Forget it. When I brought Shutara back here, I passed through Seireitei. It's changed a lot, sure, but there ain't much worth going back for."
From the looks of it, Ōetsu was the one preparing to descend, and Hikifune Kirio would soon enter the Zero Division.
But just as Ichibei was about to speak—
Shutara Senjumaru said softly, "Let me go."
Both Kirinji and Ōetsu turned toward her, surprised.
Though she is the newest member of the Royal Guard, many years have passed since her ascension. Senjumaru has fully adapted to her place in the Zero Division and to the strange companionship of its members.
Calmly, she continued:
"I once served in the 12th Division as well. I am familiar with Kirio Hikifune. Let me go down and speak to her."
Being promoted to the Zero Division is an honor, but not all captains accept the position.
Just as the Gotei 13 selects its officers, the Zero Division's recruitment is a two-way decision.
Ōetsu wanted to see Seireitei again, but since Senjumaru spoke with certainty, he deferred. After all, even if he descended, he could not guarantee Hikifune's acceptance.
But Senjumaru Shutara was different.
She knew Hikifune from the old days. There would be no issue convincing her.
Within the 12th Division, Hikifune Kirio had recently become widely spoken of.
She had finally completed the theory she had proposed long ago.
She called it the "Artificial Soul"—a manufactured, temporary soul created through controlled reiryoku structuring.
The birth and death of souls follow invisible cosmic laws.
But Hikifune asked: Can a Shinigami learn to create souls deliberately?
She published her findings in the Seireitei Communication, inspiring countless Shinigami.
Urahara Kisuke was among those influenced—he even created the Gigai-based Tenshintai while studying her principles, which allowed him to manifest Bankai in a compressed period of time.
This alone proved the validity of her theories.
But now Hikifune had successfully completed the Artificial Soul—confirming the concept beyond doubt.
It was a scientific breakthrough, yes.
But to perceptive Shinigami, it represented something far greater.
Until now, the cycle of souls—birth, transformation, and return—was untouchable, a domain belonging only to the gods.
But Hikifune Kirio had extended Shinigami research into this divine territory.
If such development continued, Shinigami could one day approach the status of true gods.
Her achievement elevated her reputation within the Gotei 13 to unprecedented heights.
Within the 11th Division, Gosuke Shigure praised Hikifune immediately upon learning she had perfected the Artificial Soul theory. But afterward, he began watching something very specific:
The sky itself.
To ordinary Shinigami, the sky holds nothing unusual—sun, moon, clouds.
But Shigure knew otherwise.
Above the sky of Seireitei lies a separate realm—the Royal Palace.
Hikifune's creation of the Artificial Soul was, in the manga timeline, the exact reason she was promoted to the Zero Division.
Obviously, she would not go there on her own.
Members of the Zero Division would have to descend.
And because of the nature of his Zanpakutō, Shigure long wanted to meet Nimaiya Ōetsu, the man who personally forged the original Zanpakutō. But there was no way to contact the Royal Guard under normal circumstances.
This time, however—Hikifune's promotion—might create an opportunity.
That day, Shigure felt a massive spike of Reiatsu descending from the sky.
It vanished just as quickly, but he understood what it meant.
The Zero Division had arrived in the Soul Society.