With Hozuki Castle currently leaderless after Mui's defeat, Makoto and the others had no choice but to stay on the island for a few days to maintain order and keep the prisoners in check.
The Hidden Cloud had already dispatched a hawk to the Hidden Grass Village to summon an official administrative replacement.
(In the original Blood Prison movie's ending, it was never mentioned who the new Warden of the castle was. But during the Boruto era, the Warden was a man named Mujo. Mujo looked very similar to Mui, was about the same age, and it was unknown if they were related).
"Strange."
Yugito, feeling incredibly bored while resting in the VIP quarters, picked up some confiscated administrative documents from the table.
After reading the profile of the upcoming replacement Warden, "Mujo," she discovered a glaring problem.
"Speaking of which... does the Hidden Grass Village even have a native clan with the 'Mu' family name?"
Yugito mused aloud, stroking her chin. "And Hozuki Castle? Isn't the Hozuki Clan native to the Hidden Mist Village? The 'Mu' surname... I haven't heard of any famous historical figures with that name before..."
"No, there actually is one," Samui replied calmly, shaking her head slightly from the armchair.
"The Second Tsuchikage of the Hidden Stone. His name was Mu."
"Then that makes even less sense!" Yugito argued, taking a sip from a glass of warm milk.
"One famous guy from the Hidden Stone, and a clan from the Hidden Mist? Those are two completely separate nations with historically terrible diplomatic relations. Why would a prison in the neutral Grass Village be named after them?"
"Wrong. That actually makes it more fitting," Karui suddenly chimed in.
With a conspiratorial grin, Karui reached into her ninja tool pouch and pulled out a worn paperback book conspicuously marked with a red [CONFISCATED/FORBIDDEN] stamp.
"What's this? And why does that make it more fitting?" Yugito curiously leaned in.
"Do you remember that day a few weeks ago? The contraband book Samui and I found in the barracks, which we showed you?" Karui wiggled her eyebrows.
"...This is that book?" Yugito fell dead silent for a moment.
Back when Kakashi's cursed masterpiece 'Vigorous Paradise', was first published and smuggled across international borders, the Raikage had personally confiscated a copy and read some of its contents in his office to "assess the cultural threat."
After reading the graphic, highly fictionalized plots about the Raikage transplanting a vagina, Onoki forming "deep physical bonds" with him and other such storylines, Ay had violently smashed his desk in half and angrily thrown the book out the window.
Of course, the magnanimous Raikage didn't officially ban the book—that would only increase demand.
But the people of the Hidden Cloud knew their limits well; at least no one would openly read this cursed literature in public.
After the book was thrown out the Raikage's window that day, it was secretly scavenged by Team Samui, who had just completed a mission and were walking up to the tower to report.
To be precise, Karui was the degenerate who picked it up.
After sharing and reading parts of it with Samui (for purely academic purposes of course), they had hunted down Yugito who was training outside, and forced her to read some of the cursed text too.
Yugito, being a serious, battle-hardened Jinchuriki, naturally had zero interest in such boring, smutty content and was completely unaware of the subsequent volume releases.
Right now, she just wanted to know why Karui was bringing up this cursed contraband again.
'Could it be that this smut book contained some actual, hidden military intelligence?'
"Of course it's not that exact book," Karui shook her head.
She peeled off the "Forbidden" label on the cover, proudly opening it.
"This is the sequel! The newly smuggled Second Edition!"
"..." Yugito was speechless.
'A sequel? What difference did that make?'
"But this one records the exact historical connections you want to know about!" Karui whispered excitedly.
"You know, there's no smoke without fire. If some anonymous author wrote such specific, detailed content about Kage-level figures, they must have had access to highly classified intelligence archives to be able to write it!"
As Karui said this, her expression suddenly turned deadly serious.
"Why?" Samui didn't follow the logic.
Yugito also looked at Karui with equal confusion.
"I once heard a Cloud scholar say that what happens in reality is often more absurd than the stories described in fiction," Karui began her grand conspiracy theory.
"Because fictional stories need to follow logical narrative rules, while reality doesn't."
"Think carefully! Are the various insane, political storylines in these books really plots that a normal human author could just invent from thin air? No! Since they're too absurd to be purely fictional, there's only one logical possibility."
Karui tapped the book. "These events must have truly happened in history, but were slightly modified by a rogue Konoha intelligence officer hiding the truth in plain sight! We can completely filter out the real, classified intelligence from the smut, discarding the false embellishments to learn the secrets of the Warring States era!"
"..."
"That actually makes a terrifying amount of sense," Samui nodded slowly, completely buying into the delusion.
"Mm."
Upon hearing this flawless deduction, Samui and Yugito both thought it perfectly reasonable.
They sat on either side of Karui and began intensely flipping through the cursed book, treating it like a decoded enemy cipher.
"No need to search, I've already finished studying this volume. What you want to know about Hozuki Castle is right on this page—" Karui smiled confidently, counted a few pages with her finger, and flipped directly to Chapter 4.
Historical records about Mu (the Second Tsuchikage) and Gengetsu Hozuki (the Second Mizukage) are incredibly scarce in the modern ninja world.
It is officially known only that the two men had a bitter, lifelong rivalry, and that Mu's iconic full-body bandages were due to horrific disfiguring burns he suffered from Gengetsu's Joki Boi explosion.
They eventually killed each other in a final duel.
But Kakashi's book "revealed" the hidden, tragic truth.
According to Vigorous Paradise: Volume 2, Mu and Gengetsu Hozuki were actually a passionate couple who were tragically forced into military opposition because of their warring villages' politics.
There was actually a deeply romantic, hidden reason behind Mu's horrific injuries from the steam explosion.
When the Stone and the Mist were at war, the 'inherently evil' scheming Second Hokage (Tobirama Senju) came to the battlefield, attempting to manipulate and profit from their conflict.
Even though Mu and Gengetsu realized the trap and stopped fighting each other in time, they were cornered.
To buy time for his cherished lover to escape, and to deal with the inherently evil Tobirama, Mu used his Fission Technique.
He tightly grappled Tobirama, holding him down while crying out tragically to Gengetsu.
"Gengetsu! Blow it up! Blow it up now! In life I was yours, in death I'll be your ghost! Don't make me look down on you!"
To protect the Stone ninja that Mu cherished, and the Mist ninja that he himself cherished, a weeping Gengetsu painfully detonated the Joki Boy.
In that moment, Gengetsu felt as if his very heart was being torn apart.
He had been forced to personally kill his beloved!
Unfortunately, Gengetsu didn't have the Uchiha Sharingan; otherwise, the emotional trauma would have awakened the Mangekyo in minutes.
The pain was just too agonizing!
What made it even more painful was that the inherently evil Tobirama Senju actually knew Space-Time Ninjutsu, using Flying Thunder God to cowardly escape the blast radius at the very last microsecond.
Only Mu bore the full, devastating brunt of his lover's steam explosion.
Thus, in later historical records, Konoha covered up the truth and it became officially recorded that the Second Mizukage's explosion burned Mu's entire body in a bitter duel.
Fortunately, Mu didn't die in the blast.
Though he was left with full-body third-degree burns and terrible disfigurement, Gengetsu Hozuki's love never wavered.
He loved Mu's inner soul, not his physical appearance.
The two Kage connected deeply in secret after the war, but their forbidden relationship was ultimately deemed unacceptable by the conservative elders of both the Stone and Mist villages.
So, they faked their own deaths in a "final duel," retreated overseas, found a secluded island paradise, and lived there together in peace for some time.
They adopted an orphan.
Their child inherited the surname "Mu," representing Mu.
On the island where they lived, Mu used Earth Release to raise the foundation of a massive fortress to protect their family.
The fortress was named Hozuki Castle, symbolizing Gengetsu Hozuki's protection.
After living on the island for a while, they ultimately couldn't set aside their nagging sense of duty toward the ninja world.
In the end, the gay lovers chose to leave their paradise and return to society.
But for the sake of their adopted child, they established a new, neutral Ninja Village near the Stone borders—the Hidden Grass Village.
The word "Grass" alludes to Wood Release—a fusion of Water (Mist) and Earth (Stone)—symbolizing the ultimate, fruitful union of Mu and Gengetsu Hozuki's love.
At the same time, since Mu possessed Earth, Fire, and Wind chakra attributes, it made perfect genetic sense that their adopted descendant, Warden Mui of Hozuki Castle, excelled at the Fire Style: Celestial Prison technique.
The Celestial Prison was actually a protective ninja technique developed by Mu in loving memory of his beloved, passed down to the descendants of the Grass Village.
"Wow... isn't it a deeply touching story?" Karui wiped a tear from her eye.
"Yes. It truly is a poignant, tragic epic of forbidden love and political sacrifice," Samui nodded solemnly.
"I never imagined the previous generation Kage of the Stone and Mist Villages had such a deeply romantic, tragic past," Yugito sighed, genuinely moved by the historical lore.
"Karui, you're right—reality doesn't need to follow logic. This has to be real intel," Yugito mused over the emotional plot she had just read, taking another sip of her warm milk.
"Though, if this were just a cheap fictional novel, the female Second Mizukage should have been the one tragically disfigured to add drama, right? How could it be the male Second Tsuchikage who got burned?"
"Huh?"
Karui was taken aback, blinking in utter confusion.
"Yugito... who told you the Second Mizukage was a woman? Gengetsu Hozuki is a man!"
Karui quickly flipped a couple of pages back to the character glossary to find an official historical illustration of Gengetsu—a tall, smirking man with a pencil mustache and no eyebrows—and shoved it in front of Yugito's face.
"Pfffft!"
Yugito violently choked, spraying warm milk all over the cursed book.
"..."