Kumogakure.
This shinobi village, built high among towering peaks, shrouded in drifting clouds and echoing with deafening thunder, was the Land of Lightning's mighty military force — and currently one of the top three strongest powers in the entire shinobi world.
And today, this very village was gathering some of the most powerful and influential figures in all the shinobi world for a conference.
"Kumogakure really is a fortress that's easy to defend and hard to attack."
From afar, Yoru stood at the front of the carriage, gazing at the village nestled within the clouds, and suddenly chuckled.
"Fugaku, are you scared to come here for a meeting?"
The Konoha delegation — who had joined up with Yoru halfway here — froze for a moment. Even Fugaku himself didn't quite grasp Yoru's meaning at first.
But Uchiha Setsuna, who had accompanied them, caught the reference immediately; his eyes lit up, and a smile spread across his face.
"Fifth Hokage, that... that thing..."
After Setsuna whispered a reminder, Fugaku finally understood what Yoru meant. He gave a wry smile and shook his head.
"Times have changed. We're here today to discuss how to deal with the Akatsuki. And besides, with you here — there's nothing to be afraid of."
"Hahahaha, the Fifth Hokage speaks true. With the Mizukage here, even if another pair of vicious fiends like the Gold and Silver Brothers showed up, they'd be nothing to worry about."
The Fourth Kazekage, Rasa, laughed aloud from the other side — clearly understanding Yoru's reference as well.
In that moment, all three villages' delegations laughed together.
After all, Konoha had sent an elite Uchiha unit, so poking fun at the "white-haired Second" was only natural.
Decades ago…
When the First Shinobi World War broke out, Kumogakure attacked Konoha — only to end in defeat.
At the postwar peace talks, the Gold and Silver Brothers refused to accept the loss. Wanting to prolong the war, they staged a coup during the alliance ceremony between the Raikage and Hokage.
Using the power of the Six Paths' treasured tools and Nine-Tails chakra, they brutally killed their own leader, the Second Raikage, and grievously wounded the Second Hokage, bringing him to the brink of death.
Although decades had passed since then, Kumogakure had gone to great lengths to make the world forget this incident. Nearly all subsequent negotiation venues were chosen outside the village, and everyone silently acknowledged this arrangement.
But this time, the Fourth Raikage had chosen to hold the meeting inside Kumogakure itself — showing how seriously he took this Kage Summit.
Then again, it wasn't hard to see why.
Kumogakure possessed both the Eight-Tails and Two-Tails — each of enormous importance to the village.
Especially the Eight-Tails' jinchūriki, Killer B, who is none other than the Fourth Raikage's brother!
The bond of the "A and B" duo, combined with the value of a jinchūriki, has driven the Raikage—who has already endured the pain of losing his father—to protect Killer B at all costs and thwart the sinister ambitions of the Akatsuki, especially as Kirigakure grows ever stronger.
As the group chatted and laughed, they approached the village entrance, where Killer B stood waiting in the distance.
Upon seeing Yoru and the others, B strode forward to greet them. Behind him came the village elders, elite shinobi, and his assistant Mabui — all showing proper courtesy.
"Mizukage-sama, you've traveled a long way! Thank you for your hard work!"
A approached with long strides, addressing Yoru first. After Yoru returned the nod with a smile, A turned to the Hokage and Kazekage.
"Didn't expect you two to come with the Mizukage… The accommodations are ready, but this alliance against Akatsuki is of utmost urgency. The longer we delay, the more things could change — let's hold the meeting tomorrow!"
"So soon?" Rasa glanced at Yoru and said gravely, "The Tsuchikage hasn't arrived yet."
"That old man won't come!"
A snorted, his tone dripping with open disdain for Ōnoki.
"The beasts in his village have long been gone, and who knows where they've been revived now. Since it was me who called this meeting, he probably tossed the invitation straight into the trash without even reading it."
Such hostility left Fugaku and Rasa a little helpless. In their view, the more allies they had against Akatsuki, the better.
As the Third Tsuchikage — the only remaining "Third" among the Five Kage — Ōnoki's Dust Release Kekkei Tōta was unparalleled. Having his help would be a huge advantage.
Sure, one could say Yoru alone would be enough, but with so many Akatsuki members, it wasn't practical to have him fight them all by himself.
Still, they all understood the deep-rooted grudge between Kumogakure and Iwagakure — going back even before the villages' founding, into the Warring States era.
After the Second Shinobi War, the AB combo had constantly trained within the Land of Earth's borders. And before the Third War, the Third Raikage had been surrounded by ten thousand Iwa-nin and ultimately died in battle.
Their enmity had long since reached the point of no reconciliation. Without the Four-Tails and Five-Tails, it wasn't surprising Ōnoki wanted no part in this.
They dropped the subject and, after some polite exchanges, followed A into the village. A welcome feast was held at a large inn, after which A personally escorted Yoru and company to a spacious row of residences.
"The left compound is for the Kazekage, the right for the Hokage, and the middle one is yours, Mizukage."
As A spoke, he signaled for ANBU to guide the other Kage to their lodgings.
Rasa and Fugaku clearly noticed A still had things to discuss privately with Yoru, so they simply gave a nod and left with their people.
A then personally led Yoru's group into the middle residence.
"You go and take care of the luggage first."
Yoru waved to Mei Terumī, and once she left the room, he turned to the Raikage.
"Alright, speak — what is it?"
"It's about certain questions regarding spiritual power."
Without beating around the bush, A began asking Yoru a series of questions:
"If someone already trained in chakra converts it into spiritual power, their strength increases noticeably — spiritual power is stronger than chakra. But if there's energy loss in the conversion… would starting with spiritual power from the beginning, instead of chakra, make someone even stronger?"
"Also — how exactly is spiritual power cultivated? Could someone with no shinobi talent use spiritual power to become strong?"
The more A asked, the more pleased Yoru became.
Clearly, A already fully accepted the concept of spiritual power — even considering it as a possible central strategy for Kumogakure and the Land of Lightning's future.
For such an eager seeker, Yoru was happy to explain. Under A's astonished gaze, he began writing words in midair.
This alone left A dumbfounded.
Anyone could use chakra to leave markings in the air — but making them remain stable like this was something far fewer could do.
And he realized Yoru was doing this not with spiritual power, but chakra.
Using both energies at once…?
After finishing the floating words, Yoru glanced at A — then at the half-open door — and smiled faintly.
"Since you're here, you might as well listen in. This should help you greatly."
Outside, someone hesitated before pushing the door open. Pale yellow short hair framed a fair face.
Standing at Yoru's side, Samui made A look a bit uncomfortable — in his plan, it wasn't time for her to appear yet. But if Yoru allowed it, so be it.
"What you're curious about, Raikage-sama, boils down to the nature of spiritual power. To understand that, we first need to understand the difference between chakra and spiritual power."
"Chakra is produced by evenly blending mental energy and physical energy. The same applies to stamina — it all comes down to your base constitution, or talent."
"Spiritual power is the same."
Letting the floating words drift before them, Yoru's gaze lingered on Samui as his voice softened.
"Despite its name, 'spiritual power' isn't purely the strength of the soul. It uses the soul as its core, but fuses multiple forms of energy into the final product."
"So, like chakra, its strength varies with talent — but its foundation lies in the soul."
"In the shinobi world, those with the Sage of Six Paths' bloodline or kekkei genkai are born stronger than the average person. Likewise, those with strong souls will have stronger spiritual power; those with weaker souls will have weaker power."
"Which brings us to the key point — how to gauge the strength of a soul, and the versatility of spiritual power."
Pulling the floating text closer like a teacher with a chalkboard, Yoru continued.
He didn't know why A had brought Samui — logically, Darui, who'd inherited the Third Raikage's Black Lightning and already begun converting his chakra into spiritual power, was the more gifted choice.
Could it be because…?
But that was A's business — Yoru just taught.
"As shinobi, you're familiar with chakra — how it flows through the body's tenketsu once refined. The Hyūga clan, for example, can shut down chakra points with the Gentle Fist."
"Spiritual power is different. In this world, ordinary means can't directly observe the soul. But the soul — the foundation of a person — holds all their core information: ideals, emotions, thoughts."
"A strong soul can bear more of this 'data' — though having more doesn't always mean greater power, strong souls are inherently more capable of bearing it."
"Certain special genjutsu, the Yamanaka clan's Mind Body Switch Technique, or your Blood Dragon Eye kekkei genkai from years past — all can stimulate a target's soul to gauge its strength."
"By the way, Raikage-sama, you've brought the Chinoike clan back into the village, haven't you?"
A paused, then nodded.
"Yes, though there aren't many of them left. And their emotions are unstable — integrating them may be difficult."
"They're like Konoha's Uchiha clan — a shinobi clan of 'great love,' with naturally strong emotional swings. Kumogakure's atmosphere is far more tolerant than Konoha's; you should be able to accommodate them."
"If you really want to identify those with strong souls, I can give one or two Chinoike members a special boost — raise their spiritual power in advance. Combined with their talent, that should meet your needs."
At this, A was overjoyed.
"Then I thank you, Mizukage-sama!"
"Alright — next, let's talk about the versatility of spiritual power…"
Yoru spoke at length, explaining every aspect. Samui listened intently, sometimes lost in thought, sometimes testing it for herself — feeling the shifts between her spiritual power and chakra.
A, on the other hand, kept asking about cultivation details — but showed no intention of converting his own chakra.
He clearly meant to wait until others in the village had mastered spiritual power before changing himself — not out of fear of harm, but to ensure he could remain as sharp and strong as ever to protect the village.
Yoru wasn't surprised by this.
After all A's questions were answered, he looked between Yoru — patient and thorough — and Samui, who took notes, practiced hands-on, yet still had questions. His brows furrowed deeply.
"No need to rush. Spiritual power is vast — you just have to take your time with it."
Yoru's tone was warm. Samui's calm, knowledgeable nature made her an ideal student, and for those eager to learn, Yoru always had patience.
Then A suddenly spoke:
"Mizukage-sama, why not take Samui as your disciple?"
"…What?" Yoru blinked.
"I know the request is abrupt — even presumptuous. But among our younger generation, Samui is the calmest and most knowledgeable. She's the one most suited to fully researching your spiritual power and helping Kumogakure complete the shift from chakra to spiritual power."
"I understand you have no obligation as Mizukage… but as Raikage, I must think of my entire village!"
With that, the Fourth Raikage looked Yoru straight in the eye — and even lowered his head.
"Please, Mizukage — I'm asking you!"