What is the most powerful force in this world?
Is it the Rinnegan?
Is it the Tenseigan?
Or perhaps the Sage Body, Sage Mode?
Or Kekkei Mora, the Six Paths power?
No, none of these.
The most powerful force in this world is Chakra… the most primal yet weak, yet also the broadest and strongest force.
So-called Sage Eyes, Sage Body, Kekkei Mora, Six Paths power are merely byproducts brought about by Chakra.
As long as one can analyze the essence of Chakra and perfectly control it, one can master all creation, becoming a god-like existence.
Precisely because of this, from the moment Ryuji obtained the Observation Device, he never stopped analyzing Chakra.
Only by analyzing Chakra's essence could he deduce the method to perfectly control it.
To this day, although the Observation Device hasn't fully analyzed Chakra's essence, it has analyzed many Chakra characteristics unknown in the Shinobi World.
Utilizing these characteristics, combined with knowledge from other worlds obtained through sign-ins, Ryuji developed countless byproducts.
Chakra-Amplifying Exoskeleton, artificial soul, Ninjutsu engraving, Chakra Storage Device, Sea of Consciousness...
But these weren't what he truly wanted. He wanted to completely master Chakra, become the ultimate in this world, even transcend the world's limits, becoming the one and only.
Although Chakra's essence hasn't been fully analyzed, from the information already obtained, Ryuji has conjectured about Chakra's nature.
That is, the energy of life.
The God Tree bearing the Chakra Fruit causes the earth to dry up, oceans to wither, and forests to decay.
Consuming Chakra within the human body leads to mental fatigue and physical soreness.
Based on this phenomenon, Ryuji conjectured that so-called Chakra is generated by absorbing life energy.
The God Tree absorbs the Earth's life energy to bear the Chakra Fruit (A/N: supplementary setting from Boruto). Humans refine Chakra by absorbing energy from body cells and mental cells.
Both origins are related to life.
Based on this conjecture, Ryuji began experiments on Chakra Generators.
Although, being just conjecture with no leads, countless experiments failed.
But during these countless attempts, many questions were verified one by one.
Ryuji grew increasingly certain of the conjecture that Chakra originates from life.
Hence, he turned his attention to the Dragon Vein and the Gelel Stone.
God bears witness, Ryuji's Mechanical City plan was absolutely not proposed for personal gain alone.
However, it simply overlapped with his original purpose.
Even without the Mechanical City plan, he would have come to explore and research the Dragon Vein and Gelel Stone.
Why?
In Ryuji's conjecture, if Chakra is a force derived from life, then the Dragon Vein and Gelel Ore should be the same.
Assuming the conjecture that Chakra originates from life energy is correct, then the Dragon Vein and Gelel Ore are Chakra born purely through natural changes without any external intervention.
If he could understand this natural change process, then it might be possible to create a Chakra Generator based on its principles.
Even further, from this birth process, clarify Chakra's essence and completely control it, becoming a god mastering all creation.
Therefore, Ryuji needed far more than just using the Dragon Vein's power like Mukade.
He needed to research it, thoroughly understand its principles.
Precisely because of this, he had the Queen of Roran seal the Dragon Vein.
He wanted to observe the connection between the seal and the Dragon Vein, the connection between the Queen and the Dragon Vein, to further research the Dragon Vein.
This tower was Queen Sara's residence and office, heavily guarded.
Ryuji had also infiltrated here.
Now, using Transformation Technique to look like one of Sara's guards, using puppet strings to control Sara walking ahead, he followed behind, heading down toward the Dragon Vein.
It must be said, Roran's architectural facilities were quite advanced.
Utilizing mechanical engineering brought by Mukade and the Dragon Vein as a power source, every tower had elevators and lighting facilities.
Even at night, interiors were bright as day.
Ryuji and Sara took the elevator to the lowest level, then stepped onto a spiral staircase seemingly leading to hell.
They walked a long way. Looking up, they couldn't see the top; looking down, they couldn't see the bottom, only a dark abyss.
Ryuji couldn't help but complain, "I'm speechless. Why do the upper parts of the tower have advanced lighting and elevators, but the lower parts use torches and staircases you have to walk?"
"Anrokuzan-sama must have his reasons for designing it this way." Sara seemed blindly trusting of that Prime Minister. Even for such illogical design, she still defended him.
Ryuji sneered at this.
A traitor puppeteer from Sunagakure, his strength merely an ordinary Jonin. Although there's nothing to criticize, there's nothing praiseworthy either.
That guy making such a design here was clearly worried about someone approaching the Dragon Vein.
But he didn't say much. This young girl was blindly trusting, even worshiping, Anrokuzan.
Speaking ill of him now might cause unexpected reactions.
"This is too slow. Let's fly."
"Fly?"
Before Sara could react, her body uncontrollably jumped from beside the staircase.
"Ahhh!!!"
Sara couldn't help but scream, then suddenly noticed the youth who had kidnapped her also jumped down.
Although fear still dominated her heart, curiosity quietly crept in, making her forget to scream.
"Release!"
Ryuji took out and opened a scroll, then formed hand seals.
As smoke rose, a mechanical bird made of thick hardwood combined with steel soared through the air, catching its master and the girl below, spiraling down into the abyss together.
"Wooah... we're flying!"
The girl brushed the hair falling over her forehead behind her ear, exclaiming with surprise and delight, completely forgetting she was kidnapped.
"It's just flying. What's so strange about that?" Ryuji said irritably. "Don't the puppets here all fly?"
"But they don't have seats for people!"
"So that Anrokuzan is an idiot, not utilizing the Dragon Vein's power properly at all."
The youth's muttering was largely blown away by the wind. The girl didn't hear clearly and loudly asked, "What did you say?"
The youth was about to repeat, but the 'purple magma' below had already come into view.
Not wanting unexpected issues, Ryuji didn't elaborate. "Nothing."
Sara noticed the youth's obvious evasion, but considering her status as a captive, she didn't press further.
Soon, the mechanical bird landed with the two at the very bottom.
A place like inside a volcano crater. Below, Chakra thick like magma flowed purple, occasionally bubbling and surging, creating waves.
The immense power was awe-inspiring and terrifying.