After locking the study door behind him, Uchiha Fugaku stepped into the hidden chamber beneath the room.
Due to the recent intrusion incident, he had already relocated the precious scrolls and weapons stored within this chamber to a backup vault.
Now, after some minor modifications, the chamber had been repurposed into a private training space.
He lit the chamber's lamp, took out a sealing scroll, and unfurled it.
"Psssh—"
With a puff of smoke, a massive scroll appeared in his hands—none other than the Scroll of Seals stolen from the Hokage Tower.
"What a complex seal..."
His eyes narrowed as he examined the scroll, noting the intricate sealing patterns engraved on it.
A critical item like the Scroll of Seals would naturally be protected with powerful enchantments. Without knowing the proper unsealing method, any attempt to force it open would instantly trigger its self-destruction.
"I still can't figure out how Uzumaki Naruto managed to steal this thing and actually break the seal..."
The thought of Naruto, a mere genin at the time, successfully sneaking the scroll out of the vault and even unlocking it, struck him as laughable.
If he hadn't seen it happen with his own eyes, he wouldn't believe it for a second.
To him, it had clearly been a setup—a carefully orchestrated scheme.
The purpose? To give Naruto a justifiable reason to come into contact with sealing arts—and to learn forbidden techniques from the scroll.
Otherwise, how could a genin like Naruto possibly succeed where even a Kage-level shinobi like himself had almost been caught during the theft?
"Five layers of seals... It's going to take some serious time to unravel them."
Activating his Sharingan, he began tracing the chakra flow within the seals, proceeding with meticulous care to dismantle them.
It was a task that demanded absolute patience and caution. One wrong move could trigger the self-destruction mechanism and destroy the entire scroll.
---
"Finally... it's done!"
It took him a full three days to disarm the five layers of seals and completely unseal the Scroll of Seals.
Without delay, he opened it, eyes scanning eagerly over the contents.
"Multi Shadow Clone Jutsu!"
The first forbidden technique listed was the Multi Shadow Clone Jutsu.
An advanced version of the Shadow Clone Jutsu, it could create dozens—hundreds—of clones, far beyond the normal limits.
But this jutsu was labeled forbidden for a reason: its chakra consumption was dangerously high. A careless user could drain themselves to death.
"The basic Shadow Clone is more than enough for me. This one's not suited for my use."
He quickly dismissed it. Despite his vast chakra reserves as a Kage-level shinobi, even he couldn't afford the reckless consumption this technique required.
Only someone with a unique chakra constitution like Uzumaki Naruto could hope to wield it effectively.
He continued flipping through the scroll.
"Four Symbols Seal."
The next technique was the Four Symbols Seal—a powerful and highly intricate sealing method.
It worked by harnessing the cyclical forces of the four symbols to suppress evil, providing immense sealing power.
Its classification as a forbidden technique stemmed from both its difficulty and power—only those with exceptional talent in sealing arts could hope to master it.
"A potential option. It'll depend on whether I have enough talent in fūinjutsu."
He kept going, scanning one forbidden technique after another.
Altogether, the scroll contained more than a dozen forbidden jutsu. Some he had heard of before, but many were entirely new to him.
Eventually, he arrived at the section detailing the technique he was most interested in—Flying Thunder God Jutsu.
He began reading it in detail.
"As expected, it requires an extraordinary space-time affinity."
Right from the introduction, the scroll emphasized that mastering this technique demanded extremely high spatial perception and aptitude.
This aligned perfectly with what he had previously suspected. Now, it was confirmed.
"Flying Thunder God Formula..."
The first step in mastering the technique was to learn how to inscribe the Flying Thunder God Formula—a special chakra marker imbued with space-time properties.
Like all chakra-nature-based jutsu, only those who possessed the relevant chakra attribute could use them to full effect.
The same rule applied here: only someone with a high spatial affinity could successfully draw and activate the formula.
The second step involved sensing the spatial coordinates anchored by the formula.
Once the chakra marker was properly drawn, it would transform into a spatial beacon—the key to teleportation.
But sensing those coordinates required even greater spatial sensitivity. Without it, the marker would be useless.
The third and final step was forming a connection with the coordinates and activating the space-time jump.
Achieving this meant the user had taken their first step toward mastering the Flying Thunder God Jutsu.
Of course, even then, it would be far from the level of the Second or Fourth Hokage. Mastery like theirs required profound understanding and absolute control.
After committing every word to memory, Fugaku began practicing the first step: drawing the Flying Thunder God Formula.
He took out a kunai and started inscribing the mark onto its handle.
"Psssh—"
A thin black line appeared, but just as it began to extend further—it stopped. Then it slowly faded, disappearing without a trace.
A failed attempt.
"Failure."
"Failure."
"Failure."
Over and over, he tried, yet every single time ended the same way.
After several hours of effort, with almost no progress, he finally stopped.
"It seems I don't have a strong enough spatial affinity. Or maybe I do have one—but it's nowhere near the level needed for Flying Thunder God."
Drawing the chakra formula was supposed to be the simplest of the three steps.
And yet he had spent hours and failed repeatedly—clear proof that his spatial aptitude was lacking.
"This jutsu isn't suitable for me... Unless I can obtain the corpse of someone with extremely high spatial talent and perform corpse refinement."
Shaking his head, Fugaku decided to temporarily give up on the Flying Thunder God Jutsu.
Such spatial prodigies were exceedingly rare. That was why, throughout history, only the Second and Fourth Hokage had ever truly mastered it.
Because he hadn't placed too much hope in success, he wasn't particularly disappointed. Closing that section, he turned to the next Eight Gates Released Formation.
With renewed focus, he began preparing to train in the Eight Gates.