Seeing all three of their gazes turn toward the remaining two weapons of mass destruction, Haruki didn't waste any time. He walked over to one of them and began explaining.
"I call this one the Fire God Cannon. It uses six rotating steel barrels to disperse heat buildup from repeated detonations, allowing for a much higher rate of fire.
"The ammunition is the same size as that used by the Fire God's Spear. Because I can't acquire large quantities of explosive tags, I only produced one hundred rounds in total.
"By turning this handle, the barrels rotate. Chakra is still required to activate the explosive tags inside each round."
After the brief explanation, Haruki once again retreated behind Dodai.
All of these weapons were made from ordinary steel—some parts even hand-filed by him. Their durability was limited, and he wasn't sure they could withstand hundreds of consecutive detonations.
To improve stability, he hadn't built it to the scale of a Gatling gun. Instead, it was closer to an aircraft-mounted autocannon from his previous life—about two meters long and weighing over three hundred jin. The ammunition chamber in particular had been heavily reinforced.
A stepped forward eagerly. It didn't take him long to master the operation. He turned the handle, spinning the barrels, and simultaneously channeled chakra to trigger the explosive tags.
Bang! Bang! Bang!
The rotation sped up. The detonations grew faster—then merged into a near-continuous roar.
In just a few seconds, over a hundred rounds were expended. Flames sprayed violently from the barrels, raising the ambient temperature dramatically. The barrels glowed red-hot—but thankfully, the weapon didn't explode.
"That's it?!"
A looked deeply dissatisfied. He had just gotten into the rhythm, and the ammunition was already gone.
"Another round of that and it would explode."
Dodai chuckled, clearly pleased with the Fire God Cannon.
There was no need to inspect the far wall—the damage was guaranteed. The true value lay in the rate of fire.
If accuracy were improved, and the projectile strength enhanced, even a Kage-level combatant might not withstand sustained bombardment.
And if all of Haruki's ideas were fully realized…
The resulting destructive power was almost unimaginable.
Who would have thought that combining something as simple as blowpipes, fireworks, and explosive tags could produce such terrifying results?
Most importantly, the structure of this weapon was simple. At its core, it relied only on explosive tags—which meant mass production was possible.
That was the truly frightening part.
"So this is just an enlarged Fire God's Spear?"
The Third Raikage remained calm as ever, turning his attention to the final weapon. From its shape, it resembled the Fire God's Spear—but on a far larger scale. The barrel alone was as thick as his arm.
"Yes, Lord Raikage."
Haruki nodded and picked up the only shell prepared for it. He detached the shell's head—nearly thirty jin in weight—revealing the empty casing as he explained.
"This is a true artillery weapon. The shells are much larger than bullets and can be loaded with far more explosive tags. The warhead itself can also be filled with additional tags for a secondary detonation. The effective range should exceed ten kilometers.
"There are also pure bombardment shells—made larger and dropped from high altitude by ninja riding flying summons. These could be packed with steel pellets or shrapnel to devastate enemy formations.
"And the Fire God's Spear itself could be miniaturized for close combat. With the right adaptations, it could be paired with taijutsu—effective at close range or mid-range alike…"
The number of explosive tags a shell could hold was staggering.
Packed tightly, fitting a thousand tags into the casing wouldn't be difficult. The warhead could hold several hundred more. If ultra-compact sealing formulas like those seen in later eras could be developed, the payload—and the power—would increase even further.
Unfortunately, explosive tags were strategic materials. Even active ninja were limited in how many they could purchase, and every transaction was registered. As a mere Academy student, Haruki could only buy small amounts. The hundred rounds used for the Fire God's Spear and Cannon had taken him years to accumulate.
Weapon construction was also inherently dangerous and required extensive calculations and testing. What he had built were only rough prototypes.
Even the Fire God's Spear and Cannon had deformed after a single use. If this artillery piece were fully loaded—especially with high-grade explosive tags—the risk of catastrophic failure would skyrocket.
"You mentioned earlier that you also possess A-rank intelligence."
The Third Raikage examined the disassembled shell with satisfaction before bringing the conversation back on track.
Between the one billion ryō and these three weapons of mass destruction, Haruki had already earned his approval. Taking him as a student posed no issue.
"That intelligence can only be disclosed after Lord Raikage accepts me as his student."
Haruki's eyes flickered slightly as he stated his condition—a layer of insurance.
"So you're playing games with me now?"
The Third Raikage laughed, clearly not offended. Then he asked casually,
"Then tell me—where did that one billion ryō come from?"
Even without hearing the intelligence yet, he was certain this boy wasn't from any known ninja clan. And even the wealthiest clans couldn't produce one billion ryō in liquid assets.
"That also has to wait until you agree."
Haruki's gaze flickered again. He was determined to lock in the teacher–student relationship first.
"You little brat!"
The Third Raikage reached out and roughly ruffled the boy's pale hair, laughing.
"Fine. I'll take you as my student. Now you can speak."
Though he claimed not to mind, his curiosity was clearly piqued.
"Yes teacher."
Haruki was overjoyed. He immediately bowed deeply, finally letting out the breath he'd been holding.
Once he became the Raikage's student, he wouldn't be sent straight to the battlefield as expendable fodder. He would gain access to the Raikage's inheritance—techniques such as the Lightning Release Chakra Mode and Hell Stab.
More importantly, he would gain access to higher-level resources to support his training.
This world placed immense importance on bloodlines.
Without a strong lineage, becoming powerful was extraordinarily difficult—chakra quantity and elemental affinity alone could be fatal bottlenecks.
To reach the very top, one needed either a secret technique inheritance or Ōtsutsuki blood.
Haruki had neither.
With no bloodline, no cheat ability, and no shortcuts, he could only rely on ingenuity to create opportunities for himself. That was why he had poured so much effort into developing these weapons—to establish merit, demonstrate value, and bypass his innate limitations.
After steadying his emotions, Haruki asked cautiously:
"Teacher… have you ever read The Biography of Katō Bin?"
"Katō Bin failed the Chūnin Exams."
Before the Third Raikage could answer, A blurted out in surprise.
Haruki's expression instantly turned strange.
Dodai also shot A a peculiar look.
Realizing the stares, A quickly lowered his head.
"Katō Bin? Katō… That surname does exist in Konoha."
The Third Raikage glanced at his son, then pondered aloud. He vaguely recalled a Katō clan in the Leaf Village.
"Then what about That Bloodline Is No Ordinary Thing?"
"What's that?"
The Third Raikage frowned. He'd never heard of it.
"And The Tragedy of the Female Ninja?"
"So Many Beauties in the Shinobi World?"
"The Carefree Rogue Ninja?"
"The Kusanagi Chronicles?"
"The Gatekeeper Sarutobi's Tales?"
"The Complete Record of the Fire Shadow?"
...
Haruki rattled off dozens of book titles in succession.
The Third Raikage's frown deepened, confusion and bewilderment growing by the second.
Meanwhile, Dodai and A wore extremely complicated expressions, staring at the boy in disbelief.