Sengoku left the weapons shop with four training tags and his remaining two thousand Ryo tucked safely inside his jacket. He didn't head straight back to his stone house. His heart hammered a steady, driving rhythm against his ribs—not out of fear, but from the sheer, electric anticipation of turning his blueprints into reality.
He had his capital, and he had his explosive cores. Now, he needed the chassis.
He steered his path toward a much louder, more cluttered district on the opposite side of the village. The air here smelled of sulfur and burning coal, punctuated by the rhythmic, deafening clang of hammers striking anvils. This was the industrial sector, a collection of blacksmiths and material workshops catering to ordinary villagers and lower-ranking shinobi.
Sengoku stepped into a busy shop overflowing with scrap metal and raw materials. The owner, a hulking man covered in grease and iron dust, was fiercely hammering a glowing red iron bar. Sengoku stood quietly by the doorway, waiting for the man to finish. Only when the blacksmith plunged the iron into a quenching trough—sending up a loud hiss and a thick cloud of white steam—did Sengoku approach the counter.
He listed his requirements with absolute precision: moderate-thickness iron sheeting, several spools of high-tensile metallic wire, standard-sized micro-rivets, and most importantly, a heavy-duty set of metalworking tools. The delicate carving knives he used for sandstone would snap instantly against iron.
The blacksmith raised a greasy eyebrow, surprised to hear a seven-year-old rattle off industrial terminology. But in a hidden ninja village, strange requests were common; just last week, another academy brat had bought out his stock of trap springs. Without asking questions, the man gathered the order.
The raw materials were cheap, but the specialized tools ate heavily into Sengoku's budget. He handed over a little more than a thousand Ryo, leaving him with very little leftover cash. But as he hoisted the heavy, clanking burlap sack over his shoulder, he knew it was worth every coin.
By the time Sengoku returned to his dark stone house, night had fully fallen.
He didn't rest. He lit his oil lamp, cleared his single workbench, and unrolled his blueprints. First, he carefully examined the training tags under the dim light, memorizing their exact dimensions and the subtle thrum of their chakra signatures. They were the heart of the weapon; the entire device had to be built flawlessly around them.
Then, the grueling work began.
Working with iron was entirely different from carving sandstone. Sengoku had to score the metal sheets, use a hand saw to painfully cut out the rough shapes, and then take a heavy file to grind the jagged edges down to his exact design specifications. His small hands cramped as he drilled the microscopic holes and hammered the rivets into place, ensuring they were flush and tight.
After ruining a few pieces of scrap metal, he finally completed the first firing mechanism. He carefully integrated the tag slot and the microscopic contact point—the crucial node where his chakra thread would touch the tag to ignite it.
When he hammered down the final rivet, the very first prototype of The Pursuer rested quietly on his workbench.
It was a dull, grey-black iron cylinder, roughly the size of a large gourd. Though the edges were slightly unpolished, the structure was incredibly dense and exuded a cold, utilitarian menace. Five small launch tubes were arranged in a circular pattern around the flat front face. Inside, the firing springs, the wire spools, and the explosive slot were all perfectly aligned.
Sengoku didn't load the needles or the wires just yet. He needed to test the core explosive function first.
Slipping the iron shell and his supplies into a bag, he slipped out of the village and headed toward an abandoned stone quarry in the surrounding wasteland. The area was desolate and silent, perfectly concealing any noise or flashes of light.
Sengoku placed the empty Pursuer shell on the packed dirt. He slid one of the training tags into the internal slot. Taking a deep breath, he extended pale blue chakra threads from his fingertips. Most of the threads latched onto the heavy iron casing to act as physical tethers, but one exceptionally fine thread slipped through a tiny seam in the metal, resting gently against the ignition contact point just above the tag.
His eyes narrowed as he visualized a combat scenario: Move, close the distance, detonate.
With a sharp mental command, he pulsed a microscopic surge of chakra down that single ignition thread.
Hiss—!
A sharp, violent sound erupted from inside the iron shell.
BOOM!
A muffled shockwave kicked up a cloud of dust. Orange fire violently burst through the seams and launch holes, instantly tearing the iron shell apart.
Sengoku waited for the smoke to clear before stepping forward. He crouched down, running his fingers over the scorched earth. The outer shell had shattered violently, fracturing perfectly along the grid lines he had filed into the interior walls. Jagged, lethal pieces of iron shrapnel were embedded deep into the surrounding dirt.
The blast radius was indeed much smaller than a standard military tag, just as the shopkeeper had warned. But confined within the pressurized iron casing, the explosion turned the metal into a devastating frag grenade. It was more than enough to shred human flesh.
Suppressing a cold smile, Sengoku cleared the debris and pulled out his materials to assemble a second, fully operational Pursuer.
This time, he loaded the five triangular steel needles into the launch tubes, carefully threading the high-tensile wire into the internal retraction spools. He slotted a fresh training tag into the chamber.
Sengoku placed the fully armed puppet on the sand. He connected his chakra threads, feeling the heavy, cold weight of the iron through his immaterial tethers.
Lift.
The grey cylinder smoothly hovered a meter into the air, completely stable.
Fire!
Sengoku twitched a specific finger. The internal mechanism snapped.
Thwip-thwip-thwip!
The five steel needles launched in a tight, fan-like spread. Trailing nearly invisible wires, they crossed the fifteen-meter distance in a blink, striking the quarry's rock wall with a sharp clatter. Three needles drove deep into the stone, while the other two deflected slightly, burying themselves in the hard earth. The tethers were secure.
Immediately, Sengoku triggered the internal retraction spools.
Instead of pulling the needles back, the sheer tension of the motorized spools violently yanked the hovering Pursuer forward. It rocketed along the taut wires, hurtling straight toward the pinned target at terrifying speed.
The moment the iron chassis slammed into the rock wall, Sengoku pulsed the ignition thread.
BOOM!
A brilliant fireball bloomed against the cliff face, the explosion echoing loudly through the empty quarry.
Sengoku stood motionless, the sharp smell of sulfur and scorched rock washing over him. He walked up to the blast site. The rock wall was blackened, heavily pitted, and gouged by the vicious shrapnel. Fragments of glowing, deformed iron littered the ground beneath it.
The launch, the pursuit mechanism, and the detonation—every single phase had worked flawlessly.
The Pursuer was complete. It was only a prototype running on a quarter-power explosive, and the internal mechanisms still required heavy optimization, but the underlying concept was a total success.
Sengoku stared at the scorched wall. He had just secured his first true method of survival.