The time I spent under Granny Chiyo's wing was like having a high-speed fiber connection to a library of forbidden knowledge. I was learning the administrative commands of the ninja world, but the most fascinating "case studies" didn't come from the scrolls they came from watching Sasori.
I'd just finished a grueling session on "Fine Subdivision Control" with Chiyo when I saw a massive project taking shape in the corner of the courtyard.
Sasori was standing in a cloud of dust, his shock of red hair a sharp contrast against the dull stone. He was working on a behemoth a puppet so large it felt like a heavy tank. It was modeled after a desert salamander, with a broad, flat body, a reinforced skull, and a massive tail ram. The sound of metal gears grinding and chakra circuits humming vibrated through the floor.
I stopped. I couldn't help it. My inner engineer was screaming.
I watched how Sasori used dozens of chakra threads to micro-manage the tools, fine-tuning the chest cavity. I looked at the joint structures, they were built to handle incredible torque and impact. And then I saw the base: a special sliding track suspension designed to glide over shifting sands.
A thought hit me like a logic error: Why am I still walking?
Large puppets were always seen as "war machines" or "artillery." But if you looked at them as a platform... they were vehicles.
I looked at my own legs. I was nine years old. Even with the furnace patching my system, I was still small. I didn't have the stride of a Jonin. I didn't have the stamina for a three-day desert sprint. I was always going to be the slow one in a squad.
What if I built a puppet that didn't just fight for me, but moved for me?
I started sketching the idea in my head. It wouldn't be a tank like Sasori's salamander. It would be a specialized mobility unit. I needed something with a high power-to-weight ratio, extreme stability, and obstacle clearance. My mind went straight back to the spider, but bigger.
A manned, eight-legged mobile platform. A low center of gravity to keep it stable in high-speed turns. A cockpit where I could sit, protected from the elements, focusing entirely on scouting and combat while the "OS" handled the walking.
I was so deep in the "blueprint" that I didn't notice Sasori had stopped working.
"Done staring?" his voice was like dry ice.
I snapped back to reality. Sasori was looking at me with those indifferent purple eyes.
"Senior Sasori," I said, pointing to the salamander. I didn't waste time with a greeting. "How are you handling the heat dissipation on a core that big? And the suspension, how are the leg joints maintaining structural integrity while adapting to uneven terrain at high torque?"
Sasori raised an eyebrow. Usually, people asked him how many people the salamander could kill. He didn't answer right away, just gave me a look of mild interest. "Thinking about building a big toy, kid?"
"No," I said. "I'm thinking about a mobility aid. My speed and stamina are my biggest vulnerabilities. I need a platform as reliable as that one to compensate for them."
"Mobility aid?" Sasori repeated the term, a faint, almost mocking curve at the corner of his mouth. "An interesting way to describe a weapon of war. You want to turn a predator into a pack animal?"
He didn't kick me out, though. He turned around, rummaged through a pile of discarded scrolls, and tossed a heavy, dusty roll at my chest.
"Take it," he said. "Those are the early design drafts for the Salamander's power transmission and suspension. I threw them out because the energy dissipation was too high for a frontline combat unit. Maybe it's enough for your... 'pack animal'."
He went back to work without another word.
I practically sprinted home. I spread the scroll out on my desk and my eyes nearly popped. To Sasori, these were "failed" designs. To me? They were a masterclass in heavy-duty robotics. The records of why the joints were "too fragile" gave me the exact tolerances I needed to stay under.
I started drawing. I didn't need the massive armor of the salamander. I needed speed. I took Sasori's suspension logic and modified it for an eight-legged spider gait. I stripped the attack systems and rerouted the energy to the mobility motors.
I discarded dozens of sketches, recalculating the weight-distribution and the chakra-pathway resistance. With Sasori's "failed" data, I was bypassing months of trial and error.
Finally, the blueprint for the "Great Spider" (O-Gumo) was clear.
It was a manned, high-speed mobile platform. It was my ticket to never being "the slow kid" again. It was the next logical step in my evolution from a "sickly survivor" to a master of my own destiny.
I looked at the final blueprint and felt a rush of adrenaline. The "Gen 1" furnace had fixed my body. Now, the Great Spider was going to give me the reach of a giant.