They were analyzing the contribution rate of magi-resin to the movement of Forming.
It was common knowledge that movement efficiency peaked at the joints. In fact, there were already established techniques for Stone Golems where the joint areas were replaced with high-quality magi-stone to improve performance.
"The problem is that we aren't dealing with solid magi-stone right now," Jin noted. "We're looking at flexible magi-resin."
Greena followed Jin's lead, offering a practical suggestion. "It would be helpful if we could actually see how much it deforms from the outside."
"In that case, we should just make the outer armor transparent," Marikka added.
"Good idea," Jin agreed. "And if we draw a grid on the magi-resin itself, we’ll be able to see exactly where and how much it’s expanding or contracting at a single glance."
Adopting these ideas immediately, Jin stripped the outer armor off the prototype golem. He then began drawing grid lines onto the magi-resin, making it look like a wireframe 3D model.
While he did that, Marikka, Rubina, and Greena worked together to fashion transparent outer armor out of cubic zirconia.
The two tasks were completed at almost the exact same time.
"Alright, let's put it back together."
The reassembly was finished in just two minutes. Since the control core remained untouched, there were no issues with its basic functions. Laojun maintained remote control of the unit.
"Laojun, try moving it slowly."
『Understood, My Lord.』
First, Laojun extended the right arm horizontally, then slowly bent it at the elbow to demonstrate the range of motion.
"Oh..."
Next, the golem stood up and performed a slow, deliberate march in place.
『How is this?』
"Yeah, that’s perfect. Keep marching slowly."
『As you wish, My Lord.』
Through this observation, the mechanics of Forming via magi-resin became visible.
"Hmm... It looks like the joints contribute about eighty percent of the movement, while the surrounding areas handle the remaining twenty."
Jin quickly calculated the approximate contribution rates.
"Is that so, Jin-sama?" Marikka asked, her voice tinged with a hint of disappointment. "If that’s the case, does that mean we can only hope for a twenty percent improvement at most?"
She had been hoping for a massive performance leap, and twenty percent felt negligible by comparison.
"No, I don't think that's right," Rubina interjected. "...Um, in a Stone Golem using magi-rock, the contribution rate at the joints is nearly one hundred percent. But with this flexible magi-resin, it dropped to eighty. I've been wondering why that is."
"I see. Go on," Jin prompted. He had a good idea of where she was going with this, but he wanted to hear her explain it.
"I think the harder the power-generating material is, the more localized the movement becomes. If the material is softer, the force spreads over a wider range."
"That’s brilliant, Rubina! I agree completely!" Greena cheered.
"It really makes sense," Marikka added, her enthusiasm returning. "Jin-sama, can we test this right away?"
"Alright, let's try it."
Jin prepared two different batches of magi-resin with varying hardness levels.
"If it’s too soft, it’ll just become fluid, so this should be the limit."
One batch was roughly the consistency of an earlobe. The other was significantly harder than the resin currently installed in the prototype.
They ran several experiments, swapping out the golem's "insides" each time.
"See? Just like I thought!"
"Yeah, Rubina's theory was spot on."
The softer magi-resin showed a lower contribution rate at the joints—dropping to about sixty percent. Conversely, the hard magi-resin pushed the rate nearly to one hundred percent. This proved that when the hard resin was used, almost all movement was concentrated at the joints.
"So the softer it is, the more the entire mass absorbs the deformation... or rather, the more the influence spreads throughout the whole material," Rubina mused.
"That seems like a solid interpretation," Jin agreed.
"Oh! In that case," Marikka added, "wouldn't it be more efficient if the magi-resin was more firmly anchored to the skeleton?"
"That’s a distinct possibility."
Jin decided to test it by roughening the surface of the skeleton to give the resin better "grip" or adhesion.
He removed the armor, stripped the magi-resin, processed the surface of the skeleton, reapplied the resin, and reattached the armor. The entire modification took him only five minutes.
"..."
The girls watched in stunned silence, awed by his sheer technical proficiency.
"Now then, let's see what happens. Laojun, if you please."
『Understood, My Lord.』
Laojun began to move the prototype golem, but the motions were visibly jerky.
『My Lord, the input-output balance has been disrupted. I report a performance efficiency increase of approximately seventy-five percent.』
"Really? We did it!"
Just by improving the adhesion between the skeleton and the magi-resin, they had achieved a seventy-five percent boost in efficiency. This meant the magi-resin wasn't just being used for the Forming action of "bending"; it could also function like a muscle to "pull" on the skeleton.
"Ah, that makes so much sense!"
"As expected of Jin-sama!"
Rubina and the others were quick to agree with his analysis. Jin then instructed Laojun to update the prototype's control sequence.
"Start experimenting with using it more like a 'muscle' in small increments."
『Yes, My Lord.』
Laojun’s control was nothing short of miraculous; within a single minute, it had optimized the golem's movements.
The result:
『My Lord, we have achieved 3.5 times the original output and twice the reaction speed.』
"Oh, that's impressive."
The reaction speed hadn't increased as much as the output, but that was to be expected. There were physical limits to how fast the magi-resin could react. Furthermore, the reaction speed had already been tuned close to its upper limit from the start. The output, however, had been riddled with energy loss, leaving massive room for improvement.
"Still... it makes me even more curious about the magi-resin used in those bandit golems," Jin mused.
That material had seemed superior to any magi-resin Jin was currently aware of. He assumed it was an ancient relic, but he found himself regretting that he hadn't been able to investigate its source more thoroughly. Then, he remembered that his body double and the others were at the site right now.
"Laojun, how are things going with Jin D and Reiko?"
『Yes, My Lord. It appears they have only just arrived at the site.』
"I see. Tell them to keep an eye out for any records or data regarding magi-resin."
『Understood.』
Jin ended his brief exchange with Laojun and turned back to the girls.
"Well, I think we've made significant progress. Does anyone have any questions or comments?"
Rubina raised her hand tentatively.
"Um, I’ve only heard a little bit about it, but were those bandit golems you captured really higher performance than this prototype we just built?"
"Yeah, it’s a fair question," Jin replied. "To be honest... yes, they were still slightly better."
"No way..."
Rubina looked genuinely shocked. She had assumed that something built by her and the others under the guidance of a Magi Craft Meister would surely be the pinnacle of technology.
"Don't let it get to you. There are a few reasons for that, and I've already figured most of them out."
Jin comforted her, explaining that once they applied these same advancements to their own design, their prototype would end up being far superior in the end.