Once Freddie finished speaking about magi-resin, it was Greena's turn. She took the floor to discuss biological materials, focusing on the thread of the ground spider.
"In recent years, the farming of 'ground spiders' has flourished, and the thread harvested from these spiders is now utilized across a wide variety of fields."
Just as she said, every nation maintained at least three farming facilities to produce GSS and Ground Spider resin.
"I believe most of these facilities make use of abandoned mines....Now, while this deviates slightly from our main topic, I would like to offer a few points of reference regarding this farming method."
The entire audience pricked up their ears, eager to hear what Greena had to say.
"Ground spiders sustain themselves by absorbing free ether as nutrition, so they require little maintenance in that regard. However, making a slight adjustment to their rearing environment can yield remarkable results."
A ground spider's vision actually operated via ultraviolet and infrared light. They were utterly incapable of perceiving the visible light seen by humans.
In the dark, they relied on infrared; in the light, ultraviolet. And that ultraviolet light was where the catch lay.
"Thread spun in an environment with ultraviolet light is weak."
On Hourai Island, ground spiders were raised in environments several dozen to several hundred meters underground, virtually untouched by light. As a result, the strength of their thread was vastly superior to anything produced in other regions.
Of course, that was not the only factor, but it was the core finding from investigations into why ground spider thread produced elsewhere was inferior in strength.
It was hypothesized that freshly spun thread had low resistance to ultraviolet light, though whether that was entirely accurate remained unknown. It was an area still waiting for proper verification.
"The precise reason is not yet fully understood, so I will refrain from debating it here....Now then, since the thread harvested from these ground spiders also reacts to magical energy..."
With that, she transitioned into the main topic: materials for magical muscles.
"Before ground spiders, the silk of insect-type magical beasts was used—creatures like the 'bagwa,' a magical beast resembling a bagworm, and the 'evil moth.' However, because their supply was unstable, they were eventually replaced by ground spiders, which can be reliably farmed."
Her explanation was somewhat roundabout, but that was because Jin had mentioned that the majority of students were unaware of this background and chose their materials blindly.
It was hardly their fault. After all, lectures on such topics were virtually nonexistent.
That was all due to the Magic Federation Rebellion, which had caused historical records conveying such knowledge to be scattered and lost.
"...And so, the thread of the ground spider still harbors untold potential for application. Discovering those uses is both the duty and the privilege of our generation. Let's do our best!"
With that, Greena concluded her segment. Thunderous applause rippled through the Grand Auditorium.
Next up was Rubina.
Jin could sense a faint wave of bewilderment washing over the crowd.
Well, I suppose that's only natural, he thought.
Everyone gathered to listen to the lecture was older than Rubina.
"My name is Rubina. I will be speaking about 'rare materials.'"
Contrary to Jin's expectations, Rubina began speaking crisply and clearly. She was evidently the type who rose to the occasion under pressure.
"Some of you may be wondering about my age. But please set that aside for a moment and hear what I have to say."
Oh, that's quite a good opening, Jin thought, impressed. She had probably spent a long time planning it.
"When you hear the phrase 'rare materials,' what comes to mind? Adamantite? Dragon-derived materials? Or perhaps Elradrite? All of them are certainly rare."
The audience seemed taken with Rubina's poised delivery, leaning in to listen intently.
"Rare materials possess magnificent properties in their own right. Adamantite is the hardest and strongest metal in the world, while dragon materials boast immense durability. Elradrite possesses an amplification characteristic that other magi-crystals lack."
Here, Rubina brought her explanation back around to the new golem.
"The golem the three of us crafted under Jin-sensei's guidance does not use any special materials. We discussed whether we should, but doing so would go against our goal of mass production and industrialization, so we utilized common materials instead."
"However," Rubina continued.
"We all agreed that we did not want to sacrifice performance in the process. That is where ingenuity came in. Through ingenuity, we were able to achieve performance that—while not entirely equal to rare materials—comes remarkably close, an accomplishment we take great pride in."
Her words flowed effortlessly. Rubina spoke without a single stumble. The audience had completely forgotten that she was only ten years old.
"The first example: 'an alternative to adamantite.' Naturally, one would want the casing protecting crucial magi-devices to be as durable as possible."
In truth, one would also want to impart a barrier effect as a countermeasure against Master-Slave Rewrite Magic.
"We analyzed the forces that would likely act upon this casing. As a result, we concluded that over ninety percent of the force would be directed from the outside inward."
That made sense. The likelihood of an outward force generating from the inside was exceedingly low.
"So we examined the structure and improved its strength by utilizing a honeycomb structure made of stainless steel. This structure is detailed in Appendix 2 at the back of your materials."
The rustle of turning pages echoed across the auditorium.
A honeycomb—a structure utilizing hexagonal shapes like a beehive.
The word "honeycomb" came from English, meaning the comb of a honeybee.
Why it was called a comb, Jin didn't know—especially when the English language had a separate word for a bee's nest: "beehive."
Regardless, this structure was exceptionally resilient against forces perpendicular to the plane of aligned hexagons. On top of that, it could be made lightweight.
In other words, against forces from specific directions, it was possible to maximize strength while keeping the weight down.
As for what would happen if you made the same structure out of adamantite... that was beside the point. It would certainly be even stronger, but there would be no end to such comparisons.
Jin had been slightly worried that Rubina might explain away every single trade secret, but she showed great discretion. Instead, she addressed the gathered engineers:
"Explaining everything would be a disservice to all of you who have taken the time to attend today. Please, devise even better innovations than ours. And together, let us carry the development of technology forward."
She brought her speech to a close.
"And with that, inexperienced though I may be, thank you for your kind attention."
Rubina gave a polite bow and stepped back.
Her cute little bow, in stark contrast to her mature, measured tone, drew a burst of fond chuckles before giving way to deafening applause.
"Thank you very much....We will now take a ten-minute break."
"Haah, haah... I-I'm done for. That was my absolute limit."
Having retreated to the dressing room, Rubina slumped limply into a chair.
"You did great, Rubina," Jin praised her. "You don't have to go back on stage, so get plenty of rest."
"Yeees..."
"Greena, Freddie, good job to you both as well."
"...It was exhausting, but it was a great learning experience."
"Same here."
Unable to just watch them sit there completely drained, Jin gave an instruction:
"Hope, Reiko. Serve them some Persica juice, please."
"Yes, understood."
"Yes, Father."
Reiko, who hadn't had a role during the lecture, was particularly eager as she fetched a magic bottle filled with Persica juice from their luggage. Hope set out the cups.
The Persica juice from Hourai Island was packed with nutrients and provided a wonderful restorative effect against fatigue.
"Ah, this is delicious."
All three of them caught their breath as they sipped the juice.
"Haha, that was good experience for you all, wasn't it?"
Speaking before a crowd drained far more mental energy than one would imagine.
Back when Jin was a newcomer, he used to get stomachaches whenever he was tasked with giving presentations to clients. That feeling had faded as he grew used to it, of course...
"Jin-sama, is it all right for you to go first in the final lecture?" Marikka asked. For her part, she seemed to want Jin to act as the closer.
"Yeah, didn't we decide that during the briefing? You're the senior authority here, Marikka, and your name is far better known."
"I-Is that sho?"
"And now, our final lecture of the day: 'The Future of Magi-Craft.' Jin-sensei, Marikka-sama, the floor is yours."
With that, Jin took the podium first, just as planned.
"I have spoken at length today offering my humble opinions, but as our time is drawing to a close, I would like to offer a few concluding thoughts."
Murmurs of "Were those humble?" and "It didn't feel long at all" drifted up from the crowd. Jin realized once again that Japanese-style self-effacing modesty did not translate very well here.
"My... no, the philosophy of a 'Magi Craft Meister' is to 'bring the blessings of magic to those who cannot use it' and to 'create things that serve the people.'"
This time, everyone listened in rapt silence.
"I have no intention whatsoever of forcing this upon all of you gathered here today. However, even if it is just a little, please do not forget to create not merely for yourselves, but for the sake of the greater public. That is all from me."
When Jin bowed, thunderous applause washed over him.
Taking his place at the podium was Marikka.
"I believe everyone gathered here is brimming with ambition. Please hold on to that ambition. At times, you will fail. You may even taste bitter defeat. However, to a greater or lesser degree, that is a path everyone must walk. Even I... and even my master, the predecessor 'Magi Craft Meister,' walked it. What matters is what you do afterward. Turn both failure and defeat into your nourishment. Let your overflowing ambition be your propulsion, and your intellect your rudder. And let a heart of compassion serve as your compass. That is all from me."
Marikka, too, was met with a tempest of applause.
The clapping refused to die down, carrying on for a full ten minutes.
And finally, the time for the question-and-answer session arrived.
Jin waited with a sense of quiet excitement, wondering what kind of questions would come his way.