The delta-wing Blow Floater crafted by Jin and the others was dubbed "Delta X01."
"Delta," of course, came from its delta-wing configuration. The "X" signified that it was an experimental prototype.
They decided to construct three identical airframes based on it, designating them "Delta X02-1," "Delta X02-2," and "Delta X02-3."
Even though they were identical models, they were named "X02" because the plan was to modify them individually from that point onward, developing them into true Blow Planes.
Incidentally, No. 1 would go to Jin, No. 2 to Lordtoss, and No. 3 to Rubina.
"All right, how about we each tinker with these on our own and... let's see, compare our results a week from now?"
"Ah, I'm all for it!"
"That sounds fascinating."
With both Rubina and Lordtoss in agreement, they decided to pursue their research separately—Jin on Hourai Island, Lordtoss in the Nord Federation, and Rubina here on Onogoro Island.
When Jin returned to Hourai Island, Reinhard had just finished building his own Blow Floater and was in the middle of a test flight.
"Oh, welcome back, Jin."
"Hey, Reinhard....Heh, you've built quite an impressive machine there."
Reinhard's Prototype Model 1 had a profile that made Jin want to call it a "motorized hang glider."
It featured triangular wings resembling a kite stretched wide horizontally, paired with a suspended cockpit.
Its Blow Engine was remarkably powerful, and by adjusting the exhaust angle, it was even capable of creeping forward and backward at low speed.
"Impressive as always."
"Haha, hearing that from you is high praise indeed....Oh, that's right, Marikka is building one too."
"Huh?"
"She isn't finished yet, so she should be over in the large-class workshop behind the laboratory."
"Is that so? I'll go have a look."
Jin was deeply intrigued to see what kind of craft Marikka, the creator of the original Blow Floater itself, was putting together.
"This must be it....Marikka, I'm coming in—"
"Hawah?!"
When Jin called out and stepped into the large-class workshop, Marikka jumped in surprise.
"J-Jin-sama, why are you here?!"
"What do you mean why...? I just got back, and Reinhard mentioned you were building a new Blow Floater of your own."
"I-Is thash... that so?"
"Man, so this is it. I see, I see."
"U-Um, Jin-sama, it's embarrassing, so please don't stare so closely."
Despite her flustered protests, the Blow Floater Marikka was building was constructed with craftsmanship that genuinely impressed Jin.
"I see, so this is Marikka's design philosophy."
If Reinhard's Blow Floater was a motorized hang glider, then Marikka's was a motorized paraglider.
It featured a cockpit suspended beneath broad main wings that stretched far to the left and right. The key difference from a conventional paraglider was that every component was rigid.
In other words, while a standard paraglider could be folded up compactly, this craft could not.
"You made the wings wide from side to side so you could twist them to act as ailerons, right?"
"Y-Yes, that's right."
Jin recalled a biography of the Wright Brothers he had read long ago.
The aircraft they built, the Flyer, had reportedly used wires in its early iterations to pull and warp the main wings for roll control.
Later on, as wings grew more rigid, dedicated ailerons made their debut.
As for precisely when that transition occurred... Jin did not know.
Marikka's design had adopted that very same principle of wing-warping.
"The propulsion system seems fairly standard, but the Blow Engines... you've installed multiple units?"
"Ah, yes. To prevent it from crashing, having backups—or rather, multiple engines—just felt safer, I thought..."
"Yeah, that makes total sense. I agree with that philosophy."
"I-I'm honored!"
Afterward, Jin returned to the Mansion. Reiko, showing tactful consideration, chose to remain behind at the laboratory.
In front of the Mansion's entrance stood his beloved wife, Elsa, ready to welcome him home.
"Welcome back."
"I'm home. Sorry for being away so long."
"Mm, it's fine. We spoke every day through the bracelet, and like I told you before you left, I had my research to keep me busy."
The research Elsa referred to revolved around the fundamental question of why magi-craft had no effect on living organisms.
Lately, her focus had been centered on severed branches.
A severed branch immediately became susceptible to magi-craft, yet it did not die the instant it was cut. Depending on the tree, taking a cutting from that branch would cause it to take root and resume growing.
Of course, cuttings did not always take, but severed branches became receptive to magi-craft immediately without exception. This convinced her that the phenomenon was not simply a matter of categorizing whether cells were alive or dead, which had sparked her entire investigation.
"So, did you figure anything out?"
"..."
Elsa silently shook her head.
"I see..."
Jin fell into thought alongside her.
"...In some manga or novel I read a long time ago, they said living creatures possess both a physical body and a spiritual body, and that the spiritual side is made up of several distinct layers."
Elsa reacted with a sharp start to his words.
"Tell me more. In detail."
"Well, even if you ask for details..."
He could not remember whether it had been occultism or psychical Sciences, and above all, it was work of fiction.
"Even so, human imagination sometimes brushes close to the truth," Elsa insisted.
Indeed, one could not simply dismiss such things as mere fantasy or delusion. More often than not, they contained fragments of the truth.
"Let's see... the spiritual body was supposedly made of several layers of subtle bodies, and things like the soul or mental energy were anchored to them... I think?"
Beyond that, Jin's memory failed him.
"...Fascinating."
Even so, the idea seemed to provide Elsa with a fresh lead.
"Spiritual lifeforms exist, so the existence of a soul cannot be denied," she murmured thoughtfully.
"You were considering a theory along those lines before, weren't you?"
"Mm....To borrow Jin-nii's phrase, 'across both East and West,' there is 'something' people call a soul or spirit. That might be the key."
"I see."
"Creating a homunculus isn't just about transferring memories. Trans Info Level 10... might be capable of transferring even that 'soul.'"
"So that's how it works..."
Elsa continued expanding on her theory.
"Knowledge and experience are acquired later. Personality, too, is not the core essence. The foundational substrate beneath them all—that might be the 'soul.'"
Jin pictured the soul as an operating system, upon which applications were installed to construct a personality.
"A profound subject. That's precisely why it's worth pursuing."
Feeling that they were gradually edging closer to the true essence of life and living beings, Jin offered Elsa his full support.
"Yeah, give it everything you've got."
Having been reborn as a homunculus herself—or perhaps precisely because of it—Elsa had discovered her own calling in pursuing the fundamental essence of life, a realization that filled Jin with genuine warmth and happiness.