"Jin-nii, I’ve been wanting to ask you something."
Elsa spoke up as Jin sat deep in thought, pondering how to create a substitute for Reiko.
"Why don't you ever build another automata with the same performance as Reiko-chan?"
At that question, Reiko gave a visible flinch.
"Reiko-chan, please don't misunderstand. I only want to know the reason. I'm not trying to replace you or say you aren't enough."
Jin beckoned Reiko over and gently stroked her hair.
"The reason I don't, huh? It’s simple. For me, one Reiko is enough."
Jin pulled Reiko close and had her sit on his lap.
"Reiko is the one who summoned me to this world. To be precise, it was her predecessor, but still. That Reiko followed her previous master’s final wishes and searched for me for a thousand years. And when I went missing because of the Warp Gate’s malfunction, it was Reiko who desperately tracked me down. I am who I am today because of her."
As he spoke, Jin continued to stroke Reiko’s head. Reiko narrowed her eyes, looking profoundly happy.
"She is a daughter far better than I deserve. That’s why I won't make another automata like her. I don't want to."
"…I understand now. Jin-nii, I’m sorry. Reiko-chan, I’m sorry too."
Elsa bowed her head deeply.
"I just remembered how close you and Reiko-chan were when we first started traveling together."
"Ah, back then…"
Jin recalled the time he had been misunderstood as having a doll fetish.
"Anyway, for those reasons, I’ve decided that there will only ever be one Reiko."
"I understand perfectly. I’m sorry for asking such a trivial thing."
Jin stopped Elsa as she apologized again. Reiko also spoke up.
"…Elsa-san, please, think no more of it."
"Now then, what should we really do?" Jin muttered, falling back into thought. "I’d hate to build a golem just for this mission and then put it into dormancy once it’s no longer needed…"
Seeing Jin struggle, Reiko made a proposal.
"…Father, if you will promise not to take a single step outside of Hourai Island, then I shall go in your stead."
"R-really? If you’re willing to do that, it would be a huge help."
More than anything else, Reiko was desperate to be of use to Jin.
"Alright. In that case, I’ll upgrade you with the latest materials and technology."
"Yes, please do."
Jin laid Reiko down on the workbench. Elsa assisted him, while Edgar observed the process.
"First, the skeleton."
He replaced the magi-adamantite with hyper-adamantite. It was a dream material—while its specific gravity was about ten times higher, its strength was improved twenty-fold. Jin speculated that the compression process had narrowed the distance between atoms, significantly increasing their bonding force. The fact that the results exceeded simple calculations was likely due to the properties of ether.
By using this, he could achieve double the strength even if he kept the weight exactly the same.
"Will the magical muscles remain the same?" Elsa asked.
"No, I’ll swap them for ones that have undergone ether impregnation treatment."
"Impregnation treatment?"
"Yeah. You know how the concentration of ether increases dramatically when you preserve materials in a free ether box? It’s that process."
While the ease of use remained the same, the upper limit of the power that could be drawn from the muscles would more than double.
"It will consume more ether as a result, but since the ether concentration in the northern lands is reportedly high, it should be effective."
"That makes sense."
"Next, I’ll add an ethenol tank for emergencies."
This was more efficient than the mana tanks he had used previously. Liquid ethenol, which contained ether, allowed for a much higher density of usable magic than gaseous mana.
"And I should make it so she can use gravity magic by default."
He integrated various magic tools for spellcasting so she could activate them without the need for chants.
"I’ll also need to increase the capacity of the ether converter and the mana driver."
One by one, he renewed every auxiliary function.
Jin-nii’s work is so meticulous, Elsa thought as she watched him. It’s so obvious how much he treasures Reiko-chan.
Though she was technically his assistant, Elsa found she had no role to play in this specific task, so she simply observed his craftsmanship.
Isn’t there anything I can do?…I know!
Coming up with an idea, Elsa quietly slipped away from Jin as he worked with total concentration.
After applying ether impregnation to the magical skin as well, Reiko’s upgrade was complete. Through careful adjustment, Jin had managed to keep her body weight identical to what it had been before.
Jin finally realized Elsa was missing.
"Elsa?"
Just then, he saw Elsa returning to the workshop. Edgar followed behind her.
"Ah, Jin-nii, is the modification finished?"
"Yeah, just now.…What’s that you’re holding?"
Edgar was carrying a bundle of folded fabric.
"This? New clothes for Reiko-chan. I made them from Ground Spider silk that underwent ether impregnation treatment."
"Oh, thank you. That’s perfect. She’s been wearing her current outfit for a long time now."
"Mhm."
Elsa presented a set consisting of drawers, a chemise, a one-piece dress, an apron, and a ribbon.
The color and design were identical to what Reiko had been wearing. Elsa had decided that she shouldn't change Reiko's preferred style just to suit her own whims.
Jin checked the dimensions just to be safe. There was only a few millimeters of error, so he made a tiny adjustment and finished.
"As expected, they’re beautifully made. Didn't the workability change a bit because of the ether treatment?"
"Yes. But I got used to it after working with it for a little while."
"Haha, you’re a real pro now. Alright, I’ll make her a new pair of shoes."
"Ah. I forgot about the shoes and socks," Elsa said, her cheeks flushing slightly with embarrassment at focusing only on the clothes.
"It’s fine, it’s fine. I’m always forgetting things myself."
Laughing, Jin pulled out some Sea Dragon leather that had also been treated with ether.
"Then you handle the socks."
"Okay."
Jin crafted the shoes and Elsa crafted the socks. They were finished in short order. Once they dressed the inactive Reiko, the process was complete.
"Wake up."
Responding to the keyword, Reiko opened her eyes.
"How is it? How do you feel?"
Reiko hopped down from the workbench and moved her limbs slowly to perform a self-check.
"Yes, I feel excellent. Thank you very much," she said with a polite bow.
"Good. Elsa made your new clothes. I helped out a little, too."
"…Is that so? Elsa-san, thank you very much."
"You’re welcome."
After explaining the new functions and confirming she could use them without issue, Reiko was perfectly prepared.
"Let’s leave the rest for tomorrow."
After a late dinner, Jin and Elsa retired to their respective rooms. Reiko and Edgar followed their masters.
Reiko-chan, huh…
As Elsa lay on the futon she had laid out, her thoughts drifted to Jin and Reiko.
…He really does cherish her.
Of course, Reiko wasn’t the only thing Jin cherished.
If one watched him closely, it was apparent even in how he ate—he finished every meal without leaving a scrap. When he crafted parts from raw materials, he worked to ensure as little waste as possible.
His tendency to not let things go to waste and the way he treasured Reiko were different yet similar, similar yet different.
It was perhaps the "mottainai" spirit of a man born and raised in Japan—a deep-seated feeling of valuing things and people alike.
"I’m a little… envious of Reiko-chan."
With that thought in her heart, Elsa gazed out the window. In the dark night sky, countless stars were twinkling.