The framework of KAI was an alloy of aluminum, copper, and magnesium.

It is an aluminum alloy commonly referred to as <.

"Is UNY rich in aluminum?"

<

Then it is no wonder this material is used.

"Well, we haven't developed an aluminum-based magic alloy yet. ......"

At this point, Jin went a little off on a tangent and decided to research aluminum alloys.

"First of all, we need to do the standard mithril addition."

He started by replacing half of the copper with mithril silver.

"Hmmm, it is strengthened after all.

The degree of strengthening was clearly increased by the magic.

"Well, we don't have much time, so let's just go as far as determining the appropriate amount of mithril silver to be added.

Jin, who did not want to take up too much time since the main purpose of his work was to modify Kai, experimented quickly.

"Hmm, the first ratio is the best."

Super duralumin is made of 94 percent aluminum, 4.5 percent copper, and 1.5 percent magnesium.

Replacing half of the copper, or 2.25 percent, with mithril silver was found to be the most efficient way to magically strengthen the material. It is approximately 2.5 times stronger.

"<>" or "<>."

Since the volume change is negligible, we can continue with <> and <>.

"I am always impressed with your work," said Jin.

Erza marvels at Jin's work, especially when he is working with metals.

This was probably due to the fact that Jin himself was good at and liked such metalworking, in addition to the metal knowledge he had learned during his time in modern Japan.

Now, let me digress.

Having developed a new material, <>, for the chi, Jin is now considering what to do with the muscle tissue.

"From the strength of the skeleton, the standard material should be sufficient.

"Yes, I think so."

The standard golem is made of threads of a ground spider, twisted in a special way. Even with this, it can produce two to five times the output of an ordinary golem, and depending on how it is used, nearly ten times the output.

The only thing left to do is to upgrade the control core.

We will replace it with all-attribute magic crystals (magi crystals) of Horai Island's standard (or advanced in the eyes of the general public).

"Let's also replace the magic nerves."

After upgrading in this way at key points and applying countermeasures against slavery magic, we reassemble it.

The work was completed in about two and a half hours.

"It looks like this was made in UNY using the technology of the old Leonard Kingdom.

"Brother Jin, how do you know this?"

"Well, since the password is spelled backwards from Leonard, I thought it might have been made by someone from the old Leonard's Kingdom."

"Oh."

"Well, I could be wrong."

With that, Jin reactivates Kai.

"There we go. "

"Yes, master."

Kai gets up. His movements are smoother than before the modifications.

"How are you feeling?"

Kai checked himself before answering.

"Yes, I'm fine, sir. Thank you very much.

"Good, please continue to protect Mr. Mirówna.

Yes, sir, I will.

Thus, Kai, the golem that accompanied Milowena, became more powerful and once again served Milowena.

"Now, one more thing..."

"Brother Jin, anything more?"

Erza looked at her watch and frowned.

"Don't worry. It won't take long. I'm going to make a bracelet for Milowina."

"Oh, I see."

It is a task she is accustomed to making, and it takes no time at all.

The color is silver with gold stripes.

"Okay, done."

Finally, Jin finished what he wanted to do and went to bed feeling satisfied.

* * * * * * * * * * * * *

The next day, July 2.

After finishing breakfast, Jin offered Milowina the bracelet.

"Well, well, well, Jin-kun, what is this?"

"This is called a , which can be used to create a barrier. It can also be used for personal identification and communication. It can also be used as a light.

"Well, thank you, Mr. Jin."

"The best feature of this device is that you can remotely control it to put up a barrier. It's a good thing that we can do this even if we have overlooked it.

Jin explained the functions to Milowina, who quickly learned them.

"Oh, and I've made some improvements to Kai, so I think he'll be useful as an escort.

"...... Jin bro."

Erza thought, "You don't have to say that so lightly, like you just polished him up a little,

（But then Erza realized that she had to say it lightly, as if she had just polished it up a bit.)

She realized that she was just trying not to make Milowina feel guilty, and kept her mouth shut. I don't know if my guess was right or not.

However, Milowina was happy to hear it, so I guess there was no problem.

"Well, thank you for everything, Jin-kun. Kai, please keep up the good work."

"Yes, Milowina-sama."

At noon on the same day, a report came to Jin.

"Oh, yes!"

Jin had just finished his lunch, so he hurriedly drank up his tea and left Soleil to clean up the mess, and headed for the command center with Reiko.

He gave himself a on his slightly burned tongue.

Elsa and Milowina decided to have a leisurely cup of tea before heading out.

"...... hmmm, that's a bit of a long shot, isn't it?"

When Erza and Milowina arrived at the command center, they saw a slightly disappointed look on Jin's face. Concerned by this, Erza called out to him.

"Brother Jin, what's wrong?"

Jin turned around,

"I don't think there is much hope for the ......1 site," he answered.

Jin replied.

Erza looked at the screen and saw the image on the screen and understood.

"...... is terrible."

Right?"

The area where the ruins are supposed to have been is full of holes. It seems that decades, maybe even a century or so ago, a large scale excavation was done.

It is not clear now whether the purpose of the digging was to find treasures that might have been buried in the ruins, or to mine underground resources such as ore.

The passage of time is scary, isn't it?

Milowina, who peeked in from the side, also commented. It must be painful to see one's hometown being razed to the ground.

Some of the holes were dug vertically, others diagonally downwards, and some of them looked like anthills.

"The former Leonard Kingdom is rich in mineral resources, so maybe this place was a mine for mineral resources.

Jin muttered in a whisper.

"Brother Jin, how did you know that this place used to be a ruin?"

Erza asked, "How did you know this place was a ruin?

"Oh, that's ......."

Jin gave some kind of signal and the screen switched.

"Oh, ......."

On the screen was the RAND team. They are holding something in their hands.

No, not something. .......

"A piece of the ruins?"

It is made of a dense whitish stone of varying sizes, and there is writing carved on the surface.

What was written on them is not clear because they are in pieces, but we can imagine that they must have been part of a mural painting because there are words that can be read as <<<> in some places.

Another group of Rand and the others were holding parts of a decaying magi-machine, and the barely legible magi formula suggested that it had probably once been a magi-brain.

"You would think so, wouldn't you?　Unfortunately."

Of course, Lando and the others had searched not only in the surrounding area but also in the basement, and they had found these in the large hall in the basement and a hidden room in the back of the hall.

"Jin, these things happen."

Surprisingly, Milowina was not too disappointed.

"Maybe it's because I saw the ruins at Diaa and Karnagh.

In short, she had realized the impermanence of all things, I guess.

"And it's because I saw the people of the village of Kaina."

Milowina says that the continuation of human life is proof of her existence.

"It is a blessing to have someone to whom you can entrust what you have built."

More than leaving records, more than building ruins.

Milowina smiles and says to Jin as if to admonish him, "Leaving behind a successor may be the meaning of human existence.