To save time, Jin returned to Horai Island via <> using Reiko's transfer gun.

The Jin family was there to greet him.

Jin, thank you for your hard work. I heard about it, but I only understood about half of it."

It seems that Elsa did not understand everything that was said in 700672.

"Jin!　I understand that there is a wonderful and profound theory that has been told to me, even though I don't understand it!"

"Jin, this is a subject that I would like to take the time to study."

Saki and Toa sensed that a door to a new world had been opened, and they were excited, even though they did not understand it.

"Jin, I couldn't understand it, but you're different, aren't you? But you don't, do you?　I'm sure one day you will explain it to us in a way we can understand.

"Jin, I am waiting for that day too.

Reinhardt and Stearina admitted that they did not understand, and said that they hoped Jin would give them an explanation when the trouble was over.

"Jin-sama, please hang in there. I will do my best to help you in any way I can.

"Me too."

Meane and Bertsch were open to cooperating with us.

Surrounded by such a dependable family, Jin felt grateful.

That day, he continued discussions with everyone until late at night.

Early in the morning of the next day, Jin immediately started his activities.

The first thing he did was to develop the <>.

< should have, and a more efficient power source was needed to prevent the "Aether Stampede" from occurring.

"Hmmm....so we're going to have one magic element converter (ether converter) and one magic power reactor (mana driver). ......"

It is indeed impossible to have both functions in a single magecrystal.

Inevitably, they would have to be placed on a magical connection board (link board), but there would inevitably be losses in connection, synchronization, and so on.

Although the devices created by Jin, the previous Magecraft Meister, and Adriana are incredibly efficient, there are still losses.

Once, when Reiko was captured by Gigarth, she destroyed Gigarth's magical core by supplying excessive mana. At that time, the magic power of the lost mana caused the surrounding area to glow brightly.

This shows that even Jin has not been able to reduce the loss to zero.

"Well, <> is not enough.

As Jin was twisting his head, Stearina appeared in front of him.

"Jin-kun, can I come in now?"

Jin welcomed her, since he had just reached a deadlock.

"Is something wrong?"

"No, I just got something interesting and thought you should see it."

With that, Stearina held out her right hand and opened her palm.

"This is ......."

"Isn't it interesting?　I was looking for some crystals and stumbled upon it."

It was a crystal with two flat crystals attached to it.

It is called a <, which means that two crystals have grown at the same time. Unlike a crystal that is simply two crystals attached to each other, this crystal has a geometric regularity.

It brought back memories of seeing specimens in my junior high school science lab.

It was a quartz crystal called <>, which had a flat shape like a butterfly spreading its wings, and it left a strong impression on my mind.

"...... Jin-kun?"

When Stearina began to wonder about Jin, who had fallen silent while staring at the crystals, Jin reactivated.

"Oh, yes!　I knew I had it!　......Stearena, thank you!"

"......I don't know what it is, but I'm glad I could be of help. So, these crystals..."

"Oh, they're called <, not just crystals attached to each other. ......"

Jin explained everything he knew about the twin crystals.

After thanking him, Stearina returned to her laboratory.

Jin, being Jin, immediately began to work on his magic to give shape to his idea.

"How about combining ......<> and <>?"

He tries it with the crystals he has prepared. The two crystals fuse together and become crystals again.

"Well, it doesn't work.

Two crystals are simply stuck together.

"Do I need to combine another one? ......<><><>......>...... this won't work."

It is only the formation of distorted crystals.

"<><>......<>!"

Jin, who has developed the artisanal magic of changing the structure of crystals while understanding their structure through <>.

And before his eyes, he had created a beautiful Japanese-style twin crystal.

"We did it!　Now we have a good prospect for the Magi Reactor."

Magi crystals are usually processed into a spherical shape. This shape was chosen empirically because of its ease of forming, beauty of shape, ease of handling, and the fact that the surface area of a sphere is the smallest compared to its volume.

It has been believed that the smaller the surface area, the more effectively the contained magic power can be used. The reason is unknown.

Jin was now daring to go against this rule of thumb.

The original magecrystal crystals are very similar to quartz crystals. In other words, they are hexagonal pillars. The crystals that are generally available are called "magi crystals.

However, Jin wondered if he could make use of the shape of the crystal. In other words, he intended to make use of the flat part of the crystal.

"If we write the magic formula (Magi Formula) here, we won't need a magic connection board (link board), and it will be easier to control!

Jin realizes that by using the shape of the crystal itself as a link board, he can control it with a degree of precision that was not possible with the sphere.

This technique would be meaningless if he could not make Japanese-style twin crystals, but it made a lot of sense to him now.

After an hour of further trial and error, he realized that he could make a Japanese-style twin crystal.

"It's done!

At last, the Magi Reactor, with an efficiency of more than 99%, was completed.

The efficiency of the previous combination of an ether converter and a mana driver has never been accurately measured, but it was probably 80% or higher.

That is still an astonishing figure, but the just completed Magi Reactor is more than 99%. That is an extraordinary efficiency.

"Get Reiko and everyone else equipped with one of these, then ......."

Jin quickly devises a use for it.

"We'll have to mass-produce them anyway."

Jin then decides to tackle his next task.

It is the well-known countermeasure against <>.

"First of all, we need to counter Aether Stampede.

The free magic element (ether) is completely controlled. That's why they developed the high-powered Magi Reactor.

"You mean the magic that converts mana back into free magic element (ether).

Suddenly, Jin thinks. Although defective, it was a decisive weapon against demons. It too had the function of taking the mana around it and turning it into its own. The method of doing so was not known at last, since all of them had been destroyed.

"That may have been what gave to the human side. ......"

It was possible, given its nature of attacking friend and foe alike once activated.

"...... and now we're developing this one."

Jin decided to generate a magic crystal (Magi Crystal) to generate the magic wave that governs the free magic element (ether).

The base is a light-attribute magi crystal. It is a crystal similar to a transparent crystal.

"Add the I received to it," he said.

When he opened the box, he found a pinch of black powder.

Jin added it at a ratio of 1 to 100 magi crystals (by weight), just as he had been taught.

"<>"

The transparent magecrystal has become tarnished. It looks a little like smoke crystal.

"So, if we use this as a generator, we can exert a great influence on the free magical element (ether).

It should be possible to release the < magic I had been thinking of.

I call it a .

By forcibly converting mana back to free magic element (ether), you can drown out your opponent's magic, except for a few magic spells.

The exception is the purely physical attacks such as <>, which are ineffective because they do not require any more supply of mana once they have been activated.

Other than that, for example, flames will be extinguished if it is a fire type, and wind type will be atomized. It should be possible to < gravity magic, and it should be possible to interfere with transfer magic.

Considering the amount of powder, I made only two.

One for Reiko's use and the other for air support.

"The other one will be used for Reiko's countermeasure against "Aether Stampede".

Reiko, who is the trump card, is likely to be stuck by "Aether Stampede" as it is now. Also, considering the possibility that <> could use super strong <>, Jin was thinking of applying a stronger shield.

Reiko would come soon if he contacted her with the manacam.

"Father, you wanted to see me?"

"Yes, Reiko. I have called you back to strengthen you even further.

Jin explained to Reiko the purpose and details of the modification. Reiko nodded her head.

"Yes, please."

Jin then set to work on Reiko's modification with all his might.