The master (My Lord) once went to the future and came back.

To be precise, I, the head of the administration of Horai Island, a.k.a. , did my best with my technology and sent him back to the future.

It is the year 3520 of the continental calendar.

The future to which the master (My Lord) was sent is 3899 years in the future, so there is still time.

However, in 379 years, I need to develop the technology to send my master (my lord) back to the past.

This is not an easy task.

I started my research on September 17, 3457, when the master (my lord) returned, Even now, 63 years have passed without any progress.

Time is a mysterious and incomprehensible dimension.

The that the Master (Mylord) once met seems to have understood time, if not completely, and to have been able to control it to some extent.

I guessed that , an entity with zero mass, was not bound by the speed of light.

If so, we, as matter, cannot reduce our mass to zero no matter how hard we try.

There is a pseudo-magic that can almost eliminate inertial mass, but it is only pseudo and temporary.

Ms. Hannah ...... helped me in this way.

She cannot use magic, but she is without a doubt the best thinker in the world.

Hannah's brilliant mind solved the first problem, <, in the following way.

"Hey, Mr. Mere Old Man, inside the <>...... no, mass doesn't mean anything in the subspace during the transition, does it?"

In other words, is a characteristic of this space.

<, which means that you are traveling faster than the speed of light.

"I wonder if it is safe to say that <> does not make sense from the point of view of the world we are in, i.e., it is zero."

After advancing Hannah's reasoning, we decided to try to see if we could make an object in transition (with mass 0) transition further.

I started by setting the > to as a trial, but it did not go well.

Then we experimented with a double <> and it worked apparently well.

"But, I don't know ...... if this can go beyond time, right?"

Hannah nodded her head.

Here, the master (Mylord) himself interjected.

"You said that the properties of space can be changed by the will power of a spirit life form.

The words of the master (Mylord) who has experienced other worlds...... and other spaces were helpful to me.

Willpower......Mental Power......Mental Catalyst.

Hanna-san has recently been studying homunculus and wanted a psychic catalyst for it.

So, I used a spirit catalyst of < for my experiment.

This is enough for experiments.

And time passed again.

I strengthened myself further and proceeded with my research. .......

* * * *

In the year 3579 of the continental calendar, if the master (Mylord) is still alive, he would be 143 years old.

Hannah, Erza, Mio, Yu, and all the members of the <> are no longer with us, except for Zion and Marikka.

Still, I am continuing my research.

Master(My Lord)...... is the only one whom I call Master(My Lord), Nido Jin-sama.

I think it is the same for you, Reiko.

With the help of Reiko, my research is gradually bearing fruit.

I cannot give you even a brief outline of this technology because it is extremely dangerous if misused, but the principle is now half understood.

The problem now is energy.

I have calculated that the energy required to travel back in time 400 years is greater than the energy released by the sun in one year.

Approximately 10 to the 36th power of joules.

This is one of the reasons why time travel is considered impossible.

It takes this much energy to travel back in time for a zero mass object, so if it had mass, it would be difficult to .......

It would be difficult to even calculate.

It would be harder than a small fish trying to swim up a waterfall with a drop of several hundred meters.

However, without solving this problem, we will never be able to return the master (my lord) to the original time.

The source of energy in this world is free magic element (ether), but at this stage it seems that we cannot even calculate how much we need to collect to reach the required amount.

However, the Master (My Lord) himself has solved this problem.

It is the three pebbles that the master (my lord) brought back.

He himself said that he brought them as a memorial of the other world, but it turned out that one of the pebbles was enough to generate enough energy.

To be precise, the pebble was filled with the energy of the other world ......<>.

Perhaps the < had anticipated this as well.

Now the question is how to get the energy out of this pebble ...... without exploding it.

Releasing it all at once is out of the question. The released <> has tens of thousands of times more energy than <>, so even if it is not converted into <>, the aftermath alone will clear the surrounding tens of kilometers of land.

Therefore, it was necessary to develop a technology to extract the necessary amount of mana without exploding.

It took about 10 years to complete the necessary technology.

It is all right if you create a out of by a magic circle and place this pebble in it to release the energy.

I will not explain the details of how to do this either.

< in the same way without using .

The only thing that remains is to find the point on the time axis where we should return the master (my lord).

This also required the cooperation of Ms. Reiko.

After all, Ms. Reiko is the person who once searched for the master (my lord) beyond the world of 3601.

With her help, we somehow made it in time.

Now, and are raging in the outside world.

The Master (Mylord) had been researching the Magi Emulator (......) for the benefit of the world, and he has been misusing it.

I, too, decided to take precautionary measures and take a defensive stance.

I put up several layers of wards, and holed myself up inside. Reiko-san sleeps in another place and waits for her master (my lord).

The day of the doomed day, 3,000 years ago, the master of the house was waiting for her.

And on that fateful day, September 17, 3899.

The old man acted just as Jin had told him in the past.

"Oh, no problem, Mr. Lao. I will take care of you one more time.

Jin cannot tell you the details of his journey back in time.

Except that Jin knew about it when he returned 400 years ago.

And I have to tell you a part of it, <>.

The slightest mistake could create a time paradox.

The magic circle under Jin's feet began to glow faintly.

The glow becomes stronger and stronger, and Jin's figure is obscured by the glow.

>

the voice of the old man.

The space was filled with light.

After a few seconds, the light disappeared. Jin is not there.

* * * * *

Traveling back in time...... it is through .

<

In such a space, a part of Jin's psyche was harboring a slight "longing for the future".

How did it work?

As he moved through hyperspace, his mind was duplicated and <> coagulated into a form based on his mind.

That is, the body of Nido Jin. <.

That compound body, or , could not exist in this hyperspace, and was <.

The rebounded <> is returned to the starting point.

Thus, Jin, the <>, unexpectedly lives 400 years in the future.