The time has also moved back about 400 years, to April 1, 3464. April 1, 3464.

It was Jin's 28th birthday.

Eight years have passed since Jin was summoned to Ars.

"Happy birthday, my dear."

"Happy birthday, Jin-san."

"Happy birthday, Jin-sama."

Jin's birthday party was being held in the hall of Nido Castle in the village of Kaina.

In attendance were Jin, the entire Jin Family, and the residents of Kaina Village.

"Thank you, everyone!

Jin, the guest of honor, thanked everyone.

The early-blooming cherries planted in the castle garden are in full bloom. The petals of the flowers are occasionally blown in by the spring breeze.

Jin was being poured a glass of sparkling wine by his beloved wife Elsa.

His beloved son Chloe and daughter Mio are sitting down and drinking juice. Nearby is Juliana, daughter of Reinhard and Bertsche.

Juliana will be six years old this year. She is older than Chloe and Mio. She seems to be aware of it, and she is taking care of the twins.

She is usually taken care of by the maidservants in the << Ivy House (Lankenhaos) >>, so she seems to be eager to take care of them on such occasions.

"Reinhard, you seem to be busy these days.

Jin spoke to his good friend Reinhard.

"Yes, I've been a bit busy with the new residents in the area.

Reinhard replied, taking a sip of the wine in his hand.

"Today is my first vacation in a long time."

Although he has excellent secretaries and automata, the final decision must be made by his lord, Reinhardt.

Reinhardt also hears important appeals from the people himself, which keeps him busy every day.

Ah, this wine is delicious.

Reinhardt sipped a glass of Erlich 3454, one of the best wines, and muttered happily.

"You should moderate your wine".

Reinhardt's wife, Bertsche, reminded him.

We can't have you working with a hangover.

"Don't worry. I have this bracelet.

<. Jin made this bracelet for the .

It is a certificate of fellowship, and has many functions. One of these functions is detoxification.

One of the functions of the bracelet is . Since caused by alcohol is considered a kind of poisoned state, turning on the detoxification function of the bracelet will sober you up in an instant.

Since that would be tasteless, Reinhardt has turned it off for now.

"Hmmm...<> have such a habit, don't they?"

Guth Eschenbach, the best naturalist in the <>, explains to his wife, Saki Eschenbach.

They had just recently returned from the Nordic Federation.

"By the way, ancient dragons... I miss them so much.

Saki had once visited the northern boundary of Japan to search for the shell of an ancient dragon with Jin, Erza, and Sion of .

"That time we went there with ," he said.

"This time it was easier because I was lent <<>."

<

The crew consisted of a small space golem < 40 cm tall, but it was later modified to accommodate up to four human passengers, albeit in a cramped space.

Although small, it is a spaceship, so it can visit extremely cold places without any problems.

It is also equipped with a small Peeper Telescope, making it ideal for research trips such as this one.

Goose remained at an altitude of 300 meters for more than a month.

This is how he had been observing the ecology of the world's most powerful dragon.

"......Yes, that's right. <.

<

Hanna was only 8 years old when they met, but now she is 16.

According to Reiko, she has grown up to be a beautiful girl who is the spitting image of her <, Adriana Barbora Zetsi.

Her extraordinary talent has been especially demonstrated in the field of physics, and recently she has been working day and night to unravel the mysteries of space and free magic element (ether).

Hanna had been asking Jin a lot of questions, hoping to get even the slightest hint of information from him, who had once wandered into another space and made contact with a , an inhabitant of the space.

"Hannah, that's enough. Today is Jin's birthday party."

It was her grandmother, Martha, who nudged Hannah.

She is 65 years old this year, but her waist is straight, her skin is shiny, and she looks young.

The development of sanitation and medical technology, including hot springs in the village of Kaina, as well as the improvement of the food situation in the village, are the reasons for her youthfulness.

"Hi, Grandma!"

Hannah, too, can't resist Martha's words. No, actually, so is Jin.

In fact, Martha is respected as a sounding board of the .

"Mmm, this food is delicious too!

"Hats off to the Peridos for their housekeeping skills.

Sion and Marikka of the are tasting the dishes.

"Itopo, right?　Too bad we can't grow it in the cold."

Itopo is a sweet potato. Therefore, it is difficult to grow it in the cold regions of the Nordic Union.

It would be possible to grow it in a greenhouse, but it is not cost-effective.

It is much more economical to buy it from the local people than to go through the trouble of cultivating it.

The price to pay is the recently discovered , which is a titanium dioxide, TiO2.

Rutile is a crystal of titanium dioxide TiO2, and its refractive index exceeds that of diamond.

On Earth, transparent crystals are rarely found, but here in Ars, huge, transparent crystals are produced.

Jin wanted to use the high refractive index (2.62 to 2.90) to make optical instruments.

The Mohs hardness is 6 to 6.5, which is lower than that of quartz, but this can be controlled by the method of use and <.

Jin thought that if it was used for glasses, thinner and lighter ones could be made, as the first prototype.

"Well, Jin, your acquaintances are very distinguished, aren't they?

Sally, a healer from the village of Kaina and wife of the village chief, Gibec, muttered with a slightly reddish face.

"The nobles and their wives from the Shoro and Egelea kingdoms, as well as the powerful people of the Nord Federation. I'm afraid to say that even the lord of the neighboring village is a friend of mine.

The noble couple of the Kingdom of Egelea is, of course, Count and Countess Kuzma, in other words, Lewis and Bina.

Bina had brought her son, Reginald, who was almost five years old.

"Here you go, Reggie, this is delicious, too.

"Yes, it's so sweet!"

Bina was feeding her son the Persica that Jin had brought from Horai Island,

（Persica. (I remember ...... Jin cured Nana and Lardo of scurvy. ......)

It is Bina who has become Countess Kuzma because of that time.

"Beena, I'll watch Reggie, go and talk to the others for a while."

Count Kuzma, Louis said to Beena in a gentle voice.

"Oh my dear, are you sure you don't mind?"

"Yes, of course. Yes, of course, since we are all here.

Thank you very much.

Bina left Reginald in Luis' arms and walked quickly toward Elsa.