Kays Translations
Just another Isekai Lover~
Chapter 104: Side Story—Thor, Mabel, and the Forbidden Astronomy
(Author’s Note: To commemorate the book’s publication, I wrote a side story.
Since it’s a side story, it doesn’t have much to do with the main story.)
While organizing the warehouse, Thor seems to have found some materials rather different from the usual ones…
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“…This information is quite difficult to understand.”
“What’s wrong, Thor-sama?”
This was my workshop in Raisenga Territory.
I was lost in thought in front of the documents when Mabel brought me some tea.
“If something is troubling you, I’m willing to listen…”
“Thanks, Mabel. Then, would you listen to me?”
It’s no good to just keep worrying.
Sometimes talking to someone helps you organize your thoughts.
I’ll have Mabel listen to me as well.
“While tidying the warehouse, I found some documents from another world.”
“Are they books like the ‘Mail-Order Catalog’?”
“I wish that had been the case. But unfortunately, what I found this time were only pages torn out from a book.”
I placed the documents in front of Mabel.
The papers were tattered and worn.
The writing had faded, leaving much of it unreadable.
The surviving text was written in characters from another world.
Without a doubt, the pages had been brought here by a Hero.
But only fragments could be deciphered.
That’s typical of ancient documents… but it’s such a shame.
“This… shows a starry sky. What’s this large sphere? On its surface, I can see clouds and seas.”
“It seems to depict the planet of the Heroes’ world.”
“A planet!?”
“More precisely, it’s the world where the Heroes lived. Apparently, this image was taken from an extremely high place.”
The Heroes’ world was a sphere with vast oceans covering its surface.
It was very mysterious and beautiful.
Mabel seemed to think the same, quietly gazing at the picture.
“The Heroes of the other world could fly that high…”
“Their flight magic is truly fearsome…”
Mabel and I nodded as we stared at the document.
“So this is the world where the Heroes lived… Is it an explanatory book about their world?”
“Not exactly. It discusses the formation of the universe.”
“The universe… so, the starry sky world…?”
“Only parts could be deciphered. According to this document, the universe is unimaginably vast. The lands where living things exist revolve around the sun, and beyond them stretches an endless darkness.”
“So that was what the Heroes’ world was like…”
“Maybe our world is the same.”
“…That’s possible.”
In this world, research on the starry sky world hasn’t progressed much.
Everyone is too busy with matters on the surface.
There are wars between countries and magical beasts.
At most, people only check their location or direction by the position of stars.
After all, the strongest nation, the Dorgalia Empire, believed that strength was the most important thing.
So they neglect the starry sky world.
Normally, this kind of research should be done by alchemists who explore the mysteries of the world.
If I get the chance, maybe I’ll do some research myself.
“If the starry sky world is that vast, maybe there are demons, demi-humans, and other creatures somewhere in the sky.”
“According to this document, none have been found yet.”
“Is that so?”
“The universe is simply too vast. Even traveling at the speed of light, reaching another sun would take years.”
“The speed of light is incredibly fast, isn’t it?”
“Super fast.”
“For example, if you stand on a mountain and use ‘light’ magic, it’s visible instantly from the foot of the mountain.”
“That’s right. Even moving at that speed, it takes years…”
“We can’t even imagine how vast the starry sky world really is.”
Mabel and I sighed.
If the universe surrounding this world was like that of the Heroes’ world, it had to be unimaginably vast.
No telling how long it would take to investigate it from end to end.
The starry sky world is full of mysteries.
It’s beyond the abilities of an alchemist like me.
It’s interesting, but I can’t research it all…
“But, the starry sky world does have a romantic charm.”
“Indeed.”
“Thor-sama… if you don’t mind, would you like to look at the starry sky together tonight? I’ll prepare warm tea and blankets, and we can place chairs outside and relax.”
“That sounds nice. Let’s do it.”
“Thank you.”
Mabel nodded with shining eyes.
“I’ve discovered secrets of the starry sky world. If possible, I want to talk about them slowly with you…”
“About… the secrets of the starry sky world…”
“Yes, Thor-sama?”
“Well, actually, I found some other documents too.”
I took out another piece of paper from the shelf.
This is also a page from a book from another world. Like the previous document, its condition is quite poor.
Still, it also contained writings related to the starry sky world.
“This one discusses a sun different from the one seen in the Heroes’ world.”
“A sun so far away it takes years even at the speed of light to reach?”
“No, even further. It’s ‘a sun 100 light years away.’”
“…I can’t even imagine that distance.”
Mabel had a blank expression.
Yeah, it’s just too vast — the starry sky world.
According to the previous document, the starlight we see is actually light from several years ago.
Because the distances are so vast, it takes years for the light to reach us.
I can’t even imagine how huge the starry sky world is —
“So then, what’s at that ‘sun 100 light years away’?”
“According to this, the ‘Gorongaragon people’ came from a planet near that sun and built a vast underground empire beneath the Heroes’ world.”
“…What?”
“That happened thousands of years ago. The ‘Gorongaragon people’ attempted to conquer the surface, but the ancient people of the Heroes’ world drove them underground. They’re supposedly still plotting to rule the surface. The scattered ruins are actually entrances the ‘Gorongaragon people’ use to watch the surface—and now the time of their revival approaches—”
“Please wait, Thor-sama.”
Mabel shook her head in confusion.
I understand how she feels.
“According to the previous document, it takes years at light speed to travel to another sun, right?”
“Yes.”
“Then how’s it possible for the ‘Gorongaragon people’ to come from a solar system 100 light years away?”
“But… this is written in a document from the Heroes’ world.”
I pointed at the page and read aloud the characters that were still legible.
Only some characters could be read.
But there was astonishing information written there:
‘──Aliens have come to Earth.’
‘──The threat of a fearsome underground empire!’
‘──Traces of extraterrestrials remain in ruins scattered across the world……’
There were also photographs or drawings, but unfortunately they had faded with age.
The text sounded extremely convincing. It was difficult to believe it was false.
However──
“These two sources contradict each other, don’t they……”
“One of them talks about ‘the vastness of space that we have yet to reach,’ right?”
“Yeah. The other one says, ‘With super technology, they can leap 100 light-years in a single bound.’”
“So, one of them must be wrong?”
“One calmly describes the vastness of space. The other, in a very urgent tone, writes about the threat of the ‘Gorongaragon aliens.’”
“Clearly, these were written by different people.”
“Mabel, which one do you think is correct?”
“The one about the ‘Gorongaragon aliens.’”
Mabel nodded.
“The reason is that the hero summoned from another world was incredibly strong.”
“I understand.”
“If the people of the Heroes’ world had fought the ‘Gorongaragon aliens’ since ancient times, that would explain why the Heroes were so powerful. Having always faced threats from space, they continued striving to become the strongest even after arriving in this world.”
“That makes sense……”
That’s right.
If this source was correct, it explained why the otherworldly Heroes had been so strong.
We don’t know exactly what kind of creatures the ‘Gorongaragon aliens’ are, but presumably, they’re beings completely different from us.
They live in a place that takes 100 years to reach at the speed of light. This isn’t just another world, but something else entirely.
Their appearance, language, and even way of thinking could be different.
If they had fought such creatures since ancient times, the Heroes’ tremendous power would be understandable.
That would also explain why the summoned Heroes adapted to this world so easily.
Compared with ‘Gorongaragon aliens’ from one hundred light-years away, the people of another world would have seemed like neighbors.
The Heroes probably wouldn’t have been surprised to be summoned here.
……This is troubling.
If I accept the existence of the ‘Gorongaragon aliens,’ then I have to accept the explanation for why the hero was so strong.
They’re a fearsome existence. Damn those ‘Gorongaragon aliens’……
“But Thor-sama, you think the source about the ‘calm universe’ is the correct one, don’t you?”
Suddenly, Mabel said this.
“……How did you know?”
“I try to watch Thor-sama’s expression carefully to serve properly.”
“Sharp.”
“But it’s strange. If the source about the ‘Gorongaragon aliens’ were correct, it would explain a great deal about the Heroes’ world, would it not?”
“But there’s one doubt.”
“A doubt?”
“The hero summoned to this world never mentioned the ‘Gorongaragon aliens’ at all.”
“……Ah.”
Mabel’s eyes widened.
It seemed she understood what I was thinking.
If the otherworldly Heroes had always been fighting aliens—or subterranean beings—they would surely have mentioned them.
They might have said things like, “This kind of magical beast is nothing compared to the Gorongaragon aliens!” or “Take this! The ultimate magic that can even defeat the Gorongaragon aliens!”—some kind of catchphrase wouldn’t be strange.
But the hero never said a single word like that.
Those heroes, who blindly aimed to be the strongest, would never omit mentioning their world’s invaders—their rivals.
They were a fearsome group of warriors who even rejoiced upon finding worthy rivals in the Demon Lord’s army.
Furthermore, the otherworldly Heroes specialized in light- and fire-element magic.
But if they had been fighting the subterranean empire, then earth attribute magic would be important.
It could be used to dig through the ground and to seal entrances from underground.
Yet the heroes dismissed earth attribute magic as “plain” and disliked it.
They probably had an unyielding sense of aesthetics.
But if they really had been fighting subterranean beings, it would be natural for them to have mastered powerful earth attribute magic.
It’s also unlikely that they would postpone learning effective magic against their enemies.
They raised their levels with maximum efficiency, hunted magical beasts, and fought demons and demi-humans.
Considering all this information together──
“This source must be wrong. We should conclude that neither aliens nor subterranean beings existed in the Heroes’ world.”
“As expected of Thor-sama.”
Mabel nodded repeatedly, convinced.
“It’s certainly strange that the heroes left no mention of the ‘Gorongaragon aliens.’”
“In that case, the source about the ‘calm universe’ must be the correct one.”
“That’s a relief. So there were no evil aliens coming from distant stars……”
“That’s right.”
“Now we can safely gaze at the starry sky with Thor-sama.”
I could understand why Mabel felt relieved.
If you were thinking that aliens might attack from beyond the stars, you wouldn’t be able to calmly do any stargazing.
“Perhaps the document about the ‘Gorongaragon aliens’ was merely an excerpt from a story.”
“That’s right… Now, about the third document—”
“There’s still more!?”
“The next document concerns ruins in the Heroes’ world.”
I placed the third paper on the table.
It had a picture of a stone structure.
“In the Heroes’ world, there were structures where the sun passed directly overhead only twice a year, as well as ruins used to measure the positions of the stars. The sun and night sky appear to have been important there too.”
“Is that so?”
“Maybe that was the secret to the otherworldly hero’s strength.”
“If that’s the case, maybe we should also investigate the world of the starry sky here.”
“That’s true. I’ll ask Her Majesty the Demon Lord for permission to create items for astronomical observation.”
“Maybe it would be good to have a facility for observing the sky too.”
“An observatory, huh… yeah.”
I decided to write a letter to Demon Lord Rukie.
For now, I would tell her about the astronomical observation items and the observatory.
Just in case, I decided to attach the three documents and their translations.
While thinking about these things, I began preparing.
—A few days later, at the Demon Lord’s Castle—
“Kelve.”
“Yes, Your Majesty.”
“A request came from Thor, saying ‘I want to build an observatory.’ What do you think?”
This was the throne room of the Demon Lord’s castle.
Demon Lord Rukie faced Chancellor Kelve, holding a parchment.
“He says that by looking at the stars, we might be able to understand the hero better.”
“Looking at the stars?”
“Yes.”
“In that case… maybe he wants to build a watchtower under the pretext of building an observatory.”
“A watchtower?”
“If it’s Thor-sama, he can probably create an item that lets him see over great distances. If he built an observatory equipped with such an item in Raisenga Territory’s mining district, it could be used to watch the Empire. Perhaps his true purpose is preparation against foreign threats.”
“Does he think such practical things?”
“Once a year or so, such things might happen.”
“The letter also included documents from the Heroes’ world and their translations.”
“Documents from the Heroes’ world? What kind of content?”
“It said, ‘These are precious documents, so please read them together with the Chancellor.’”
“Understood. Then, I’ll take my leave.”
Chancellor Kelve stood and moved beside the throne.
Then, Demon Lord Rukie and Chancellor Kelve began reading the ‘Documents about the Universe’ from the Heroes’ world—
“—Hmm hmm.”
“—I see.”
“…So this is the appearance of the stars…”
“…Interesting from a military perspective…”
“…The universe… planets…”
“…I-Is it an invasion!? From beyond the stars!?”
“…So they’ve been watching the stars since long ago in that world. How romantic…”
“…An underground empire!? Terrifying aliens!? No, according to Thor-sama’s guess, that’s wrong… but… hmm…”
“I see. Sounds interesting. I think we should approve the installation of the observatory.”
“Y-Yes! Let’s permit the building of the observatory. I don’t believe in aliens or anything… but learning about the world is a good thing. There are no aliens, absolutely!!”
Thus, Demon Lord Rukie and her Chancellor approved construction of the observatory.
Demon Lord Rukie became interested in the universe, and Chancellor Kelve decided to seal away the second document as dangerous information.
At the same time, Thor began creating a ‘telescope’ based on the ‘Mail-Order Catalog’—
A few years later, astronomy in the Demon Lord’s Domain had advanced tremendously, and researchers from other countries began visiting to seek instruction…
—but for now, no one knew this yet.
Side Story “Thor, Mabel, and the Forbidden Astronomy”—The End