The Royal Military Academy's Impostor Owns a Dungeon [BL]

The Aetheryon Royal Family, the current ruling family of the elven race, who mainly resided in the Lumira Galaxy, actually lorded over several galaxy groups.

It sounded impressive on paper. Grand, majestic, powerful. The kind of thing one could be proud of.

But the truth was far less glamorous.

Because fortunately or unfortunately, the current members of the family could only trace their roots to the relatives of the last pure-blooded Aetheryons.

As a story that could fill history books, most would be aware that the true main branch had been gone for generations.

Elior personally thought this was a blessing. Because really, who would ever want to be fully related to that insane Elven King?

Certainly not him. He thanked the stars every day that his bloodline was diluted enough to keep him sane.

Of course, his ancestors probably had their own issues they were guilty of; after all, fighting between the orcs and the elves didn’t really die down until the dawn of corruption. But from what he knew, it shouldn’t be as repulsive as that beheaded elven King.

Then again, not everyone shared his sentiment. There were always those who obsessed over bloodlines and purity.

And because he knew what was at stake, he could also understand their frustration. To many elves, their diluted bloodline meant their leaders no longer had guaranteed access to the ancestral bloodline ability that was supposed to legitimize their rule. And to the elders, that felt like their race was being abandoned by the gods.

And who would like that, right? Especially when the other leaders of the other races seemed to be doing fine with passing on their bloodline abilities.

Sure, the current royals technically had Aetheryon blood. They were by no means fake in that regard. Still, as a branch family whose ancestors had manifested the sacred ability maybe three times in their entire history, the connection was significantly less impressive. Especially when compared to the extinct main branch, whose members all possessed it.

But then, up until some time ago, it had never been the biggest concern. It was not as though better candidates were hiding somewhere, because even the naysayers couldn’t wield the bloodline either. Most of them were even more distantly related and had nothing to back up their complaints except loud opinions.

So everything had been fine. Not spectacular, but at least things were fine.

If only it had stayed like that.

Because it all came crashing down when the unsuspecting Elior accidentally manifested the controversial ability.

It happened when they were much younger, back when he and Eren actually shared an enviable brotherly relationship. The kind that made tutors sigh in relief and elders feel proud. Back when they were simply two mischievous boys who thought the universe would forgive anything they did.

On that ill-fated day, they had decided to escape their lessons. A brilliant idea, according to seven-year-old logic. After all, what could go wrong when the teachers were boring, and the palace hallways were wide open?

Their tiny feet carried them deep into the forest, giggling, arguing, and daring each other to go farther and farther until they stumbled across a crystal cave they had never seen in all their seven years of life.

The cave was breathtaking.

Columns of translucent crystal jutted from the ground like ancient pillars, each one glowing faintly with soft hues of blue and lavender.

The walls, on the other hand, shimmered with delicate fractures that caught the faintest light and scattered it like stardust. While pools of clear water reflected the entire cavern upward, as if an inverted sky lived beneath the surface.

To the two children, it felt like entering a secret world. With something that inviting, how could they possibly resist the temptation to look?

And as children would, they eagerly went inside, absolutely convinced that nothing bad could possibly happen to them.

Nothing did, at least not while they were going in. They ran around, touched everything shiny, poked anything that sparkled, and laughed at their reflections in the mirrored pools.

The trouble began when they tried to go back.

Something in the cave made them sick. It was slow at first, like dizziness. But it grew stronger and heavier, settling into their bones like poison.

Eren passed out first.

And as the elder brother twin, even if it was only by minutes, Elior tried his best to stay awake. He staggered. He crawled. He dragged Eren inch by inch toward the exit, refusing to leave him behind.

By the time they reached the outside, the entire palace had already been thrown into a frenzy searching for them. Patrol beasts were deployed. Guards were shouting their names. Lights from the sky fleets swept the forest floor.

Apparently, during that period of disappearance, their terminals could not be contacted or tracked at all, and it nearly pushed the extremists into using the incident as an excuse to start another war.

Elior could still remember the relief that washed over him when he saw people running toward them. Even years later, even after everything changed, he could not forget that moment.

But why?

Perhaps because everything changed after that day.

Because what came after the relief was Elior passing out. He remained ill for an entire week with a fever so high that healers feared he might never wake.

And then one morning, he simply woke up in a body that felt different altogether—as if, in trying to cool itself down, his body had undergone transformation as a desperate measure.

Young Elior noticed nothing at first, but the maid who entered his room certainly did.

She screamed. And in similar surprise, the physician fumbled and dropped a whole tray of medicine. Then, within moments, they began shouting for everyone within hearing distance.

That was how the palace discovered that Elior had turned into an animal.

It was chaos. Panic. Celebration. All mixed in one.

Once the adults pieced everything together, they confirmed what none of them had expected. Elior, out of the countless people in their family history, had actually managed to use the Aetheryon bloodline ability.

It was apparently something to celebrate.

As a child, Elior had smiled, overwhelmed by the strange pride in his parents’ tearful faces.

They cried about destiny. They cried about legitimacy. They cried about how Elior would finally secure their family’s claim to the throne, ending the unnecessary and fruitless struggle that the opposition always banked on to shake their rule.

As expected, it was nice to be hugged by happy family members.

So all in all, it should have been a fulfilling day. And it was.

At least until Elior looked back at his brother.

Eren was standing there. Silent. Motionless. His expression unnervingly grim for a seven-year-old.

Concerned, the recovering prince asked his younger twin if something was wrong.

And maybe that was the moment everything shifted—the fateful day that marked what was to come.

Because Elior believed Eren when he said nothing was wrong, even going as far as to congratulate him.

And yet from that day on, things had never been the same.

__

It started with the most mundane things.

The younger twin, who always insisted on individuality and uniqueness so people would finally stop mistaking them for each other, suddenly began doing the exact opposite.

Overnight, Eren made it a point to wear the same clothes, eat the same food, and even mirror Elior’s daily routines. And while that would’ve been normal for a family member, it hadn’t been that way for the young Eren, who liked being flamboyant and unique.

Heck, if Young Elior had the same level of awareness he possessed as an adult, then maybe he would have noticed the strangest things. How Eren would take a bite only when he did. And how his brother would drink only when he did. Almost like a strange, silent echo that had even bigger goals.

At the time, Elior barely noticed. In fact, even if he had, it would have been pointless, because everything became a whirlwind the moment he was named the official heir. All thanks to the discovery that he could wield the Aetheryon bloodline ability.

So the young prince was busy. Very busy. And even the word ”busy” felt like an understatement. It was as if the entire royal palace woke up one morning and decided to pile centuries’ worth of expectations onto his tiny seven-year-old shoulders.

Lessons. Ceremonies. Rituals. Etiquette. History. Comparisons to ancestors he had never even heard of. Lectures about ruling, destiny, sacrifice, posture, posture again, and then posture while breathing correctly.

Not that they hadn’t been learning that before, but suddenly even those people who would’ve preferred to see them bumbling about were pushing for learning as if he was the answer to their odd prayers.

And while all of it sounded like a grand promotion, Elior had never actually wanted the position.

After all, who would willingly take such a thankless job where people would just criticize you for every little thing?

But just because he did not want the position did not mean others felt the same.

While Young Elior was drowning in reading materials thicker than his arms, Eren’s world was closing in with every passing day.

Because everyone knew the ancient truth. It was a grim one, whispered in royal households across galaxies.

What usually happened to spare princes?

Didn’t they usually die?

Moreover, as twins who should have been similar in every way, how was it that his brother was able to use their bloodline ability?

Was he not a real Aetheryon? Or worse, did Elior steal what was also supposed to be his?