Over a thousand years ago, the nomadic Demi-humans discovered this unique cave during their travels through the Astra. What they did not realize at the time was that this cave, presumably just a place to rest for a time, would become the birthplace of the Demi-human renaissance.
After decades of exploration, the Demi-humans discovered the technological remnants of an ancient civilization. Piece by piece, they surmised that the people of this ancient civilization utilized the enormous cave for experimentation. At the same time, the cave-dwelling Demi-humans realized that their bodies had grown much stronger than those who maintained their nomadic ways. Their sensitivity to Lumina had increased by no small measure, as well. This phenomenon, strangely enough, seemed to be the exclusive experience of the Demi-humans. No changes were seen in any Aurorians and Caelestites who visited. The only thing other races could sense was that the ecosystem within the cave was unique, namely that it seemed unaffected by the changing seasons. The climate of the cave was always pleasantly warm and comfortable. As a result of this realization, the Demi-humans declared this cave their heaven-sent Promised Land, and their massive city constructed here came to be known as the Secret Territory.
After over ten generations of hard toil, the Demi-humans created for themselves a glorious and independent civilization, one that did not simply utilize the ancient technology of the cave, but built on it and improved it. The glorious Demi-human motherland was, for hundreds of years, a center of technological and industrial advancement, and agricultural prosperity... That is, until it was invaded and overrun by the Eclipsite menace.

"The ventilation and lighting systems sustained irreparable damage early in the invasion. The smell of gunpowder could not be cleared out, though it did nothing to mask the stench of blood in the air. The vicious Eclipsites, their bodies twisting and writhing in the smoke, killed indiscriminately with no hesitation and no remorse. They took no prisoners, and slaughtered all the citizens upon capture without exception, like ravenous beasts.
Some of our kin attempted to fight back and wrested a child from the clutches of a mob of Eclipsites... Only to fail in their escape, and fall victim to a mass of clawing, howling monsters. We lost contact with the front lines a few hours prior... We feared the worst had befallen them. Our only hope... were those who had escaped through the underground pathways. We prayed against the fate that our children made it there safely... I will never forget what I saw that day: our people lying dead in the street or crushed under ruins, the light in their eyes long since gone... Mountains of corpses towering in a landscape marked by smoking flames and screams of agony...
Our beautiful motherland had been transformed into a living hell. For their sins... those foul, murderous Eclipsites must pay!"
Excerpted from a notebook found in the Secret Territory by the Illumina Expedition Team

According to the elders, we should be the last wave of fighters to enter the cave. I call them "elders", but they are nothing but a group of young Demi-humans. The real elders, who had lived long lives, have long since perished in the fight against the Eclipsite menace.
Though we had steeled our hearts for the worst after receiving our kinsmen's distress call, when we saw our great cave reduced to a pile of rubble and ruin... When we saw the mountains of corpses of our fellow Demi-humans... In this hellish landscape, we all but lost the will to fight. Thankfully, the kind and comforting words of the elders brought us to our senses. Even though they look just a few years younger than us, I...
Damned Eclipsites, they'll pay for their evil! A hundred of their heads for every fallen Demi-human! None of us could ever forget the faces of our comrades as their lives were taken from them... We've lost our home, our lives... What else can they take from us? Is there no other refuge for us Demi-humans in this land? Would it not be better for us to stand against our invaders one last time, and die like our compatriots: piled atop one another, with no regard for age or status? They've paid the ultimate price in defense of our home, so now it's our turn to do the same. Let Eclipsite blood serve as our funeral garb, and let their corpses serve as our burial mounds! We'll fight for our home, down to the very last of us...
Excerpted from the diary of an Unnamed Half-Aurorian, Half-Demi-human.

When I think about the withered bones that littered the ruins... Or those brave Illumina soldiers who never let go of their weapons, even as the life faded from their eyes... Back then, all I could think about was abandoning that doomed expedition.
The extinction of the Demi-humans had taken place hundreds of years ago, and the Eclipsites were the masters of the cave now. What we, as outsiders, choose to call it does not change that fact. What's more, Eclipsite attacks on other settlements had all but stopped after they invaded the Demi-humans' homeland. It seems they are content to live and be left alone in the depths of the Secret Territory. None of us truly know what they do in there...
That's why it fell to us to find out.
At first, the Illumina Expedition Teams were brimming with courage and optimism, hoping that they would be the ones to deal a decisive blow to the Eclipsites. Their thoughts were about safeguarding their loved ones, and the Illumina Federation... But reality soon showed everyone the folly of their optimism. Over time, countless Expedition Team members were either slaughtered by the cave-dwelling Eclipsites, or lost in the vast depths of the Secret Territory. In some instances, entire teams would go missing, never to be seen again. Opposition to the expeditions grew over time. Nevertheless, the leaders of Illumina insisted on the expeditions, in order to "discover the truth." This simple motive, born of Illumina's creed, resulted in the loss of countless brave soldiers, as well as lifetimes of sorrow for their families and loved ones.
Eventually, deserters became common in the front lines, and we were among them. We abandoned our fallen comrades, ignored our orders, and fled the Secret Territory with our lives intact. Presumably, we've been classified as "Missing in Action" in Illumina's public records, but our military records most likely list us as deserters. What happened to our relatives? Were they punished for our cowardice? I'm afraid we'll never know, because there's no returning to the Federation for us. We have no choice but to spend the rest of our lives in this desert.
Though I do miss my family and my hometown from time to time, my will to stay alive far outweighs my homesickness. At the end of the day, we're still alive, and we have an entire desert to call home now. In some ways, I think knowing when to give up is a kind of wisdom of its own. If we were as devoted to our homeland as the Demi-humans were back then, we'd only have two choices: explore the Secret Territory and be killed by the Eclipsites, or violate orders and return home to be tried and executed. Either way, death was the only outcome.
We haven't gotten any news of the Illumina Federation's exploration of the Secret Territory lately. They've most likely given up, as the other city-states have shown no sign of continuing their efforts, either. It seems the entire world has finally recognized the Secret Territory as a lost cause, a place under the control of the Eclipsites and no one else. And that's a damn good thing, I think. Secret Territory and Illumina, Demi-humans and Eclipsites. We're sick of all of it.
First-hand account of a first-generation Rediesel Wrench member, who wishes not to be named.