On an ordinary small slope on planet Maru, a young man lay with a small sprig of grass native to this world between his teeth. From the outside, he looked like a lazy, common shepherd; however, beneath this facade, an air of something strange—something that did not quite fit the pastoral landscape—could always be sensed. Though his eyes were quite sharp, the dark circles beneath them were prominent, giving him a sickly appearance. His thin, wiry frame only served to emphasize this ill-looking aura.
As he lay there, the young man watched the sun of Maru vanish from the sky and stared up at the heavens filled with clouds of gray dust. Watching the sky had been his favorite thing to do since he was born on this planet covered in crimson dust. Although he could not see a sky filled with stars like in his former life, he could still catch occasional faint flickers. Besides, there wasn't much else to do here. The endless stretches of hills, sands, and barren lands didn't offer many options.
This was the most normal state of Maru. Though dust storms sometimes robbed him of this pleasure, he didn't complain much. After all these years, he had grown used to it. Moreover, those storms added a different atmosphere to this deep desolation that usually drained a person's energy and made them want to do nothing at all.
It was unclear how many hours the young man had been lying there. However, as if waiting for a specific time, he slowly rose from his spot and spat out the grass. He stretched a little and checked the livestock he had brought out to graze. These animals resembled Earth's sheep, but they were quite different. Their skin was thicker and reddish. Their eyes were bright. They had wool, but it was more like a protective layer fused to the skin, evolved to shield them from acid rain. These animals were not a native species; they were a crossbreed of ordinary sheep and a species brought back from the Nightmare Dimension. They were the only ones who had survived and adapted to those genes. While their adaptation to the environment had increased, their reproductive capacity had plummeted accordingly. This flock was one of about ten scattered around the city, and the total number of all flocks combined did not exceed five hundred. The young man was one of the shepherds tasked with looking after one of these flocks—about fifty sheep. More accurately, his family held the official duty, but the task of watching the flock had been passed down to him.
Seeing no issues with the animals, he changed his position without disturbing his comfort and continued to lie down. The animals could keep grazing until midnight, so the newly darkened sky was still quite early for him. It was enough to just check for any problems—a stray animal, one caught somewhere and injured, or one excluded for other reasons. He didn't spend much time on it, giving them only a cursory glance.
As he lay there, his mind drifted into the memories of his past life. His was a rather strange situation. It couldn't exactly be called a "transition"; it was more like a rebirth in a different world. However, his memories hadn't been preserved since birth. Perhaps his infant body wasn't developed enough to carry all those memories, and his physical form had sealed them away to ensure survival. The mystery of his birth solved itself naturally as he grew. At first, it was just remembering through dreams. But as he got older—specifically when he reached adolescence—he fully awakened all his memories and realized he had crossed over to another world, perhaps a parallel universe.
He let out a short sigh and stopped thinking, deciding to stop digging through bad memories. He had lived on this planet for more than five years since his memories awakened. Yet, he still couldn't help but miss his old, bustling life sometimes. His former life hadn't been incredibly comfortable either, but at least when he wanted to wander, there were places to have fun, sights to see, and delicious food to eat. Here, however, it felt exactly like a restricted medieval village.
In terms of barrenness and danger, it was far worse than the Earth's Middle Ages. At least his family lived inside the city in the relatively protected farm district. Although this area was on the outer edge of the city, it was considered much safer than other places because it was one of the sites that met the meat demands of the city's elite. This was why the young man was so relaxed and dared to be so lazy.
The young man was in his early twenties. However, he was quite confused about what kind of life he wanted. Normally, in his old life, someone his age would be studying at a university or working in a profession. But that wasn't how things worked here. He had started school here at the age of seven and learned the history of this planet. He knew what kind of world he lived in. They had told them about the planet's conditions and humanity's bloody, dark history from the very first days. It wasn't exactly an act of vengeance. It just felt like they wanted to tell people: "If we don't become stronger, and if there are no explorers who risk their lives in the dimensions, our end will be like that of our ancestors. Destruction, pillaging, and misery. A handful of wretches who couldn't even protect their own home..."
His school life hadn't lasted very long. What was taught in school was limited for an ordinary person like him. Reading, writing, basic numbers—elementary problems. Anything beyond that was a luxury on this planet. Perhaps there was extra education for the children of people who went to the dimensions, but he hadn't heard of it. Honestly, he didn't care much. First-hand information about dimensions usually spread as rumors. Unless it was a secret technique or a martial art found there, people didn't hide much. Humanity needed the explorers who risked their lives to survive. Even the strongest man in the city couldn't say for sure that he would return alive if he entered a Disaster-level dimension tomorrow. For this reason, they re-entered dimensions quite rarely.
The young man knew about the dimensions; he was aware of the kind of planet he lived on. This was the main reason he was confused. Normally, the work his family did involved looking after animals and planting the grass eaten by the specially crossbred livestock. Though it seemed difficult, it was a very comfortable job compared to those living outside the city or even most in the outer city. Because of this, his family didn't want him to risk his life.
The young man, however, was aware of how fragile their comfort was. The walls of the city they lived in had been destroyed in various places and rebuilt at least four or five times in the last ten years alone. If one looked further back, this city wasn't always in this location. Only fifty years ago, it was somewhere else. Mutated creatures had attacked that city, and it couldn't resist.
Those who could flee when that city fell had built the current city from scratch. So, no matter how safe it seemed, it wasn't truly safe to him. It was uncertain when another wave of creatures would attack. What he was certain of, however, was that if an attack occurred, his and his family's ordinary lives would not be among those protected—they would be on the side that gets abandoned. This was how humanity had survived for 500 years. For this reason, the young man wanted to try his luck and go to the Nightmare Dimension. Yet, he felt quite helpless regarding his family.
Besides all this, while their work seemed easy, the wages they received weren't great either. He was responsible for the animals, but in 20 years, he had never even tasted their meat. The rare meat he could eat was the older specimens of white maggots that enriched the soil with minerals. These maggots seemed like a perk of their job, but they didn't have the right to eat them as they pleased either. Because they were doing something perhaps even more important than the animals they raised: they were making the soil in this small settlement capable of growing at least some grass. Therefore, only the old and weak ones were recycled for food by his family. Although he didn't like the taste of the maggots, he knew there was no better alternative under these conditions. In fact, having maggot meat pass through his throat was enough to make him wealthier than most people.
He continued to lie there, but his mind was still elsewhere. There were two Disaster-level dimensions for humans to choose from: The Abyss and The Nightmare. Initially, people were more hopeful about the Abyss, but it was the first dimension the young man had ruled out without a second thought. In the early days, the return rate for people going there was much higher than the Nightmare Dimension.
However, it wasn't long before it was understood that the Abyss was a complete trap. The Abyss was like a strange intersection of spaces where chaos and order intertwined, and rules were constantly distorted. It waited for people like a spider waiting for a fly to land on its web, and once they landed, it turned into a monster that slowly wrapped them up and consumed them entirely.
Furthermore, the Abyss was known as the Graveyard of Civilizations. It was said that pieces of lost or vanished civilizations—and even their timelines—were somehow pulled into the Abyss and became fragments played on an eternal loop. In this way, it acted more like the trash heap of the universe. But this wasn't a junk pile arranged in heaps. It was a Disaster-level dimension where everything, including time and space, mixed regardless of energy levels, and from this mixture, strange species were born that one couldn't even imagine.
As a dimension, there was no "Abyss" identified with Cthulhu or demons from his old life, but there was an Abyss far more sinister and dangerous. Besides that, it was a much more rewarding journey for those who could return, but for the young man, it was no different from a suicidal act like throwing himself into a lake full of crocodiles. He knew that greed would cost a life, and for humanity, this lesson had been quite bloody. He didn't have a death wish yet, so he had dismissed the Abyss without thought.
The Nightmare Dimension was more complex. It was believed that this dimension was born from the imagination and emotions of all living beings. For this reason, it was also quite unstable. However, this instability contained much more order than the Abyss. In the Nightmare Dimension, situations like time and space confusion usually didn't happen. Instead, there were shifting conditions like storms suddenly forming in sunny weather, sudden hail and snow, earthquakes, and floods within fixed locations.
But that wasn't the only problem. The biggest issue in the Nightmare Dimension was the instability of the creatures. Countless unsolvable creatures born from imagination hid there. In a dimension that housed the fears and anxieties of all living beings, numerous creatures that continued to thrive on emotions maintained their existence.
Old myths said that terrifying crows, corpse-men, scarecrows, vampires—whatever living things feared—lived somewhere in the Nightmare Dimension. So, this dimension also lived up to its name as a Disaster-level dimension. However, to the young man, the biggest problem was encountering non-material creatures like ghosts at the first stage. It was often these types of creatures that killed people and prevented them from returning. Because when material and very powerful beings were encountered, if they weren't in a bloodthirsty mood, humans still had a chance to survive because they were like ants to those creatures. But a creature on the ghost side could destroy humans just with the spiritual pull and radiation it emitted while even just moving.