This world is hardly some peaceful and idyllic medieval setting. People here use magic rather than our version of technology, but since everyone can use magic in varying but repeatable ways, it is fairly advanced and follows a similar template for research compared to our world. It might not look that way at a glance because many of the things I would have taken for granted as being evidence of an advanced civilization are either ineffective, inefficient, or obsolete, and those things which are not are niche. But, advancement is ubiquitous once you know what to keep an eye out for.

One example would be air conditioning. That's a pretty simple and obvious quality of life enhancement, and yes, they have it. Enchanters create runic plates which can maintain the temperature of an area, and which can be maintain their charges via monster cores and by having someone periodically injecting their own Aether into those cores to maintain a steady power supply between recharges. Ergo, no problems with internal temperatures, so clunky air conditioning units are unnecessary. Never mind whether or not it's "needed" given the physical abnormality of the people of this world compared to my old world, comfort is comfort.

Refrigeration? Same concept, actual refrigerators are a product of our need to containerize and carefully seal the food we want to keep cool. They don't have the same shape and style here, because they don't need it. If you can just designate "This shelf/Larder/Etc." and make the air there extra cool, you don't need to use the same rectangular behemoth, so refrigeration tends to just manifest as shelves or in cellars where you put your food.

Well what about things like tractors? The benefits are marginal when the farmers have superhuman strength, endurance, and special abilities to produce exceptional harvests in comparatively small areas. That's assuming a modern tractor would even be able to plow the incredibly dense soil, though some artifice could resolve that readily enough should you add some Aether infusions. The point being though that if there are tractors I haven't seen them, but they also don't appear to be able to fill the same function to the same degree here.

Hospitals? Well, they kind of have something similar, but they're more like clinics, and outside of a military facility or somewhere you might expect mass casualties with regularity… They are an awful lot smaller than I am accustomed to, more like clinics, often with only a single doctor in attendance. These clinics even tend to look rather rustic, but then again there is little that our modern medical equipment can bring to the table when the doctor can literally magic away traumatic injuries… So does it actually matter if the "hospital" in this tiny village is just a dirt floor hut? You'll get equal or (usually) much greater quality of care in that dirty little hut than even brilliant doctors on earth can accomplish. Not that most buildings are straw huts with dirt floors… But I think it makes the point.

In other words, while this isn't a world that a person on Earth would be likely to recognize as modern at a glance, it's mostly stone buildings with few apparent appliances, they'd likely think it's not far from an ancient society somewhat similar to the Greeks or Romans but with a midevil flair. That perception would be a mistake though, attributable to them not understanding what they are looking at. Magic is the Technology here, and although it lags behind in some areas, in many ways Grendel is far more advanced than modern Earth.

I don't think anyone knows where Aether actually comes from. Some people speculate that it comes from the Dungeons, while the priests of course say it comes from the gods. For once I think the priests might be right about it, but only because it was a god that gave me the chance to come here. Not an omniscient and omnipotent god, definitely not, but sufficiently far beyond humanity as to make bothering to differentiate them from our idealized version of a god a pointless philosophical exercise.

Dungeons though, are real, and the primary purpose of any nations military is to police and patrol the dungeons in a region. Periodically there are Aether surges, and those Aether surges sometimes cause new dungeons to be created and old dungeons to stop producing monsters, so while it's somewhat stable you always have to be careful because any unchecked dungeons in your vicinity are an enormous threat.

Dungeons produce monsters organically, which is already enough of a problem, but many types of monsters, once produced, can continue reproducing on their own. If left alone, a dungeon population may soon go out of control, leading to a monster surge.

As a rule an actual city will be sufficiently militarily prepared to withstand an unexpected monster surge; but a monster surge doesn't end on its own unless it's coupled with an Aether surge which causes the dungeon feeding that surge to stop producing creatures, and even if that does happen and the dungeon responsible for the monster surge stops magically producing monsters, unless the population is eliminated, the reproducing monsters will continue reproducing even in a defunct dungeon or the townships their future generations build.

If it weren't for the fact that so many species of monster are every bit as hostile towards each other as they are to humans, humanity would've long ago been wiped out due to the difference in numbers alone. It is fortunate for humanity that monsters don't like monsters, either. Unfortunately for humanity, Monster Lords exist.

Monster Lords are only produced from a dungeon, not born, and they are very rare. Every dungeon will have a dungeon boss. Not one in a hundred Dungeons will produce a Monster Lord in the entire dungeons life. Monster Lords are stronger than their brethren, and are far more intelligent, and far more charismatic. They are the villain's of this world, and the reason humanity has no true chance.

Any dungeon which has creatures capable of reproduction might attempt to create their own cities or even kingdoms, but Monster Lords are something special. They don't stop at trying to establish their own nation for themselves and their people; they'll subjugate other species, and turn those species into a part of their fighting force. When a Monster Lord takes over an area, it is exceedingly difficult to reclaim the area later. Sometimes impossible.

How strong is a Monster Lord? I can't be too precise because I've never actually seen one in person; but the one responsible for the destruction of my village was supposedly a Goblin, and even though I never saw him personally, he had Minotaur's among the minions which destroyed my village. Those, I did see. From what I've read, Minotaur's are typically close in strength to a level 400 human fighter.

I have no way to know if it's actually true, but from what I understand there's only one group in all of humanity that can fight a Monster Lord on even footing, the Sky Marshal and his army. They are humanities most elite fighters, funded by annual donations from every country we have left. If the Sky Marshal is unwilling or unable to engage, the Monster Lord is free to continue its assault until its army is wiped out around it, or it decides to stop attacking on its own for reasons I am not clear on.

"The System" seems to have appeared around 20,000 years ago, though records from that time period are poor so it's not an exact number. At the time the system appeared, humanity was the dominant species on the planet. The priests claim that the system appeared as a result of the monster invasion, as the gods chose to arm humanity with tools appropriate for resisting the monster invasion.

The Goddess I met hinted that the system might have originated with the invasion rather than as a response to it, but frankly it wasn't a long talk and she wasn't terribly clear in her responses to the questions she did answer, so I might be misunderstanding. She was… Odd. She did suggest that she'd defanged it though, whatever that is supposed to mean. It looks like a pretty good tool to me regardless, and I didn't actually get the impression I was supposed to be avoiding it.

Regardless, after the monster invasion began humanity experienced a period of crises, with kingdoms collapsing all over the world. No one knew where dungeons would appear or how to deal with him, or even how important it was that they be located quickly and controlled, or anything else we now take for common knowledge. It was a period of immense destruction, and the loss of life must have been staggering.

To deal with the monster invasion, a number of steps ended up being taken to ensure humanities survival. Among those steps an evacuation system was created, allowing people to flee to the cities in the clouds as they are sometimes called. Whether referred to as the "Cities in the Sky" or "Cities in the Clouds", either way it is something of a misnomer as they are actually distinct pocket dimensions, making them extremely difficult to invade.

Each of these special cities has 3 portals, 2 of which connect to some of the other cities in the sky, while the third leads to the ground somewhere on the actual planet of Grendel. When a monster invasion occurs which cannot be driven back by the available forces, the evacuees get to flee through the nearest portal, with that portal being destroyed when the monsters get close.

A new portal to the ground will eventually be created, either to the same area if they decide to retake it, or deeper into human territory if the powers that be decide it is better to retreat. Once a particular City in the Sky has been opened, it will remain open from then on, though only those who meet the requirements are allowed to stay and live there beyond an initial evacuation period.

What are the requirements to live in a City in the Clouds? Apparently there is some sort of a chart for each city. I don't know which specific person or group is responsible for the cutoffs in any given chart, but in general prepubescent children are allowed to stay, and those who have reached puberty but have not yet reached 16 are allowed to stay if they possess a Tier 3 skill, and beyond that it is a combination of age and level.

It's harsh to say, but children born with some form of physical or mental deformity are an exception to this rule. Even though they do not make any claims relating to genetics, and even though they do not use the same terminology or seem to be aware of the morality concerns associated with doing this, humanity has accidentally stumbled upon and actively practices both positive and negative eugenics here. The weak are abandoned or outright culled, and the strong protected.

As an example of how it works, if you are an adult at level 100, you'll be going back to the ground at the first opportunity, and the same holds true for a 200 year old adult who is level 200, while a 20 year old at level 150 would be allowed to stay. The actual number of potential residents and the respective cutoffs for a particular city are determined by the capacity of the city in the sky at the time of invasion, with infrequent updates to the chart after that.

Cities in the Clouds are prepared far in advance of being needed, but then, they have to be. Once a new City in the Sky is opened it stops growing; and even if it were a large sized city when it opens, the cities in the sky don't have naturally occurring resources, not even soil or water, so everything needs to be imported, and even once soil and water are imported, the areas are simply too small for any food production or water recycling techniques to sustain the entire city in perpetuity.

It's not nice, but there's no real choice either. Humanity must stay connected to the ground or it would die off, and staying connected to the ground means they need to continue fighting, and to continue fighting they prioritize the well-being of the people who are capable of fighting.

I've drifted a little bit, but the cities in the clouds are as close to safe as anything gets in this world. I was 7 years old when I found myself, most likely an orphan now, living in the City in the Sky known as Virtue.