This was a rather peculiar world.
It was not that this world possessed a civilization unlike any other, nor that it held extraordinary mysteries.
The reason this world was peculiar was that the cities where people lived were all categorized in a simple, easy-to-understand manner.
For example, one country used this method.
The city located at the heart of that country was called City A.
With City A as its hub, cities spread out one after another, each named City B, City C, City D, all the way to City Z, based on factors such as their location, scale, and prosperity.
As for the level of civilization here, it was not particularly advanced.
At the very least, it had neither Academy City's extreme civilization, twenty or thirty years ahead of the outside world, nor Battle City's Falling Star Engineering, which had emerged due to the existence of Omni-element. Judging by its level of civilization alone, it was roughly equivalent to the twenty-first century.
Of course, whether some unknown Black Technology lay hidden behind such a civilization was another matter entirely.
But that was merely the surface of this world.
What truly made this world peculiar was the accidents that could occur at any time.
No.
They were not accidents.
They were true disasters.
And now, in City D, a man-made disaster suddenly erupted.
"Emergency evacuation notice! Emergency evacuation notice!"
A mechanical broadcast suddenly rang out over the entirety of City D.
"An unidentified group of monsters has appeared in City D! An unidentified group of monsters has appeared in City D! They are aggressive! Extremely dangerous! Extremely dangerous!"
"Disaster level: Demon!"
"Residents of City D, please proceed quickly to the nearest shelters! Residents of City D, please proceed quickly to the nearest shelters!"
The endlessly repeated broadcast rang out through