In the end of the world, human beings mutate and are divided into levels A-E according to the degree of brain development (no special powers, but the higher the level, the smarter, and the stronger the quality in all aspects). Some people have lost their minds and become zombie-like creatures. They have no sense, no pain, and are highly contagious. They are called "ghouls". (Note: Ghouls can't swim and will directly enter the water. Sunk, so the sea surface is safe, but the shallow sea area is more dangerous) The surviving humans established a federation and reshaped the distribution system. All newborns must undergo a level test, and the educational resources they will receive in the future are determined based on the level. Therefore, the higher the level, the higher the social status in general, but it is not absolute. In the end, it still depends on your personal ability. In order to solve the predicament of the end of the world, the Federation has been committed to studying the causes of mutations. This is probably the background. Because we have just entered the apocalypse, technology is not much different from modern times (although it has nothing to do with modern times...)
Demining: non-traditional "apocalyptic writing", novice author, scummy writing style, convulsive updates, please try not to read it
Mission: No matter how difficult it is, people will not be torn apart