This novel plot has a unique impression, a reincarnation set at post apocalyptic world where 1/3 of planet population left.
It was the world of might and magic though, where dragon, elf, dwarf, demon king, dark lord, gods, and beastmen lives. But after apocalypse invasion from alien, they banded together to stay alive. Well, there is still internal strife about racism and political power for sure.
Humans race gain the rein, because of the blessing of the planet, and they have achieved a dramatic advanced of science and technology.
Sadly, mostly the old ways of using magic has forgotten, and something happened about 1000 years ago that makes most about previous history of this planet blank.
Now, they live at 8 separated location of moving floating city. Kinda reminds me about "Balamb Garden" of final fantasy VIII, but with a bigger scale.
This setting almost similar to final fantasy VIII. They trained the students at the early age for combat too.