DEAD DEAD DEMON'S DEDEDEDE DESTRUCTION (Deddo Deddo Demonzu Dededededesutorakushun), by Inio Asano. First published in 2014 and first published in North America in 2018.
PLOT:
Three years ago, a giant flying saucer appeared over Tokyo, destroying buildings and killing hundreds. The conflict has come to a standstill, and as the government debates how to handle the menace others simply try to live out their lives. That's certainly true for Kadode and her best friend Oran. As they deal with friendships, exams, and awkward crushes on teachers, they wonder if there's any point to it all.