~~The following program contains adult themes and scenes of violence and sexual assault that may not be suitable for some viewers and is inappropriate for children. The content is intended for mature audiences only.~~

Centuries ago, vicious and bloodthirsty demons who were immune to all manner of weaponry plagued mankind. Humanity's cries for help brought forth the Idaten; battle deities who would use their incredible speed to hunt the demons down, and then seal them away. In the following 800 years of peace, the Idaten have not had any enemies to fight. But that is about to change...
I must say, peace does nothing
 for resilience...
...أقرّ وأعترف، السّلام لا ينفع للصمود
Frieden lässt einen
ernsthaft weich werden.
Acostumbrarse a la paz no es bueno.
Acostumbrarse a la paz no es bueno.
C’est terrible
ce que la paix les a ramollis…
Certo che è spaventoso
come ci si rammollisca in tempi di pace.
Devo dizer que a paz não
ajuda na resiliência...
Привычка к миру — страшная вещь...