Nanatsumi Project: Sono Ichi
Genres: Avant Garde
Type: ONA, Episodes: 1
Aired: Jan 2, 2012
Source: Original
Rating: PG-13 - Teens 13 or older
Synopsis:
This is a world where demons live, where the night continues all the time.
Children are studying at school to threaten humans every day.
A story of a small day in such a world.

(Source: Official YouTube Channel)