Koi Koi Seven

Tetsuro Tanaka is transferred to Gokoh Academy full of high expectations. However, expectations fade with a bad premonition the moment he steps onto the campus and finds all the students except him are girls! Wow! It's Heaven! He's a prince surrounded by pretty maidens! Wrong! A series of weird and frightening incidents fall upon him. Then, 6 charming girls who are called Koi Koi Seven appear as his guardians. Army combat helicopters and anti-tank guns attack Tetsuro for no particular reason. This school is far from a paradise. It is a hell he desperately tries to survive day to day. (Crunchyroll)