Battle Royal High School
English name: Battle Royal High School
Genres: Action, Horror, Supernatural
Type: OVA, Episodes: 1
Aired: Dec 10, 1987
Studio: D.A.S.T.
Source: Manga
Rating: R+ - Mild Nudity
Synopsis:
Hyoudo Riki is just an ordinary guy who likes to wear a tiger mask while Kung-Fu fighting, which means he fits in real well at BATTLE ROYAL HIGH SCHOOL!

Unfortunately for Riki, he's the doppleganger in our world of Byoudo, Master of the Dark Realm, and when a dimensional gate opens between the two worlds, the evil Fairy Master tricks Byoudo  into making an attempt to conquer our beautiful, and better lit, world.

Now poor Riki is semi-possessed by his opposite number, and the minions of the Fairy Master are mutating his classmates into hideous lustful monsters. To make matters worse, all the inter-dimensional commotion has attracted the attention of a sword-happy exorcist and the heroic Zankan of the Space-Time Police!

Which all means that Riki is about to take one bitch of a mid-term. The course is survival, and forget "Pass/Fail". The test is graded "Live/Die".