High School DxD Hero: Taiikukan-ura no Holy
English title: High School DxD Hero Episode 0: Holiness Behind the Gym
Japanese title: ハイスクールD×D HERO体育館裏のホーリー
Type: TV Special
Episodes: 1
Source: Light novel
Genres: Action, Comedy, Romance, Supernatural, Ecchi
Studios: Passione
Producers: Genco, Movic, AT-X, Memory-Tech, Hakuhodo DY Music & Pictures, Kadokawa, Bandai Namco Arts
Duration: 24 min
Rating: R+ - Mild Nudity

Alternative version of final four episodes of High School DxD BorN.