Makai Kishi Ingrid
English title: Hell Knight Ingrid
Japanese title: 魔界騎士イングリッド
Alternative titles: The Dark Knight Ingrid, Taimanin Murasaki
Type: OVA
Source: Visual novel
Episodes: 4
Status: Finished Airing
Aired: Jun 26, 2009 to Aug 27, 2010
Duration: 29 min per ep
Rating: Rx - Hentai
Studios: Anime Antenna Iinkai
Producers: Pixy
Genres: Fantasy, Hentai
Themes: Martial Arts, Mythology

Dark existences were secretly invading Tokyo, the diabolic city. Behind the success of ninjas of justice called Taimanin, the darkness starts the action... Hell knight Ingrid revealed the betrayal of a diabolic doctor, Sabato Kiryuu, who has belonged to a group of darkness, Kanomado. She follows after him who managed to escape from the spot. However, she gets the counterattack from Kiryuu in a certain hideous church and becomes captive. With vengeance, Kiryuu tries to destroy Ingrid's noble soul and decoy her boss, Edwin Black the vampire, into coming to save her. He encourages a group of monsters who have the desire for revenge against Ingrid to disgrace her body...

(Source: DLsite)