Seikoujo: Haitoku no Biden Dorei
English title: Dark Chapel
Japanese title: 聖肛女～背徳の美臀奴隷～
Type: OVA
Episodes: 2
Source: Visual novel
Genres: Hentai
Studios: Studio Jam
Producers: Milky Animation Label, MS Pictures
Duration: 28 min per ep
Rating: Rx - Hentai

Sister Rosaria is working at the village`s local church. Everything has been peaceful and many days of happiness have passed. One day a new priest and a sister arrive...and her happiness is suddenly shattered. The two are imposters, villains on the run for theft and murder. But that isn`t the only problem...the man is a former priest who sexually assaulted sister Rosaria many times in the past. Now, the village`s peace is in her hands; if she doesn`t obey "Father Edwards", he has sworn to kill every single one of the villagers...

(Source: AniDB)