Yondemasu yo, Azazel-san.
Japanese title: よんでますよ、アザゼルさん。
Type: OVA
Source: Manga
Episodes: 4
Status: Finished Airing
Aired: Feb 23, 2010 to Jun 23, 2014
Duration: 21 min per ep
Rating: R+ - Mild Nudity
Studios: Production I.G
Producers: Fonishia
Genres: Comedy, Supernatural
Themes: Gag Humor, Mythology
Demographics: Seinen

The great detective Akutabe has an assistant, Rinko Sakuma, who is trying to learn to summon demons. This is the story of her misadventure when she actually manages to summon 2 demons unexpectedly. 

(Source: ANN)