Viper-GTS

Carrera is a female demon whose job is to create a wish granting contract with a human being in exchange for their soul. Along with her partners/rivals Mercedes and Rati, they carry out this job for the benefit of the demon world. When Carrera is summoned by the nerdy Ogawa, she finds him to be more interesting than her previous cilents and develops a crush. Mercedes tries to get involved with Ogawa also to compete with Carrera. However, the female angels are upset by this disturbance and are willing to purify the demons with their precious "holy water" to save Ogawa's soul.

[Taken from ANN]