The Camouflage Engagement of a Saint and a Demon King

Hinata, an employee of a black company, is summoned to Exia, a human country in another world, as a "Saint." However, even there, it is a corrupt black country. Hinata tries hard to do her new job, but is discarded as a nuisance when a junior saint appears. She ends up being held prisoner by the demon kingdom of Dominus, but there she meets a young demon named Atlas, and they hit it off over work-related complaints! Then, the story takes an unexpected turn...!? (Source: Kodansha, translated)