Nanajima Kana manga
Souta Inui is a manager at Megapro talent agency, an agency responsible for turning young, beautiful women into stars. Inui, however, spends his time at the office ogling posters of the idols his agency manages, yet to bring in any new talent or take on a single client himself. When told to go to the streets and scout talent, Inui falls and unwittingly grabs ahold of a devil girl's tail, at the same time asking her to join his talent agency. Now bound by contract, the girl has no choice but to abide by his wish, making it her goal the become the number 1 idol in Japan. But who is this girl? Why is Inui the only one that can see her tail? Is she really a demon aged many thousands of years? No matter the reason or history, it's now up to Inui to turn this aggressive devil with a (literally) killer voice into the number 1 idol in Japan.