Tokyo 7th シスターズ

Tokyo 7th Sisters (Tokyo 7th シスターズ) is a Japanese idol raising simulation and rhythm game released for iOS and Android in February 2014,[1] developed and published by Donuts Co. Ltd.[2] with music produced and published under record label Victor Entertainment. The game has a story mode (called Scout in-game) in which players search for idol cards while progressing through the story and a battle mode in which players battle other players or certain in-game characters using their idol cards.

The story centers on "new generation" idols from the studio "777 (Three Seven)", referred to as Nanastar, in the year 2034, in a future where idols are considered a thing of the past. The player acts as the manager of Nanastar, whose job is to recruit and train a number of different girls by collecting and leveling collectible cards. The cast of characters includes more than 50 fully-voiced, unique idols from different backgrounds.

(from Wikipedia)